Other Parts Discussed in Thread: TPS54260
Hi Sir,
My customer is using TPS54260 to power MCU. Before MCU power on, tps54260 is working in Eco-mode. when the voltage supervisor reset the MCU, the load will transient to 60mA, and then the output voltage will drop for about 400mV which will trigger the UV and reset the MCU again.
Two ways will solve this problem, and the transient drop will be limited below 100mV :
1. Add additional 3mA load to exit eco-mode before MCU POR.
2. Change the compensation parameter: the failure board using (100nF+10k) parallel with 1nF, just change the 100nF to 10nF will solve this problem.
I want to confirm what's the root cause of this issue, does eco-mode transient to DCM behavior will influence a lot?
The compensation make a big difference, but the measured real cross frequency of the failure board is 3kH, it should not bring so much voltage drop.
In the waveform: Green is output, Purple is comp voltage. Blue is the reset signal from voltage supervisor.
Best regards
