The design is a simple saturation-limited push-pull converter. There is no special reason to use PNP transistors; I used them simply because I had a box full of them around. You may well turn over the design to use NPN transistors.
The 2SC945 is a bias switch for startup. When applying 12V power, this transistor applies enough bias to the power transistors to get the oscillation started. Soon later, the 100uF capacitor charges up, the transistor goes off, and the power transistors self-bias into cut-off, such that cross-conduction is eliminated. After removing power, the 6k8 resistor discharges the bias timing capacitor, as otherwise the circuit would be unable to restart!
The secondary rectifiers are ultrafast diodes. These are NOT 1N4007! And the 220nF capacitors for the secondary filter are no typos; the diodes deliver almost pure DC, since the oscillation waveform is square, so only some noise filtering is needed. No electrolytics are necessary here.
Read More Source:http://ludens.cl/Electron/dcdc/dcdc.html
Thank you.
Related Links
All circuits of DC converter high voltage
All circuits of DC converter step up
All circuits of High voltage generator
All circuits of Step up voltage converter
All circuits of Step up dc converters
0-1000V Regulated High Voltage Power Supply
A flyback converter high voltage supply by 555
The variable High-Voltage Power Supply 0-3kV
Nitrogen Laser High Voltage Power Supply
High Voltage Converter: 90 V from 1.5 V
High Voltage mini power supply by 2N2222
High volt mini Amplifier with UJT transistor
This entry was posted on Saturday, January 26th, 2008 at 10:24 am and is filed under dc converter, high voltage power supply, switching power supply.
