Principle diagram of polarity conversion chopper type switching regulated power supply

As the name suggests, the polarity of the output voltage of the polarity conversion power supply is opposite to that of the input voltage, but this is only one aspect of the problem. The absolute value of the output voltage must be higher than the absolute value of the input voltage, otherwise it will be different from the buck switch. Power supply confusion. It is not difficult to see from this that the variable polarity chopper switching power supply is a combination of the above-mentioned buck and boost power supplies. The figure is the schematic diagram of the polarity conversion chopper type switching regulated power supply. When the switching adjustment component transistor VT is turned on, the input voltage Ui is added to L, generating current and storing energy, and the diode VD is reversely blocked. When the transistor VT is turned off, the current in the inductor L gradually decreases, and the polarity of the induced electromotive force is as shown in the figure. This induced electromotive force turns on the diode VD and charges the capacitor C. The output voltage Uo on the capacitor C has the opposite polarity to the input voltage Ui. When the voltage on the load is about to drop, capacitor C discharges the load again. At this time, the output voltage Uo can be higher than the input voltage Ui.