Driving IGBT Modules 1.0 Driving IGBTs When using high power IGBT modules, it is often desirable to completely isolate control circuits from the gate drive. A block diagram of this type of gate drive is shown in Figure 1. This circuit provides isolation for logic level control and fault feedback signals using opto-couplers and separate isolated floating power supplies for each gate drive circuit. There are a number of advantages to this type of gate drive topology including: On and off driving voltages that are stable and independent of the power device switching frequency and duty cycle. Adaptability to provide very high output currents required to drive large IGBT modules. Control circuits that are isolated from power circuit switching noise and high voltages. Capability to provide local power for protection circuits such as desaturation detectors. Figure 1: Fully Isolated Gate Driver 2.0 OPTO-Isolated Hybrid Gate Drivers Powerex offers one DIP (dual-in-line-package) and eight SIP (single-in-line-package) hybrid circuits recommended for IGBT module gate drives. All nine packages provide isolation for control input signals by means of built-in, highspeed opto-couplers. All of the opto-couplers have been selected to provide from 2500VRMS to 4000VRMS isolation and immunity to power circuit common mode transient noise of greater than 15kV/µs. This feature allows convenient common referencing of high and low side control signals. The high-speed types, VLA502-01 and VLA513-01, are designed for applications with switching frequencies up to 60 kHz. The VLA567-01R is a DIP dual channel gate driver while the SIP modules are all single channel gate drivers. The hybrid gate drivers feature output stages designed to provide the pulse currents necessary for efficient switching of Powerex IGBT modules. All drivers are designed to provide a substantial off-state bias of -5V to -12V in order to ensure robust noise immunity. Hybrid gate drivers simplify gate drive design by minimizing the number of components required. In addition to high performance gate drive, many of the drivers also provide short circuit protection. Publication Date: 02-5-2016 Rev. 1 1 Application Notes To help simplify design of fully isolated gate drive circuits, Powerex provides a family of hybrid circuits that supply the required gate drive, short-circuit protection, and isolated power for efficient reliable operation of Powerex IGBT modules. For optimum performance, parasitic inductance in the gate drive loop must be minimized. This is accomplished by connecting decoupling capacitors as close as possible to the pins of the hybrid driver and by minimizing the lead length between the drive circuit and the IGBT. Back-to-back zener diodes rated at approximately 18V should be connected between the gate and emitter terminals as closely as possible to the pins of the device as shown in Figure 1. These zener diodes protect the gate during switching and short-circuit operation as the maximum allowable gate-to-emitter voltage on the IGBT is typically ±20V. The gate drivers typically have a built-in 180Ω input resistor that is designed to provide proper drive for the internal opto-isolator when VIN = 5V. If other input voltages are desired, an external resistor should be connected between the logic control signal and Pin 1 to maintain the proper opto-drive current of 16mA. The value of the required external resistor can be computed by assuming that the forward voltage drop of the opto-diode is 2V. For example: If 15V drive is required then Rext = (15V - 2V)/16mA - 180Ω ≈ 630Ω. Application Notes Table 1 lists the key features and typical application range for the Powerex family of hybrid gate drivers. Table 1: Hybrid Gate Drivers and Features TYPE CHANNELS DRIVEN INTEGRATED DC-DC CONVERTER SHORT CIRCUIT PROTECTION ACTIVE CLAMPING SOFT SHUTDOWN OUTPUT CURRENT USABLE RANGE VLA541-01R 1 No VCE Desaturation No Yes +/-3A 600V, up to 200A, 1200V, up to 150A VLA542-01R 1 No VCE Desaturation No Yes +/-5A 600V, up to 600A, 1200V, up to 400A VLA513-01 1 No None No No +/-5A VLA546-01R 1 No VCE Desaturation No Yes – Adjustable +/-5A VLA500-01 1 Yes VCE Desaturation No Yes – Adjustable +/-12A 600V, up to 600A, 1200V, up to 1400A VLA500K01R 1 Yes VCE Desaturation No Yes – Adjustable +/-12A 600V, up to 600A, 1200V, up to 1400A 1700V, up to 1000A VLA502-01 1 Yes VCE Desaturation No Yes – Adjustable +/-12A 600V & 1200V High Frequency Modules VLA552-01R 1 Yes VCE Desaturation Yes Yes – Adjustable +/-24A All 600V 1200V, 1000A up to 3600A 1700V, 1000A up to 3600A VLA567-01R 2 Yes VCE Desaturation No Yes – Adjustable +/-8A 600V, up to 1000A 1200V, up to 1000A Publication Date: 02-5-2016 Rev. 1 600V, up to 600A, 1200V, up to 400A High Frequency Modules 600V, up to 600A, 1200V, up to 400A 1700V, up to 400A 2 Figure 2 is a photograph of a VLA567-01R gate driver with built-in short-circuit protection. 