IRS2092 BTL from single supply

[Mark Kelly]

I have looked at the many threads on the IRS2092 and this doesn't appear to have been addressed.

I have been using Tripath T amp chips as driver amplifiers for small sinusoidal power supplies in multiphase motor drives for turntables. I wish to change and I am investigating using the IRS2092 driver chips and discrete MOSFets.

Can I run a pair of IRS2092 in BTL on a single supply? The existing motor drives use a single switchmode supply and I don't want to go bipolar if I don't have to.

Looking at AN1138, it looks as though I could reference the power reference plane to ground and the power ground plane separately to ground - in BTL there is no negative speaker reference so I just have to watch the ground reference of the output filter bypass caps. Since the inputs are all floating I'm assuming I just reference the input ground plane to the incoming signal from my existing frequency generator module.

Another question, I can't get IRFI4024s as used in IRAUDAMP7 at the moment. I was thinking of substituting IRFZ44Zs which seem to have appropriately low gate charge, Trr and RDS values. Has anyone tried these and found any problems?

 

[MOER]

Irs2092

Do not use high gate charge FETs with IR chips. They run hot. There are several which we use from IR, Fairchild and Infineon.

Low Qg FEts work better and can tolerate 10 ohm gate resistors. FETs with Qg above 35 need lower gate resistors of <4.7R >2.2R

Steve Mantz
Zed Audio

 

[Cuzziol]

Mark Kelly. good day.
I wonder if it was successful in its project with a single power source in IRS2092.
I'm worried about the GND. What was your solution ??

 

[nigelwright7557]

The irs2092 has quite a weak gate driver.
Much more than a irf4019 mosfet and it starts to fall apart.
You need external gate buffers to drive high gate capacitance mosfets.

 

[CBS240]

Something like these. CSD18534KCS

 

[Cuzziol]

OK thank you.
I will do the testing this week