Application
Second Release: July 10, 2012
NOTES:
BG2B – Universal Gate Drive Prototype Board
Description: The BG2B is a two channel gate drive circuit for high power IGBT modules. The BG2B utilizes
Powerex hybrid gate drivers and DC to DC converters to provide efficient switching of modules rated up to 400A.
The hybrid gate drivers include high speed opto-couplers for control signal isolation and desaturation detection
to protect the IGBT from short circuit conditions. The hybrid DC to DC converters provide fully isolated control
power for each driving channel. The BG2B also provides an isolated fault feedback signal.
Features:
1.5A, 3A or 5A Peak Output Current
2500VRMS isolation for control power and signals
Standard AMP MTA .100” input connector
Operates from a single 15 VDC or 24 VDC supply
Wide output voltage swing +15V/-8V
Compact Size 3” x 2.2” (76mm x 56mm)
Applications:
BG2B is designed for use with Powerex NF and
A series IGBT modules.
Use VLA106-15242 DC to DC converter for
operation with 15 VDC control power
Use VLA106-24242 DC to DC converter for
operation with 24 VDC control power
Ordering Information: BG2B-1515 is a kit with a bare BG2B board, two M57159L-01 and two VLA106-15242
BG2B-3015 is a kit with a bare BG2B board, two VLA504-01 and two VLA106-15242
BG2B-5015 is a kit with a bare BG2B board, two VLA503-01 and two VLA106-15242
BG2B Application Guide
Peak Drive
Current (IOP)
Minimum RG
Typical Application*
Part Number
M57159L-01
+/- 1.5A
4.2 Ω
Up to 100A
VLA504-01
+/- 3A
3.0 Ω
Up to 200A
VLA503-01
+/- 5A
2.0 Ω
Up to 400A
Gate Driver
(IGBT Module Rating)
DC/DC Converter
VLA106-15242
for 15 VDC input
VLA106-24242
for 24 VDC input
* Compatible IGBT module depends on voltage rating, switching frequency and selected RG. Refer to Powerex application notes for details.
Note: VLA504-01 and VLA503-01 gate drivers replace older types M57959L and M57962L. VLA106-15242 replaces the older M57145L-01
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Figure 2: VLA106-15242, VLA106-24242
Block Diagram
VCE
Detector
t Adjust
2 trip
1 VCE
4 VCC
Control 14
Input
180
Interface
Buffer
detect
+
9
VIN
-
3.3K
8
10
11
Rectifier
Fault Latch
and Timer
Fault 8
Oscillator
Figure 1: VLA503-01/VLA504-01/M57159L-01
Block Diagram
24V
VZ=8.2V
3
VCC
2
VO
1
VEE
Voltage Regulator
Current Limiter
5 VO
13
Opto Coupler
6
VEE
Circuit Explanation: The BG2B is a basic two channel gate driver designed around the recommended
application circuits for the Powerex M57159L-01, VLA503-01 and VLA504-01 hybrid IGBT gate drivers in
combination with either VLA106-15242 or VLA106-24242 isolated DC to DC converters.
A functional block diagram of the VLA503/504-01 and M57159L-01 hybrid gate drivers is shown for
reference in Figure 1. These gate drivers are optimized for use with Powerex NF and A series IGBT modules.
The drivers use a high speed open collector type opto-coupler to provide 2500VRMS isolation of control signals.
The output stage is designed to provide high current gate drive with the appropriate on- and off-state bias
voltages for large IGBT modules. The gate driver includes a desaturation detection circuit to provide protection
against short circuit conditions. For additional detailed information on the characteristics and operation of these
gate drivers please refer to the individual device data sheets.
Figure 2 shows a block diagram of the VLA106-15242 and VLA106-24242 hybrid DC to DC converters.
These two devices are identical except that VLA106-15242 is designed to operate from a 15 VDC input and the
VLA106-24242 is designed to operate from a 24 VDC input. These DC to DC converters use a transformer to
provide 2500VRMS isolation for gate drive power. The converter’s regulated 24VDC output is split using a
resistor and zener diode to provide +15.8V and -8.2V for the hybrid gate driver. For additional detailed
information on the operation of the hybrid gate drivers and DC to DC converters please see the individual device
data sheets.
A complete schematic and component selection guide for the BG2B is shown in Figure 3. The board will
normally be operated with two input voltage sources. A 5V logic source (+V L) provides drive for the high speed
opto-couplers inside the hybrid gate drivers and pull-up voltage for the fault signal isolation optos OP1 and OP2.