3.0 Hybrid DC-to-DC Converters Power is typically supplied to hybrid IGBT gate drivers from low voltage DC power supplies that are isolated from the main DC bus voltage. Isolated power supplies are required for high side gate drivers because the emitter potential of high side IGBTs is constantly changing. Isolated power supplies are often desired for low side IGBT gate drivers in order to eliminate noise problems created by ground loops. As a rule of thumb, the gate drive power supplies should have an isolation voltage rating of at least two times the IGBTs V CES rating (i.e. VISO = 2400V for 1200V IGBT). In systems with several isolated supplies, inter-supply capacitances must be minimized in order to avoid coupling of common mode noise. The recommended power supply configuration for Powerex hybrid IGBT gate drivers is shown in Figure 3. Figure 3: Hybrid Driver DC-to-DC Converter Two supplies are used in order to provide the on- and off-bias for the IGBT. The recommended on-bias supply (VCC) voltage is +15V and the recommended off-bias supply voltage (VEE) is in the -5V to -15V range. These supplies should be regulated to within +/-10%. The range indicated on the individual driver datasheets is acceptable. Electrolytic or tantalum decoupling capacitors should be connected at the power supply input pins of the hybrid driver. These capacitors supply the high pulse currents required to drive the IGBT gate. The capacitance required depends on the size of the IGBT module being driven. Powerex provides three isolated DC-to-DC converters for use with gate drivers that do not have built in power supplies. The characteristics of these DC-to-DC converters are summarized in Table 2. Powerex DC-to-DC converters are designed with minimum inter-winding capacitance in order to minimize dV/dt coupled noise. The VLA106-15242 is a single-in-line isolated DC-to-DC converter that produces a regulated +15.8V/-8.2V output from an input of 12V to 18V DC. The VLA106-24242 produces a regulated +15.8V/-8.2V output from an input of 21.6V to 26.4V DC. A photograph of the VLA106-15242 is shown in Figure 4 and has the same package and footprint as the VLA106-24242. Publication Date: 02-5-2016 Rev. 1 3 Application Notes Figure 2: Photograph of the VLA567-01R Dual Channel Drive IC Table 2: DC-to-DC Converters for Hybrid Gate Drivers TYPE INPUT (VOLTS) OUTPUT CURRENT POWER (WATTS) VLA106-15242 12 – 18 1 @ +24V(+15.8V / -8.2V), 100mA 2.4 VLA106-24242 21.6 – 26.4 1 @ +24V(+15.8V / -8.2V), 100mA 2.4 VLA124-1500GTR 13.5 – 16.4 1 @ +15.8V, 100mA 1 @ -11.6V, 100mA 2.7 Figure 4: Photograph of the VLA106-15242 4.0 Basic Gate Driver (VLA513-01) Powerex offers a basic opto-isolated hybrid gate driver, VLA513-01. This driver consists of a high speed opto-coupler for input signal isolation followed by a current boosting output stage. The output stage is designed to provide the high pulse currents necessary for efficient switching of high current IGBT modules. A photograph of the VLA513-01 is shown in Figure 5. Figure 5: Photograph of the VLA513-01 This gate driver is designed to drive modules that require peak gate currents of 5A and high switching frequencies up to 60kHz. The internal schematic and application circuit is shown on the datasheet. 5.0 Gate Drivers with Short Circuit Protection Standard Powerex IGBT modules are designed to survive low impedance short circuits for a minimum of 10 µs. In many cases, it is desirable to implement short circuit protection as part of the gate drive circuit in order to provide the fast response required for reliable protection against severe low impedance short circuits. Several Powerex hybrid gate drivers provide this type of protection as shown in Table 1. The VLA500 series (VLA500-01, VLA502-01 and VLA500K-01R), VLA541-01R, VLA542-01R, VLA546-01R, VLA552-01R and VLA567-01R all use desaturation detection as described in Section 5.1. 5.1 Desaturation Detection Figure 6 shows a block diagram of a typical desaturation detector. Publication Date: 02-5-2016 Rev. 1 4 Application Notes The gate drive DC-to-DC converters are decoupled using low impedance electrolytic capacitors. 