TPS92630-Q1 dimming ratio

Yamuichi-san,

The appropriate applications engineer has been notified of your question, and will respond accordingly.

Regards,
Eric Hackett

Astsushi-san,

We can reach high dimming ratio using PWM dimming ratio by adding external circuit. What is your requirement on the dimming ratio? And what pwm frequency do you use, as it has big relationship on the dimming ratio.

Dear Anda-san,

Thank you for your response.

The customer needs PWM dimming ratio 5000:1. I don't know the PWM frequency and will confirm it.

If you can, could you please give the example for 5000:1? I will provide it to the customer.

And  the thermal condition may be severe, because the condition is below;

- supply voltage: the battery (around 7 to 16V)

- LED VF: 3.3V (max 3.6V)

- LED current: 50mA/ch (3ch: 150mA)

Could you please teach other product for this condition if you can recommend?

Best regards,

Atsushi Yamauchi

Hi Atsushi-san,
You mean customer only use 1 LED per channel? What is the highest test temperature of the board? If customer need to test the board under 85C, recommend customer to use two tps92630-q1 to keep current constant under 16V input voltage.

Dear Anda-san,

Thank you for your reply.
Could you please give the example of 5000:1? I will confirm whether they can set PWM frequency or not.

Best regards,
Atsushi Yamauchi

Hi Yamaochi-san,

As we discuss over the mail, the TPS92630-Q1 can only realize 1000:1 dimming ratio using the circuit below. Could you help to close the problem?