SKHI 23/12 Absolute Maximum Ratings Ta = 25 °C, unless otherwise specified Symbol Conditions VS ViH IoutPEAK IoutAV VCE SEMIDRIVERTM dv/dt Visol IO Supply voltage primary Input signal voltage (HIGH) (for 15 V and 5 V input level) Output peak current Output average current Collector emitter voltage sense Rate of rise and fall of voltage (secondary to primary side) Isolation test volt. IN-OUT (2 sec. AC) minimal RGon minimal RGoff charge per pulse Operating temperature Storage temperature Values Units 18 V VS + 0,3 V ±8 ± 50 1200 A mA V 75 kV/µs 2500 V 2,7 2,7 4,8 - 25 ... + 85 - 25 ... + 85 Ω Ω µC °C °C SKHI 23/12 RGon min RGoff min Qout/pulse Top Tstg Features Characteristics • SKHI 23/12 drives all SEMIKRON IGBTs with VCES up to 1200 V (VCE-monitoring adjusted from factory for 1200 V-IGBT) • Double driver circuit for medium power IGBTs, also as two independent single drivers • CMOS / TTL (HCMOS) compatible input buffers • Short circuit protection by VCE monitoring • Soft short circuit turn-off • Isolation due to transformers (no opto couplers) • Supply undervoltage monitoring (< 13 V) • Error memory / ouput signal (LOW or HIGH logic) • Driver interlock top / bottom • Internal isolated power supply Symbol Conditions min. typ. max. Units VS IS ISO2) ViT+ 14,4 15,0 0,321) 0,12 15,6 VG(on) VG(off) Supply voltage primary Supply current (max.) Supply current primary side (standby) Input threshold voltage (HIGH) min. 15 V input level for 5 V input level Input threshold voltage (LOW) max. for 15 V input level for 5 V input level Turn-on output gate voltage Turn-off output gate voltage f Maximum operating frequency td(on)IO td(off)IO td(err) tTD VCEstat RGon RGoff Cps Input-output turn-on propagation time Input-output turn-off propagation time Error input-output propagation time Dead time Reference voltage for V CE monitoring Internal gate resistor for ON signal Internal gate resistor for OFF signal Primary to secondary capacitance Medium Power Double IGBT Driver ViT- Ta = 25 °C, unless otherwise specified 12,5 2,4 V A A V V 3,6 0,50 + 15 -8 see fig. 15 1,4 1,4 1,03) 106) 5,25) 224) 224) 12 V V V V µs µs µs µs V Ω Ω pF Typical Applications • • • • High frequency SMPS Half and Full bridges Three phase motor inverters High power UPS 1) This current value is a function of the output load condition 2) Operating fsw = 0 Hz 3) This value does not consider ton of IGBT and tMIN adjusted by RCE and CCE ; see also fig. 14 4) Matched to be used with IGBTs < 100 A; for higher currents, see table 4 5) With R CE = 18 kΩ, CCE = 330 pF; see fig. 6 6) Factory adjusted; other values see table 3 2 Driver Electronic – PCB mountable 31-10-2005 © by SEMIKRON SKHI 23/17 ... Absolute Maximum Ratings Ta = 25 °C, unless otherwise specified Symbol Conditions VS ViH IoutPEAK IoutAV VCE SEMIDRIVERTM dv/dt Visol IO Supply voltage primary Input signal voltage (HIGH) (for 15 V and 5 V input level) Output peak current Output average current Collector emitter voltage sense Rate of rise and fall of voltage (secondary to primary side) Isolation test volt. IN-OUT (2 sec. AC) minimal RGon minimal RGoff charge per pulse Operating temperature Storage temperature Values Units 18 V VS + 0,3 V ±8 ± 50 1700 A mA V 75 kV/µs 4000 V 2,7 2,7 4,8 - 25 ... + 85 - 25 ... + 85 Ω Ω µC °C °C SKHI 23/17 RGon min RGoff min Qout/pulse Top Tstg Features Characteristics • SKHI 23/17 drives all SEMIKRON IGBTs with VCES up to 1700 V (VCE-monitoring adjusted from factory for 1700 V-IGBT) • Double driver circuit for medium power IGBTs, also as two independent single drivers • CMOS / TTL (HCMOS) compatible input buffers • Short circuit protection by VCE monitoring • Soft short circuit turn-off • Isolation due to transformers (no opto couplers) • Supply undervoltage monitoring (< 13 V) • Error memory / ouput signal (LOW or HIGH logic) • Driver interlock top / bottom • Internal isolated power supply Symbol Conditions min. typ. max. Units VS IS ISO2) ViT+ 14,4 15,0 0,321) 0,12 15,6 VG(on) VG(off) Supply voltage primary Supply current (max.) Supply current primary side (standby) Input threshold voltage (HIGH) min. 15 V input level for 5 V input level Input threshold voltage (LOW) max. for 15 V input