科技專利與專利與管理
專利閱讀報告
Patent No. US8822889 B2
TEMPERATURE CONTROL SYSTEM
Patent No. US
8791654 B2
PULSE WIDTH MODULATION
CIRCUIT
AND
ILLUMINATION APPARATUS
Patent No. US20130043895 A1
Fan speed control device
Teacher：Chen Rui Tang
Student：MA3L0101
Yang Yu Ruei
Outline
1.
Abstract
2.
Background
3.
Brief Description Of The Drawings
4.
Detailed Description
5.
Claim
6.
Design Around
7.
Reference
TEMPERATURE CONTROL SYSTEM
1.Abstract
A temperature control system includes a
temperature control circuit
having a plurality of predetermined temperature values, a switch control circuit
and a heating control circuit. The temperature control circuit outputs control
signals according to the plurality of predetermined temperature values. The
switch control circuit turns on according to the control signals and outputs the
DC voltage to the heating control circuit which begins to get hot. The
temperature control circuit detects a temperature of the heating control circuit
from time to time and turns off the switch control circuit when the temperature
of the heating control circuit is equal to a selected predetermined temperature.
2.Background
Technical Field
The disclosure generally relates to control systems, and especially to a
temperature control system for testing the performance of electrical devices
under different temperatures.
Description of Related Art
The performance of electrical devices such as computers, servers,
notebooks and so on at different temperatures (thermal performance) is a
significant concern. Thermal performance reflects an operational state of the
electrical device in different temperature environments. When the thermal
performance of an electrical device is tested, a simulation of different
temperature environments is needed. Traditionally, a special hot box is
designed for testing an electrical device placed therein. The temperature in the
hot box can be adjusted. Consequently, the hot box provides a simulated
environment at different temperatures for testing the electrical device. However,
the special hot box is a very expensive and complex piece of equipment which
demands an excessive amount of time in use.
Therefore there is a room for improvement in the art.
3.Brief Description Of The Drawings
Many aspects of the embodiments can be better understood with
references to the following drawings. The components in the drawings are not
necessarily drawn to scale, the emphasis instead being placed upon clearly
illustrating the principles of the embodiments. Moreover, in the drawings, like
reference numerals designate corresponding parts throughout the several
views.
FIG. 1 is a block view of an embodiment of a temperature control system.
FIG. 2 is a circuit view of the embodiment of FIG. 1.
4.Detailed Description
The disclosure is illustrated by way of example and not by way of
limitation in the figures of the accompanying drawings in which like references
indicate similar elements. It should be noted that references to “an” or “one”
embodiment in this disclosure are not necessarily to the same embodiment,
and such references mean at least one.
Referring to FIG. 1, an embodiment of a temperature control system
includes a temperature control circuit 100, a switch control circuit 200, a
heating control circuit 300, an input circuit 400, an output circuit 500 and a
power supply 600.
The temperature control circuit 100 includes a plurality of predetermined
temperature values. The temperature control circuit 100 outputs control
signals according to the plurality of predetermined temperature values. The
switch control circuit 200 includes a switch control circuit input terminal, a
switch control circuit output terminal and a switch control circuit control
terminal. The switch control circuit input terminal receives a DC voltage. The
switch control circuit control terminal receives the control signal.
The switch control circuit 200 is turned on according to the control signal
and outputs the DC voltage at the switch control circuit output terminal. The
heating control circuit 300 receives the DC voltage and may produce heat. The
temperature control circuit 100 detects a temperature of the heating control
circuit 300 and turns off the switch control circuit 200 when the temperature of
the heating control circuit 300is equal to a selected predetermined
temperature. At that point, the switch control circuit 200 stops outputting the
DC voltage.
In one embodiment, the input circuit 400 includes a keyboard for inputting
the selected predetermined temperature values into the temperature control
circuit 100. The output circuit 500 includes a display unit (not shown) and an
alarm module (not shown). The display unit displays the current temperature of
the heating control circuit 300 and the predetermined temperature values
available. The alarm module makes a sound to indicate when the temperature
of the heating control circuit 300 is equal to the selected predetermined
temperature.
Referring to FIG. 2, the temperature control circuit 100 includes a
temperature control chip U. The temperature control chip U includes a first pin
P1, a second pin P2, a third pin P3, a fourth pin P4, a fifth pin P5 and a sixth
pin P6. The first pin P1 and the second pin P2 output control signals. The third
pin P3 and the fourth pin P4 detect the temperature of the heating control
circuit 300. The fifth pin P5 is electrically connected to the input circuit 400.
The sixth pin P6 is electrically connected to the output circuit 500.
The switch control circuit 200 includes a delay, a first fuse F1 and a
second fuse F2. The first fuse F1 includes a first fuse first terminal and a first
fuse second terminal. The second fuse F2 includes a second fuse first terminal
and a second fuse second terminal. The delay includes a winding unit M, a first
switch unit K1 and a second switch unit K2. The first switch unit K1 includes a
first switch unit first terminal and a first switch unit second terminal. The
second switch unit K2 includes a second switch unit first terminal and a second
switch unit second terminal.
The winding unit M is electrically connected to the first pin P1 and to the
second pin P2 for receiving control signals. The first switch unit first terminal
and the second switch unit first terminal are electrically connected to the power
supply 600 in order to receive the DC voltage. The first switch unit second
terminal and the second switch unit second terminal are electrically connected
to the first fuse first terminal and the second fuse first terminal. The first fuse
second terminal and the second fuse second terminal are electrically
connected to the heating control circuit 300.
