Hello Guys,
I was following the circuit fig.3 in www.ti.com/lit/an/snaa058b/snaa058b.pdf . I am using the MosFETs 4xIRFP240 and 4xIRFP9240 in the out put stage. But somehow it doesn't turn ON the MosFETs!!
I tried +_37V and +_80V for the power rail. Both cases the circuit behaved the same, the bias voltage can be adjusted from 2.2V to 3.7 volt at the gate to gate of MOSFETS!!
What I have done is, instead of 750Ohm (RB2) I put a 10k Trimpot to get higher bias voltage!!
Is it a correct logic? Now I can adjust the 10k Trimpot to adjust the bias voltage form 4.4V to 8V!!
Power rail voltage +_37V I have 4 MOSFETS each in the out put. Bias current 4xIRFP240( 4x25ma) 4xIRFP9240(5mA, 5mA, 10mA and 25mA)
Input 100mvPP out put 6VPP. If I increase the input level, the output start clipping!!
Why this phenomena?
Regards
Sijo