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. Figure 6: Desaturation Detector Block Diagram When the IGBT turns on, the comparators (+) input is pulled down by D1 to the IGBT’s V CE(sat). The (–) input of the comparator is supplied with a fixed voltage (VTRIP) which is typically set at about 8V. During normal switching, the comparators output will be high when the IGBT is off and low when the IGBT is on. If the IGBT turns on into a short circuit, the high current will cause the collector-emitter voltage to rise above VTRIP even though the gate of the IGBT is being driven on. This presence of high VCE when the IGBT is supposed on is called desaturation. The detect diode (D1) must be an ultra-fast recovery diode with a current rating of at least 100mA and a blocking voltage equal to or greater than the VCES rating of the IGBT module being used. Desaturation can be detected by a logical AND of the driver’s input signal and the comparator output. When the output of the AND goes high, a short circuit is indicated. The output of the AND is used to command the IGBT to shut down in order to protect it from the short circuit. A delay (t TRIP) must be provided after the comparator output to allow for the normal turn on time of the IGBT. The tTRIP delay needs to be set such that the IGBTs VCE has enough time to fall below VTRIP during normal turn on switching. If tTRIP is set too short, erroneous desaturation detection will occur. The maximum tTRIP delay is limited by the IGBT’s short circuit withstanding capability. The driver’s default settings are sufficient for many applications and therefore these capacitors can be omitted. For Powerex S, S1, and T-Series IGBT modules, the maximum safe limit is 10µs. 5.2 Operation of Powerex Desaturation Detectors (VLA500 series, VLA541-01R, VLA542-01R, VLA546-01R, VLA552-01R, VLA567-01R) Powerex offers several hybrid integrated circuit gate drivers that implement desaturation detection. A photograph of the VLA502-01 is shown in Figure 7. The VLA500 series drivers all have the same pin layout and approximate dimensions. The VLA500 series, VLA567-01R and VLA552-01R all have built-in DC-to-DC conversion that provides isolated gate drive power consisting of +15.3V (VCC) -7.6V. Transformer coupling provides 2500VRMS isolation (4000VRMS for the VLA500K-01R and VLA552-01R) between the 15V control supply (VD) and the gate drive power. This feature allows the drivers to provide completely floating gate drive that is suitable for high or low side switching. Figure 7: Photograph of a VLA500 Series Gate Driver Figure 8 is a flow diagram showing the logical operation of Powerex desaturation detectors. A block diagram for the Powerex desaturation detector operation is shown in Figure 9. Publication Date: 02-5-2016 Rev. 1 5 Application Notes In this circuit, a high voltage fast recovery diode (D1) is connected to the IGBT’s collector to monitor the collector-toemitter voltage. When the IGBT is in the off-state, D1 is reverse biased and the (+) input of the comparator is pulled up to the positive gate drive power supply which is normally +15V. Figure 8: Protection Circuit Operation As described, the driver monitors the VCE of the IGBT. The driver detects a short circuit condition when VCE remains greater than VTRIP for longer than tTRIP after the input on signal is applied. The trip time (tTRIP) can be adjusted with an external capacitor. A relationship between the capacitor value and the trip time can be found on the driver datasheet, a general discussion is provided in Section 5.2.1. When a desaturation is detected, the hybrid gate driver performs a soft shutdown of the IGBT and starts a timed (tRESET) lock-out. The soft turn-off helps to limit the transient voltage that may be generated while interrupting the large short circuit current flowing in the IGBT. During the lock-out, a fault feedback signal is asserted and all input signals are ignored. Normal operation of the driver will resume after the lockout time has expired and the control input signal returns to its off-state. 