level for 5 V input level Turn-on output gate voltage Turn-off output gate voltage f Maximum operating frequency td(on)IO td(off)IO td(err) tTD VCEstat RGon RGoff Cps Input-output turn-on propagation time Input-output turn-off propagation time Error input-output propagation time Dead time Reference voltage for V CE monitoring Internal gate resistor for ON signal Internal gate resistor for OFF signal Primary to secondary capacitance Medium Power Double IGBT Driver ViT- Ta = 25 °C, unless otherwise specified 12,5 2,4 V A A V V 3,6 0,50 + 15 -8 see fig. 15 1,4 1,4 1,03) 106) 6,35) 224) 224) 12 V V V V µs µs µs µs V Ω Ω pF Typical Applications • • • • High frequency SMPS Half and Full bridges Three phase motor inverters High power UPS 1) This current value is a function of the output load condition 2) Operating fsw = 0 Hz 3) This value does not consider ton of IGBT and tMIN adjusted by RCE and CCE ; see also fig. 14 4) Matched to be used with IGBTs < 100 A; for higher currents, see table 4 5) With R CE = 36 kΩ, CCE = 470 pF; see fig. 6 6) Factory adjusted; other values see table 3 2 Driver Electronic – PCB mountable 31-10-2005 © by SEMIKRON Block diagramm SKHI 23 Fig. 1 The numbers refer to the description on page B14 – 45, section B. Fig. 2 Dimensions (in mm) and connections of the SKHI 23 1948 Driver Electronic – PCB Drivers 19-08-2003 © by SEMIKRON SEMIDRIVERTM SKHI 23/12 SEMIDRIVERTM SKHI 23/17 Medium Power Double IGBT Driver Overview The new intelligent double IGBT driver, SKHI 23 respectively SKHI 23/17 is a standard driver for all power IGBTs in the market. SKHI 23/12 drives all IGBTs with VCE up to 1200 V. SKHI 23/17 drives all IGBTs with VCE up to 1700 V. To protect the driver against moisture and dust it is coated with varnish. The adaption of the drivers to the application has been improved by using pins to changing several parameters and functions. The connections to the IGBTs can be made by using only one MOLEX connector with 12 pins or by using 2 separate connectors with 5 pins for each IGBT. The high power outputs capability was designed to switch high current double or single modules (or paralleled IGBTs). The output buffers have been improved to make it possible to switch up to 200 A IGBT modules at frequencies up to 20 kHz. A new function has been added to the short circuit protection circuitry (Soft Turn Off), this automatically increases the IGBT turn off time and hence reduces the DC voltage overshoot enabling the use of higher DC-bus voltages. This means an increase in the final output power. Integrated DC/DC converters with high galvanic isolation (4 kV) ensures that the user is protected from the high voltage (secondary side). The power supply for the driver may be the same as used in the control board (0/+15 V) without the requirement of isolation. All information that is transmitted between input and output uses ferrite transformers, resulting in high dv/ dt immunity (75 kV/µs). The driver input stages are connected directly to the control board output and due to different control board operating voltages, the input circuit includes a user voltage level selector (+15 V or +5 V). In the following only the designation SKHI 23 is used. This is valid for both driver versions. Any unique features will be marked as SKHI 23/12 (VCE = 1200 V) or SKHI 23/17 (VCE = 1700 V) respectively. A. Features and Configuration of the Driver a) A short description is given below. For detailed information, please refer to section B. The following is valid for both channels (TOP and BOTTOM) unless specified. b) The SKHI 23 has an INPUT LEVEL SELECTOR circuit for two different levels. It is preset for CMOS (15 V) level, but can be changed by the user to HCMOS (5 V) level by solder bridging between pins J1 and K1. For long input cables, we do not recommend © by SEMIKRON 19-08-2003 the 5 V level due to possible disturbances emitted by the power side. c) An INTERLOCK circuit prevents the two IGBTs of the half bridge to switch-on at the same time, and a “deadtime” can be adjusted by putting additional resistors between pins J3 and K3 (RTD1) and pins J4 and K4 (RTD2). Therefore it will be possible to reduce the deadtimet tTD (see