123duermed
New Member
Hello
I'm making a buck regulator, but I'm having some issues. The regulator is supposed to regulate 50-300V down to 14V. But now when I'm testing it, I gets some problems. First of all the duty cycle gets low very fast. It goes from about 60% to about 5% when the input voltage goes from 22-30V. When the duty cycle get to low, the regulator stops. It seems that the mosfet does not get enough time to switch on and off, when the duty cylce get very low. I'm running the duty cycle at 40KHz, and tried down to 10 kHz, but I'm still having the same problem.
Also the source voltage when the mosfet is off, gets a lot of ringing. Why? Do I need to change something in my buck circuit to improve this? See the picture. I'm also attaching the circuit
I'm making a buck regulator, but I'm having some issues. The regulator is supposed to regulate 50-300V down to 14V. But now when I'm testing it, I gets some problems. First of all the duty cycle gets low very fast. It goes from about 60% to about 5% when the input voltage goes from 22-30V. When the duty cycle get to low, the regulator stops. It seems that the mosfet does not get enough time to switch on and off, when the duty cylce get very low. I'm running the duty cycle at 40KHz, and tried down to 10 kHz, but I'm still having the same problem.
Also the source voltage when the mosfet is off, gets a lot of ringing. Why? Do I need to change something in my buck circuit to improve this? See the picture. I'm also attaching the circuit