The heating control circuit 300 includes a heating element R and a
temperature-sensing element T. The heating element R includes a heating
element first terminal and a heating element second terminal. The
temperature-sensing element T includes a temperature-sensing element first
terminal and a temperature-sensing element second terminal. The heating
element first terminal and the heating element second terminal are electrically
connected to the first fuse second terminal and the second fuse second
terminal.
The
temperature-sensing
element
first
terminal
and
the
temperature-sensing element second terminal are electrically connected to the
third pin P3 and the fourth pin P4. The temperature control circuit100 detects
the temperature of the heating control circuit 300 by means of the
temperature-sensing element T. In one embodiment, the heating element R is
a heating resistor; and the temperature-sensing element T is a thermocouple.
In use, the selected predetermined temperature value is input into the
temperature control chip U by the input circuit 400. The temperature control
chip U outputs the control signal to the winding unit M. The winding unit M is
powered on and closes the first switch unit K1 and the second switch unit K2.
The power supply 600 provides the DC voltage to the heating element R and
the heating element R begins to heat. The temperature-sensing element T
detects the temperature of the heating control circuit 300 and continuously
transmits the temperature of the heating control circuit 300 to the temperature
control chip U via the third pin P3 and the fourth pin P4.
When the temperature of the heating control circuit 300 is equal to the
selected predetermined temperature value, the temperature control chip U
outputs a control signal to turn off the switch control circuit 200. The winding
unit M is powered off and the first switch unit K1 and the second switch unit
K2 are opened. The power supply 600 stops providing the DC voltage to the
heating element R as the temperature control system reaches the selected
predetermined temperature value.
5.Claim
It is to be understood, however, that even though numerous
characteristics and advantages have been set forth in the foregoing
description of preferred embodiments, together with details of the structures
and functions of the preferred embodiments, the disclosure is illustrative only,
and changes may be made in detail, especially in matters of shape, size, and
the arrangement of parts within the principles of the disclosure to the full extent
indicated by the broad general meaning of the terms in which the appended
claims are expressed.
What is claimed is:
1. A temperature control system comprising:
a temperature control circuit comprising a plurality of predetermined
temperature values; the temperature control circuit is adapted to output control
signals according to the plurality of predetermined temperature values;a switch
control circuit comprising a switch control circuit input terminal, a switch control
circuit output terminal and a switch control circuit control terminal; the switch
control circuit input terminal is adapted to receive a DC voltage; the switch
control circuit control terminal is adapted to receive the control signals; and the
switch control circuit is adapted to turn on according to the control signals and
output the DC voltage at the switch control circuit output terminal; the switch
control circuit comprises a delay, a first fuse and a second fuse; the delay
comprises a winding unit, a first switch unit and a second switch unit; the
winding unit is adapted to receive the control signals; the first switch unit and
the second switch unit are adapted to receive the DC voltage; the first switch
unit and the second switch unit are electrically connected to the heating control
circuit via the first fuse and the second fuse respectively; and a heating control
circuit adapted to receive the DC voltage and emit heat; wherein the
temperature control circuit is adapted to detect a temperature of the heating
control circuit and turn off the switch control circuit when the temperature of the
heating control circuit is equal to a selected predetermined temperature value;
and the switch control circuit is adapted to stop outputting the DC voltage.
2. The temperature control system of claim 1, further comprising an input
circuit and an output circuit; the input circuit is adapted to input the selected
predetermined temperature value in the temperature control circuit; and the
output circuit is adapted to display the temperature of the heating control circuit
and the corresponding predetermined temperature values and indicate that the
temperature of the heating control circuit is equal to the selected
predetermined temperature value.
3. The temperature control system of claim 2, wherein the input circuit
comprises a keyboard; and the output circuit comprises a display unit and an
alarm unit.
4. The temperature control system of claim 2, wherein the temperature
control circuit comprises a temperature control chip; the temperature control
chip comprises a first pin, a second pin, a third pin and a fourth pin; the first pin
and the second pin are adapted to output the control signals; and the third pin
and the fourth pin are adapted to detect the temperature of the heating control
circuit.
5. The temperature control system of claim 4, wherein the temperature
control circuit further comprises a fifth pin and a sixth pin electrically connected
to the input circuit and the output circuit.
6. The temperature control system of claim 4, wherein the first fuse
comprises a first fuse first terminal and a first fuse second terminal; the second
fuse comprises a second fuse first terminal and a second fuse second terminal;
the first switch unit comprises a first switch unit first terminal and a first switch
unit second terminal; the second switch unit comprises a second switch unit
first terminal and a second switch unit second terminal; the winding unit is
electrically connected to the first pin and the second pin for receiving the
control signals; the first switch unit first terminal and the second switch unit first
terminal are electrically connected to a power input terminal for receiving the
DC voltage; the first switch unit second terminal and the second switch unit
second terminal are electrically connected to the first fuse first terminal and the
second fuse first terminal; and the first fuse second terminal and the second
fuse second terminal are electrically connected to the heating control circuit.
