TPS566235: TPS566235 error amplifier's detailed function

fred cheng

Part Number: TPS566235

Sorry , the datasheet mention there's a error amplifier for better accuracy,but i have trouble locate it on the schematic below ,

1.What is its detail function ?and how does it work in TPS566235?since there's usually no error amplifier in DCAP 3 mode

2.and last where's its compensation circuit?

over 5 years ago

0 Gerold Dhanabalan - Online Design Tools over 5 years ago

TI__Genius 14455 points

The error amplifier is the opamp shown with connections to 0.6V and FB. The compensation needed for the amplifier is internal.

Regards,

Gerold

0 Yuchang Zhang over 5 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Mastermind 18510 points

Hi, Input more Based on Geold’s Comments, the EA at FB and 0.6 reference works as integrator to cancel the difference between FB and reference caused by ripple which help to get better regulation and internal compensation shown as the ripple injection in the diagram.

Yuchang

0 fred cheng over 5 years ago in reply to Yuchang Zhang

Prodigy 140 points

Thank you both ,

To me ,it's kind of like voltage mode combine Dcap 3 just for higher gain at low frequency and DC , is that right?

and since Dcap3 is originally featured in its DC offset cancel advantage,is that not enough ?

0 Yuchang Zhang over 5 years ago in reply to fred cheng

TI__Mastermind 18510 points

I think you may think it like you mentioned from Frequency domain, and actually the purpose is used to cancel the 1/2 Ripple offset, and adding this function based on Dcap2, which is called Dcap3.

Yuchang

0 fred cheng over 5 years ago in reply to Yuchang Zhang

Prodigy 140 points

I am still confusing one thing ,based on what you said about DCAP3,

so every DCAP3 mode IC always have a error amplifier for DC offset cancellation instead of just one comparator, is that right?

yet based on the dcap3 architecture below , i can't find\ a error amplifier in it

0 Yuchang Zhang over 5 years ago in reply to fred cheng

TI__Mastermind 18510 points

Such like that, the Sample&Hold should be for that fiction, different IC may have different design, for applications side, you may just know Dcap3 has regulations improvement by this function block added.

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TPS566235: TPS566235 error amplifier's detailed function