TPS54201: Does TPS54201DDCR support 4096 discrete steps?

Hi Webber,

Yes. The PWM pin of TPS54201 can accept the 29kHz PWM signal with 4096 steps from the LP5009.

However, you need pull-up resistor at OUTx pin of the LP5009 so that it can create the voltage level for the PWM pin of the TPS54201, and I do not see any in the above picture.

May I understand what your input voltage, output voltage and output current of TPS54201 are?

Best Regards,

Steven

Hi Steven,

We will place the pull-high resistance at out pin of the LP5009. please refer to the below photo.

The votages of TPS54201 are

input: 5V

Series VF: 8V

IF: 1A

Sincerely

Webber

Hi Webber,

TPS54201 is a Buck LED driver and it cannot work for VF_LED > Vin condition.

Best Regards,

Steven

Hi Webber,

You are welcome. Could you show me the I-V curve of your LED if possible? I am wondering if the series Vf will be lower than the input voltage when the LED current is small and you may need a buck-boost LED driver.

Best Regards,

Steven

Hi Steven,

Here is the I-V curve of my LEDs.

Sincerely

Webber

Hi Webber,

Do you need to drive four such LEDs in series?

Best Regards,

Steven

Hi Steven,

It would be appreciated if you suggest the IR LED driver.
Here are the conditions,
Vin: 5V
Series VF: 6V~8V
IF: 100mA~1000mA

Sincerely

webber

Hi Webber,

My understanding is that you need to drive 4 such LEDs in series. Am I correct?

If this is the case, then I would recommend you use TPS923652 / TPS923653 in buck-boost connection. Normal boost LED driver does not fit your application as there is a chance that the LED voltage will be lower than the input voltage. (For example, if you use TPS923652/3 in boost connection in such a case, there will be a leakage current from your input voltage, inductor, Schottky diode, sense resistor and LED.)

Best Regards,

Steven

Hi Webber,

You are welcome. I am going to close this thread. Feel free to contact me if you have any further question.

Best Regards,

Steven