also table 3). The interlocking may also be inhibit by solder bridging between pins J5 and K5 to obtain two independent drivers. d) The ERROR MEMORY blocks the transmission of all turn-on signals to the IGBT if either a short circuit or malfunction of Vs is detected, a signal is sent to the external control board through an open collector transistor. It is preset to “high-logic” but can be set to “low-logic” (ERROR). e) The Vs MONITOR ensures that Vs actual is not below 13 V. f) With a FERRITE TRANSFORMER the information between primary and secondary may flow in both directions and high levels of dv/dt and isolation are obtained. g) A high frequency DC/DC CONVERTER avoids the requirement of external isolated power supplies to obtain the necessary gate voltage. An isolated ferrite transformer in half-bridge configuration supplies the necessary power to the gate of the IGBT. With this feature, we can use the same power supply used in the external control circuit, even if we are using more than one SKHI 23, e.g. in three-phase configurations. h) Short circuit protection is provided by measuring the collector-emitter voltage with a VCE MONITORING circuit. An additional circuit detects the short circuit after a delay (adjusted with RCE (this value can only be reduced) and CCE (this value can only be increased) and decreases the turn off speed (adjusted by Rgoff-SC) of the IGBT. SOFT TURN-OFF under fault conditions is necessary as it reduces the voltage overshoot and allows for a faster turn off during normal operation. i) The OUTPUT BUFFER is responsible for providing the correct current to the gate of the IGBT. If these signals do not have sufficient power, the IGBT will not switch properly, and additional losses or even the destruction of the IGBT may occur. According to the application (switching frequency and gate charge of the IGBT) the equivalent value of Rgon and the Rgoff must be matched to the optimum value. This can be done by putting additional parallel resistors Rgon, Rgoff with those already on the board. If only one IGBT is to be used, (instead of paralleled IGBTs) only one cable could be connected between driver and gate by solder bridging between the pins J12 and K12 (TOP) as well as between J19 and K19 (Bottom). j) Fig. 1 shows a simplified block diagram of the SKHI 23 driver. Some preliminary remarks will help the understanding: Driver Electronic – PCB Drivers 1949 • Stabilised +15 V must be present between pins X1.8,9 (Vs) and X1.10,11 (⊥); an input signal (ON or OFF command to the IGBTs) from the control system is supplied to pins X1.2 and X1.4 (Vin) where HIGH=ON and LOW=OFF. The pin X1.1 can be used as a shield for the input signals. • Pin X2.5 on TOP (and X3.5 on BOT) at secondary side is normally connected to the collector of the IGBTs to monitor VCE, but for initial tests without connecting the IGBT it must be connected to pin X2.1 on TOP (and X3.1 on BOT) to avoid ERROR signal and enable the output signals to be measured. • The RESET is performed when both input Vin signals are zero (TOP = BOT = LOW). The following overview is showing the input treshold voltages VIT+ (High) min typ max 15 V 9,5 V 11,0 V 12,5 V 5V 1,8 V 2,0 V 2,4 V VIT- (Low) min typ max 15 V 3,6 V 4,2 V 4,8 V 5V 1,8 V 0,65 V 0,8 V • To monitor the ERROR signal in “high-logic”, a pull-up resistor must be provided between pin X1.3 and Vs. • Table 1 (see page B 14–46) shows the factory adjustment and the different possible adjustments of the pins. B. Description of the Circuit Block Diagram (Fig. 1) The circuit in Fig. 1 shows the input on the left and output on the right (primary/secondary). Fig. 4a Connecting the SKHI 23 with short cables 1. Input level circuit This circuit was designed to accept two different CMOS logic voltage levels. The standard level is +15 V (factory adjusted) intended for noisy environments or when long connections (I > 50 cm) between the external control circuit and SKHI 23 are used, where noise immunity must be considerate. For lower power, and short connections between control and driver, the TTL-HCMOS level (+5 V) can be selected by solder bridging between J1 and K1, specially useful for signals coming from uP