7. The temperature control system of claim 6, wherein the heating control
circuit comprises a heating element and a temperature-sensing element; the
heating element comprises a heating element first terminal and a heating
element second terminal; the temperature-sensing element comprises a
temperature-sensing element first terminal and a temperature-sensing
element second terminal; the heating element first terminal and the heating
element second terminal are electrically connected to the first fuse second
terminal and the second fuse second terminal; the temperature-sensing
element first terminal and the temperature-sensing element second terminal
are electrically connected to the third pin and the fourth pin; and the
temperature control circuit is adapted to detect the temperature of the heating
control circuit by the temperature-sensing element.
8. The temperature control system of claim 7, wherein the heating
element is a heating resistor; and the temperature-sensing element is a
thermocouple.
9. A temperature control system comprising:
a temperature control circuit comprising a plurality of predetermined
temperature values; the temperature control circuit is adapted to output control
signals according to the plurality of predetermined temperature values;
a switch control circuit adapted to receive a DC voltage and the control
signals, turn on according to the control signals and output the DC voltage; the
switch control circuit comprises a delay, a first fuse and a second fuse; the
delay comprises a winding unit, a first switch unit and a second switch unit; the
winding unit is adapted to receive the control signals; the first switch unit and
the second switch unit are adapted to receive the DC voltage; the first switch
unit and the second switch unit are electrically connected to the heating control
circuit via the first fuse and the second fuse respectively; and
a heating control circuit adapted to receive the DC voltage and emit heat;
wherein the temperature control circuit is adapted to detect a temperature of
the heating control circuit and turn off the switch control circuit when the
temperature of the heating control circuit is equal to a selected predetermined
temperature value; and the switch control circuit is adapted to stop outputting
the DC voltage.
10. The temperature control system of claim 9, wherein the switch control
circuit comprises a switch control circuit input terminal, a switch control circuit
output terminal and a switch control circuit control terminal; the switch control
circuit input terminal is adapted to receive the DC voltage; the switch control
circuit control terminal is adapted to receive the control signals; and the switch
control circuit output terminal is adapted to output the DC voltage.
11. The temperature control system of claim 9, further comprising an input
circuit and an output circuit; the input circuit is adapted to input the selected
predetermined temperature value in the temperature control circuit; and the
output circuit is adapted to display the temperature of the heating control circuit
and the corresponding predetermined temperature values and indicate that the
temperature of the heating control circuit is equal to the selected
predetermined temperature value.
12. The temperature control system of claim 11, wherein the input circuit
comprises a keyboard; and the output circuit comprises a display unit and an
alarm unit.
13. The temperature control system of claim 11, wherein the temperature
control circuit comprises a temperature control chip; the temperature control
chip comprises a first pin, a second pin, a third pin and a fourth pin; the first pin
and the second pin are adapted to output the control signals; and the third pin
and the fourth pin are adapted to detect the temperature of the heating control
circuit.
14. The temperature control system of claim 13, wherein the temperature
control circuit further comprises a fifth pin and a sixth pin electrically connected
to the input circuit and the output circuit.
15. The temperature control system of claim 13, wherein the first fuse
comprises a first fuse first terminal and a first fuse second terminal; the second
fuse comprises a second fuse first terminal and a second fuse second terminal;
the first switch unit comprises a first switch unit first terminal and a first switch
unit second terminal; the second switch unit comprises a second switch unit
first terminal and a second switch unit second terminal; the winding unit is
electrically connected to the first pin and the second pin for receiving the
control signals; the first switch unit first terminal and the second switch unit first
terminal are electrically connected to a power input terminal for receiving the
DC voltage; the first switch unit second terminal and the second switch unit
second terminal are electrically connected to the first fuse first terminal and the
second fuse first terminal; and the first fuse second terminal and the second
fuse second terminal are electrically connected to the heating control circuit.
16. The temperature control system of claim 15, wherein the heating
control circuit comprises a heating element and a temperature-sensing
element; the heating element comprises a heating element first terminal and a
heating element second terminal; the temperature-sensing element comprises
a temperature-sensing element first terminal and a temperature-sensing
element second terminal; the heating element first terminal and the heating
element second terminal are electrically connected to the first fuse second
terminal and the second fuse second terminal; the temperature-sensing
element first terminal and the temperature-sensing element second terminal
are electrically connected to the third pin and the fourth pin; and the
temperature control circuit is adapted to detect the temperature of the heating
control circuit by the temperature-sensing element.
6.Design Around
1.K1、K2 部分改為電晶體開關電路
2.將單元 200 改為兩個繼電器取代
PULSE WIDTH MODULATION CIRCUIT
AND
ILLUMINATION APPARATUS
1.Abstract
An illumination apparatus includes a power supply, a pulse width
modulation (PWM) circuit, a switching unit, and an illuminating unit. The power
supply supplies a supply voltage to the PWM circuit and the illuminating unit.
The PWM circuit outputs a first level voltage by being fully charged by the
voltage of the power supply and outputs a second level voltage by being fully
discharged. The switching unit is turned off according to the first level voltage
and controls the illuminating unit to stop emitting light. The switching unit is
turned on according to the second level voltage and controls the illuminating
unit to emit light.
2.Background
Technical Field
The present disclosure relates to illumination apparatuses, particularly
relates to a pulse width modulation circuit and an illumination apparatus.
Description of Related Art
Light emitting diodes (LEDs) are widely used in various electronic devices,
such as a backlight module of a liquid crystal display (LCD). In some LCDs, a
constant current from a power supply is used for driving the LEDs to emit light.
