TPS61194-Q1: Inductance howling

Amelie Zheng

Genius 10865 points

Part Number: TPS61194-Q1
Other Parts Discussed in Thread: TPS61194

Hi Team,

My customer now use the TPS61194 to boost 12V to 24V and output current is 4*90mA.

They found that inductance of TPS61194 is howling when PWM frequency is 1kHz/10kHz.

If the PWM duty cycle is 100%, the inductance is not howling.

Customer also change the inductance to the following value, but still howliong.

600KHZ 22uH /2.6A

300KHZ 47uH/2A

1300KHZ 10uH/2.6A

The SCH is as following:

The LCD:

over 5 years ago

0 Charles-Chen over 5 years ago

TI__Genius 11836 points

Hi Amelie,

Can you try to use 20KHz PWM input dimming signal instead?
Please also provide the current waveform of inductor when it howls.

0 Amelie Zheng over 5 years ago in reply to Charles-Chen

TI__Genius 10865 points

Hi Charles,

I talked with customer just now. They don't have the current probe to test the inductance current.

Because the max frequency is 20k. If they set up 20kHz, will it be unstable?

0 Charles-Chen over 5 years ago in reply to Amelie Zheng

TI__Genius 11836 points

Hi Amelie,

You can try frequency above like 18KHz. And it is also OK to use 20KHz. And if you can't provide the waveform of inductor, it is also OK to provide the waveform of SW. And try to provide the waveform of SW in an appropriate timescale to check whether the loop is stable or not.

If it is possible, please also provide the low pass filter result of SW.

0 Charles-Chen over 5 years ago in reply to Charles-Chen

TI__Genius 11836 points

Hi Amelie,

What's the latest progress? Do you get any feedback from customer?

0 Charles-Chen over 5 years ago in reply to Charles-Chen

TI__Genius 11836 points

Hi Amelie,

I will close this thread since you have no reply. You can ask in this thread if you get any feedback from customer.

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TPS61194-Q1: Inductance howling