IRS2092 BTL MODE

Hello,

I want to operate two IRS2092 amplifiers in BTL mode. Both are on the common board and have a common power supply. Each has its own VCC. The BTL inverter opamp also has a separate power supply +/-15V. If both amplifiers are connected separately with the speaker to GND, both play excellently. They are able to deliver 2x 400W 8Ω (+/-80V). The problem is in bridge mode. With an 8Ω load in BTL it reaches a maximum of 100W, then growl and pulsate. as if the amplifiers are arguing. With a 16Ω load everything is fine and the power goes very high. Why is there a problem with BTL at 8Ω? Thank you for every comment. I am attaching a schematic of one amplifier. The second is identical.

2092 50p.jpg
 
With 8 ohm, a bridge amp has a load of 4 ohms for each single amp. The theoretical output is 4x the watt of the single amp. The current is 4 times as high, which will trigger the protection instead of blowing the FET's. Lower the voltage to 60 Volt and it should work with 8 ohms.
With 16 ohms you give the amps an 8 ohm load each, which is OK. The simple 1x1 of amp bridgeing.