TPS61178: Switching is audible as load is increased

KUNVICHET LEE75

Part Number: TPS61178

I am using this part to boost the input voltage (6-12V) up to output 12V 4A. I followed the Webench design tool. When the AC/DC_12V is at 12V, the circuit works fine with no audible sound. As the AC/DC_12V input voltage is lowered to less than 8V and/or load increased to around 3A, the circuit starts making audible, squealing sound. The sound gets louder as the load increases. I've changed the inductor L1 to 3.3uF, but the sound 190823 - TPS61178 Boost.docxis still there. Do you have a suggestion?

Thank you,

Vichet

over 6 years ago

0 Helen chen over 6 years ago

TI__Mastermind 40080 points

Dear Sir,

Your compensation network need to be changed, please change to 15k/6.8nF to check whether it could be helpful.

0 KUNVICHET LEE75 over 6 years ago in reply to Helen chen

Prodigy 240 points

Hi Hellen,

I replaced R165 with 15K and C281 with 6.8nF as you suggested, but that still did not work. In fact the IC stopped switching altogether. I replaced the IC, it worked briefly and failed again. I'm not sure if I'm doing something wrong or if the IC is not as robust as it should be, because this is the 3rd time I replaced this IC. Right now, my supply is 7.2V and the output is also 7.2V.

thanks,

Vichet

0 Helen chen over 6 years ago in reply to KUNVICHET LEE75

TI__Mastermind 40080 points

Dear Sir,

Could you please send the sch and the layout file to us?

0 Zack Liu over 6 years ago in reply to KUNVICHET LEE75

TI__Mastermind 34231 points

Hi Vichet,

Can you share the layout and have you captured the SW, Vout, iL waveform?

What's the inductor saturation current rating that you are using?

0 Zack Liu over 6 years ago in reply to Zack Liu

TI__Mastermind 34231 points

Dear Sir,

I'll close this thread since haven't got any replies from you. You can post a new thread if you still have any questions.Thanks.

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TPS61178: Switching is audible as load is increased