I was trying to design a current mode boost converter in CCM using a MCP1630 and the specifications of the design are as follow:

Vinmin=2.7V (minimum input voltage).
Vinmax=4.2V (maximum input voltage).
Vout=5V     (Output voltage).
Iout=5A     (Maximum output current).
RL=5 Ohm    (load resistor Vout/Iout).

I have calculated the components and they are as follow:

Dmin=0.16   (Minimum duty cycle)
Dmax=0.46   (Maximum duty cycle)
L=5uH       (Inductor value)
Ipeak=2.2A  (Peak current)
C=200uF     (Output capacitor)
Fc=8kH      (Crossover frequency)

The sense resistor is selected to be Rs=0.36 ohm, because the maximum current sense signal for MCP1630 is 0.9V (for Ipeak=2.2A Vsense=Ipeak*Rs=0.36*2.2=0.8v, we let 0.1V as a margin).

For the feedback control I have sellected a type 2 amplifier with the following components:

    *Divider network: Rup=Rlow=10k
    *Refrence voltage Vref=2.5V

I provide the circuit bellow:

enter image description here

Unfortunatly, when I simulated my circuit, I never get 5V at the output, instead I get 3.94 and the duty cycle approaches 90% and I don't know what is the reason for that failure. Please try to figure out where I have mistaken!!

Bellow I provide you with the signals:

enter image description here

  • \$\begingroup\$ IRF540 needs >5V Gate drive to turn on fully. Try a logic level FET. \$\endgroup\$ – Bruce Abbott Aug 17 at 3:06
  • \$\begingroup\$ the MCP1630 provides 5V à its DRVR output, so I dont think that this is the problem, but I will try with another logic FET, Thanks \$\endgroup\$ – luxina pado Aug 17 at 3:29
  • \$\begingroup\$ compute the energy into the inductor; ensure you know where that energy ends up. \$\endgroup\$ – analogsystemsrf Aug 17 at 3:52
  • \$\begingroup\$ I still could not troubleshoot the circuit. Please any help ? \$\endgroup\$ – luxina pado Aug 21 at 10:23

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