ir2110 problems

Thread Starter

ian123

Joined Aug 24, 2011
73
I have dc bus capacitor right by mosfets now but cant go over 2 amps then oneside of the bridge doesnt turn on
 

praondevou

Joined Jul 9, 2011
2,942
3 possibilities.

Either there is no more PWM at the input or the 2110 latched up (high-side) or undervoltage lockout is activated.

Verify first if you still have PWM at the input.
 

Thread Starter

ian123

Joined Aug 24, 2011
73
Yes i still have a type of pulsed widh modulation as i said earlier in the thread i use a pic 12f509 that turns on the low side first then waits 10ms hn turns on the high side everything worksat low voltage and low current but a soon as i turn the voltage up passed 30v at 2.2 amps one side does not turn on so load is only onedirecton
 

SgtWookie

Joined Jul 17, 2007
22,227
Sounds like you are trying to drive an inductive load, and as you turn up the voltage, the reactive spikes are causing your uC to reset.

You may have to completely isolate your uC from your bridge using optoisolators.
 

praondevou

Joined Jul 9, 2011
2,942
So you are saying you still have PWM on both inputs, right.

one side does not turn on so load is only onedirecton
If there is current in one direction that means there is at least one MOSFET conducting on the side that doesn't work anymore. Which one is it?

The high side output of the 2110 can latch up if output to the gate goes below it's zero reference. But then it would normally be always on.

Are you sure Vcc is ok?
 

Thread Starter

ian123

Joined Aug 24, 2011
73
ok gp0 goes low but why since it is a TTL input there should not be too much load on the micro. should i put 680 ohm resistors inline with gpo and Hin
 

praondevou

Joined Jul 9, 2011
2,942
ok gp0 goes low but why since it is a TTL input there should not be too much load on the micro. should i put 680 ohm resistors inline with gpo and Hin
Can you please clarify this? First you are saying you have PWM at the 2110 inputs now you say one input is LOW. So what is it?:confused:
 

praondevou

Joined Jul 9, 2011
2,942
Then the problem is what SgtWookie suggested, some noise,radiated or conducted, is confusing your MC.

Before doing anything else, verify your physical layout.

PIC not near any switching component.
No power wires near the PIC.
Bypass capacitors near the PICs supply voltage.

It may also help if you post a picture of the layout.
 

Thread Starter

ian123

Joined Aug 24, 2011
73
Still have the problem when the voltage reaches over 22volts and the current is more than 2.2 amps. is there a problem with the layout do you think it wise to add opto's and if so do i try to isolate the gnd as well
 

praondevou

Joined Jul 9, 2011
2,942
Mount C7 and C8 near (maybe on top of it) their respective 2110s.

Mount a bypass capacitor of 100nF ceramic directly on the PIC from "+" to gnd.

Then try again and post the result.
 
Top