Inverter using IRS21531 IC powering down

Thread Starter

MGPERF

Joined Jun 8, 2021
67
Hello,

I am using an IRS21531 as mosfet driver occasionally the IC will power down and I will need to disconnect the power and then restart for it to work again. Any idea what could be happening? I do not have a very large bulk capacitor could that be what's happening?
 

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shortbus

Joined Sep 30, 2009
9,328
Personally I'm surprised the circuit part you show is working at all. Why are the VS and all of the mosfet sources tied to ground? The high side of the gate driver needs a boot strap circuit to turn it on, not just a big capacitor. But the ground/common thing is a big worry.
 

Thread Starter

MGPERF

Joined Jun 8, 2021
67
Shortbus, it is a step up inverter it's connected to a steady 12v dc which it inverts to 400 vac. Does this mean it would still need the bootstrap setup? I also changed the configuration of the mosfets. Does this new configuration fix what you are talking about?
 

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shortbus

Joined Sep 30, 2009
9,328
Any high side mosfet switch needs a boot strap. Or a floating DC-DC converter can be used. And if your using this like I think you are I'm pretty sure you need a H bridge not just a 1/2 bridge like you show, since I see this is going to a transformer, since they only work on AC. Then from the transformer secondary you need to change back to DC to charge a cap.

VS on that chip means "voltage,source", so putting that to ground is a short.

You need to do some reading of application notes, for gate drivers. They can be found online by Googleing.

This is for your CDI ignition, right? What happened to it being so easy?
 

MisterBill2

Joined Jan 23, 2018
11,643
Showing us only part of the circuit (because that is all we need to see) is not a good way to get useful answers. Feedback is required for regulation and I see no feedback.
 
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