how to get the current from the sensefet?

[wanily1983]

sensefet

hi,guys
i am designing a SMPS and now encounter a problem. i want to get the Isense not the Vsense to process, so i can't using the Rsense. can someone give some advice about this?
another question: how to convert a voltage to a current linearly and the current can mirror to other citcuit block?
regards
wanily

 

[v_c]

I am trying to understand your question ...

Are you asking how you can directly sense a current in a branch without using a resistor to sense the voltage first and inferring the value of the current?

Sensing a large current value without a resistor in SMPS could be very expensive -- but I am not sure if this is what you want.

Can you clarify what you are trying to do?

Best regards,
v_c

 

[rockycheng]

Maybe you want to mix the Vsense with the compensation ramp. In that case you do need to use the current instead of voltage. I think you could use a voltage buffer and a resistor to transfer the sensed voltage into current. Then it's easy to mirror it to other branches.