TPS61196-Q1: TPS61196-Q1 inductor high-frequency sound

Mars Huang

Part Number: TPS61196-Q1
Other Parts Discussed in Thread: TPS61196

Hello, everyone,

The current use of TPS61196 12V boost to 21V, but when the PWM (500HZ) adjust the brightness of the inductor will be high-frequency sound, how to improve?

Or need to modify the inductance value? There are different types of inductor replacement, but still there will be high-frequency, thank you.

over 6 years ago

0 Caryss Li over 6 years ago

TI__Expert 4550 points

Hi Mars,
When you hear the noise, have you cheked if the driver is working as you desinged? such as output current, output voltage and switching frequency? And did you look the inductor current wavefom? is it stable?

0 Mars Huang over 6 years ago in reply to Caryss Li

Prodigy 160 points

Hi Caryss,
add another point.
High-frequency noise only appears when the PWM width becomes smaller, that is, when the brightness becomes bright, is there any advice? Thank you.

0 Caryss Li over 6 years ago in reply to Mars Huang

TI__Expert 4550 points

Hi Mars,
Have you checked the inductor current? is there satuation happened?

0 Mars Huang over 6 years ago in reply to Caryss Li

Prodigy 160 points

Hi Caryss,
Due to the current probe repair, so it can not measure.
However, I use the inductor Isat = 1.6A, TPS61196 output using only about 0.1A noise occurs, it will not be another reason? Thank you.

0 Caryss Li over 6 years ago in reply to Mars Huang

TI__Expert 4550 points

Hi Mars,
Have you seen low frequency in inductor current?

0 Mars Huang over 6 years ago in reply to Caryss Li

Prodigy 160 points

Hi Caryss,
There are adjustments PWM = 90HZ, 200HZ, 500HZ But when the brightness increases (PWM narrowing) will hear the noise, any suggestions? thank you.

0 Caryss Li over 6 years ago in reply to Mars Huang

TI__Expert 4550 points

Hi Mars,
When you hear noise from inductor, there must be current flowing through inductor in the range of human ear could recogaize, which is 20~20Khz. Since your boost switching frequency should be several K hz ( I couldn't tell the resistor value from the plot) , if the boost is working normally, there shouldn't be such frequency shown in inductor current. So I'd like you to check on the inductor current, and see if the current frequency is same as you designed. And also you check the DS voltge of MOSFET to find out if the swithcing frequency is as designed.

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TPS61196-Q1: TPS61196-Q1 inductor high-frequency sound