LM61460-Q1: LM61460 LIGHT LOAD Efficiency

Ian Wang

Part Number: LM61460-Q1
Other Parts Discussed in Thread: LM61460

Dear Sir,

We measured the efficiency of EVM but light load efficiency looks poor.

Could you help to check the efficiency of light load (output=5V, 100mA) and I found the input current 18mA when power on ( no loading)

I measured the efficiency about 50-60% by 13.5V/20V/24V and they can’t mapping with datasheet curve.

What else need setting in EVM for test light load efficiency?

Thanks, Ian.

over 5 years ago

0 Andy Chen over 5 years ago

TI__Mastermind 34625 points

Hi Ian,

Do you modify the EVM components?

Pls measure input voltage on VINS terminal and output voltage on VOUTS terminal for efficiency testing.

B R

Andy

0 Ian Wang over 5 years ago in reply to Andy Chen

TI__Mastermind 29710 points

Hi Andy,

EVM is new w/o modify, here is my test point, if any comments? Thanks.

0 Andy Chen over 5 years ago in reply to Ian Wang

TI__Mastermind 34625 points

Hi Ian,

You need to use another DMM to measure actual input voltage on VINS and output voltage on VOUTS terminal on EVM. Do not read Vin on Power supply and Vout on E-load which may cause big error.

0 Ian Wang over 5 years ago in reply to Andy Chen

TI__Mastermind 29710 points

Hi Andy,

We measure VINS and VOUTS looks similar result as below,

input voltage(V)	input voltage(V)	input current(mA)	power(mW)	output voltage(V)	output voltage(V)	output loading(mA)	output loading(A)	efficiency(%)
13.5	13.47	54.7	736.809	5	5	100	0.1	67.86%
20	20.04	42.8	857.712	5	5	100	0.1	58.29%
24	24.05	38.1	916.305	5	5	100	0.1	54.57%

We found there are still have 17.5mA when power on-no load.

Do you have EVM test result or if any comments? Thanks.

Thanks, Ian.

0 Andy Chen over 5 years ago in reply to Ian Wang

TI__Mastermind 34625 points

Hi Ian,

Pls check the device top marking or test SW node waveform to see if it's FPWM version part as the Vin current is so high at no load condition.

0 Ian Wang over 5 years ago in reply to Andy Chen

TI__Mastermind 29710 points

Hi Andy,

Which EVM we can get better light load efficiency as d/s?

Thanks, Ian.

0 Andy Chen over 5 years ago in reply to Ian Wang

TI__Mastermind 34625 points

Hi Ian,

Pls use LM61460AA with Auto Mode at light load condition for higher efficiency.

B R

Andy

Power management

Power management forum

LM61460-Q1: LM61460 LIGHT LOAD Efficiency