TPS62843: How to evaluate the efficiency @ very light load

Hello Minghan,

Thank you for using E2E,

I would recommend using a digital multimeter to measure the input current for such a small output current.

The digital multimeter measuring range should be around in uA and set the power line cycles to more than 10 for accurate measurements.

Thank you & regards,

Moheddin.

Hi Moheddin,

Thank you for your kindly reply.

I do have to use digital multimeter which measuring range should be around in uA. I do have set the PLC to more than 10 for accurate measurements.

However, the measurement jump violently in a large range as well. I use average function for light load Iin measurement now for providing accurate efficiency data for select the ICs for this socket in my system. Are there any approach better?

Thanks,

Minghan

Hello Minghan,

I would recommend using 1mF capacitor across digital multimeter( 100 PLC) as shown below to measure the input current accurately. 

Thank you & regards,

Moheddin.

Hi Moheddin,

Thank you for your kindly support.

You mean add a 1mF cap in parallel with the digital meter as shown below? Could you kindly explain why this approach will smooth the input current @ PSM mode?

Thanks,

Minghan

Hi expert, Awaiting for your kindly reply.