TPS54200: Can you please check the TPS54200 converter output voltage below conditions?

i appreciate your reply.

I have additional questions.

Q1). Is the (min)duty=7.35% value calculated in the datasheet the calculated value when Load=1A?

Q2). If the LED Buck Driver efficiency η, Vin, and Vout are determined, is there a formula to calculate the duty in the TPS54200 Driver?
(As an example, in the TPS92640 product, Duty can be calculated using the following formula.)

If the actual efficiency of the TPS54200 we are using is η = 53%, Vin = 12V, and Vout = 1.5V, is there a formula to calculate Duty?

Best regards,

Dear Team,
Thanks for your answer.

I have additional questions.

Q1)

TPS54200 Minimum Duty when Calculated load Current was 1A was 7.35% ( t_MIN_ON (MAX) * f_SW (MAX) = 105ns * 700kHz = 7.35%).

Using the formula Vout = Vin * Duty, which represents the relationship between Vin, Vout, and Duty in the Buck LED Driver, (1.5V = 12V * Duty, ∴ Duty = 12.5%) The required duty is 12.5%.

So, Is it Possible the desired output voltage of 1.5V be stably output at 1A Load?

Q2)

The actual circuit configuration to be used is as follows.

When calculating efficiency η, η = ((Pout)/(Pin)) * 100% = 46.7%, and omitting V_FB (100mV under) to obtain the duty to be used is as follows.
(Duty) = ((1.5V) / (0.467) * (12)) = 26.76%

The load in the current circuit to be used is approximately 0.5A, and the Minimum Duty when calculating efficiency is calculated to be 26.76%.

Considering the efficiency of the LED Driver (26.76%) , I am curious whether it will be possible to stably output a voltage of 1.5V at 0.5A Load.

It is difficult to determine whether 1.5V voltage can be stably output at 0.5A Load with the Minimum Duty of 7.35% at Load Current 1A.

What do you think about this?

Alternatively, I think it would be possible to make a judgment if there were test results for Minimum on Duty and Switching Frequency at Load 0.5A.
Can you Send me the relevant data?

I always appreciate for your answers.

Best Regards,

Hi Customer,

Si Yoon Kim said:

Q1)

TPS54200 Minimum Duty when Calculated load Current was 1A was 7.35% ( t_MIN_ON (MAX) * f_SW (MAX) = 105ns * 700kHz = 7.35%).

Using the formula Vout = Vin * Duty, which represents the relationship between Vin, Vout, and Duty in the Buck LED Driver, (1.5V = 12V * Duty, ∴ Duty = 12.5%) The required duty is 12.5%.

So, Is it Possible the desired output voltage of 1.5V be stably output at 1A Load?

Yes, it is possible.

Si Yoon Kim said:

When calculating efficiency η, η = ((Pout)/(Pin)) * 100% = 46.7%, and omitting V_FB (100mV under) to obtain the duty to be used is as follows.
(Duty) = ((1.5V) / (0.467) * (12)) = 26.76%

The load in the current circuit to be used is approximately 0.5A, and the Minimum Duty when calculating efficiency is calculated to be 26.76%.

Considering the efficiency of the LED Driver (26.76%) , I am curious whether it will be possible to stably output a voltage of 1.5V at 0.5A Load.

It is difficult to determine whether 1.5V voltage can be stably output at 0.5A Load with the Minimum Duty of 7.35% at Load Current 1A.

What do you think about this?

May I understand which dimming mode do you use? Analog dimming or PWM dimming?

Si Yoon Kim said:

Alternatively, I think it would be possible to make a judgment if there were test results for Minimum on Duty and Switching Frequency at Load 0.5A.
Can you Send me the relevant data?

The range of the switching frequency has already been stated in the datasheet. For the minimum-on time, sorry but currently we do not have such data.

Best Regards,

Steven

Dear Team,
Thanks for your answer.

I plan to proceed with PWM dimming, but I also want to check analog dimming.

I'm just wonder if the output will be stable under those conditions.

I always appreciate for your answers.

Best Regards,

Hi Customer,

I am currently out of office. I will reply to you before next Tuesday. Thanks for your understanding.

Best Regards,

Steven

Hi Customer,

Do you have an EVM at hand? If so, you can test the condition on the EVM. If not, I am willing to do a bench test for you but that may take some time.

Best Regards,

Steven

Dear Team,
Thanks for your answer.

Unfortunately, I don't have an EVM.

Is a bench test essential to check whether stable operation is possible under conditions considering efficiency?

Considering efficiency, if it is impossible to predict whether the TPS54200 can produce stable output, I would like to request a Bech Test.

I always appreciate for your answers.

Best Regards,

Hi Customer,

Bench test can reveal the actual operation status of the device at your desired working condition.

I have put this into my test queue and should be able to reply to you before this Friday.

Best Regards,

Steven

Dear Team,
Thanks for your answer.

That's good news.
thank you

Best Regards,

Hi Customer,

You are welcome. I will let you know once I have got the results.

Best Regards,

Steven

Dear Team,

Please check the current status of this Questions.

Thank you

Best Regards,

Hi,

We will update the results later, thanks for your patience.

BR

Patrick

Dear Team,

Please check the current status of this Questions.

Thank you

Best Regards,

Hi,

Steven is working on this bench test, please allow us more time to get the results. Sorry for the late and thanks for your patience.

BR

Patrick

Hi Customer,

My bench test shows this device works well with Vin = 12V, Iout = 1A, load = single SFH 4715A IR-LED condition under both PWM dimming and analog dimming.

Best Regards,

Steven

Dear Team,
Thanks for your answer.

That's good news.

Would it be possible to get the Bench Test Report?
thank you

Best Regards,

Hi Customer,

Sure. I can send you the test result over e-mail. I have sent you a friendship request on this E2E forum with my e-mail address attached. Please send me an e-mail and let's continue the talk there.

Best Regards,

Steven

Hi Customer,

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

Best Regards,

Steven