DC step-up is to lower the DC battery voltage to the required voltage improve their basic work processes are: low-voltage high-frequency oscillation pulse – pulse transformer voltage step-up to a predetermined value – pulse rectifier to obtain high-voltage direct current, so the DC boost circuit is DC / DC circuit type.
In the use of battery-powered portable devices, the DC boost circuit through the circuit needed to obtain high-voltage, these devices include: cell phones, pagers and other wireless communications equipment, camera flash, portable video display device, power equipment such as electric shock, etc. swatter.
First, several simple DC boost circuit
Here are some simple DC boost circuit, the main advantages: the circuit is simple, low cost; disadvantages: low efficiency, use of low battery voltage, output power is small. The circuit is suitable for use in the multimeter, the alternative high-pressure laminated battery.
Second, 24V high voltage power supply CRT
Some cameras use CRT 11.4cm (4.5 inches) pure flat CRT as the display component, the high-voltage anode voltage components +20 kV, focus electrode voltage of +3.2 kV, accelerating voltage was +1000 V, high voltage components for the DC 24V power supply . The following circuit is to replace the maintenance of these displays designed for high voltage parts (circuit selected from the network of articles, original author unknown). The circuit is also designed for other step-up circuit design reference.
Basic principles: NE555 constitute pulse generator, adjust potentiometer VR2 can generate a frequency of about 20kHz pulse, pulse width adjustment potentiometer VR1. TR1 to promote the class, the pulse transformer T1 with reverse polarity excitation, ie cutoff TR1 turns on TR2, TR1 TR2 close of conduction, D3, C9, VR3, R7 and D4, R6, TR3 composition of high-voltage protection circuit. VR2 for adjusting the frequency of high-pressure regulator VR2 adjust the size.
VR2 use precision adjustable resistors. T2 can be used, adapted TV line output transformer. I use the Toyo SE-1438G Series 35cm (14 inch) color TV line output transformer, with the anode voltage transformers up to 20kV, and then R8 appropriate choice of resistance to acceleration voltage was +1000 V, R9 of the resistance to focus electrode voltage of +3.2 kV can be. The parts are aluminum box package, aluminum ground, thus reducing interference on the circuit.