However, when such LEDs emit light for a long time, the temperature of the PN
junction of the LEDs may get too high and the brightness and uniformity of the
LEDs emitted light may be reduced.
Therefore, there is room for improvement in the art.
3.Brief Description Of The Drawings
Many aspects of the embodiments can be better understood with
references to the following drawings. The components in the drawings are not
necessarily drawn to scale, the emphasis instead being placed upon clearly
illustrating the principles of the embodiments. Moreover, in the drawings, like
reference numerals designate corresponding parts throughout two views.
FIG. 1 is a block diagram of an illumination apparatus in accordance with one
embodiment.
FIG. 2 is a circuit diagram of the illumination apparatus of FIG. 1 in accordance
with one embodiment.
4.Detailed Description
The disclosure is illustrated by way of example and not by way of
limitation in the figures of the accompanying drawings in which like references
indicate similar elements. It should be noted that references to “an” or “one”
embodiment in this disclosure are not necessarily to the same embodiment,
and such references mean at least one.
Referring to FIG. 1, an illumination apparatus 100 includes a power
supply 11, a pulse width modulation (PWM) circuit 12, a switching unit 14 and
an illuminating unit 16. In the embodiment, the illumination apparatus 100 can
be used as a backlight module of a liquid crystal display (LCD). In other
embodiments,
the
power
supply 11 is
external
of
the
illumination
apparatus 100.
The power supply 11 provides a supply voltage to the PWM circuit 12 and
the illuminating unit 16.
The PWM circuit 12 generates a pulse voltage according to the supply
voltage. In this embodiment, the duty cycle of the pulse voltage is adjustable.
The pulse voltage of the PWM circuit 12 includes a first level voltage and a
second level voltage. In the embodiment, the first level voltage is logic low
voltage level and the second level voltage is logic high voltage level. The PWM
circuit 12 includes a charging unit 124and a discharging unit 126.
The charging unit 124 is connected to the power supply 11, the
discharging
unit 126 and
the
switching
unit 14.
The
charging
unit 124 generates the first level voltage when being charged by the supply
voltage of the power supply 11.
The discharging unit 126 is connected to the power supply 11 and the
switching unit 14. The discharging unit 126 generates the second level voltage
when the charging unit 124 discharges via the discharging unit 126.
The switching unit 14 is turned off according to the first level voltage and
controls the illuminating unit 16 to stop emitting light. The switching unit 14 is
turned on according to the second voltage and controls the illuminating
unit 16 to emit light.
The illuminating unit 16 includes a plurality of LEDs.
Referring to FIG. 2, the power supply 11 includes a power terminal V1. The
power terminal V1 provides supply voltage to the PWM circuit 12 and the
illuminating unit 16.
The charging unit 124 includes a first diode D1, a first resistor R1, a
second resistor R2, a first transistor Q1, a capacitor C1, a first node A1, and a
second node A2. The cathode of the first diode D1 is connected to the second
node A2 through the first resistor R1. The anode of the first diode D1 is
connected to the discharging unit 126. A gate of the first transistor Q1 is
connected with the second node A2. A drain of the transistor Q1 is connected
to the power terminal V1 through the first node A1. A source of the first
transistor is grounded. The second resistor R2 is connected between the
power terminal V1 and the first node A1. The capacitor C1 is connected
between the gate and the source of the first transistor Q1. In the embodiment,
the first transistor Q1 is an n-channel enhancement type metal oxide
semiconductor field effect transistor.
The discharging unit 126 includes a second diode D2, a third resistor R3,
a fourth resistor R4, a second transistor Q2, and a third node A3. The cathode
of the second diode D2 is connected to the third node A3 through the third
resistor R3. The anode of the second diode D2 is connected to the second
node A2. A gate of the second transistor Q2 is connected to the first node A1. A
source of the second transistor Q2 is connected to the third node A3. A drain of
the second transistor Q2 is grounded. In the embodiment, the second
transistor Q2 is a p-channel enhancement type metal oxide semiconductor
field effect transistor. In this embodiment, the resistance of the first resistor R1,
the third resistor R3, and the capacitance of the capacitor C1 are adjustable.
The switching unit 14 includes a third transistor Q3. A gate of the third
transistor Q3 is connected to the third node A3. A drain of the third transistor
Q3 is connected to the illuminating unit 16. A source of the third transistor Q3 is
grounded. In the embodiment, the third transistor Q3 is an n-channel
enhancement type metal oxide semiconductor field effect transistor.
The illuminating unit 16 includes a port 162. The port 162 is connected to
the drain of the third transistor Q3.
The principle of the illumination apparatus 100 is illustrated as follows:
When the power terminal V1 is powered on, the difference in voltage of
the cathode and the anode of the first diode D1 is greater than 0.7V. The first
diode D1 is turned on and the first capacitor C1 is charged by the supply
voltage of the power terminal V1. The difference in voltage of the cathode and
the anode of the second diode D2 is less than 0.7V, the second diode D2 is
turned off. When the first capacitor C1 is fully charged, the difference in voltage
between the gate and the source of the first transistor Q1 is greater than the
0V and the first transistor Q1 is turned on. The first node A1 is almost equal to
0V. The difference in voltage of the gate and the source of the second
transistor Q2 is less than 0V, the second transistor Q2 is turned on. The third
node A3 is almost equal to 0V. The difference in voltage of the gate and the
source of the third transistor Q3 is less than 0V, the third transistor Q3 is turned
off. The port 162 stops receiving the voltage of the power terminal V1. The
illuminating unit 16 stops emitting light. Therefore, the temperature of the PN
junction of the LEDs can be reduced.
