TPS92511: Efficiency calculation

Marvn Arcangel

Part Number: TPS92511

Hi Team,

A customer is asking for the reason why the efficiency of their circuit is only 65%z. kindly refer to the schematic and value below:

the input is 4-20V. do you know what could be the problem? ist it the inductor?

Regards,

Marvin

over 2 years ago

0 Steven Li over 2 years ago

TI__Mastermind 23190 points

Hi Marvin,

Efficiency can be related to a lot of factors. I do not see any abnormal thing from the schematic. Please let the customer check their measurement method of efficiency first.

Also, may I understand who is the end customer?

BR,

Steven

0 Marvn Arcangel over 2 years ago in reply to Steven Li

TI__Genius 12535 points

Steven Li said:
Also, may I understand who is the end customer?

I updated the thread tracking toolkit with the customer information.

I'll get back to you with more information once the customer responds.

0 Marvn Arcangel over 2 years ago in reply to Marvn Arcangel

TI__Genius 12535 points

Hi Steven,

Here's more information:

I am using a 1W Led, with Vled=2.1V with the Led driver configured for 500mA. For now the circuit is mounted in a protoboard. I am using the basic circuit given in the datasheet.
I used two different inductors:
- MPN:TYS5040101M-10 which has 100uH and 0.7A of current that gives around 65% eficiency
- MPN: BWVS00808040101M00 which has 100uH and 1.1A of current that gives 70% of efficiency

The led MPN is GR CS8PM1.23-KPKR-1
For the efficiency measurement I measure the V_in, I_in of the power source and Vled, ILed.

+1 Steven Li over 2 years ago in reply to Marvn Arcangel

TI__Mastermind 23190 points

Hi Marvin,

Well received.

Since the output power (1W) is not large in such an application. The DCR (DC resistance) of the inductor will contributes a lot to the efficiency. I see BWVS00808040101M00 has lower DCR than TYS5040101M-10 and therefore will consume less power. Also, the BWVS00808040101M00 has a larger saturation current rating and will produce less inductor current ripple and therefore have less AC loss.

BR,

Steven

+1 Steven Li over 2 years ago in reply to Marvn Arcangel

TI__Mastermind 23190 points

Hi Marvin,

Since a new thread regarding the same question is created (https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1240569/tps92511-efficiency-calculation), I will close this one. Feel free to let me know if there is any further question.

BR, Steven

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TPS92511: Efficiency calculation