A control power supply (+VS) provides power for the gate driver and is connected to the primary side of the DC
to DC converters at pins 8,9 and 10,11. The +VS source is decoupled with the low impedance electrolytic
capacitors C4 and C8. These capacitors are connected close to the input pins of each DC to DC converter to
provide a stable, well-filtered DC source. A 150uF capacitor was selected for C4 and C8 to provide the required
ripple current and filtering assuming a maximum driving load and a significant distance to the main filter
capacitor of the +VS supply. These capacitors will be larger than necessary if the driving load is smaller or the
VS supply main filter capacitors are nearby. The DC to DC converters provide isolated gate drive power which
consists of +15.8V (VCC) at pin 3 and -8.2 (VEE) at pin 1 with respect to common at pin 2. The gate drive power
supplies are decoupled using the low impedance electrolytic capacitors C1, C2, C5, and C6. It is very important
that these capacitors have low enough impedance and sufficient ripple current capability to provide the required
high current gate drive pulses. The 82uF low impedance capacitors used on the BG2B are sized to supply 5A
gate pulses at a 10KHz rate. If the application is operating at lower frequency or lower peak current it may be
possible to reduce the size of these capacitors.
The isolated VEE and VCC supplies provided by the DC to DC converters are connected to the hybrid
gate drivers at pins 4 and 6 to provide gate drive power. The hybrid gate driver amplifies the control input signal
and produces high current gate drive at pin 5. The gate drive current is adjusted by selecting the appropriate
series gate resistance (RG). RG will normally be adjusted to provide suitable drive for the module being used
considering dynamic performance, losses and switching noise. For more information on selecting RG see
Powerex IGBT module application notes. Protection against gate voltage surges is provided by DZ1, DZ2, DZ4,
and DZ5. These zener diodes also help to control short circuit currents by shunting miller current away from the
gate.
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Figure 3: BG2B Schematic and Component Selection
VLA106-15242/VLA106-24242
11
8
3
R1
+
+ C1 C2
5
+
OP1
CN1
+VL
CN2
DZ3
C4
GND
+VS
FO
IN1
IN2
D1 D2
1
14 13
14
13
DZ1
DZ2
RG1
C3
10
10
J1
1
E1
M57159L-01/VLA503-01/VLA504-01
VLA106-15242/VLA106-24242
11
1
8
3
DZ6
OP2
14 13
14
13
10
10
+
E2
G2
R2
+ C5 C6
R3
D3 D4
1
C8
+
G1
DZ4
DZ5
RG2
C7
J2
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M57159L-01/VLA503-01/VLA504-01
Component Selection:
Designation
D1, D2, D3, D4
DZ1, DZ2, DZ4, DZ5
DZ3, DZ6
C1, C2, C5, C6
C4, C8
C3, C7*
R1, R2
R3
OP1, OP2
CN1**
CN2
Typical Value
0.5 A, 1000V
16V, 1W
30V, 1W
82F, 35V
150uF, 35V
0-200 pF
4.7k, 0.25W
4.7K, 0.25W
NEC PS2501
MTA .100”
¼” Ring Lug
Description
VCE detection diode – ultra fast recovery
Gate Voltage Surge Protection
Detect input pin surge voltage protection
Power supply filter – Electrolytic, low Impedance
Control power filter – Electrolytic, low impedance
Adj. Trip time – Multilayer ceramic or film*
Fault sink current limiting resistor
Fault feedback pull-up resistor
Opto-coupler for fault signal isolation
Input and gate drive connectors
Collector voltage sensing connection
Example: Mfg./PN
ON Semi MUR1100E
1N4745
1N4751
Panasonic EEU-FC1V820
Panasonic EEU-FC1V151
EPCOS B37979---------
NEC PS2501
AMP 640457-6
AMP 34151
* Not required in all applications. Please see hybrid gate driver application notes for details.
** Recommended mating connector AMP CST-100 Housing P/N 770602-6 with crimp contact 770666-2.
Short circuit protection is provided by means of desaturation detection. For details on the operation of
this circuit consult the hybrid gate driver individual data sheets. The collector voltage of each IGBT is detected
through the series connected high voltage blocking diodes D1, D2 and D3, D4. The combined blocking voltage
of the series connected diodes must be equal to or greater than the VCES rating of the IGBT. For applications
using lower voltage IGBT modules it is possible to use a single detection diode in each channel. DZ3 and DZ6
protect the gate driver’s detect input (Pin 1) from voltage surges during reverse recovery of the high voltage
blocking diodes. The capacitors C3 and C7 are used to adjust the drivers protection circuit trip time. The
driver’s default settings are sufficient for many applications so it may be possible to omit these capacitors. For
details on the use of C3 and C7 consult the individual gate driver data sheets.
