IX6611 Evaluation Board
User Manual
IXUM6611-0716
The IX6611 Evaluation Board is created to simplify the IX6611 driver’s accommodation in a new design.
It is a standalone device that can be easily connected to any IGBT or MOSFET to evaluate its
performance under different operating conditions.
Description and Board Schematic
The IX6611 is a secondary side, intelligent, high-speed gate driver designed to drive IXYS IGBTs and
power MOSFET devices. The IX6611 gate driver contains the necessary circuit blocks for pulse
transformer-isolated applications. High frequency, narrow pulses are used for bi-directional data transfer
across the isolation boundary to avoid duty cycle restrictions and to prevent transformer saturation. The
IX6611 includes the necessary monitoring and protection functions such as Supply Under-Voltage
Lockout, Supply Over-Voltage Lockout, Thermal Shutdown, external IGBT Overcurrent and Overvoltage
protection. For more information, see the IX6611 Datasheet.
This Evaluation Board is a two-layer surface mount board with all components assembled on the top layer
to simplify signal monitoring. It contains connectors for an input signal and power for input signal
conditioner, and connectors to power the isolated IX6611 driver and an external IGBT/MOSFET
connection.
The Evaluation Board Electrical Schematic diagram is shown in Figure 1.
Figure 1. Evaluation Board Electrical Schematic Diagram
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It contains IX6611 driver U1 with the required decoupling/filtering capacitors and isolation transformer
T1, which provides up to 4 kV DC isolation between a signal source and IX6611 driver.
Logic IC U2 and U3 with R16C12 network and MOSFETs Q1, Q2 are used as a signal conditioner,
which converts the typical PWM input signal into two short pulses representing rising and falling edges
of the input signal. These pulses are applied to the primary winding of the transformer T1B to be
transmitted to the secondary side, where IX6611 uses them to restore the gate drive pulse to the source
pulse’s shape. This helps avoid limitations to the maximum input pulse length.
Test points P11 and P12 enable monitoring of these pulses on the T1B primary side, while test point P13
allows for comparison of their position with the input signal, as seen in Figure 2.
Legend:
Channel 1 (blue) INPUT signal – P13 test point
Channel 2 (magenta) – P11 test point
Channel 3 (green) – P12 test point
Channel 4 (red) – IGBT gate pulse P1, P2 test pints shorted together
Figure 2. PWM Signal Transmission
Logic IC U2, U3 should be powered from an external power supply through connector J3 with VCC
voltage in the range of 3.0 V to 5.0 V.
Diodes D2 on the T1B secondary side are used to separate pulses representing rising and falling edges of
the input signal before applying them to inputs of the IX6611 driver.
Transformer T1A is used by the IX6611 driver to transmit fault conditions to the signal source level.
Diodes D1 separate Fault 1 and Fault 2 signals, converting them to positive polarity pulses in respect to
signal ground. Test points P3 and P8 allows for monitoring of Fault 1 and Fault 2 events as single short
pulses. See the IX6611 Datasheet for more information about fault conditions and their representation.
The IX6611 Gate driver U1 should be powered from an isolated (with respect to signal ground) power
source with isolation that is equal to or exceeding the value expected during the evaluation. Power should
be applied through connector J1. Because the common point of isolated power supply is connected
directly or through low resistance current sensor to the IGBT’s emitter, close attention should be paid to
avoid electrical shock in case this point is at a high potential with respect to signal ground. Capacitor C13
rated at 6.3 kV is used to prevent electrostatic discharge.
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Gate drive voltage applied to J1 is directly transmitted to the IGBT/MOSFET’s gate, so its recommended
value should be in the range of +12 V to +18 V for positive voltage and – 5 V to – 7 V for negative
voltage. Positive voltage outside this range may trigger overvoltage or undervoltage protection, as
described in the IX6611 Datasheet. If negative voltage is not required for MOSFET operation, pin #3 of
the connector J1 should be shorted to pin #2 of the same connector.
This Evaluation Board contains gate current limiting resistors R2 and R3 for positive and negative gate
voltage. Its value is set at 1 Ohm and serial resistors should be added, if required, to accommodate the
IGBT/MOSFET used to get the best performance.
The Evaluation Board also contains current sense resistor R10 equal to 0.1 Ohm, which is enough to
trigger overcurrent protection at 3 A IGBT/MOSFET current. If overcurrent protection is used, the
IGBT’s emitter should be connected to pin #4 of J2 and bus voltage should be connected to pin #5 of J3
(see Figure 2a). If higher current value is required, an additional shunt resistor should be connected in
parallel between pins #4 and #5 of the connector J2 (see Figure 2b). If overcurrent protection is not used,
IGBT’s emitter and bus voltage should be connected to pin #5, while pin #4 should be left open or
shorted to pin #5 (see Figure 2c). If the IGBT desaturation event is used as an overcurrent trigger, internal
current sense resistor R10 should be removed and external resistive divider with Zener protection diode
should be used as shown in Figure 2d. Zener’s diode threshold should not exceed 5 V to prevent IX6611
internal logic damage.
