Class D with IR2110 driver

jbeca

Member
2019-09-03 10:46 pm
Good day,

I am building a class d amplifier. The modulate stage is working just fine but the gate driver outputs a 60Hz sine wave. I am using the set up as seen in the image below. the supply voltage on the IRFB4019 is 28V. The input pwm signal are inverted using a xor gate ic and the dead time is set using a 1nF and a 1k pot. I simply don't understand why I am not getting an output. can somone please help.

Screenshot 2020-02-20 at 10.47.48 AM.png
 
I am using the set up as seen in the image below.
C7 is completely spurious, C6 can be as little as 22nF for that MOSFET and it'll hold enough charge to drive the gate. The lowly 1N4148 is being stressed every time this circuit is powered up as it may carry a spike of several amps to charge up C7 - the bootstrap capacitance only has to be enough to charge the MOSFET gate without drooping more than 10% in voltage, its often chosen to be 10+ times the effective gate capacitance. It is crucial that its is very low inductance.

Since class D using a high switching frequency there is no problem at all with the bootstrap cap discharging due to leakage, which would be a reason to increase C6.


D1 needs to be connected to +12V.