based controllers. Fig. 4b Connecting the SKHI 23 with long cables 2. Input buffer This circuit enables and improves the input signal Vin to be transferred to the pulse transformer and also prevents spurious signals being transmitted to the secondary side. Fig.3 Selecting J1, K1 for 5 V level (TTL-HCMOS) 3. Error memory and RESET signal When connecting the SKHI 23 to a control board using short connections no special attention needs to be taken (Fig. 4a). The ERROR memory is triggered only by following events: Otherwise, if the length is 50 cm or more (we suggest to limit the cable length to about 1 meter), some care must be taken. The TTL level should be avoided and CMOS/ 15 V is to be used instead; flat cable must have the pairs of conductors twisted or be shielded to reduce EMI/RFI susceptibility (Fig. 4b). If a shielded cable is used, it can be connected to pinX1.1 and coupled to 0 V through a capacitor, resistor or by solder bridging between pins J20 and K20. As the input impedance of the INPUT LEVEL SELECTOR circuit is very high, an internal pull-down resistor keeps the IGBT in OFF state in case the Vin connection is interrupted or left non connected. 1950 Driver Electronic – PCB Drivers • • short circuit of IGBTs Vs-undervoltage In case of short circuit, the VCE monitor sends a trigger signal (fault signal) through the pulse transformer to a FLIP-FLOP on the primary side giving the information to an open-collector transistor (pin X1.3), which may be connected to the external control circuit as ERROR message in “high-logic” (or “low-logic” if pins J2 and K2 are bridged). If Vs power supply falls below 13 V for more than 0,5 ms, the FLIP-FLOP is set and pin X1.3 is activated. For “high-logic” (factory preset), an external RC must be connected, preferably in the control main board. In this way the connection between main board and driver is also monitored. 19-08-2003 © by SEMIKRON Function pin description input level selector J1 / K1 adjustment by factory possibilities of functions not bridged soldering bridged ⇒5V HCMOS soldering bridged ⇒LOW-aktiv adjustment according table 3 soldering bridged ⇒no interlock adjustment according tab. 4a/b ⇒15V CMOS error - logic J2 / K2 not bridged ⇒HIGH-aktiv interlock time interlock of TOP and BOTTOM RCE TOP J3 / K3 (TOP RTD1) J4 / K4 (BOT RTD2) J5 / K5 CCE TOP Rgon TOP Rgoff TOP J6 / K6 ⇒ J7 / K7 RCE= 36 kΩ SKHI 23/17 not equiped ⇒ ⇒ J8 / K8 CCE= 330 pF SKHI 23/12 not equiped CCE= 470 pF SKHI 23/17 not equiped ⇒ ⇒ J9 / K9 Rgon= 22 Ω SKHI 23/12 not equiped Rgon= 22 Ω SKHI 23/17 not equiped ⇒ ⇒ J11 / K11 TOP: one IGBT/ paralleled IGBTs RCE BOT J12 / K12 J13 / K13 Rgoff= 22 Ω Rgoff= 22 Ω equiped with IRgoff= 0 Ω equiped with ⇒RgoffSC= 22 Ω not bridged ⇒2 cables to gates SKHI 23/12 SKHI 23/17 not equiped not equiped ⇒ ⇒ J14 / K14 RCE= 18 kΩ SKHI 23/12 not equiped RCE= 36 kΩ SKHI 23/17 not equiped ⇒ ⇒ J15 / K15 CCE= 330 pF SKHI 23/12 not equiped CCE= 470 pF SKHI 23/17 not equiped ⇒ ⇒ J16 / K16 Rgon= 22 Ω SKHI 23/12 not equiped Rgon= 22 Ω SKHI 23/17 not equiped ⇒ ⇒ IRgoff BOT J17 / K17 RgoffSC BOT J18 / K18 BOT: one IGBT/ paralleled IGBTs shield J19 / K19 © by SEMIKRON 19-08-2003 SKHI 23/17 not equiped ⇒ RgoffSC TOP Rgoff BOT SKHI 23/12 not equiped RCE= 18 kΩ SKHI 23/12 not equiped J10 / K10 Rgon BOT not bridged ⇒interlock activ IRgoff TOP CCE BOT not equiped ⇒max. tTD = 10 µs J20 / K20 Rgoff= 22 Ω Rgoff= 22 Ω equiped with IRgoff= 0 Ω equiped with ⇒RgoffSC= 22 Ω not bridged ⇒2 cables to gates not bridged ⇒no screening adjustment according tab. 4a/b adjustment according tab. 4a/b adjustment according tab. 4a/b adjustment according tab. 4a/b soldering bridged ⇒1 cable to gate adjustment according tab. 4a/b adjustment according tab. 4a/b adjustment according tab. 4a/b adjustment according tab. 4a/b adjustment according tab. 4a/b soldering bridged ⇒1 cable to gate soldering bridged ⇒screening to GND Driver Electronic – PCB Drivers 1951 7. Output buffer Fig. 5 Driver status information ERROR, and RESET If “low-logic” version ERROR is used (pins J2 and K2 are bridged), an internal pull-up resistor (internally connected to VS) is provided, and the ERROR signal from more SKHI23s can be connected together to perform an wired-or-circuit. The ERROR signal may be disabled either by delivering zero to both signal inputs (RESET = active = Vin-TOP = Vin-BOT = 0) or by switching the power supply (VS) off. The “RESET” signal width must be more than 5 µs long (see Fig. 5). 