This is why the startup circuit on T2 was here
Measure a voltage on C13 when the amp is 'not working' (before giving input signal). If it is less than 8-10 volts, then it is needed to reduce the resistor between Vb and +65V. Also, if the resistor is too small, then it can produce too high voltage on C13 and damage the driver. To be safe, simply put a 15V Zener diode (стабилитрон) parallel to C13.
Also, if this will not help, then it will be needed to insert delayed SD signal for IR2110.
Hi ,I have try as your suggestion . But there is 15VDC offset on out output also and amp did not start. Why?
I have only blown my output stage once with an high supply voltage around 190V (and 13200uF of low ESR caps). I was doing power testing and I was in another room with two closed doors and two concrete walls inbetween, yet I could hear the bang in detail.
The result was a lot of vapourized PCB (thick polygons, not just tracks), exploded TO-220 cases, vapourized TO-220 leads, and some small SMD parts disappeared.
And this happened with a quite mature design, not just the first prototype.
In other words, be careful
btw: Your design lacks many important things.
btw2: An high-speed op amp can't do the work as a hi speed comparator, and vice-versa. A comparator is a one bit analog to digital converter. An op-amp is intended to produce an analog output. Comparators exhibit very high gain and slew rates at the expense of the inability to make them work in a NFB loop. 5mV of overdrive are enough to change the state of the outputs completely within a few dozen nanoseconds.
Did you ever hear a welding inverter blow? 5 Kw version smps I was working on, with big igbt, always be carefull and use a limiter in powerlines as I do now.
These things shall happen once. Upon that failure I developed a simple system that detects a short in output stage, shutting down gate drive within 1us. No more meltdowns. Once, while testing said prototype in a party, it got some mechanical damage while I was not present. One output MOSFET lost gate contact and blew. The amplifier worked again after cutting out the damaged MOSFET (the design uses pairs of TO-220). The party continued till end.
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