MS1003SH datasheet(9/41 Pages) SHINDENGEN

9 / 41 page

MS1003SH･MS1004SH

Application Note Ver.2.2

SHINDENGEN ELECTRIC MFG. CO. , LTD

9/41

3.2 Oscillation

3.2.1 On-trigger circuit

As shown to the right, when a negative edge

of the Z/C pin voltage reaches VZ/C (0.25 V),

the gate signal is output, and the main

switching device is turned on.

Current-critical operations are performed by

detecting energy discharge timing with the

control coil voltage before turning on the

main switching device.

To minimize noise, negative edge detection

detects a trigger while the Z/C pin voltage

falls from Hi to Low. The VZ/C voltage

(0.25V) incorporates 50 mV hysteresis for

improved noise resistance.

3.2.2 Quasi-resonance

In a circuit having resonating capacitor Cq between the drain

and the source of the main switching device, as shown to the

right, when the secondary diode current reaches 0 A, damping

begins at the resonance frequency based on the primary

inductance LP of the main transformer and the resonating

capacitor.

Adjusting the time constant of the CR connected to the Z/C

pin as shown on the right allows the main switching device to

be turned on at a trough of the damping voltage waveform,

thereby reducing turn-on losses.

VZ/C

約0.25V

2次整流ダイオード電流

VDS

コントロール巻線電圧

Control coil voltage

Secondary rectification diode current

Approx.

0.25 V

Z/C端子

Vin端子

GND端子

時定数により

ONタイミングを決定

Vin pin

Z/C pin

GND pin

The time constant

determines on-timing.

MS1003SH Datasheet(PDF) 9 Page - Shindengen Electric Mfg.Co.Ltd

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