An Introduction to How DC Power Supplies Control CC/CV Modes
DC power supply is a device used to provide stable DC current, commonly used in applications such as electronic devices, communication systems, and motor drives. In practical applications, it is often necessary to control the output current or output voltage of a DC power supply to meet different working requirements.
The most common control modes for DC power supplies are CC (constant current) and CV (constant voltage) modes. In CC mode, the current output by the power supply remains unchanged, while in CV mode, the voltage output by the power supply remains unchanged. The CC/CV mode for controlling DC power supply can be implemented using different technologies and methods.
A common implementation method is to use feedback control circuits. In this method, the output current or output voltage of the DC power supply is detected by sensors and fed back to the control circuit, which adjusts the output of the DC power supply based on the feedback signal. For example, in CC mode, when the output current is lower than the set value, the control circuit will increase the output current by adjusting the output of the power supply until it reaches the set value. In CV mode, when the output voltage is lower than the set value, the control circuit will adjust the output of the power supply to increase the output voltage until it reaches the set value.
Another implementation method is to use PWM (Pulse Width Modulation) technology. PWM is a technology that converts analog signals into digital signals, adjusting the output current or output voltage by controlling the pulse width of the signal. In this method, the output current or output voltage of the DC power supply is compared with a reference signal through a comparator, and then the conduction time of the switching device is controlled based on the comparison result to adjust the output current or output voltage. For example, in CC mode, when the output current is lower than the set value, the control circuit will increase the conduction time of the switching device, thereby increasing the output current until it reaches the set value. In CV mode, when the output voltage is lower than the set value, the control circuit will reduce the conduction time of the switching device, thereby increasing the output voltage until it reaches the set value.
In addition to these common control methods, there are other techniques that can be used to control the CC/CV mode of DC power supply. For example, current folding technology can be used to protect the power supply when the output current reaches the set value, thereby achieving constant current control. Soft switching technology can also be used to improve the efficiency and response speed of DC power supplies. In addition, digital signal processors (DSPs) or microcontrollers can be used to achieve more advanced control functions, such as automatic adjustment of power output, real-time monitoring, and protection.