A typical IGBT connection in case of ACL utilization is shown in Figure 3.
(a)
(b)
(c)
(d)
Legend:
a)
b)
c)
d)
Internal 0.1 Ohm current sense resistor used
External shunt resistor R3 added to increase current rating
Over-current protection is not used
Over-current protection with IGBT de-saturation monitoring - internal current sense resistor removed
Figure 3. IGBT Connection for Overcurrent Protection Utilization
Network R6C7 is used to filter high frequency noise from the current sense resistor. Resistive divider
R4/R9 sets the active clamping (ACL) threshold. If ACL is used, serial resistor Rs should be connected to
pin #3 of the connector J2 to set the appropriate ACL threshold.
ACL starts when the IGBT is in an off state with the gate driven low by negative voltage supply and the
collector voltage exceeding the threshold set by Zener diodes Vc = Vzd1+ Vzd2 + Vzd3 - |Vn| with
respect to the emitter. A current flowing through Zener diodes and resistor R2 creates a voltage drop
across ZD3, which turns ACL protection on. Because the ACL threshold is set at 3.1 V with respect to
negative power supply, serial resistor Rs value required to trigger ACL at this moment is equal.
Rs = Vzd3 / 3.1 – 2, kOhm
where Vzd3 is a ZD3 diode stabilization voltage.
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Figure 4. IGBT Connection for ACL Utilization
When ACL activates, the IX6611 gate driver’s outputs become tri-state and the IGBT gate starts charging
by Zeners diodes current. When IGBT becomes active, the collector voltage drops, ACL disables and
negative voltage applies to the IGBT gate, again disabling it. If energy stored in the inductor is very high,
this sequence of operations may repeat until the remaining energy in the inductor is not enough to trigger
ACL protection. Diodes D2, D3 protect the IGBT gate from going above the power supply voltage.
However, if the power supply used is not able to sink the current, Zener diodes should be used for gate
protection.
The dimensions of the Evaluation Board are 1.5” x 3.0” x 0.8” (L x W x H).
The location of the Evaluation Board components is shown in Figure 5.
Figure 5. Evaluation Board Components Location
Using the Test Board
Installation
This Evaluation Board contains four connectors to provide power and accommodate IGBT/MOSFET,
which should be installed prior to the start of an evaluation. The recommended IGBT/MOSFET
connection schematic diagrams are shown in Figures 3 and 4.
Connector J1 of the Evaluation Board should be powered from an isolated power supply with respect to a
signal ground and isolation voltage above expected during the test.
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It is recommended to apply VCC voltage to the connector J3 and power to connector J1 before the input
signal is applied to the connector J4.
Powering Device
Warning!
This Evaluation Board does not have reverse polarity protection. Close attention should be paid to the
correct polarity of the power supply connection to prevent damage to the Evaluation Board.
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Warranty and Use
IXYS CORP. MAKES NO WARRANTY, REPRESENTATION OR GUARANTEE, EXPRESS OR
IMPLIED, REGARDING THE SUITABILITY OF ITS PRODUCTS FOR ANY PARTICULAR
PURPOSE, NOR THAT THE USE OF ITS PRODUCTS WILL NOT INFRINGE ITS INTELLECTUAL
PROPERTY RIGHTS OR THE RIGHTS OF THIRD PARTIES WITH RESPECT TO ANY
PARTICULAR USE OR APPLICATION AND SPECIFICALLY DISCLAIMS ANY AND ALL
LIABILITY ARISING OUT OF ANY SUCH USE OR APPLICATION, INCLUDING BUT NOT
LIMITED TO, CONSEQUENTIAL OR INCIDENTAL DAMAGES.
IXYS Corp. products are not designed, intended, or authorized for use as components in systems intended
for surgical implant into the body, or other applications intended to support or sustain life, or for any
other application in which the failure of the IXYS Corp. product could create a situation where personal
injury or death may occur.
IXYS Corp. reserves the right to make changes to or discontinue any product or service described herein
without notice. Products with data sheets labeled "Advance Information" or "Preliminary" and other
products described herein may not be in production or offered for sale.
IXYS Corp. advises customers to obtain the current version of the relevant product information before
placing orders. Circuit diagrams illustrate typical semiconductor applications and may not be complete.
IXYS Corp.
1590 Buckeye Dr.
Milpitas, CA 95035-7418
Phone: 408. 457.9000
Fax: 408. 496.0222
http://www.ixys.com
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