LP5030: LP5030 overvoltage

add a test picture when Vout is ste 50% PWM cycle.You can see a noticeable voltage drop in the red circle.

Hi Pan,

Please give me some time to test it and I will reply you later.

BR, Jared

Have you finished test?

Hi Pan,

Sorry for late reply.

I tested it on EVM and the waveform is same as you. But I want to what do you mean about "This will cause the current passing through the LED to increase from my set 9.8mA to 20mA."? Is it instantaneous or persistent, how do you observe this current?

BR, Jared

By testing the voltage difference on the LED string resistance, the current I=V/R can be obtained.

The downstroke of the instantaneous pressure difference corresponds to the overshoot of the instantaneous current.

My series resistance is 45ohm, corresponding to a normal voltage difference of about 450mV, as shown in the figure. 

The voltage difference corresponding to overshoot is about 900mV, so the current is considered to be 20mA.

You said that the same waveform with overshoot was also measured on the demo board. Is there any way to reduce this voltage overshoot?

Hi Pan,

Can I know what impact this overshoot will have on your circuit?

BR, Jared