I’m using a 3.3V DC-DC boost converter (https://www.torexsemi.com/file/xcl101/XCL101.pdf) as the power source for my audio circuit. There is a popping sound (headphone output) that happens when the circuit is turned on. There is no audible noise after power up. I viewed the boost converter’s output on my scope at power up, and there’s an AC-coupled voltage spike of about 2.5V that quickly decays back to zero:
I’m using 10 uF capacitors at the input and output of the boost converter, as shown in the datasheet:
How can I eliminate this AC-coupled voltage transient that’s creating the popping sound?
I don’t have any popping noise issue when using a bench power supply. It’s only a problem using the boost converter. This is my audio circuit:.
I put the 1k resistor at the output in an attempt to eliminate the popping sound, as a discharge resistor. There is a large decoupling capacitance at the output because I needed a low cut off frequency. The op amps are power op amps that have the required current capability.
I tried using a different 3.3V booster circuit, and did not hear the pop sound. The booster IC is different, and the circuit includes a diode and 68 uF output cap:
Datasheet of 3.3V booster: