Hi. I am designing a Buck Converter using PIC16F877A. I need to use a Gate Driver to drive the MOSFET that acts as a switch in buck converter. PIC provides PWM from CCP1 module that is input to HIN pin of IR2110. Now the problem that I am facing is that when the duty cycle of PWM increases from 60% the PWM stops working. Its continuous 5V on PWM pin or sometimes its 0V. When duty cycle is less than 60%, it works fine. When PIC is tested independently by disconnecting from the gate driver, it gives PWM even when duty cycle is greater than 60%. The frequency of pwm is 25 kHz. I am unable to identify the cause of the problem. If anyone can help,, I will be thankful..

Regards..

 

Show your schematic!