5.2.1 Trip Time Adjustment The desaturation trip time (tTRIP) can be adjusted in the gate drivers that offer desaturation protection by connecting CTRIP as shown in the application example circuits found on the applicable device datasheets. As an example, Figure 10 shows the relationship between CTRIP and tTRIP for the VLA500-01. Figure 10: Adjustment of tTRIP for the VLA500-01 Similar curves for the other gate drivers can be found on the individual detailed datasheets. The driver’s default trip time (no CTRIP connected) will work for most applications. However, when modules are used with relatively large gate resistance (RG) the driver may incorrectly detect a short circuit. The false trip occurs because it takes longer than t TRIP for the device to reach an on-state voltage less than VTRIP. In such applications, extending tTRIP may be necessary. In addition to being able to adjust the trip time, the shutdown speed can be adjusted in the VLA500 series devices. This adjustment may be necessary in some applications to limit transient voltages during a short circuit shutdown. Publication Date: 02-5-2016 Rev. 1 6 Application Notes Figure 9: Block Diagram for Desaturation Detection Usually, this is only necessary when a booster stage is being used with the driver to drive large modules. More information about this adjustment can be found on the detailed datasheets and application notes. 6.0 Active Clamping The VLA552-01R gate driver has a built-in active collector clamp circuit. The details of the active clamping circuit can be seen in Figure 11. An essential part of the active clamp circuit is a string of zener diodes. The total zener voltage, VZ, is typically set to 950V when driving 1200V IGBT modules and 1350V when driving 1700V IGBT modules. The DC link voltage must be less than VZ. When a surge voltage exceeds the total zener voltage, a positive voltage is fed back to Pin 26 of the hybrid IC and the active clamping circuit is initiated. Figure 12 shows the behavior of the active clamping circuit for a high current turn-off. Figure 12: Clamp Circuit Behavior The active clamping circuit does help to control high surge voltages but it does not guarantee that the IGBT’s VCES rating will never be exceeded. Therefore, it is prudent to test any foreseeable conditions as part of the system evaluation. Finally, the following voltage relationship must be adhered to VDC_Link < Vosc_peak < Vz < Voff_surge. Publication Date: 02-5-2016 Rev. 1 7 Application Notes Figure 11: Active Clamping Circuit Detail 7.0 Gate Drive Requirements 7.1 Selecting the Gate Resistor (RG) Equation 1: Conservative Equation for Minimum RG RG(MIN) = (VCC + |VEE|)/IOP Example: With VCC = 15V and -VEE = 10V RG(MIN) for VLA542-01R will be: RG = (15V + 10V)/5A = 5 Ω In most applications, this limit is unnecessarily conservative. Considerably lower values of RG can usually be used. The expression for RG(MIN) should be modified to include the effects of parasitic inductance in the drive circuit, IGBT module internal impedance and the finite switching speed of the hybrid drivers output stage. Equation 2 is an improved version of Equation 1 for RG(MIN). Equation 2: Improved Equation for RG(MIN) RG(MIN) = (VCC + |VEE|)/IOP - (RG)INT – Ø Large IGBT modules that contain parallel chips have internal gate resistors that balance the gate drive and prevent internal oscillations. Table 3 lists some example internal RG values for modules containing parallel chips. The value of Ødepends on the parasitic inductance of the gate drive circuit and the switching speed of the hybrid driver. The exact value of Øis difficult to determine. It is often desirable to estimate the minimum value of R G that can be used with a given hybrid driver circuit and IGBT module by monitoring the peak gate current while reducing R G until the rated IOP is reached. The minimum restriction on RG often limits the switching performance and maximum usable operating frequency when large modules outside of the driver’s optimum application range are being driven. Further steps to address this issue are provided in Section 8.1. Table 3: Internal Gate Resistance Part Number Internal RG [Ω] CM300DX-24S1 6.5 CM450DY-24S 4.3 CM1800DY-34S 1.1 The RMS gate current is used to determine the power requirements for R G by the equation P=i2R where i is the RMS gate current. When measuring RMS gate current, be certain that the instrument has a sufficiently high sampling rate to accurately resolve the relatively narrow gate current pulses. Most “true RMS” DMMs are not capable of making this measurement accurately. The RMS gate current can also be estimated from the gate drive waveform. Figure 13 shows a typical gate current waveform. Publication Date: 02-5-2016 Rev. 1 8 Application Notes RG must be selected such that it falls within the range specified on the IGBT module