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TPS61041 boost converter high-frequency pitch noise heard

Dong Hui
Prodigy 220 points
Other Parts Discussed in Thread: TPS61041

I have used TPS61041 in a battery operated device to generate a 30mA @ 13V output for an OLED display. The input voltage is a Li-ion cell voltage (~3.8V) or 4.2V when charger is connected. I have used a 10uH inductor (Coilcraft LPS3015-103ML) and shottkey diode (MBRM120L) in the design. The input cap is 10uF ceramic and the output caps are 4.7uF + 0.1uF both ceramic. The feedback resistors are 1.43M and 150K. The feedback cap is 22pF. 

When this boost converter is running with 15mA load, I can hear a high-frequency pitch noise being generated by the converter. When I measure the output ripple, I can see a 5KHz ripple at 100 to 200mV. The switching frequency is varying but approximately 1MHz. I can see ringing at the end of each switching cycle.

Can anyone give me some suggestion how to get rid of this noise???

  • 0
    TI__Guru**** 150870 points

    This is typically coming from the piezo electric effect of ceramic caps.  I would recommend more Cout to reduce the voltage ripple.

    As well, using ceramic caps in smaller case sizes helps reduce the noise.  There are also special ceramic caps with reduced audible noise as a result of their special mechanical construction.