1) FAULT RESET ERROR1) switching on of IGBT no no active 0 possible no active 0 not possible yes no active 1 not possible yes active 0 not possible default logic (HIGH); for LOW logic the signals are complementary Table 2 ERROR signal truth table The open-collector transistor (pin X1.3) may be connected through a pull-up resistor to an extemal (internal VS for the “low-logic” version) voltage supply +5 V...+24 V, limiting the current to lsink 6 mA. 4. Power supply (Vs) monitor The supply voltage VS is monitored. If it falls below 13 V an ERROR signal is generated and the turn-on pulses for the IGBTs gate are blocked. 5. Pulse transformer It transmits the turn-on and turn-off signals to the driver’s secondary side. In the reverse direction the ERROR signal from the VCE monitoring is transmitted via the same transformer. The isolation is 4 kVAC. The output buffer is supplied by the +15V/- 8V from the DC/DC converter and amplifies the control signal received from the pulse transformer. If the operation proceeds normally (no fault), the signal is transmitted to the gate of an IGBT through Rgon and Rgoff. The output stage has a MOSFET pair which is able to source/sink up to 8 A peak current to/from the gate improving the turn-on/off time of the IGBT. Additionally, we can select IRgoff (see Fig. 2) either to discharge the gate capacitance with a voltage source (standard) or with a current source, specially design for the 1700 V IGBT series (it speeds up the turn-off time of the IGBT). The present factory setting is voltage source (IRgoff = 0Ω). and to change to current source IRgoff, must be adjusted, while Rgoff = 0. 8. Soft turn-off In case of short-circuit, a further circuit (SOFT TURN-OFF) increases the resistance in series with Rgoff and turns-off the IGBT at a lower speed. This produces a smaller voltage spike (due LSTRAY ’ di/dt) above the DC link by reducing the di/dt value. Because in short-circuit conditions the Homogeneous IGBT’s peak current increases up to 8 times the nominal current (up to 10 times with Epitaxial IGBT structures), and some stray inductance is ever present in power circuits, it must fall to zero in a longer time than at normal operation. This “soft turn-off time” can be reduced by connecting a parallel resistor Rgoff-SC (see Fig. 2) with those already on the printed circuit board. 9. VCE monitoring This circuit is responsible for short-circuit sensing. Due to the direct measurement of VCEstat on the IGBT’s collector, it blocks the output buffer (through the soft turn-off circuit) in case of short-circuit and sends a signal to the ERROR memory on the primary side. The recognition of which VCE level must be considered as a short circuit event, is adjusted by RCE and CCE (see Fig. 2), and it depends of the IGBT used. For the drivers SKHI23/12 typical values RCE =18 kΩ and CCE =330 pF for SKHI 10 are delivered from factory (Fig. 6, curve 2). Using SKHI 10/17 the driver will be delivered with RCE = 36 kΩ and CCE = 470 pF from factory. The VCEref is not static but a dynamic reference which has an exponential shape starting at about 15 V and decreases to VCEstat (determinated by RCE), with a time constant τ (controlled by CCE). 6. DC/DC converter In the primary side of the converter, a half-bridge inverter transfers the necessary energy from VS to the secondary of a ferrite transformer. In the secondary side, a full bridge and filters convert the high frequency signal coming from the primary to DC levels (+15V/- 8V) that are stabilised by a voltage regulator circuit. 