Step Up Converter

239

02:45:21

Weird design it turned out to be, couldn't precisely measure the efficiency but it's somewhere around 60%. I have a recommendation though, one which I can't apply here in EC. If you substitute the BJT transistor with an optocoupler, you can separate the ground of the two parts of the circuit, thereby reducing the amount of RF switching noise, that the mosfet can introduce through the common node (ground).

published 9 years ago

hurz

9 years ago

You pump current only in one direction, so no need for a bridge rectifier. A single diode at secondary would do the job. Also the OpAmp in between 555 and Mosfet doesn't do anything helpful. The frequency 50kHz is much to high for a coupling coefficient of 0.999 transformer.

thebugger

9 years ago

Yeah I agree about the rectifier, typically these circuits use just a single diode, but this way the rectifier will also rectify any stray negative voltage that may appear. The op amp doesn't do anything indeed, it just boosts the output from the 555 timer from 3.5V to 5V and plus, depending on the op amp, some have way better MOS driving capabilities than the timer itself. The frequency thing I didn't quite get the relevancy.

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