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Design >> High-Power Design >> Problems in My High Voltage Generator
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Message started by lingling on May 30^th, 2017, 12:27am

Title: Problems in My High Voltage Generator
Post by lingling on May 30^th, 2017, 12:27am

Good day,
I have built many timer circuits like the following picture shows but the only problem I’ve ran across is the supply voltage/current,3 to 18 volts,if current exceeds 1.5 amps it will smoke the 555 timer,it has happened to me several times and i haven’t solved this problem. this circuit works well with a ignition coil, jacobs latters,stunguns,and others as well.
The circuit given here has three sections namely oscillator, switching stage and a step up stage. The oscillator is build around a NE555 timer operating at 25 KHz. The output of the NE555 coupled to the base of the power transistor TIP3055 which is the switching device. The power transistor drives primary of the step up transformer at 25 KHz and as a result a high voltage will be induced across its secondary.

Thank you.
PS: This is the TIP3055's PDF:http://www.kynix.com/uploadfiles/pdf9675/TIP3055.pdf and the schematic diagram is given below,please have a reference.

Title: Re: Problems in My High Voltage Generator
Post by mhx on Jun 11^th, 2017, 9:48am

lingling wrote on May 30^th, 2017, 12:27am:

The 555 delivers the base current for the 2n3055.
Given the base resistor, the possible base current times 12V times a
duty of 50%, should be more than enough to thermally overload
the IC. Add an emitter follower or something?

Another problem could be the primary of the transformer -- there
will be a large leakage inductance and subsequently a nasty spike
when the 2n3055 attempts to turn off. Maybe this spike reaches
the IC pins and drives them below ground?

-marcel