UCC2894: Support for external sink circuit

Satoshi

Guru 19645 points

Part Number: UCC2894

Can UCC2894 use on "external sink circuit" to VREF input?

I worry about possibility to increase VREF voltage by external sink.

Is there no problem to VREF connect from external sink circuit?

Best regards,

Satoshi

over 5 years ago

0 John Griffin1 over 5 years ago

TI__Mastermind 34465 points

Hello Satoshi,

I am not sure what your question is.

Are you using the UCC2894 with an external SYNC and seeing an increase in the value of VREF ?

Please attach a schematic and further details.

Regards

John

0 Satoshi over 5 years ago in reply to John Griffin1

Guru 19645 points

John-san

Thank you for reply,

I'm not yet using UCC2894, one customer is considering whether UCC2894 can use external sink current circuit to VREF pin.

I guess that above function increase VREF voltage (on internal VREF voltage) larger than 5V, is it correct?

If correct, is increase VREF voltage no problem?

Best regards,

Satoshi

0 John Griffin1 over 5 years ago in reply to Satoshi

TI__Mastermind 34465 points

Hi Satoshi-san,
It is not possible to do this.
VREF is an output signal and if you try to apply a voltage to it the IC will get damaged.
So the answer is no.
You will damage the IC in this situation.

Regards

John

0 Satoshi over 5 years ago in reply to John Griffin1

Guru 19645 points

John-san

Thank you for reply, I understood.

By the way, is there active cramp PWM controller IC for matched external sink circuit?

Best regards,

Satoshi

0 John Griffin1 over 5 years ago in reply to Satoshi

TI__Mastermind 34465 points

Satoshi-san,

None of the active clamp controllers or the pwm controllers are qualified to sink current into the REF pin.

REF is a fixed voltage output and any attempt to force current into this pin will dame the ic.

Regards

John

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UCC2894: Support for external sink circuit