datasheet and that the output current rating (IOP) of the hybrid gate driver is not exceeded. If RG is computed using Equation 1, then IOP will not be exceeded under any condition. VIN iG Triangle approximation for IG RMS calculation --0-VIN --0-iG --0-VGE VGE Application Notes VIN:5V/div, VGE: 5V/div, iG:5A/div, t:400ns/div, RG=1.0ohm, CL=0.33µF Figure 13: Typical Gate Current Waveform If we assume the turn-on and turn-off pulses are approximately triangular we can estimate RMS gate current using the equations given in Figure 14. In most applications, the peak gate current is much larger than the average current supplied by the DC-to-DC converter so it is reasonable to assume that the RMS ripple current is roughly equal to the RMS gate current. The RMS ripple current can be estimated using Equations 4 and 5 from Figure 14. For example, if we use a triangular approximation to estimate the RMS current of the turn-off pulses shown in Figure 13, we see that ip(off)=13A and tp(off)=1280ns. Eqn. 3 RMS Current for Repetitive Triangular Pulses Where: ip = Peak Current tp = base width of pulse f = frequency tp ∙ f 3 iRMS = ip Eqn. 4 RMS Current for Turn-on Gate Pulses iG(on)(RMS) = ip(on) tp(on) ∙ f 3 Where: ip(on) = Peak Turn-On Current tp(on) = Base width of On pulse f = frequency Eqn. 5 RMS Current for Turn-off gate Pulses If the switching frequency f = 20kHz and assuming that the on- and off-gate drive pulses are equivalent, then the RMS gate current will be approximately 1.70ARMS. 7.2 Supply Current The current that must be supplied to the IGBT driver is the sum of two components. One component is the quiescent current required to bias the driver’s internal circuits. The current is constant for fixed values of VCC and VEE. The second component is the current required to drive the IGBT gate. This current is directly proportional to the operating frequency and the total gate charge (QG) of the IGBT being driven. With small IGBT modules and at low operating frequencies, the quiescent current, IH, will be the dominant component. The amount of current that must be supplied to the hybrid driver when VCC = 15V and VEE = -10V can be determined from Equation 7. Publication Date: 02-5-2016 Rev. 1 iG(off)(RMS) = ip(off) tp(off) ∙ f 3 Where: ip(off) = Peak Turn-Off Current tp(off)= Base width of Off pulse f = frequency Eqn. 6 Total RMS Gate Current iG(RMS) = iG(on)(RMS)2 + iG(off)(RMS)2 Or assuming iG(off) = iG(on) (On and Off current pulses are symmetric) the RMS gate current is: iG(RMS) = ip 2 ∙ tp ∙ f 3 Where: ip = Peak Gate Current tp = base width of gate drive pulse f = frequency Figure 14: Gate Current Equations 9 Equation 7: Required Supply Current for Hybrid Drivers ID = QG x fPWM + IH Where: ID = Required supply current QG = Gate charge fPWM = Operating frequency IH = “H” input current maximum for driver 7.3 Single Supply Operation Figure 15: Single Supply Operation of IGBT Hybrid Drivers The voltage of the single supply and the zener diode can be varied to allow use of standard supplies. For example, if a 24V DC-to-DC converter is to be used, then a 9V zener diode would give +15V/-9V, which is acceptable for all of the hybrid gate drivers. The two limiting factors that need to be observed if changes are made are: (1) Voltages must be within the allowable range specified on the gate driver data sheet and (2) The turn-on supply should be 15V +/-10% for proper IGBT performance. 7.4 Total Power Dissipation The hybrid IGBT driver has a maximum allowable power dissipation that is a function of the ambient temperature. With VCC = 15V and VEE = -10V, the power dissipated in the driver can be estimated using Equation 8. Equation 8: Total Power Dissipation PD = ID x (|VCC| + |VEE|) The power computed using Equation 1.8 can then be compared to the derating curves shown on the driver datasheet. The derating curve for the VLA542-01R is shown in Figure 16 and shows a maximum allowable ambient temperature of 60°C. Figure 16: Derating Curve for VLA542-01R Publication Date: 02-5-2016 Rev. 1 10 Application Notes Using a dual supply as in Figure 3, the current drawn from VCC (ID+) is nearly equal to the current drawn from VEE (ID-). Only a small amount of current flows in the common connection (ICOM). In many applications, it is desirable to operate the hybrid driver from a single isolated supply. An easy method of accomplishing this is to create the common potential using a resistor and a zener diode. In order to size the resistor for