TLV61220 Boost circuit Issue

Parth Singh92

Prodigy 20 points

I have been trying to use the TI base example for a 3.3 V boost circuit.

I had initially designed it on a pcb attached below:

It didn't work as expected.

Then I designed it on a breadboard using the protoadvantage testing smd to dip.

But the results are still similar.

The initial output after input is around 0.9V is 5.2 V, but as the input voltage is increased the output voltage steadily decreases from 5.2V and after Vin > 3.8 V Vout < 3.8V

over 9 years ago

0 Jasper Li over 9 years ago

TI__Mastermind 46905 points

The layout is critical for the normal operation of a boost converter. please refer to the application note "www.ti.com/.../slva773.pdf" to modify the PCB. you can also try to place the COUT beside the IC, and connect the COUT and IC with solder directly.

0 Parth Singh92 over 9 years ago in reply to Jasper Li

Prodigy 20 points

Dear Jasper,
For the breadboard design I modified the circuit to R2 = 140 k ohm and the output is stable at 4.21 V but none of the R2 values 182k ohm and 120 k ohm work and don't provide a stable output and the output follows the input.
What could be the issue with the system, rest of the circuit is untouched.

0 Jasper Li over 9 years ago in reply to Parth Singh92

TI__Mastermind 46905 points

As i said, the root cause of the issue should be the layout. the output capacitor is critical for a boost converter, but it is far away from the IC in the layout. a breadboard can't solve the layout problem. try to place the output capacitor above the IC and connect it with solder directly to the IC in the current PCB

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TLV61220 Boost circuit Issue