The working process is quite easy to understand switching power supply, linear power supply, so that the power transistor operating in the linear mode. compared with linear power, PWM switching power is to let power transistor work in on or off state.V- Ann is small (when turned on, low voltage, large electrical current; turned off, high voltage, electrical current is small) VA /power device is the product of power semiconductors losses. Compared with the linear power supply, PWM switching power supply more efficient work process by "chopping", that is cut into the magnitude of the input DC voltage equal to the input voltage amplitude of the voltage pulse to achieve.
1.STR-53041 is a thick film ICs for TV power switching circuit consists of two NPN type transistor and a PNP transistor and a regulator and a number of resistors in five ends .STR-53041 devices .3 termination power input terminal 4 of the common ground terminal, the second end of the feedback terminal, one end of the sampling signal input, the TV using the 5 'end idle. 2.TR1 oscillation transistor is NPN type, it and P B winding and a feedback winding of the transformer T form a feedback oscillator circuit .TR2 are NPN type transistor and the regulator ZD constitute sampling comparison circuit provided by the comparison voltage .TR3 transformer T D windings are PNP transistors constituting the sampling signal current amplifier circuit for driving the oscillating tube, perform pulse width modulation circuit output voltage amplitude stability. 3.STR53041 natural oscillation frequency is lower than the TV line frequency, it is subject to the line frequency flyback transformer FBT came forward driving pulse synchronization work 15.75KH. to eliminate the image appears horizontal frequency interference.
