TPS61291: Voltage drop when output current more than 100mA

fedi makni

Part Number: TPS61291
Other Parts Discussed in Thread: TPS610986,

Hello
I used both the TPS610986 and TPS61291 boost converter in order to power a load that consume around 200mA in both situation (TPS610986 powering the load then use the TPS61291 to power the same load) the boost converter voltage drop down to around 0.45V. Both of them work correctly with load that consume 10-20mA but with higher load the voltage drop down i didn't understand the reason as the datasheet mention that both could work fine by supplying 200mA. ( I also tried a load that consume 100mA but i faced the same problem)
Input voltage: 3V I also used 2V
Output voltage: 3.3V
Could you please tell me how to fix it.
Thanks
PS: attached the schematic of both boost converter that I used

over 4 years ago

0 Jasper Li over 4 years ago

TI__Mastermind 46905 points

Hi Fedi,

could you share the layout? please also check current rating of the inductor, make sure the current of the inductor is higher enough.

also share the waveform the VIN and VOUT? check if the VIN becomes too low.

0 fedi makni over 4 years ago in reply to Jasper Li

Prodigy 90 points

Hello, I am following the same layout as recommended in the datasheet. my inductor current rating is around 1.2A so i think it's ok. the output voltage reach 2V but the input voltage suddenly drop down to 0.75V when i connect the load. Thank you.

0 Jasper Li over 4 years ago in reply to fedi makni

TI__Mastermind 46905 points

Hi Fedi,

i think the input voltage is too week to support the output power. please increase the power supply capability.

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TPS61291: Voltage drop when output current more than 100mA