PMP21112: Fixed-output version of PMP21112

Joseph Chiu

Part Number: PMP21112

I have a customer requirement for a boost circuit to go from 12Vin to 24Vout at 2.5A *OR* 10A nominal. The customer really wants one design to handle both cases.

It looks like reference design PMP21112 would be great for this - but instead of using PWM to adjust the output voltage, it seems like I could simply get rid of the feedback/PWM network and just use a fixed resistor-divider for the FB signal?

In the PMP2112 reference schematic, TP2 labeled "IN" seems to be just a test point to measure the output voltage? Or am I misunderstanding its purpose?

Thanks!

Joseph

over 5 years ago

0 Ryan Manack over 5 years ago

TI__Intellectual 2610 points

Hi Joseph,

You are correct, you can simply use a fixed resistor divider and remove R11, R12, R13, C16 and C17.

R7 is a 50ohm resistor in series with the feedback divider. This resistor and TP2 allows us to measure the bode plot of the power supply. Here is a great blog with useful references to describe more.

Thanks,

Ryan

0 Joseph Chiu over 5 years ago in reply to Ryan Manack

Prodigy 130 points

Ah, that explains the 50 ohm resistor. So obvious now that you said that!

Thank you very much for your prompt reply! Much appreciated!

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PMP21112: Fixed-output version of PMP21112