minimum loss, we must first determine the current flowing in the common connection (ICOM). A circuit diagram showing how the hybrid drivers can be used with a single supply is shown on Figure 15 and a complete schematic is shown on each driver’s datasheet. The power computed using Equation 8 includes the dissipation in the external gate resistor (R G). This loss is outside the hybrid driver and can be subtracted from the result of Equation 8. The dissipation in R G is difficult to estimate because it depends on drive circuit parasitic inductance, IGBT module type and the hybrid driver’s switching speed. In most applications, the loss in RG can be ignored. Direct use of Equation 8 will result in a conservative design with the included loss of RG acting as a safety margin. When operating large modules at high frequencies, the limitations on ambient temperature may be significant. Additional derating information for other hybrid gate drives can be found on the individual detailed datasheets. 8.0 Operational Waveforms Figure 17 is a typical waveform showing the gate-to-emitter voltage during a slow shutdown in the VLA500-01 driver. Approximately 2.8µs after the detect input pin (Pin 1) voltage exceeds VSC, the gate-to-emitter voltage is slowly brought to zero in about 6µs. This slow shutdown is very effective in protecting IGBT modules having a minimum short circuit withstand time of 10µs which includes the entire A- and NF-series IGBT module line-up. Figure 18 shows the collector-emitter voltage (VCE) and collector current (IC) for an IGBT module during a short circuit. This waveform shows the effectiveness of the slow shutdown in controlling transient voltage. Application Notes Figure 18: Slow Shutdown During Short Circuit Figure 17: Fall Time Characteristics 8.1 Driving Large IGBT Modules In order to achieve efficient and reliable operation of high current, high voltage IGBT modules, a gate driver with high pulse current capability and low output impedance is required. Powerex hybrid gate drivers are designed to perform this function as stand-alone units in most applications. The VLA552-01R gate drive IC can provide ±24A peak gate drive current, making it capable of driving the highest current IGBT modules available [ 2500A/1200V (CM2500DY-24S) and 1800A/1700V (CM1800DY-34S) new Mega Power Dual modules]. An example of this is shown in Figure 18. Figure 18: VLA553-01R/02R Mounted to New MPD Module Publication Date: 02-5-2016 Rev. 1 11 9.0 Application Examples Fully isolated gate drive circuits can be easily designed by combining hybrid gate drive circuits with hybrid DC-to-DC converter modules. Combining these circuits typically involves designing a printed circuit board with appropriate shielding and support components. Figures 19 and 20 show examples of prototype circuit boards that demonstrate how a fully isolated gate driver can be implemented with hybrid circuits. The following sections describe examples of fully isolated gate drive. 9.1 Figure 20: BG2G Fully Isolated Prototype Gate Drive for Dual IGBT Modules The Powerex BG1B, BG2A, BG2B, BG2C, BG2E and BG2G driver boards are prototypes of fully isolated gate drive circuits designed to drive IGBT modules. The BG2G is made specifically for mounting directly to the NX-series dual IGBT modules. The BG2A and BG2G are shown in Figures 19 and 20 respectively. Table 4 gives a complete listing of available prototype boards and the other accessory products that are used in each. Table 4: Prototype Boards Prototype Board Suffix Gate Driver Part No. Peak Drive Current (IOP) Minimum RG Desat. Detection Typical Application* (IGBT Module Rating) BG1B -3015 VLA541-01R +/- 3A 3.0 Ω Yes Up to 200A BG1B -5015 VLA542-01R +/- 5A 2.0 Ω Yes Up to 600A BG2B -1515 M57159L-01 +/- 1.5A 4.2 Ω Yes Up to 100A BG2B -3015 VLA541-01R +/- 3A 3.0 Ω Yes Up to 200A BG2B -5015 VLA542-01R +/- 5A 2.0 Ω Yes Up to 600A Recommended DC/DC Converter VLA106-15242 For 15VDC Input VLA106-24242 For 24VDC Input BG2C -5015 VLA513-01R +/- 5A 2.0 Ω Yes Up to 600A BG2G -8015 VLA567-01R +/- 8A 2.0 Ω Yes Up to 1000A Included in Gate Driver BG2A -NF VLA500-01 +/- 12A 1.0 Ω Yes Up to 1400A Included in Gate Driver BG2A -K VLA500K-01R +/- 12A 1.0 Ω Yes Up to 1000A – 1700V Included in Gate Driver BG2A -NFH VLA502-01 +/- 12A 1.0 Ω Yes Up to 600A – NFH Series Included in Gate Driver Up to 1000A – BG2E -NXL VLA500-01 +/- 12A 1.0 Ω Yes Included in Gate Driver 1200V, NXL Series Up to 600A – BG2E -NXLK VLA500K-01R +/- 12A 1.0 Ω Yes