The charging time of the capacitor C1 can be calculated according to the
following formula:
Vt=V*[1-exp(-t/RC)].
In the above formula, Vt is the voltage of the capacitor C1, V is the voltage
of the power terminal V1, t is the charging time, C is the capacitance of the
capacitor C1, R is the resistance of the resistor R1. When the charging time t is
equal to the value of 5RC, the voltage of the capacitor C1 is 0.99V1. The
charging process is almost completed.
When the third node A3 is equal to 0V, the capacitor C1 discharge via the
second diode D2. The difference in voltage of the cathode and the anode of
the second diode D2 is greater than 0.7V, the second diode D2 is turned on.
The difference in voltage of the cathode and the anode of the first diode D1 is
less than 0.7V, the first diode D1 is turned off. When the difference in voltage of
the gate and the source of the first transistor Q1 is less than 0V, the first
transistor Q1 is turned off. The first node A1 is equal to the voltage of the
power terminal V1. The voltage of the third node A3 is also equal to the voltage
of the power terminal V1. The difference in voltage of the gate and the source
of the second transistor Q2 is greater than 0V, the second transistor Q2 is
turned off. The difference in voltage of the gate and the source of the third
transistor Q3 is greater than 0V, the third transistor Q3 is turned on. The
port 162 receives the voltage of the power terminal V1. The illuminating
unit 16 emits light.
The discharging time of the capacitor C1 can be calculated according to
the following formula:
Vt=V*exp(-t/RC).
In the above formula, Vt is the voltage of the capacitor C1, V is the voltage
of the power terminal V1, t is the discharging time, C is the capacitance of the
capacitor C1, R is the resistance of the resistor R3. When the discharging time
t is equal to the value of 5RC, the voltage of the capacitor C1 is 0.006V1. The
discharging process is almost completed.
The duty cycle of the PWM circuit 12 can be adjusted through the
resistance of the first resistor R1 and the second resistor R2. The emitting light
frequency of the illuminating unit 16 is more than 50 HZ.
As described, the temperature of the PN junction of the LEDs can be
reduced. Therefore, the brightness and the uniformity of the LEDs are
improved.
5.Claim
It is to be understood, however, that even though information and
advantages of the present embodiments have been set forth in the foregoing
description, together with details of the structures and functions of the present
embodiments, the disclosure is illustrative only; and that changes may be
made in detail, especially in matters of shape, size, and arrangement of parts
within the principles of the present embodiments to the full extent indicated by
the broad general meaning of the terms in which the appended claims are
expressed.
What is claimed is:
1. An illumination apparatus being powered by a supply voltage of a
power supply, the illumination apparatus comprising:
a pulse width modulation (PWM) circuit for receiving the supply voltage
connected to the power supply;
a switching unit; and
an illuminating unit adapted to emit light;
wherein the PWM circuit outputs a first level voltage when being fully
charged by the supply voltage, the switching unit is turned off according to the
first level voltage and controls the illuminating unit to emit light, the PWM
circuit outputs a second level voltage when fully discharged, the switching unit
is turned on according to the second level voltage and controls the illuminating
unit to stop emitting light.
2. The illumination apparatus of claim 1, wherein the PWM circuit
comprises a charging unit connected to the switching unit, the charging unit is
used for being charged by the supply voltage and generating a first level
voltage when the charging process is completed.
3. The illumination apparatus of claim 2, wherein the PWM circuit further
comprises a discharging unit connected to the charging unit and the switching
unit; the discharging unit generates a second level voltage when the charging
unit is fully discharged via the discharging unit.
4. The illumination apparatus of claim 3, wherein the charging unit
comprises a first diode, a first resistor, a second resistor, a first transistor, and
a capacitor; the anode of the first diode is connected to the power supply, the
cathode of the first diode is connected to a gate of the first transistor via the
first resistor a drain of the first transistor is connected to the power supply via
the second resistor; a source of the first transistor is grounded, the capacitor is
connected between the gate and the source of the first transistor.
5. The illumination apparatus of claim 4, wherein the discharging unit
comprises a second diode, a third resistor, a fourth resistor and a second
transistor; the anode of the second diode is connected between the gate of the
first transistor and the capacitor, the cathode of the second diode is connects
to the power supply via the third resistor and the fourth resistor; a gate of the
second transistor is connected to the drain of the first transistor, a source of the
second transistor is connected to the power supply via the fourth resistor, the
source of the second transistor is further connected to the switching unit, a
drain of the second transistor is grounded.
6. The illumination apparatus of claim 5, wherein the first transistor is an
n-channel enhancement type metal oxide semiconductor field effect transistor;
the second transistor is a p-channel enhancement type metal oxide
semiconductor field effect transistor.
7. The illumination apparatus of claim 5, wherein the resistance of the first
resistor and the third resistor are adjustable and the capacitance of the
capacitor is adjustable; the lighting frequency of the illuminating unit is more
than 50 HZ.
8. The illumination apparatus of claim 1, wherein the switching unit
comprises a third transistor, a gate of the third transistor is connected to the
PWM circuit, a drain of the third transistor is connected to the illuminating unit,
a source of the third transistor is grounded.
