Nov. 7, 1961
G. N. ¢OTTON
3,008,084
VOLTAGE REGULATING SYSTEM
Filed Aug. 4, 1958
3O
INPUT
VOLTAGE
W
3|
32
34
OUTPUT
35
FIRST sues
a7 /“\
REGULATING
ACTI(_>I_4___'\ 36
sacouo snca
\
'____>
,’
‘
\\____
/
\\_’/
OUTPUT
secono STAGE
\
38
TIME——>
FIG. 3
INVENTOR.
GILBERT N. COTTON
BY
I
659 569777
ATTORNEYS
United States Patent O?iice
3,008,084
Patented Nov. 7., 1961
it
2
3,008,084
at 10 and 11. The resistances R1 and R2 are shown at
12 and 13, respectively, and the zener diode indicated Z2
VOLTAGE REGULATING SYSTEM
- Gilbert N. Cotton, Parana, ()hio
at 14 completes with the resistance R3 at 15 to bridge the
(2522 15th St, Cuyahoga Falls, Qhio)
circuit. This circuit may be used with double anode zener
diodes. However, these would be used to‘ ensure a low
. Filed Aug. 4, 1958, Sler. No. 752,826
3 Claims. (Cl. 323-75)
This invention relates to a very accurate voltage regu
lating system in which a plurality of resistor bridges are
used with the dynamic impedance of the zener reference
diodes balanced out by said resistor bridges.
The invention further relates to a two stage voltage
regulator circuit in which the output of the ?rst stage is
the input to the second stage resistor diode bridge.
temperature coei?cient of voltage.
The circuit works
equally as Well with ordinary zener diodes.
The second stage of the regulator is similar to the ?rst
stage. The output of the ?rst stage is placed across the
input of the second stage. The output terminals of the
?rst stage, therefore, are indicated at 16 and 17, and these
are put into the input terminals of the second stage at 18
and 19, respectively. There are in this second bridge
similar resistances indicated R5, R6 and R7 and Z1 for the
'In general in connection with voltage regulator circuits, 15 zener diode, and these ‘are at 20, 21, 22 and 23, respec
a number of zener voltage regulators have been used and
the ability of these voltage regulators to regulate the out
tively. In the output circuit ‘from this are the terminals
24 and 25 and to the ?nal output terminals 25 and 26. In
put voltage to 0.01 percent or in some extreme cases even
the connection between terminals 24 and 25 is a resistance
0.005 percent make them ideally suited to certain applica
shown at 2.7. With 27 in circuit, current is made constant
tions particularly in regulated power supplies, transistor 20 as well as voltage, and a standard open circuit voltage is
circuits, etc.
This invention particularly relates to a voltage regu
lating system in which a two stage resistor bridge is used
with zener diodes in each ‘of the bridges providing regula—
provided.
If the ?rst stage, as shown in FIG. 1, is balanced and
the impedance Z2 constant, then E0 at 16 would be con
stant and independent of input voltage changes. How
tion to 0.000001 percent or less. Further, the system is 25 ever, if the impedance Z2 were not constant which results
capable of accepting a change in input voltage (AEi)
in a change in the output voltage, i.e., reversed in polarity
which is at least 400 percent of the minimum input volt
to the change in input voltage, it must be concluded that
age without an observable change in output voltage (AEO) .
Z2 increases or decreases from the static value. The in
Many devices can only Work in a range of 10 or 13 per
crease or decrease of Z2 is dependent upon the polarity of
cent input voltage change and then are able to reduce
the input voltage change. The change in E0 under con
this to only a 0.01 percent change in output voltage.
sideration here is a short term change, as shown in FIG. 3,
Regulation is herein de?ned ‘as
since the voltage docs. return to the original value withi:
the long term regulation capability of the circuit after a
AEo
certain time lapse.
