Tool/software:
Hi,
I am experiencing in a design that uses the TPS922055 LED driver.
When I apply a 10 Hz PWM signal with 50% duty cycle to the EN/PWM pin for dimming, the power inductor in the buck converter circuit emits a audible sound.
The circuit operates correctly without sound in a continuous-on state.
Here's my condition
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Driver IC: TPS922055
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Input Voltage (VIN): 48V
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Output Voltage (VOUT): Approximately 23V - 27V
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Output Current (IOUT): Approximately 1.2A
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Switching Frequency (fSW): 300 kHz
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Inductor: PIC1205HP220MF
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Dimming Mode: PWM dimming.
1. What is the official recommended minimum PWM dimming frequency for the EN/PWM pin to ensure stable operation at 50% duty cycle range?
2. Are there any other circuit modifications you would recommend to mitigate this audible noise, other than increasing the PWM frequency or switching to analog dimming?
I have attached a schematic of the driver section and inductor's datasheet for your detailed review.
PIC1205HP220MF.pdfLED DRIVER SCH.pdf
Thank you for your time and assistance.
Best regards,
