Hi. I had this unusual problem with the inverter when I connected the batteries. Initially at lower loads (50 watts) it worked fine. But when I started connecting additional loads (100 watts) and batteries in parallel, the inverter would work for 15 seconds and then stop functioning. The emitter resistors would get hot indicating a stuck oscillator. Finally, I managed to blow up the IC probably because of an inrush during one of those off cycles. The power transistors were all safe! In hindsight, I feel, the input voltages to the IC needs to be fed through a resistor of a nominal value say 100 ohms - the circuit consumes just about 10 mA. Secondly, a relay in the circuit that cuts of the low side supply to the square wave generator first followed by a delayed cut off the high side supply will reduce the load on the power line switch/ relay. Any one had similar experience?
login
