MJD44H11 データシートの表示（PDF） - Powerex

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MJD44H11

Gate Driver

Powerex 

Powerex, Inc., 200 E. Hillis Street, Youngwood, Pennsylvania 15697-1800 (724) 925-7272

M57161L-01

Hybrid IC for IGBT Gate Driver

M57161L-01

1. Principle of Operation – RTC Detection and Short-Circuit Protection

Powerex F-Series (trench gate) IGBT modules have a built-in

+

VSC

RTC (Real Time Control) circuit. The purpose of the RTC is to limit

DELAY

COMPARE

short-circuit current and maintain a 10µs short-circuit withstanding

capability. The RTC circuit limits the current by actively reducing the

AND

Shut-Down

gate voltage when excessive collector current is present. The M57161L- Input

01 gate driver uses a gate voltage detection circuit to sense the

GATE

RG

DRIVE

C

F-Series

IGBT

G Module

activation of the RTC circuit inside the F-Series IGBT module. A

simplified schematic of the RTC detector circuit is shown in Figure 1.

+

RTC

E Circuit

This circuit consists of a comparator with its (-) input connected

to the gate of the IGBT module and its (+) input supplied with a fixed

Figure 1 RTC Detector E

reference voltage of VSC. In the normal ON state, the voltage on the

gate of the IGBT is nearly equal to the positive gate drive supply voltage, which exceeds VSC and makes the

comparator output low. In the normal OFF state, the gate voltage is nearly equal to the negative gate drive supply

voltage, which is less than VSC making the comparator output high. If a short circuit occurs, the RTC circuit inside

the F-Series IGBT module will activate and pull the gate voltage down below the VSC reference. This abnormal

presence of a gate voltage less than VSC when the IGBT is supposed to be on indicates

that the module’s RTC has been activated. This condition is identified by a logical AND of

Start

the gate driver’s control input signal and the comparator’s output as shown in Figure 1.

The output of the AND will go high when a short-circuit condition is detected. The output

of the AND is then used to command the IGBT to shut down in order to protect it from the

short circuit. A delay is provided after the comparators output to prevent the circuit from

Is

VGE< VSC NO

indicating a short-circuit condition during the normal transition of gate voltage at turn-on.

YES

2. Operation of the M57161L-01 RTC Detector

The Powerex M57161L-01 hybrid gate drive circuit implements RTC detection as

described above. A flow chart for the logical operation of the short-circuit protection is

shown in Figure 2. When the IGBT module’s RTC is activated the hybrid gate driver

performs a soft shut-down of the IGBT and starts a timed lock-out, ttimer, typically 2.0ms.

The soft turn-off helps to limit the transient voltage that may be generated while

interrupting the 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 lock-out time has expired and the control input signal returns to

its off state.

This protection scheme is superior to conventional desaturation detection because

it avoids the need for a high voltage detection diode, and reduces spacing requirements on

the gate drive printed circuit board. In addition, noise immunity is improved because the

driver is not connected to the high voltage on the IGBT’s collector.

Is Input

Signal ON NO

YES

Delay

Is

VGE< VSC NO

YES

Slow Shut-down

Disable Output

Set Fault Signal

Wait ttimer

3. Adjusting Protection Delay Time

The M57161L-01 has a default short-circuit detection time delay (tTRIP) of

approximately 3.5µs. This will prevent erroneous detection of short-circuit conditions as

long as the series gate resistance (RG) is near the minimum recommended value for the

module being used. The 3.5µs delay is appropriate for most applications so adjustment

will not be necessary. However, in some low frequency applications it may be desirable to

use a larger series gate resistance to slow the switching of the IGBT for reduced noise and

turn-off transient voltages. As the RG is increased, the rise of gate voltage is slowed and in

Is Input

Signal OFF

NO

YES

Clear Fault

Signal

Enable Output

Figure 2 Flow Chart

4

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