If the gate driver’s short circuit protection is activated it immediately shuts down the gate drive and pulls
pin 8 low to indicate a fault. Current flows from Vcc (pin 3 of DC to DC converter) through the LED in fault
isolation opto (OP1, OP2) to pin 8. The transistor in the fault isolation opto turns on and pulls the fault signal line
(FO) at pin 4 of CN1 low. This opto isolated signal can now be used by the controller to detect the fault condition.
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Figure 4: BG2B External Wiring Diagram
C1
CN2
RC Filter to
remove noise on
fault signal
RC~10us
To logic
level control
circuits
CMOS type
buffer must sink
15mA
G1
E1
CN1
GND
+VS
FO
IN1
IN2
+VL
C2E1
E2
G2
1
E2
IGBT Module
Interface Circuit Requirements: A typical interface circuit for the BG2B is shown in Figure 4. A single control
power supply (+VS) is connected to pin 5 of CN1 with its common at pin 6. This supply provides all of the gate
drive power for both channels via the hybrid DC to DC converters. The current drawn from the +VS supply will
vary from less than 100mA to more than 500mA depending on the switching frequency and size of IGBT being
driven. Consult the hybrid gate driver application notes for details on determining the required supply current for
the gate driver. The gate driver supply current can then be converted into current drawn from the +VS supply
using the efficiency specification on the DC to DC converter data sheet.
A 5V logic supply is connected at pin 1 of CN1 and shares the same common at pin 6 of CN1 as the
15V control supply. The 5V supply is directly connected to pin 14 of the hybrid gate driver which is internally
connected to the anode of the LED in the high speed opto coupler. The 5V supply is also used to pull the output
side of the fault isolation opto couplers high.
The control signal interface is designed for use with standard 5V CMOS logic. The control input signals at
pins 2 and 3 of connector CN1 are used to turn the IGBTs on and off. These signals are active low which means
that the gate driver output will be high (IGBT on) when they are pulled low. These control pins are connected
directly to pin 13 of the hybrid gate driver which is connected internally through a 180Ω limiting resistor to the
cathode of the LED in the high speed opto coupler (see figure 1). When the control signal is pulled low, current
flows from the 5V logic supply through the LED to turn the gate driver’s output on. The control pins must be
pulled low with a buffer that is capable of sinking at least 16mA in order to turn on the high speed opto coupler
inside the hybrid gate driver. A CMOS buffer that actively pulls its output high in the off state (74HC04 or similar)
is recommended for maintaining good common mode noise immunity. Open collector drive that allows IN1 and
IN2 to float will degrade common mode noise immunity and is therefore not recommended.
The fault signal line on pin 4 of CN1 is active low which means that a fault condition will be indicated by
a low level signal. During normal operation pin 4 is pulled high to the +VL supply by the 4.7K resistor R3. If
either of the hybrid gate drivers detects a short circuit condition its fault isolation opto (OP1, OP2) will turn on
and pull pin 4 of CN1 low. When a fault is detected the hybrid gate drivers disable the output and produce a
fault signal for a minimum of 1ms. Any signal on the fault line that is significantly shorter than 1ms can not be a
legitimate fault so it should be ignored. Therefore, for a robust noise immune design, it is recommended that an
RC filter with a time constant of approximately 10μs be added between pin 4 and the controller as shown in
figure 4.
Printed Circuit Layout: Figure 5 shows the layout of the BG2B two channel gate driver board. The compact 3”
x 2.2” circuit board with only 24 components clearly demonstrates the advantage of using hybrid gate drivers
and DC to DC converters. One important feature is the use of three ground plane islands for the regions of the
PCB having high voltage differences. Two of the islands are tied to the IGBT emitter/circuit common (Pin 2 of
the DC to DC converters) of each output channel. The third island is connected to logic interface common at pin
6 of CN1. This layout provides shielding to help prevent undesirable coupling of noise between the control side
and the gate drive channels.
Additional Information: Detailed information about the operation and electrical characteristics of the M57159L01, VLA503-01 and VLA-504-01 hybrid gate drivers can be found on the individual device data sheets. Electrical
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characteristics such as input voltage range, efficiency, and output voltage regulation of the VLA106-15242 and
VLA106-24242 DC to DC converters can also be found on the individual device data sheets. Information about
calculating gate drive current and selection of series gate resistors (RG) can be found in the general IGBT
module and gate drive application notes. For applications using higher current IGBT modules refer to the
application notes for the VLA500-01 hybrid gate driver and BG2A reference design. For applications using high
frequency optimized NFH series IGBT modules refer to the VLA502-01 application note. All of these documents
are available on the Powerex website at www.pwrx.com. For design assistance with any of the products
covered in this application note contact your local Powerex representative or Powerex application engineering at
(724) 925-7272.
Figure 5: BG2B Printed Circuit Board Layout
Component Side
Solder Side
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