1952 Driver Electronic – PCB Drivers Fig. 6 VCEref waveform with parameters RCE, CCE 19-08-2003 © by SEMIKRON Adjustements for SKHI 23/12 Fig. 7a VCEstat as function of RCE Fig. 7b tmin as function of RCE and CCE Adjustements for SKHI 23/17 Fig. 7c VCEstat as function of RCE Fig. 7d tmin as function of RCE and CCE The VCEstat must be adjusted to remain above VCEsat in normal operation (the IGBT is already in full saturation). resistance is difficult to predict, because it depends on many parameters, as follows: To avoid a false failure indication when the IGBT just starts to conduct (VCEsat value is still too high) some decay time must be provided for the VCEref. As the VCE signal is internally limited at 10 V, the decay time of VCEref must reach this level after VCE or a failure indication will occur (see Fig.6, curve 1). A tmin is defined as function of VCEstat and τ to find out the best choice for RCE and VCE (see Fig.6, curve 2). The time the IGBT come to the 10 V (represented by a “” in Fig. 6) depends on the IGBT itself and Rgon used. The RCE and CCE values can be found from Fig. 7a and 7b for SKHI 23/12 and from Fig. 7c and 7d for SKHI 23/17 by taking the VCEstat and tmin as input values with following remarks: • RCE > 10KΩ • CCE < 2,7nF Attention!: If this function is not used, for example during the experimental phase, the VCE MONITORING must be connected with the EMITTER output to avoid possible fault indication and consequent gate signal blocking. 10. Rgon, Rgoff These two resistors are responsible for the switching speed of each IGBT. As an IGBT has input capacitance (varying during the switching time) which must be charged and discharged, both resistors will dictate what time must be taken to do this. The final value of © by SEMIKRON 19-08-2003 • • • • DC-link voltage stray inductance of the circuit switching frequency type of IGBT The driver is delivered with two Rg resistors (22 Ω) on the board. This value can be reduced to use the driver with bigger modules or higher frequencies, by putting additional resistors in parallel. The outputs Gon and Goff were previewed to connect the driver with more than one IGBT (paralleling). In that case we need both signals ON/OFF separately to connect additional extremal resistors Rgon and Rgoff for each IGBT. If only one IGBT is to be used, we suggest connecting both outputs together by solder bridging between pins J12 and K12 and respectiveley pins J19 and K19 to save on external connection. We also suggest using two restistors for Rgon and two resistors for Rgoff when using low values of resistance, due the high current peak (up to 8 A) which could damage a single resistor. 11. Interlock The interlock circuit prevents the IGBT turning on before the gate charge of the other IGBT is completely discharged. It should be set to delay time longer than the turn-off time of the IGBT. From the factory: tTD = 10 µs. By putting additional resistors onto the pins J3/K3 (RTD TOP) and onto the pins J4/K4 (RTD BOT) the interlock time tTD can be reduced (see table 3). Driver Electronic – PCB Drivers 1953 RTD1 = RTD2 interlock time tTD 10 kΩ 0,9 µs 22 kΩ 1,8 µs 33 kΩ SK-IGBT-Module RGon Ω RGoff Ω CCE pF RCE kW Irgoff Ω SKM 75GB123D 15 15 470 36 0 2,5 µs SKM 100GB123D 12 12 470 36 0 47 kΩ 3,2 µs SKM 150GB123D 10 10 470 36 0 68 kΩ 4,0 µs SKM 200GB123D 8,2 8,2 470 36 0 100 kΩ 5,0 µs 6,8 6,8 470 36 0 7,7 µs SKM 300GB123D 330 kΩ not equiped (adjustement by factory) 10 µs Table 4b 1700V IGBT@ DC-link< 1000V *) Only starting values, for final optimization. The adjustment of RgoffSC (factory adjusted RgoffSC = 22 Ω) should be done observing the overvoltages at the module in case of short circuit. When having a low inductive DC-link the module can be switched off faster. It have to be considered: RTD1 = RTD2 10 kΩ Table 3 adjustement of interlock time The shown values should be considered as standard values for a mechanical/electrical assembly, with acceptable stray inductance level, using only one IGBT per SKHI 23 driver. The final optimised value can be found only by measuring. Fig. 8 Interlock function time diagram C. Operating Procedure 1. One dual IGBT connection To realize the correct switching monitoring of one IGBT-module components must be used (Fig. 9). Fig. 9 Preferred dual IGBT-module standard circuit and short-circuit some additional Typical component values: *) SK-IGBT-Module RGon Ω RGoff Ω CCE pF RCE kW Irgoff Ω SKM 75GB123D 22 22 330 18 0 SKM 100GB123D 15 15 330 18 0 SKM 145GB123D 12 12 330 18 0 SKM 150GB123D 12 12 330 18 0 SKM 200GB123D 10 10 330 18 0 SKM 