AEi
By the addition of a second stage to the ?rst stage,
a short term change in voltage will not appear at the out
An object of this invention is to provide a new and im~
put of the second stage. The reason for this is that the
proved resistor ‘bridge voltage regulating circuit using
cascading of an even number of stages, which individually
zener diodes.
have a reversal of polarity in the regulation on a short
A further object of this invention is to provide a new
and improved voltage regulating system using a resistor 40 term basis, results in a complete cancellation of the short
term effect. The addition of the second stage also im
bridge with a zener diode in one leg of the bridge for feed
proves the long term regulation.
ing the input to a second stage which uses a similar resistor
This may be clearly seen in connection with FIG. 3,
diode bridge and provides a very accurate voltage output
where the input voltage at 30 will drop suddenly as. at 31
because of near perfect overall regulation.
to a new value as at 32 over the time interval indicated
A further object of this invention is to provide a
until the step ?nishes as at 33. This results in a short term
reference voltage so accurate and stable that it becomes
a new source of standard reference voltage that has many
voltage change, which is the output of the ?rst stage and
advantages over the present wet-cell type of standard.
To the accomplishment of the foregoing and related
ends, said invention then consists of the means herein
is indicated by the curve shown at 34 and commences at
the same instant of time as the step 31. The change on
claims; the following description setting forth in detail
stage to be across the input terminals of the second stage,
the regulating action of the second stage will be the mirror
image of the change in the ?rst stage, and this voltage
the reversal will be the mirror image of the ?rst change
after fully described and particularly pointed out in the 50 as indicated at 35. By causing the ‘output of the ?rst
one approved means of carrying out the invention, such
disclosed means, however, constituting but one of the
various ways in which the principles of the invention
may be used.
wave form is indicated at 36 and 37. The regulated out
55 put of the second stage is as indicated by the straight
line 38.
FIG. 2 shows a typical circuit involving this invention
in which 110 volt A.C., 60 cycle, is put across a “Variac”
diode voltage regulating system;
4-0 connected to an isolating transformer shown generally
FIG. 2 is a diagrammatic presentation of a circuit of
60 at 41 having a ratio of 110—120 and a resistance in the
this invention; and
line, together with a recti?er such as IN93 indicated at 42,
FIG. 3 shows the input voltage versus time and illus
and a typical condenser such as a 50 microfarad, 60 volt
trates ( 1) the extreme case of a step function change in
tantalytic condenser indicated at 43.
input voltage, (2) the regulating action of the ?rst and
The remaining elements of the circuit could be com
second stage, and (3) the output of the second stage.
This invention is a voltage regulating system using 65 pared in order but they are substantially similar to those
of FIG. 1. Further descriptions of this invention seem
resistor bridges in which the dynamic impedance of the
unnecessary, and FIG. 2 is only illustrative of the use of
zener diode is balanced out by the resistor bridge and the
In the drawings:
FIG. 1 is a schematic diagram of a resistor bridge zener
imperfect regulation of the ?rst bridge cancelled by the
mirror image action of the second bridge.
this invention.
Typical double anode zener diodes suitable for use in
this invention are types IN229, IN430, etc.
FIG. 1 shows the schematic view of this invention in 70 Although the present invention has been described in
which the line voltage is put across the terminals L1 and L2
connection with a few preferred embodiments thereof,
3,008,084
3
4
?rst stage is fed to the input of a second stage resistance
bridge in which the Zener diode resistance is similarly
positioned, and in which any imbalance in the impedance
of the zener diode results in a reversal of polarity of the
input voltage in the output voltage of the ?rst stage, and
in which the second stage e?ectively cancels said reversal
variations and modi?cations may be resorted to by those
skilled in the art without departing from the principles
of the invention. All of these modi?cations and varia—
tions are considered to be within the true spirit and scope
of the present invention ‘as disclosed in the foregoing de
scription and de?ned by the appended claims.
of polarity so that the output of the second stage is a
constant voltage.
I claim:
1. In a zener diode resistance bridge, a ?rst stage
3. The zener diode resistance bridge of claim 1, in
resistor bridge having an input voltage and a zener diode
which
a resistance is placed in one of the output terminals,
in one of the legs of said bridge, whereby the dynamic 10
whereby a standard open circuit reference voltage is pro
impedance of the ?rst Zener ‘diode is balanced out by the
vided in which the current is constant as well as the volt
?rst resistor bridge, and the output terminals connected
age.
to the input terminals of a similar bridge having a zener
diode similarly positioned, whereby the dynamic imped
ance of the second zener diode is balanced out by the sec
15
References Cited in the ?le of this patent
ond resistor bridge.
2. In a voltage regulating circuit of a resistance type
bridge having zener diodes as one leg of said bridge, a
?rst stage resistance bridge in which the output of said
UNITED STATES PATENTS
2,864,053
Woodworth ___________ __ Dec. 9, 1958