9. The illumination apparatus of claim 8, the third transistor is an
n-channel enhancement type metal oxide semiconductor field effect transistor.
10. The illumination apparatus of claim 1, wherein the first level voltage is
logic low voltage level, the second level voltage is logic high voltage level.
11. A pulse width modulation (PWM) circuit being powered by a power
supply controlling a switching unit to be turned on or turned off, the PWM
circuit comprising:
a charging unit adapted to generate a first level voltage when being fully
charged by the power supply, the switching unit being turn off according to the
first level voltage; and
a discharging unit adapted to generate a second level voltage when the
charging unit fully discharges via the discharging unit, the switching unit being
turned on according to the second level voltage.
12. The PWM circuit of claim 11, wherein the charging unit comprises a
first diode, a first resistor, a second resistor, a first transistor, and a capacitor;
the anode of the first diode is connected to the power supply, the cathode of
the first diode is connected to a gate of the first transistor via the first resistor a
drain of the first transistor is connected to the power supply via the second
resistor, a source of the first transistor is grounded, the capacitor is connected
between the gate and the source of the first transistor.
13. The PWM circuit of claim 12, wherein the discharging unit comprises a
second diode, a third resistor, a fourth resistor and a second transistor; the
anode of the second diode is connected between the gate of the first transistor
and the capacitor, the cathode of the second diode is connected to the power
supply via the third resistor and the fourth resistor; a gate of the second
transistor is connected to the drain of the first transistor, a source of the second
transistor is connected to the power supply via the fourth resistor, the source of
the second transistor is further connected to the switching unit, a drain of the
second transistor is grounded.
14. The PWM circuit of claim 13, wherein the resistance of the first resistor
and the third resistor are adjustable and the capacitance of the capacitor is
adjustable, such that the duty cycle of the second level voltage and the first
level voltage can be adjusted.
15. The PWM circuit of claim 13, wherein the first transistor is an
n-channel enhancement type metal oxide semiconductor field effect transistor
and the second transistor is an n-channel enhancement type metal oxide
semiconductor field effect transistor.
16. The PWM circuit of claim 11, wherein the switching unit comprises a
third transistor, a gate of the third transistor is connected to the PWM circuit, a
drain of the third transistor is connected to the illuminating unit, a source of the
third transistor is grounded.
17. The PWM circuit of claim 16, wherein the third transistor is an
n-channel enhancement type metal oxide semiconductor field effect transistor.
18. The PWM circuit of claim 11, wherein the first level voltage is a logic
low voltage level, the second level voltage is a logic high voltage level; the duty
cycle of the pulse voltage is more than 50 Hz.
19. An illumination apparatus being powered by a supply voltage of a
power supply, the illumination apparatus comprising:
a pulse width modulation (PWM) circuit connected to the power supply;
the PWM circuit comprising a charging unit and a discharging unit;
a switching unit; and an illuminating unit adapted to emit light;wherein the
charging unit generates a first level voltage when being fully charged by the
power supply, the switching unit is turned off according to the first level voltage
and controls the illuminating unit to emit light, the discharging unit generates a
second level voltage when the charging unit fully discharges via the
discharging unit, the switching unit is turned on according to the second level
voltage and controls the illuminating unit to stop emitting light.
5.Design Around
1.將單元 12 利用單晶片整合為一 PWM 區塊
2. 單元 14 可改為 BJT 型的 NPN 或者 PNP 的電晶體
FAN SPEED CONTROL DEVICE
1.Abstract
A fan speed control device is applied to a fan including a speed control
signal port and a speed signal port. The fan speed control device includes a
speed regulating circuit. The speed regulating circuit includes a signal control
unit electrically connected to the speed signal port of the fan, and an
adjustable resistor is electrically connected between the signal control unit and
the speed control signal port of the fan. The resistance of the adjustable
resistor may be varied to change the voltage and current supplied to the fan,
and the rotational speed of the fan changes according to the operating voltage
and current supplied. The signal control unit obtains speed signals from the
speed signal port and processes and displays the current testing parameters
of the fan.
2.Background
Technical Field
The disclosure generally relates to a fan speed control device for
controlling rotational speed of fans.
Description of Related Art
Computer cases and servers use fans for cooling purposes, so it is
important to test the performance (e.g., rotational speed) of the fans.
During testing, the rotational speed of the fan in the electronic device
gradually reaches a reference value, if the computer fan and the electronic
device are working normally (e.g., indicator light lights normally), which
signifies the computer fan matches the electronic device. However, the
rotational speed of the computer fan can not be adjusted in real-time during
testing, which makes carrying out a test very difficult.
Therefore, there is room for improvement within the art.
3.Brief Description Of The Drawings
Many aspects of a fan speed control device can be better understood with
reference to the following drawings. The components in the drawings are not
necessarily drawn to scale, the emphasis instead being placed upon clearly
illustrating the principles of the fan speed control device. Moreover, in the
drawings, like reference numerals designate corresponding parts throughout
the several views. Wherever possible, the same reference numbers are used
throughout the drawings to refer to the same or like elements of an
embodiment.
FIG. 1 is a block view of one embodiment of a fan speed control device applied
to a fan of the disclosure.
FIG. 2 is a schematic view of the fan speed control device shown in FIG. 1 of
the disclosure.
