I am trying to get +/- 12V and +/- 5V voltage in my board. I am getting lot of noise on the primary side itself as well it is carrying to the secondary side. I am driving the MOSFET with 100KHz PWM signal from microcontroller. I am thinking the source of noise is MOSFET switching. The schematic is as shown below
I have 3.3V PWM signal from controller but at the MOSFET gate I have a voltage -0.8 to 2.5V, thinking which is not sufficient to open completely. If I remove the capacitor C96 and added 50ohm resistor then I can see 0 to 3.3V signal at gate. still I have noise on primary side as well I increased capacitor C98, C99 to 1nF.
Noise is appearing on ground as well and same noise is effecting PWM signal at microcontroller. I am out of ideas on how to remove that noise. Any suggestions can be appreciated.
I tried to add some oscilloscope shots since I don't have reputation in this site so I can't update.
switching is like one MOSFET is switched OFF while another is ON, both MOSFETs never ON at a time.
Some oscilloscope shots
I have added a 250 ohm resistance between MOSFET gate and IC31 NAND gate by removing capacitor C96, C97 and diode resistance network. it means i gave direct PWM signal after NAND gate. I got less noise but still noise is there, below are the scope shots.
I have a noise on signal as well on ground so can it be some curret floating on the board which is causing noise?