TPS54200: TPS54200 PWM Pin frequency

gorden tsai

Prodigy 210 points

Part Number: TPS54200

Hi Sir:

Would U tell me what's of frequency range for PWM pin when working on analog dimming and PWM dimming ?

Thanks

Gorden

over 5 years ago

0 Sean Zhou over 5 years ago

TI__Mastermind 22745 points

Hi Gorden,
When TPS54200/1 works at analog dimming mode, the pwm frequency is suggested between 10kHz to 50kHz, when works at PWM dimming mode, it suggested between 0 to 1kHz.
Best Regards
Sean

0 gorden tsai over 5 years ago in reply to Sean Zhou

Prodigy 210 points

Hi Sean:

Our application is for IRLED analog dimming,As attached waveform,

When power up the TPS54200 have output and working in analog dimming

If do fast power cycle one times which TPS54200 without output ,

If wait 24V input discharge complete then power up that TPS54200 working normally .

How I fixed power faster cycle issue ? any recommendation

Thanks

Gorden

0 Sean Zhou over 5 years ago in reply to gorden tsai

TI__Mastermind 22745 points

Hi Gorden,
I'm not clear about your description, could you explain when you give detail explain about" If do fast power cycle one times which TPS54200 without output , If wait 24V input discharge complete then power up that TPS54200 working normally ." Thanks.
Regards
Sean

0 gorden tsai over 5 years ago in reply to Sean Zhou

Prodigy 210 points

HI Sean:

Sorry ,let U confuse .

I explain with waveform as attached .Hope this can help understood my issue.

Thanks

Gorden

0 Sean Zhou over 5 years ago in reply to gorden tsai

TI__Mastermind 22745 points

Hi Gorden,
Yesm understand, what's the minimum voltage when you discharge the input voltage, the minimum input voltage ofr TPS54200 is 4.5V, if the input voltage drop below 4.5V, the internal reference and logic will reset. I'm affraid this my has happended in your circuit.
Regards
Sean

0 gorden tsai over 5 years ago in reply to Sean Zhou

Prodigy 210 points

Hi Sean:
Yes,The input voltage drop below 4.5V,and then raise to 24V right away ,Does TPS54200 can work this condition? U can reference as above waveform.

Thanks
Gorden

0 Sean Zhou over 5 years ago in reply to gorden tsai

TI__Mastermind 22745 points

Hi Gorden,
What; your led configuration? When your input voltage voltage drops to a low value, there is not enough voltage for your output LED and FB voltage will be low, and it amy trigger internal OCP and enter into Latch mode(TPS54200). Then this matches your phenomenon. Please provide your schematic and I want to confirm.
Regards
Sean