What is an adjustable switching power supply?An adjustable switching power supply is a power converter that adjusts the power supply of the device in the circuit by converting the voltage of the input power supply into the output voltage. Compared with linear regulators, adjustable switching power supplies have higher efficiency and smaller size.
The advantages of adjustable switching power supplies are high efficiency, good reliability, small size and light weight. However, it also has some disadvantages, such as large output ripple and strong electromagnetic interference. Therefore, when using an adjustable switching power supply, attention should be paid to electromagnetic compatibility, temperature management and noise control.
Structure and principle of adjustable switching power supply
The adjustable switching power supply includes components such as input filter capacitor, rectifier bridge, power switch, output filter inductor, output filter capacitor and feedback control circuit.
The working principle is to switch the input voltage into high-frequency pulses through high-frequency switching devices (such as MOSFET, IGBT, etc.), transform and filter the voltage and current through components such as transformers and output filter circuits, and finally output the required voltage and current.
Specifically, the working process of the adjustable switching power supply is as follows
Input filtering: The input voltage is filtered through the input filter capacitor to remove high-frequency noise in the power supply.
Rectification: The filtered voltage is converted from AC to DC through a rectifier bridge.
Switching conversion: The rectified DC enters a high-frequency switching device, such as a MOSFET tube, to convert the voltage into a high-frequency pulse. The switching frequency is usually above 20kHz, which can make the switching device switch at high speed and reduce power loss.
Transformer: The high-frequency pulse signal is transformed by the transformer to adjust the output voltage and current. The output of the transformer also needs to be filtered by a filter circuit to remove high-frequency noise and clutter.
Output filtering: The current output by the transformer is filtered by the output filter inductor and filter capacitor to remove high-frequency noise and clutter and obtain a smooth output current.
Feedback control: The adjustable switching power supply usually uses a feedback control circuit to keep the output voltage stable. The principle is to sample and compare the output voltage to obtain a feedback error signal, and then adjust the output voltage by controlling the duty cycle of the switching device to keep it stable.
Summary:The adjustable switching power supply converts the input voltage into a pulse signal through a high-frequency switching tube, and outputs a stable DC voltage after being processed by a transformer, a filter circuit and a voltage regulator circuit.
The feedback control circuit can achieve precise adjustment of the output voltage to meet the needs of different circuit devices.
