TP2104 , TN2106 heating problem

[VASANSNS]

mosfet totem-pole shoot-through -patent

Hi,
i am using a driver circuit in my project which uses TP2104 and TN2106 transistors. I have attached the schematic diagram for reference.
I am trying to operate the transistors at VDD = 22v and Vss = -3.5v and at 35Mhz.
But the transistors are melting down at this operating range even though they are designed to operate in this range.
Can anyone kindly suggest me as to what is wrong with the design.
Regards
SNS

 

[dick_freebird]

tn2106

First off, not all MOSFETs "like" to operate linear. You
should be sure these ones do. Is 5.5V less losses,
enough to drive the gate fully on and off? Are there
startup periods during which the cap network is pumping
and produces a weak, hence dissipative gate drive level?

Pay attention to startup simulations and see if you are
transitioning through, or to, someplace you don't want to
be.

Second, a degree of nonoverlap timing needs to be
built into the circuit. Shoot-through current, especially
with higher voltages, can shed a whole lot of energy
per cycle. There appears to be no thought given to
that in this design. Your '244 may not produce enough
break-before-make to allow the transistors to live.

To test this latter try breaking the totem-pole and substitute
a resistor load for the low side or high side, in turn, and
see if the smoke stays inside the case.

 

[millwood]

tp2104 - forum

I don't know of any switches that can run at 35Mhz.

2ndly, the output from your driver IC '244 is 0v - 5.5v. as such you will never fully turn off either mosfet so they are tremendous shotthrough current going through the mosfet - approximately (24v-(-3.5v)/(3.3ohm*2+Rds(on) for both the p- and n-channel mosfets).

 

[VASANSNS]

Thank you for the reply. I have changed the driver IC to MD1211 from supertex which has a peak source and sink current of about 2A and operates upto 12v.

I tried to analyze the circuit as below. the diodes are present to give a fixed bias across the 10K resistor, irrespective of changes in VDD or VSS. Since the transistors are biased the input signal is amplified to operate between the rails.

I am not sure if this analysis is correct as i am relatively new to this. could some one correct me if i am wrong.