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switching regulator.
The regulator whose adjustment element works in the switching state is called a switching regulator. The adjustment element working in the switching state is called an adjustment switch, which includes transistors, thyristors, saturated chokes, etc. The DC regulator whose adjustment switch uses transistors is called a transistor DC switching regulator. Assume that the switching cycle of the regulator is T, the conduction time interval is t, and the cut-off time interval is t2, then the working cycle t=t,/T. When the output voltage of the regulator is the specified value, the adjustment transistor works at a certain τ. During the switch-on period, the power input voltage passes through BG, and the filter inductor L charges the capacitor C. At this time, BG. is cut off; during the switch-off period, the magnetic energy stored in L and the electric energy in the capacitor C are released to the load, forming a path through BG, so BG. is called a freewheeling diode, and the voltage on the capacitor is the output voltage. The AC component of the voltage on the capacitor is the ripple voltage, which depends on the switching operating frequency and the size of LC. The higher the switching operating frequency, the larger the LC, and the smaller the ripple voltage. When the output voltage changes due to changes in input voltage or load current, the voltage regulator can automatically change the duty cycle τ of the adjustment transistor BG. to stabilize the output voltage. For example, when the output voltage rises, after sampling and comparing with the reference voltage, the voltage difference is amplified by the amplifier composed of BG and BG? and then controls BG. , BG, so that the output pulse conduction time interval of the multivibrator is reduced, so the t: of the adjustment tube is reduced, that is, τ is reduced, so the output voltage drops to the specified value. When the output voltage decreases, the output pulse conduction time interval of the multivibrator increases, so the t of the adjustment tube increases, that is, τ increases, so the output voltage rises to the specified value. Since the adjustment tube works in a switching state, one of the main advantages of the switching regulator compared with the linear regulator is that it has higher efficiency, so the power supply is small in size and light in weight. It is particularly suitable for aviation and spacecraft. At present, electronic equipment such as electronic computers are also widely powered by switching regulators. However, its adjustment time is usually longer than that of a linear regulator, and the output ripple voltage is correspondingly larger.
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