TPS61169: output current

Allan Fan

Expert 7090 points

Part Number: TPS61169
Other Parts Discussed in Thread: , TPS61500

Team,

Customer is evaluating TPS61169EVM for IP Camera flashing application in below spec requirement.

Vin: single cell battery 3-4.2V

Iout: 200mA

LED#: 4

Based on customer's need, we follow the equation from datasheet and changed R5=1ohm, D1 continuous forward current= 1A, inductor: 10uH or 20uH with Ilrms=2A, but somehow the Iled output current is either lower or higher than expected.

Also in some cases Ilpk seems touched 1.2A minimum current limit threshold though I didn't expect it from estimation. Would you please have a look attached test data and provide some comments or suggest us other solution if tps61169 is not a good one? Thanks.

TPS61169 test data.zip

Thanks.

Allan

over 6 years ago

0 Sean Zhou over 6 years ago

TI__Mastermind 22745 points

Hi Allan,
Here are suggestions for you:
1). Add another measure about input volatge near TPS61169 Vin pin;
2).It appreantly that the device has trigged the current limit 1.2A;
3). I can't understand when use 3V, 10uH, the waveforms seems ok, but when you increase the voltage to 4.2V, it became unstabel?
4). Could you please use the multimeter to measure the resitand between FB and GND, I guess there may someting effected this .
5). can you try to use 2R to replace 1R to see whether there any improvement? Let's find whether the phenomenon goes with the output current or not.
Regards
Sean