Application Notes BG1B Universal Gate Drive Prototype Board Description: The BG1B is a single channel gate drive circuit board for high power IGBT modules. The BG1B utilizes Powerex hybrid gate drivers and DC-to-DC converters to provide efficient switching of single or chopper modules rated up to 400A/1200V. 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 BG1B also provides an isolated fault feedback signal. Features: Applications: 3A or 5A Peak Output Current The BG1B can be used for driving single or chopper 2500VRMS isolation for control power and signals IGBT modules and was designed specifically to Uses Standard AMP MTA .100 input connector provide a direct mounting option for the following small NX package devices: CM150EX-24S, Operates from a single 15 VDC or 24 VDC supply CM200EX-24S and CM300EX-24S. Wide output voltage swing +15V/-8V Compact Size 2.6 x 2.1 (65mm x 54mm) 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: BG1B-3015 is a kit with a bare BG1B board, one VLA541-01R and one VLA106-15242 BG1B-5015 is a kit with a bare BG1B board, one VLA542-01R and one VLA106-15242 BG1B Application Guide Gate Driver Peak Drive Typical Application* Minimum RG DC-to-DC Converter Part Number Current (IOP) (IGBT Module Rating) VLA541-01R 3A 3.0 Up to 200A VLA106-15242 for 15 VDC input VLA106-24242 for 24 VDC input VLA542-01R 5A 2.0 Up to 400A *Compatible IGBT depends on voltage rating, switching frequency and selected R . Refer to Powerex application for details. G Publication Date: June 8, 2015 1 Rev. 1 Application Notes Circuit Explanation: The BG1B is a basic single channel gate driver designed around the recommended application circuits for the Powerex VLA541-01R and VLA542-01R hybrid IGBT gate drivers in combination with either VLA106-15242 or VLA106-24242 isolated DC-to-DC converters. A functional block diagram of the VLA541-01R/VLA542-01R and hybrid gate drivers is shown for reference in Figure 1. These gate drivers are optimized for use with Powerex 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 datasheets. 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 converters regulated 24 VDC 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 datasheets. A complete schematic and component selection guide for the BG1B is shown in Figure 3. The board will normally be operated with two input voltage sources. A 5V logic source (+V ) provides drive for the high speed opto-couplers inside L the hybrid gate drivers and pull-up voltage for the fault signal isolation optos OP1 and OP2. A control power supply (+V ) provides power for the gate driver and is connected to the primary side of the DC- to-DC converters at Pins 8, 9 S 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 150F 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 +V supply. These capacitors will be larger than S 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 (V ) at Pin 3 and -8.2 (V ) at Pin 1 with respect to common CC EE 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 82F low impedance capacitors used on the BG1B are sized to supply 5A gate pulses at a 10 kHz 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). R will normally be adjusted to provide suitable drive for the module being used considering dynamic performance, G 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 and DZ2. These zener diodes also help to control short circuit currents by shunting miller current away from the gate Fault Latch V t Adjust CE trip 2 Fault 8 and Timer Detector V detect CE 1 V CC 8 3.3K 4 3 V CC + 9 V 24V 2 IN V O Interface 14 Control V O 10 5 180 Buffer 1 Input - V EE 11 13 V =8.2V Z Opto Coupler Voltage Regulator V EE 6 Current Limiter Figure 1: VLA541-01R/VLA542-0R Figure 2: VLA106-15242, VLA106-24242 Block Diagram Block Diagram Publication Date: June 8, 2015 2 Rev. 1 Oscillator Rectifier