dom444
Junior Member level 2
Last edited:
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The dual switch topology in post #1 isn't bad. If you drive it correctly, the transistors won't run hot.
Do you drive it with 0/12V square wave as required? Did you check the waveform with an oscilloscope?
Well that answers your question then. If you only drive it with 5V then the top BJT will have a ~7.5V drop across it, while the lower one will be saturated. Your options are to either use a 12V drive, lower the supply on the BJTs to 5V (and maybe use a 1:2 transformer), or modify the circuit itself.
What does you GDT look like? parameters? DCR, LP, #turns , µeI am testing this gate drive pulse transformer circuit but the top 2n2222 connected to positive rail runs hot the ground one runs cool should they not have used higher current transistors to drive s coil?.
and should there not be a 1k resistor on its base as well as the other if anyone can help?.
View attachment 131870
What does you GDT look like? parameters? DCR, LP, #turns , µe
It looks like you driving equivalent of 560Ω high 360Ω which is // ( Ciss +Rg) low.
If you made your own then a turns ratio direct from 50Ω transformer could be around 1:3 with 5Vpp drive. Compare bipolar and single sided with DC offset. It is the DC content of your drive that makes the transformer warm.
The high side NPN in your circuit has larger Vce and with the excitation current of your primary and larger Vce of the emitter follower is limited by the impedance of 2pi f L which is affected by saturation and operating frequency and inductance.
The reference design is lacking all these details, which are essential to get good results.