Included in Gate Driver 1700V, NXL series *Compatible IGBT module depends on voltage rating, switching frequency and selected RG. Refer to Powerex application note for details. The BG2C incorporates the VLA513-01 high-speed gate driver. The VLA513-01 has +/-5A output current capability and is also capable of switching high frequency NFH-series modules. The VLA513-01 is capable of driving standard speed 600V and 1200V modules up to 600A and 400A respectively and high frequency NFH-series modules at 60kHz switching up to 200A or at 30kHz switching up to 400A. Control on/off signals are optically isolated using the hybrid gate driver’s built-in opto-coupler. Opto-couplers are also provided to isolate the fault feedback signal. All isolation is designed for a minimum 2500VRMS between the input and output. Full schematics for the gate drive boards are given on the board’s application note. 9.2 Plug & Play Gate Drivers for NX Dual and New Mega Power Dual Modules In contrast to the prototype driver boards discussed in the previous section, the plug & play drivers, VLA536-01R and VLA552-01R/-02R, are fully populated minus the gate resistor. PC boards intended for mass production use. They are made to mount directly to the top surface of an IGBT module and mate with the gate drive pins. The gate resistor is the only component purposely not included on the boards, allowing the user to adjust the gate drive speed as needed. All of the plug & play drivers offer desat detection as outlined in section 5.1. The VLA553-01R is made specifically for the 1200V New Mega Power Dual Module, while the VLA553-02R is made specifically for the 1700V New Mega Publication Date: 02-5-2016 Rev. 1 12 Application Notes Figure 19: BG2A Power Dual Module. In addition, the VLA553-01R/-02R drivers offer active clamping as described in section 6. The active clamping, which is provided by the on-board VLA552-01R ICs and a string of zener diodes, are used to set the clamping voltage. The main difference between the VLA553-01R and VLA553-02R is that the former has a typical zener clamp voltage of 950V, as intended for 1200V IGBT modules and the latter has a typical zener clamp voltage of 1350V, as intended for 1700V IGBT modules. The VLA555-01R/02R is equivalent to the VLA553-01R/02R except with a fiber optic interface. The VLA536-01R, shown in Figure 21 is made for mounting directly to NX dual modules and provides a gate drive current of ±5A, which is sufficient for driving all S, S1 and T series dual NX size modules in the 62mm x 122mm package. 9.2.1 Fiber Optic Input Plug & Play Gate Drivers for New Mega Power Dual Modules The VLA555 is essentially a version of the VLA553, which takes in optical control signals, rather than 5V logic, to trigger the IGBT gate driver. Once again, there are two versions. The VLA555-01R and the VLA555-02R, which have zener diodes set up for active clamping on 1200V and 1700V modules respectively. 9.2.2 Gate Resistor Slots on the VLA553 and VLA555 Driver Boards The VLA553 and VLA555 gate drive boards have four component slots for each gate drive channel. These are designed to allow a combination of turn-on and turn-off gate resistor values via customer specific Schottky barrier diodes and resistors. 10.0 Related Application Notes Table 5 lists additional application notes relevant to IGBT module accessories including gate drivers and development boards. Clicking on the application note name will bring up the associated pdf document. The datasheets for the specific gate drivers include more information such as product specifications and application circuit examples. Table 5 Additional Reading Application Note Product Type IGBT Module Application VLA500 Gate Driver IC 600V Module up to 600A 1200V Module up to 1400A VLA502 Gate Driver IC High Frequency NFH series 600V and 1200V Modules BG1B Single Channel Gate Drive Development Board EXS Series 600V up to 600A EXS Series 1200V up to 400A BG2A Dual Channel Gate Drive Development Board 600V Module up to 600A 1200V Module up to 1400A 1700V Module up to 1000A BG2B Dual Channel Gate Drive Development Board 600V Module up to 600A 1200V Module up to 400A BG2C Dual Channel Gate Drive Development Board 600V Module up to 600A 1200V Module up to 400A And High Frequency NFH series 60kHz switching up to 200A 30kHz switching up to 400A BG2G Dual Channel Gate Drive Development Board 600V up to 1000A 1200V up to 1000A Publication Date: 02-5-2016 Rev. 1 13 Application Notes Figure 21: VLA536-01R