MP8758HGL FB and VOUT

DC-DC Power Converters
1

Hi,
I am currently designing a CPU board in which I use the MP8758HGL DC/DC converter for a microprocessor core power supply (up to 8Amp). As I am going to manufacture some prototypes, I want to measure the real processor’s core power consumption for our application. For that, I have a shunt resistor (R152 - 0.01R) in converter’s output (after the inductor and output capacitors). My questions are:
1.- Should I take the voltage after that shunt resistor for the feedback signal and for converter’s VOUT pin?
2.- Why do we need the VOUT signal in the MP8758HGL converter? I suppose that the output voltage is set by the converter depending on the values of the FB pin resistor divider. The datasheet says that VOUT pins are for outputs Vsense. How does the converter know what is the output voltage?

Attached you can see a picture of my current design.

Thanks in advance,
Joseba.

MP8758HGL
MP8758HGL1229×648 266 KB

2

Any answer for my questions?

3

Hi Joseba -
Thank you for utilizing MPS Technical Forum ! and we apologize for the delayed response. We appreciate your patience and follow up.

Answer to your requests:

  1. The connection after the shunt of 10mOhms should work.
  2. The converter determines what the output voltage is based on the feedback network.
    The VOUT pin signal in combination with the FB is necessary for the one-shot ON-timer to help keep the frequency steady at 500kHz.

Regards,
Nouman