I am trying the below circuit on a simulator. i am few queries. it would be great if someone can clarify my doubts please.
Circuit1
- Cicuit1.JPG (61.45 KiB) Viewed 4020 times
I have put a buck converter without PWM. Here the Voltage raises to steady state of 48.5V across the 3.5 Ohm resistor. Till now things look Ok to me. The second circuit i have put a PWM.
Circuit2
- Cicuit2.JPG (58.23 KiB) Viewed 4020 times
Here I have added the PWM using 555 timer. The max voltage i am able get now is 13.81. If i reduce the Vin for 555 timer to 5V, then the voltage across 3.5 Ohm resistor reduces to 4.18V. Offcourse i can see 1/3 drop in current acros 5 Ohm resistor connected to base of Transistor. I tried increasing the 100K resistor value to much higher in M Ohms, but that didn't increase the base current and not able to achieve higher voltage. Is there something wrong in the way I have connected grounding of 555 timer 3uF capacitor.
Finally i want to move towards giving feed-in of DC converter voltage to 555 timer Vc to maintain certain output voltage.
Any help is much appreciated...
Regards...