4.Detailed Description
FIG. 1 is a block view of one embodiment of a fan speed control device 100applied
to a fan 200 of the disclosure. The fan speed control device 100 is used tocontrol and
adjust the rotational speed of the fan 200 to test the performance of the fan 200.
The fan 200 can be a computer fan that is used for cooling purposes, and which
draws cooler air into a computer from the outside, or expels warm air to the outside
from the inside.
The fan 200 includes
a
power
port 201,
a
ground
port 202,
a speed control signal port 203, and a speed signal port 204. The power
port 201 is electrically connected to a power supply unit 20 for powering
the fan 200. The ground port202 is electrically connected to ground, and
the speed control signal port 203 and the speed signal port 204 are electrically
connected
to
the fan speed controldevice 100.
The speed control signal
port 203 can be electrically connected to a motor (not shown) of the fan 200. In
this embodiment, the fan speed controldevice 100 includes a speed regulating
circuit 11 electrically connected to thespeed control signal port 203 and to
the speed signal port 204.
The speed regulating circuit 11 includes an adjustable resistor 111, a
signalcontrol unit 112, a signal processing unit 113, and a display unit 114. The
adjustable resistor 111 can be a potentiometer, variable resistor or rheostat
that varies the resistance in the speed regulating circuit 11. The adjustable
resistor111 includes a fixed contact 115 and a sliding contact 116 that can be
moved relative to the fixed contact 115. The fixed contact 115 is electrically
connected to the signal control unit 112, and the sliding contact 116 is
electrically connected to the speed control signal port 203 of the fan 200. Thus,
by moving or adjusting the sliding contact 116, the resistance of the adjustable
resistor 111 is variable so as to change operating voltage and current supplied
to
the fan 200,
the fan 200.
thus
adjusting
and
changing
the
rotational speed of
The signal control unit 112 is electrically connected to the speed signal
port 204, the fixed contact 115, the signal processing unit 113 and the display
unit 114.
The
signal control unit 112 can
receive
signals
as
to
the
rotational speed from thespeed signal port 204 as input and process the
signals, to output the results of different operations performed in relation to
the fan 200. For example, when the rotational speed of the fan 200 changes,
the fan 200 sends the speed signal to the signal control unit 112 through
the speed signal
port 204,
the
signal controlunit 112 processes
the speed signal and obtains the parameters applied in the testing of
the fan 200, such as resistance, operation voltage and rotational speed. The
parameters applied in the testing are then transmitted to the signal processing
unit 113.
The signal processing unit 113 can process the testing parameters from
the signal control unit 112, and generate corresponding test information for
display on the display unit 114. In this embodiment, the display unit 114 can be
a touch screen.
Referring to FIG. 2, the fan speed control device 100 further includes a
housing 12for receiving the speed regulating circuit 11, a first probe 121, a
second probe122, a rotating knob 123, and a power connector 125. The
display unit 114 and the rotating knob 123 are located on one of the sidewalls
of the housing 12, and the rotating knob 123 is mechanically connected to the
sliding contact 116 to adjust and change the resistance of the adjustable
resistor 111. For example, when the rotating knob 123 is rotated clockwise, the
sliding contact 116 moves toward the fixed contact 115, and the resistance of
the adjustable resistor 111 is decreased. When the rotating knob 123 is rotated
counterclockwise, the sliding contact 116 moves away from the fixed
contact 115, and the resistance of the adjustable resistor 111 is increased.
The
first
probe 121 is
electrically
connected
to
the
sliding
contact 116 through a wire, and the second probe 122 is electrically connected
to
the
signal control unit112.
The
first
probe 121 and
the
second
probe 122 can respectively contact thespeed control signal port 203 and
the speed signal
port 204 of
the fan 200 during
testing.
The
power
connector 125 is electrically connected to an external power source (e.g., the
power supply unit 20) to power the speed regulating circuit 11.
In use, the power connector 125 is electrically connected to the power
supply unit20, and the first probe 121 and the second probe 122 are
electrically
connected
to
the speed control signal
port 203 and
the speed signal port 204 respectively. By turning the rotating knob 123, the
resistance of the adjustable resistor 111changes, so the operating voltage and
current
supplied
to
the fan 200 is
varied
accordingly.
Thus,
the
rotational speed of the fan 200 may be adjusted by changing the operating
voltage
and
current.
signal control unit 112 via
The fan 200 transmits
the speed signal
a speed signal
port 204,
and
to
the
the
signal controlunit 112 obtains and transmits the testing parameters of
the fan 200, such as operating voltage, resistance and rotational speed, to the
signal processing unit113. The signal processing unit 113 processes the
parameters of the testing and generates test information to be displayed on the
display unit 114.
In summary, in the fan speed control device 100 of the present disclosure,
by operating the rotating knob 123, the resistance of the adjustable
resistor 111changes, and the operating voltage and current supplied to
the fan 200 is varied accordingly. Thus, the rotational speed of the fan 200 can
be adjusted in real-time and in small increments during testing, until the
rotational speed of the fan 200reaches a reference speed.
5.Claim
In the present specification and claims, the word “a” or “an” preceding an
element does not exclude the presence of a plurality of such elements. Further,
the word “comprising” does not exclude the presence of elements or steps
other than those listed.
