UCC2895: EAO output

Bob Li

Part Number: UCC2895

when testing, EAO(pin2) and EAN(pin1) are connected directly, if EAP(Pin20) voltage is 5V, but I founded EAO voltage is 1.4V and there was no output voltage.

could you give some advice or comments?

another query is about datasheet Fig 6 Ramp and COMP, RAMP is Pin 3 voltage, am I right?

what is COMP? is it EAO?

Thanks in advance.

over 5 years ago

0 Bliss Zhou over 5 years ago

TI__Expert 3050 points

Hi Bob,
1,I think you can disconnect the power stage and then to debug the UCC2895 circuit. after you fix the it you connect the power stage to testing.
2, ramp is Pin 3。

thanks

0 Bliss Zhou over 5 years ago in reply to Bliss Zhou

TI__Expert 3050 points

Hi Bob,
I haven’t heard back from you, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out) .

0 Bob Li over 5 years ago in reply to Bliss Zhou

Prodigy 130 points

Bliss Zhou said:
Hi Bob,
1,I think you can disconnect the power stage and then to debug the UCC2895 circuit. after you fix the it you connect the power stage to testing.
2, ramp is Pin 3。

thanks

and what is comp pin?

0 Bliss Zhou over 5 years ago in reply to Bob Li

TI__Expert 3050 points

Bob,
you can refer to datasheet UCC2895 www.ti.com/.../ucc2895.pdf.

thanks

0 Bob Li over 5 years ago in reply to Bliss Zhou

Prodigy 130 points

Hi Bliss, the comp pin is EAO(pin2) for the ucc2895 IC. am I right? pls confirm it. thanks.

0 Bliss Zhou over 5 years ago in reply to Bob Li

TI__Expert 3050 points

Bob,

I hope my reply as below can help to you.

PIN2 is the error amplifier output , PIN20 is the Non-inverting input of the error amplifier and PIN1 is inverting input of the error amplifier.If the device UCC2895 is placed primary side, the error amplifier is used as voltage follower.you can refer to UCC2895 reference design http://www.ti.com/lit/ug/sluu109b/sluu109b.pdf ,

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UCC2895: EAO output