9 Replies Latest reply on Jul 25, 2020 7:00 AM by s1m0n3t

    Design of a low voltage and high current DC-DC converter


      Hi all,

      I'm dealing with a quite strange design. I have a single 5V power source with few amps of current (about 3A) and I need to drive a load (about 0.8mOhm of resistance, but variable in function of voltage/current) with a current from -10A to 10A, at 100mV of maximum voltage.

      I'm searching for an IC which can help me, but I don't found any suitable device, at this moment.

      I would try a discrete configuration like the following schematic:

      I can send an alternate (square wave) current with one or another direction in the transformer, using a PWM signal on CTRL1 or CTRL2, with 50% duty cycle.

      If i use a 10:1 ratio transformer (for example), I will have a reduced maximum voltage, but with more current (about 10 times). Correct?

      And then, with another PWM on CTRL3 or CTRL4, I can modulate the output from zero to positive maximum and to negative minimum voltage, measuring the voltage to the feedback point, or the current in series of the load (R1) with an hall effect sensor.

      I probably don't even need two input windings, but I can send a single square wave in input and activate Q3 or Q4 to obtain a positive or negative output. And perhaps one of the two outgoing mosfets should be type P?

      What do you think about this solution? Anyone have alternative ideas or suggestions?