Switching power supply products will be optimized in the design of many electronic products, excellent switching power supply can effectively protect electronic products from high voltage damage, and can effectively improve the service life of the products. Power resistors are often seen in switching power supply products, which are often used by designers to protect power products when designing switching power supplies.
 

 

The linear power supply may be less efficient because of the energy consumption of transmission devices and loads in series. The higher the pressure drop on the load, the lower the efficiency. To improve efficiency, designers often use another power topology. The switching power supply adopts unregulated input DC voltage and switches at high frequencies (10kHz to 1MHz). The duty cycle determines the rectified and smoothed DC output voltage.
 
Power resistors and dividers are also used to adjust the output of the switching power supply, but switching frequency and duty cycle also need to be adjusted. By avoiding loss caused by voltage drop of linear voltage regulator, switching power supply can achieve up to 95% efficiency. Because the size of the high frequency transformer and filter / energy storage capacitor is much smaller, the switching power supply may also be more compact than the linear AC-DC power supply with similar power.
 

 

 

The main disadvantage of the switching power supply is that it requires a minimum load, no-live load condition may damage the power supply. To avoid this, the designer often uses a power resistor as the dummy load. If the main load is off, the resistor can be used to absorb the minimum specific load current. The dummy load resistor, of course, also has power consumption, which affects the overall power efficiency and therefore needs to be taken into account when the resistor is selected. Another approach to circumvent this problem is to use a shunt resistor at the output when the load is open. Other resistors are also used for switching power supply designs for safety purposes. Low-resistance, high-power resistors generally prevent over-voltage conditions. And the current-limiting design can prevent the short circuit.
 

 

A switching power supply product, generally designed with a power electrical appliance, may also be used in a DC-DC converter design to adjust a value of the dc voltage to another value. The buck converter is very similar in operation to the aforementioned switching power supply design. The boost converter uses the charge pump technology to output a higher voltage than the input. Both technologies use similar methods to adjust the output voltage and provide circuit protection.