Buck converter help needed

[jayzac]

I am designing buck converter for my MPPT project. Below is my attached schematic. All of the port pin is used to link the buck converter board to the microcontroller board. However i wish to test the buck circuit individually without microcontroller by supplying DC input and PWM signal (signal generator)at pin 2 of MOSFET driver. The both mosfet is fail to turn on.

1. Is there any problem with my circuit ?
2. Is my testing method correct?

 

[perumal.seenivasan]

Hi,

Your testing method is correct. No issues. Few things to verify.

In general, signal generator output will not be sufficient enough to drive other circuit. Also it should be minimum 3.3V. If not, add a driver/buffer circuit in between signal generator & pin 2
Have you pulled up 3rd (SD) pin to 1st pin (VCC). It should be pulled up
I am sure you have connected some voltage (10 to 20V) to pin 1 & some voltage to Q1 mosfet. Confirm



Have you connected pin3 of U1 to its pin 1?


With Thanks,
S.Perumal

 

[jayzac]

Nope i connected pin3 to 5v from voltage regulator. Is it ok to have 5v or better to have Vcc from solar input?

 

[perumal.seenivasan]

5V is Ok.

Instead of giving PWM signal (from signal generator) to pin 2, you can try pulling it directly to power (VCC/5V) or GND and see either High or Low MOSFET is getting turned ON. This will confirm that MOSFET driver chip is good or not