EVM3834C-PA-01A no load current consumption

DC-DC Power Converters
1

Dear technical support,
During my evaluation using EVM3834C-PA-01A development board, I noticed a suspicion behavior. Without any load connected to the output, it consumes about 18mA from input (Vin=5V, Vout=1V). Can you explain why it’s the case?

Kind regards,
Sasan

2

Hello Sasan,

That’s weird, the quiescent current should have a typical value of around 500uA.
A few questions that may need answers to consider what is happening here:

  • Does this current consumption change when you decrease the input?
  • Do your losses come as expected when there is a load?
  • What kind of setup are you using here? Long wires can add line resistance / inductance that can contribute to loss here. If you optimize this, does the no load current consumption change?
  • How is this 18mA being measured?
3

Hello Krishan,

Thanks for your reply.

1- Yes, the current consumption decreased to 12.7mA when I decreased the input voltage from 5Vto 3V
2- When I connect the load, the overal efficieny is good as I expected
3- I used the same setup, including power supply, wires and so on to evaluate another SMPS. That one doesn’t have any no-load current consumption
4- It measured by the power supply, to make sure, I measured it with a multimeter. The result was the same

4

We have a design with the MPM3822C used for 5.0V to 1.8V conversion. When there is no current being drawn on the output (i.e. no load), we are seeing 15mA drawn on the 5.0V source. We get this by measuring the voltage across a 75mohm resistor in series between the 5.0V source and the regulator input. Is this to be expected?

Does the MPM3820 draw any less current at no load?