UCC2801: UCC2801

nader niakan90

Intellectual 470 points

Part Number: UCC2801
Other Parts Discussed in Thread: UC3842, UCC2803

I need help to build a test circuit for UCC2801. Thanks

over 4 years ago

0 Teng Feng over 4 years ago

TI__Genius 13660 points

Hi Nader,

do you need a open loop test with the maximum duty operation?

Thanks.

0 nader niakan90 over 4 years ago in reply to Teng Feng

Intellectual 470 points

I would prefer FB operation with maximum duty cycle. Thanks

0 nader niakan90 over 4 years ago in reply to nader niakan90

Intellectual 470 points

Hi Teng,

Any update ? I appreciate it.

0 Teng Feng over 4 years ago in reply to nader niakan90

TI__Genius 13660 points

Hi Nader,

UCC2801 is single end PWM control.

I recommend you to use dual end PWM control UCC2808.

Below is an example to force UCC2808 to work at maximum duty cycle for FB or Push-pull.

Regards,

Teng

0 nader niakan90 over 4 years ago in reply to Teng Feng

Intellectual 470 points

Hi Teng,

Thank you for the circuit, however I need to use UCC2801. This is an existing design and I can not replace UCC2801 with UCC2808. What do you think about the following test circuit. Although the circuit is designed for UC3842, I still think it should work for UCC2801 as well, What is your take on this circuit ? Thanks

0 Teng Feng over 4 years ago in reply to nader niakan90

TI__Genius 13660 points

Hi Nader,

there is only one DPWM output (Pin6) in UC3842, how it controls FB?

Teng

0 nader niakan90 over 4 years ago in reply to Teng Feng

Intellectual 470 points

Hi Teng,

I do see, neither in UCC2801 nor in UC3842, any output controlling FB. Looks like FB is controlled by 1/2 of VREF, through the COMP op-amp. Even in our application, FB is connected to a constant voltage and also connected to COMP through a feedback resistor. Am I missing something ? Please advise. Thanks

0 Teng Feng over 4 years ago in reply to nader niakan90

TI__Genius 13660 points

Hi Nader,

Could you show a circuit for your description? Thanks.

0 nader niakan90 over 4 years ago in reply to Teng Feng

Intellectual 470 points

Hi Feng,

I believe the test circuit for UC3842 can be used for UCC2801 and UCC2803.

+1 Teng Feng over 4 years ago in reply to nader niakan90

TI__Genius 13660 points

Hi Nader,

Yes, you are right, UCC2801 has the same pin configuration with UC3842,

UCC2801 can work at open loop and maximum duty cycle, with above circuit.

Thanks.

Power management

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UCC2801: UCC2801