1. A fan speed control device used for controlling rotational speed of
a fan to test the performance of the fan, the fan comprising a speed control signal
port and aspeed signal port, the fan speed control device comprising:
a speed regulating circuit comprising:
a signal control unit electrically connected to the speed signal port of
thefan; and an adjustable resistor electrically connected between the
signal controlunit and the speed control signal port of the fan, wherein the
resistance of the adjustable resistor is varied to change operating voltage and
current supplied to the fan, and the rotational speed of the fan is adjusted
according
to
the
current
operating
voltage
signal control unit obtains speed signal from
and
current,
and
the
the speed signal port and
processes current testing parameters of the fan.
2. The fan speed control device as claimed in claim 1, wherein the
adjustable resistor comprises a fixed contact and a sliding contact, the fixed
contact is electrically connected to the signal control unit, and the sliding
contact is electrically connected to the speed control signal port of the fan and
is moved towards or away from the fixed contact.
3. The fan speed control device as claimed in claim 2, wherein the
signalcontrol unit
accepts
signal
as
to
the
rotational speed from
the speedsignal port as input, processes the speed signal, to output the results
of different operations performed in relation to the fan.
4. The fan speed control device as claimed in claim 3, wherein when the
rotational speed of the fan changes, the fan sends the speed signal to the
signal control unit
processes
through
the speed signal
the speed signal
and
port,
obtains
the
testing
signal controlunit
parameters
of
thefan according to the speed signal, the testing parameter comprises current
resistance, operation voltage and rotational speed.
5.
The fan speed control device as
claimed
in claim
4,
wherein
the speedregulating circuit further comprises a signal processing unit and a
display unit, the signal processing unit and the display unit are electrically
connected to the signal control unit, the signal processing unit receives and
processes the testing parameters from the signalcontrol unit, and generate
corresponding test information for display on the display unit.
6. The fan speed control device as claimed in claim 5, wherein the display
unit is a touch screen, the adjustable resistor is a potentiometer, variable
resistor or rheostat.
7. The fan speed control device as claimed in claim 5, further comprising
a housing and a rotating knob, wherein the speed regulating circuit is received
in the housing, the display unit and the rotating knob are located on one of
sidewalls of the housing, and the rotating knob is mechanically connected to
the sliding contact to adjust and change the resistance of the adjustable
resistor.
8. The fan speed control device as claimed in claim 7, further comprising
a first probe, a second probe and a power connector, wherein the first probe is
electrically connected to the sliding contact, and the second probe is
electrically connected to the signal control unit, the first probe is electrically
connected to the speed control signal port, and the second probe is electrically
connected to the speed signal port, and the power connector is electrically
connected to an external power source to power the fan speed control device.
9. A fan speed control device applied to a fan to control rotational speed of
the fan to test the performance of the fan, the fan comprising a speed control
signal port and a speed signal port, the fan speed control device comprising:
a signal control unit electrically connected to the speed signal port of the
fan; and an adjustable resistor electrically connected to the fan and the signal
control unit, the adjustable resistor comprising:
a fixed contact electrically connected to the signal control unit; and
a sliding contact electrically connected to the speed control signal port of
the fan, wherein the sliding contact is moved towards or away from relative to
the fixed contact to vary the resistance of the adjustable resistor, voltage and
current supplied to the fan is changed, the rotational speed of the fan is varied
with the changes of the current operating voltage and current, and the signal
control unit receives speed signal from the speed signal port and processes
current testing parameters of the fan.
10. The fan speed control device as claimed in claim 9, wherein the signal
control unit accepts speed signal from the speed signal port as input,
processes the speed signal, and provides results as output to perform different
operations.
11. The fan speed control device as claimed in claim 3, wherein when the
rotational speed of the fan changes, the fan sends the speed signal to the
signal control unit through the speed signal port, the signal control unit
processes the speed signal and obtains testing parameters of the fan
according to the speed signal, the testing parameter comprises current
resistance, operation voltage and rotational speed.
12. The fan speed control device as claimed in claim 11, further
comprising a signal processing unit and a display unit, wherein the signal
processing unit and the display unit are electrically connected to the signal
control unit, the signal processing unit receives and processes the testing
parameters from the signal control unit, and generate corresponding test
information that fits to be displayed on the display unit.
13. The fan speed control device as claimed in claim 12, wherein the
display unit is a touch screen, the adjustable resistor is a potentiometer,
variable resistor or rheostat.
14. The fan speed control device as claimed in claim 12, further
comprising a housing and a rotating knob, wherein the adjustable resistor, the
signal control unit, the signal processing unit and the display unit are received
in the housing, the display unit and the rotating knob are located on one of
sidewalls of the housing, and the rotating knob is mechanically connected to
the sliding contact to adjust and change the resistance of the adjustable
resistor.
15. The fan speed control device as claimed in claim 14, further
comprising a first probe, a second probe and a power connector, wherein the
first probe is electrically connected to the sliding contact, and the second probe
is electrically connected to the signal control unit, the first probe is electrically
connected to the speed control signal port, and the second probe is electrically
connected to the speed signal port, and the power connector is electrically
connected to an external power source to power the fan speed control device.
6.Design Around
1.利用微控制器產生PWM訊號，搭配相關電路，控制風扇速度
7.Reference
[1]GOOGLE 專利，https://www.google.com/?tbm=pts&gws_rd=ssl
[2]風扇轉速控制器，http://24h.pchome.com.tw/prod/DRAE2M-A65460371