What is auxiliary power supply?
Provide different power supply requirements for all individual circuits. The principle of switch controlled voltage regulation is that switch K is repeatedly turned on and off at certain time intervals. When switch K is turned on, input power E is provided to load RL through switch K and filtering circuit. During the entire switch on period, power E provides energy to the load; When switch K is disconnected, input power source E interrupts the supply of energy. It can be seen that the input power supply provides energy to the load intermittently. In order for the load to receive continuous energy supply, the switch stabilized power supply must have an energy storage device that stores a portion of the energy when the switch is turned on and releases it to the load when the switch is turned off. In the diagram, the circuit composed of inductor L, capacitor C2, and diode D has this function. Inductance L is used to store energy. When the switch is turned off, the energy stored in inductance L is released to the load through diode D, allowing the load to receive continuous and stable energy. Because diode D keeps the load current continuous, it is called a freewheeling diode. The average voltage EAB between AB can be expressed as follows: EAB=TON/T * E, where TON is the time the switch is turned on each time, and T is the duty cycle of the switch (i.e. the sum of the switch on time TON and off time TOFF). As can be seen from the equation, changing the ratio of switch on-time to duty cycle also changes the average voltage between AB, therefore, automatically adjusting the ratio of TON and T with changes in load and input power supply voltage can maintain the output voltage V0 unchanged. Changing the on-time TON and duty cycle ratio, that is, changing the pulse duty cycle, is a method called "Time Ratio Control" (TRC).