300GB123D 8,2 8,2 330 18 0 Table 4a 1200V IGBT@ DC-link< 700V 1954 Driver Electronic – PCB Drivers 2. Paralleling IGBTs The parallel connection is recommended only by using IGBTs with homogeneous structure (IGHT), that have a positive temperature coefficient resulting in a perfect current sharing without any external auxiliary element. Care must be considered to reach an optimized circuit and to obtain the total performance of the IGBT (Fig. 10). The IGBTs must have independent values of Rgon and Rgoff, and an auxiliary emitter resistor Re as well as an auxiliary collector resistor Rc must also be used. The external resistors Rgonx, Rgoffx, Rex and Rcx should be mounted on an additional circuit board near the paralleled modules, and the Rgon/Rgoff should be changed to zero ohms. The Rex has a value of 0,5 Ω and its function is to avoid the main current to circulate by the auxiliary ermitter what could make the ermitter voltage against ground unbalanced. 19-08-2003 © by SEMIKRON The Rcx assumes a value of 47 Ω and its function is to create an average of VCEsat in case of short circuit for VCE-monitoring. The mechanical assembly of the power circuit must be symmetrical and low inductive. The maximum recommended gate charge is 4,8 µC. Fig. 12 Output voltage VGE and output current (IG) Fig. 10 Preferred circuit for paralleld dual IGBT-modules D. Signal Waveforms The following signal waveforms were measured under the conditions below: • VS = 15 V Fig.13 Short circuit and ERROR propagation time worste case (VIN with SC already present) • Tamb = 25 °C • load = SKM75GB120D • RCE = 18 kΩ • CCE = 330 pF • UDC = 600 V • IC = 100 A All results are typical values if not otherwise specified. Fig.14 Effect of Rgoff-SC in short - circuit Fig. 11 Input and output voltage propagation time © by SEMIKRON 19-08-2003 Fig. 15 Maximum operating frequency x gate charge Driver Electronic – PCB Drivers 1955 The limit frequency of SKHI 23 depends on the gate charge connected in its output pins. If small IGBT modules are used, the frequency could theoretically reach 100 kHz. For bigger modules or even paralleled modules, the maximum frequency must be determinate (Fig. 15). QG is the total equivalent gate charge connected to the output of the driver. The maximum allowed value is limited (about 4,8 µC). E. Application / Handling 1. The CMOS inputs of the driver are extremely sensitive to overvoltage. Voltages higher than (VS + 0,3 V) or under - 0,3 V may destroy these inputs. Therefore the following safety requirements are to be observed: • To make sure that the control signals do not see overvoltages exceeding the above values. • Protection against static discharges during handling. As long as the hybrid driver is not completely assembled the input terminals must be short circuited. Persons working with CMOS devices should wear a grounded bracelet. Any floor coverings must not be chargeable. For transportation the input terminals must be short circuited using, for example, conductive rubber. Places of work must be grounded. The same safety requirements apply to the IGBTs. 2. The connecting leads between the driver and the power module must be as short as possible, and should be twisted. 3. Any parasitic inductance should be minimized. Overvoltages may be damped by C or RCD snubber networks between the main terminals [3] = C1 (+) and [2] = E2 (-) of the power module. 4. When first operating a newly developed circuit, low collector voltage and load current should be used in the beginning. These values should be increased gradually, observing the turn-off behavior of the free-wheeling diodes and the turn-off voltage spikes across the IGBT by means of an oscilloscope. Also the case temperature of the power module should be monitored. When the circuit works correctly, short circuit tests can be made, starting again with low collector voltage. 5. It is important to feed any ERROR back to the control circuit to switch the equipment off immediately in such events. Repeated turn-on of the IGBT into a short circuit, with a frequency of several kHz, may destroy the device. For further details ask SEMIKRON 1956 Driver Electronic – PCB Drivers 19-08-2003 © by SEMIKRON