MS1003SH･MS1004SH

Application Note Ver.2.2

SHINDENGEN ELECTRIC MFG. CO. , LTD

17/41

4. Pin functions

4.1 Z/C pin

The Z/C pin detects the NC coil voltage and outputs a turn-on signal. The pin has the following functions:

1) Gate on-trigger

2) Prevention of false turn-on (Tondead)

3) Trough skip

4.2 F/B pin

The F/B pin determines the ON range during constant voltage control. The pin has the following functions:

1) Determination of ON range for the F/B pin voltage (gate off-trigger)

2) Timer latch protection during no control or drooping

4.3 GND pin

The GND pin is used as the ground reference of the IC.

4.4 OCL pin

The OCL pin uses a detection resistor to limit the primary current. The pin has the following functions:

1) Determination of the maximum primary current peak (pulse-by-pulse)

2) Determination of the primary current peak during the four-step soft start

3) Determination of the primary current peak during the AutoStby

4) Leading edge blank function

4.5 VG pin

The VG pin outputs a gate voltage and has the following functions:

1) Output of gate signal

2) Soft drive

4.6 Vcc pin

The Vcc pin is the IC power terminal and has the following functions:

1) UVLO

2) OVP latch

3) Vcc assist

4) ON/OFF of the startup circuit

5) Unlatching

6) Vcc-GND short circuit protection

7) Indirect control in super standby mode

4.7 Vin pin

The Vin pin is connected to the positive side of the input capacitor and is used to power on the IC.