Comparison Between High Frequency DC Power Supply And Switching Power Supply

The working process of the high-frequency DC power main circuit is that the input power is first subjected to preliminary AC voltage stabilization by the pre-stabilizing circuit, and then converted into DC power through isolation rectification by the main working transformer, and then is intelligently controlled by the control circuit and single-chip microprocessor controller Finely adjust the linear adjustment component to output a high-precision DC voltage source.

1. Power transformer and rectifier: convert 380V AC power into the required DC power.
2. Pre-stabilizing circuit: Use relay components or thyristor components to pre-adjust and initially stabilize the input AC or DC voltage, thereby reducing the power consumption of linear adjustment components, improving work efficiency, and ensuring high accuracy of the output voltage source. and high stability.
3. Linear adjustment component: Finely adjust the filtered DC voltage so that the input voltage reaches the required value and accuracy requirements.
4. Filter circuit: Block and absorb the pulsation wave, interference, and noise of the DC power supply to the maximum extent, thereby ensuring that the output voltage of the DC power supply has low ripple, low noise, and low interference.
   The voltage feedback circuit of the high-frequency DC power supply works in a linear (amplified) state, while the switching power supply means that the tube used for voltage adjustment works in the saturation and cut-off areas, that is, the switching state.

The high-frequency DC power supply generally samples the output voltage and then sends it to the comparison voltage amplifier with the reference voltage. The output of this voltage amplifier is used as the input of the voltage adjustment tube to control the adjustment tube so that the junction voltage changes with the change of the input, thereby adjusting Its output voltage, but the switching power supply changes the output voltage by changing the on and off time of the regulating tube, that is, changing the duty cycle!

Judging from its main characteristics: the high-frequency DC power supply technology is very mature, the production cost is low, it can achieve high stability, the ripples are small, its own interference and noise are relatively small, but because it works at the power frequency (50Hz) , the transformer is relatively large and has low efficiency (generally the efficiency at full load is only about 80%). The overall volume is large and bulky. And the input voltage range is required to be high; while the switching power supply operates in a high-frequency state, the size of the transformer It is relatively small and lightweight, but the output ripple is larger than that of higher-frequency DC power supplies. However, due to its simple structure, low cost and high efficiency (the efficiency of switching power supplies on the market can also reach more than 90%), it has been replaced in many occasions. High-frequency DC power supply is the future development trend of power supply.