Components of a DC regulated power supply? What is the design principle?
With the development and innovation of power electronics technology, DC power supply technology has been constantly innovating. Currently, DC stabilized power supplies are widely used in almost all electronic devices. It has the characteristics of small size, light weight and high efficiency. For the rapid development of today's electronic information industry, this is an essential power supply method. So, what are the main components of the DC regulated power supply? What is the design principle?
1. What are the main components of a regulated DC power supply?
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1. Main circuit
Inrush Current Limit: Limits the inrush current on the input side at power-on.
Input filter: Its function is to filter the chaos existing in the grid and prevent the clutter generated by the machine from returning to the grid.
Rectification and filtering: rectifies AC power directly to the grid to convert it to a more uniform DC power supply
Inverter: converts rectified direct current into high frequency alternating current, and the core of the power supply is stable high frequency direct current.
Output rectification and filtering: provide stable and reliable DC power supply according to load requirements
2. Control circuit
On the one hand, samples are taken from the output terminals compared to the set value, and then the inverter is commanded to change its pulse width or pulse frequency to stabilize the output, which is determined by the power protection circuit. The control circuit implements various measures to protect the power supply.
3. Detection circuit
Enter various parameters and device data to make the protection circuit work.
4. Auxiliary power supply
Execute the work of the power supply (remote start), power protection circuit and control circuit (PWM, etc.) of the software chip.
2. Detailed description of the construction principle of the stable DC power supply
The working principle of a transformer is based on the law of electromagnetic induction for the conversion of voltage, current and impedance. When building a DC stabilized power supply, the power transformer usually converts the 220V single-phase AC voltage to a lower AC voltage to meet the requirements of the following circuits. Based on the DC voltage and current values required by the circuit, determine the number of outlets on the secondary side of the power transformer and the voltage and wattage each outlet should provide. In addition, in order to reduce the size and weight of the power transformer, a high-frequency power transformer should be selected.
Using the unidirectional conductivity of a diode to convert AC voltage to DC unidirectional voltage is called rectification. In actual design, the appropriate rectification method should be selected according to the output accuracy and the required quality characteristics of the produced power supply.
When designing a DC regulated power supply, the AC voltage can be filtered by the property that the voltage across energy storage elements (such as inductors and capacitors) cannot change abruptly to a less volatile DC output. The filtered DC power output always contains more AC components, so it cannot be applied directly across the load and must be stabilized.
On the contrary, when the Zener tube is broken, it exhibits voltage stabilization performance within a certain current range, so it can be used to stabilize the DC output voltage. However, this power supply has lower stability and lower output accuracy. Therefore, a three-terminal built-in voltage regulator is usually selected. As long as the power supply meets the design requirements, the design cycle can be shortened and the design cost can be reduced, and the output is stable and reliable.
