2010.04 Ver. 1.21 Copyright Grenergy OPTO, Inc. www.grenergy-ic.com

9

GR8836

Over-voltage Protection (OVP) on VCC

To prevent power MOSFET from being damaged,

the GR8836 is implemented an OVP function on

VCC.

When the VCC voltage is higher than the

OVP threshold voltage, the output gate driver circuit

will be shut down immediately to stop the switching

of power MOSFET.

The VCC OVP function is an auto-recovery type

protection. If OVP happens, the pulses will be

stopped and recover at the next UVLO on. The

GR8836 is working in a hiccup mode.

Improve EOS Immunity on VCC Pin

If the auxiliary power supplies the GR8836 is too

high above 20V, to prevent the GR8836 from being

damaged due to over stress of unexpected

environmental energy such as ESD or surge, the

user could add a resistor on VCC pin to improve the

immunity. The value is around few tens of Ohms. A

51 Ohm is recommended.

Gate Clamp

Driver output is clamped by an internal 18V

clamping

circuit

to

prevent

from

undesired

over-voltage gate signals. And under the conditions

listed below, the gate output will turn off immediately

to protect the power circuit.

Fault Protection

There are several critical protections integrated in

the

. CS pin floating

. RT pin floating

. RT pin short to ground

. Secondary rectify diode short protection

. Comp pin floating