One, switching power supply schematic --- what is a switching power supply
1. Switching power supply is a use of modern power electronics technology to control the ratio of switching switching time, to maintain a stable output voltage power supply. Switching power supply is usually composed of pulse width modulation control IC and MOSFET. Compared with linear power supply, the cost of two switching power supply increases with the output power, but the growth rate will be different.
2. Ordinary power supply is usually a linear power supply, linear power supply, refers to the regulation of the tube is in a linear state of power supply, switching power supply is a relatively new type of power supply. It is high efficiency, light weight, can be raised, lowered voltage, high output power. The high frequency of switching power supply is the direction of its development. High frequency makes switching power supply miniaturization, switching power supply into a wider range of applications. In addition, the development and application of switching power supply in energy saving, resource conservation and environmental protection is of great significance.
3. Switching power supply is the use of electronic switching devices (such as transistors, FETs, thyristors thyristors, etc.), through the control circuit, so that the electronic switching devices constantly "on" and "off", so that the electronic switching switching devices modulate the input voltage. Realize DC/AC, DC/DC voltage conversion, adjustable output voltage and automatic adjustment.
4. Switching power supply generally has three working modes:: frequency, pulse width fixed mode, frequency fixed, pulse width variable mode, frequency, pulse width variable mode. It consists of four main parts: the main circuit, switching power supply control circuit, detection circuit and auxiliary power supply.
Two, switching power supply schematic diagram - switching power supply working principle
Switching power supply can make the power transistors work in the on and off state. In effect, the input DC voltage amplitude is converted into a pulse voltage equal to the input voltage amplitude. The principle of operation is applied to the power transistor volt-ampere product is very small (in the on state, the voltage is low, the current is large; in the off state, the voltage is high, the current is small), that is, the power transistor produces very small loss.
Three, switching power supply schematic diagram - switching power supply operating conditions
In addition to the above switching power supply operating principle, in the switching power supply operating principle of operation at the same time, the switching power supply is also a certain state of operation, such as switching, work, it is not a linear state, but in the work of the electronic equipment. In the case of DC, switching power supply at work is DC, not AC; the latter switching power supply of high frequency in the working state of electronic equipment is high frequency, not close to the work of the low-frequency state. In the operating principle of the switching power supply, these operating conditions are certain.
Four, switching power supply schematic diagram --- switching power supply components
1. Main circuit
Inrush current limitation: limiting the power supply input side of the inrush current.
Input Filter: Used to filter stray waves in the grid, preventing machine-generated stray waves from feeding back into the grid.
Rectification and Filtering: Directly rectifies grid AC power into smoother DC power. Inverter: The rectified DC power supply is changed into high-frequency AC power, which is the core part of a high-frequency switching power supply
Output Rectifier and Filter: Provide stable and reliable DC power supply according to the load requirements.
2. Control circuit
Sampling from the output, compared with the set value, and then control the inverter, change its pulse width or pulse frequency, so that the output is stable; according to the data provided by the test circuit, identifying the protection circuit, and provide a variety of power supply control circuit. Safeguard.
3. Test circuit
Provides various parameters of the protection circuit operation and various instrument data.
4. Auxiliary power supply
To realize the power supply software (remote) start, protection circuits and control circuits and other working power.
The above is brought to you by us on the switching power supply schematic diagram of the relevant introduction.