As a common switching power supply, the core function of the power array is to convert AC power into DC power to power electronic devices. In order
to ensure stable stability, high efficiency and safety, current mode control (CMC) technology has been widely used.
Why does the power supply need current mode control?
Fast response: In the fast charging scenario, the power supply needs to be able to quickly adjust the output current to meet the charging needs
of the device.
High efficiency: By accurately controlling the on-time of the switch tube, the switching loss can be reduced and the power conversion efficiency
can be improved.
Protection function: Current mode control can realize overcurrent protection, short-circuit protection and other functions to ensure the safety of
equipment and users.
Load regulation: In the case of increased load changes, current mode control can quickly adjust the output to keep the output voltage stable.
Commonly used current mode control schemes in power supply
Maximum current mode control: suitable for fast response occasions, such as fast charging.
Average current mode control: suitable for occasions with high precision requirements, such as precision instrument power supply.
Digital PWM control: combined with a digital signal processor (DSP), it can achieve more flexible and precise control.
Application of current detection technology in power supply
Resistor detection method: connect a small resistor in series in the output circuit, and calculate the current by measuring the voltage across the resistor.
Current transformer method: isolate the current signal, suitable for high voltage and large current occasions.
Hall effect sensor method: non-contact measurement, suitable for miniaturized design.
Advantages of current mode control of power supply
Fast dynamic response: In the case of sudden load changes, current mode control can respond quickly and keep the output voltage stable.
High efficiency: By accurately controlling the on-time of the switch tube, the switching loss is reduced and the conversion efficiency is improved.
Good anti-interference: Current mode control has the ability to suppress noise and voltage.
Easy to implement overcurrent protection: By monitoring the current, the power outage can be quickly cut off to protect the equipment.
Design considerations for current mode control of power supply
Stability: Design a reasonable compensation network to ensure the stability of the system.
Noise suppression: Use suppression circuit to suppress the impact on noise measurement results.
Temperature compensation: Consider the impact of temperature on component parameters and perform temperature compensation.
EMC design: Comply with electromagnetic compatibility standards to reduce interference with other equipment.
Power Development The Future of Current Mode Control
Integration: Integrate current detection circuits into power devices to reduce circuit board area.
Digitalization: Use digital signal processors (DSPs) to achieve more accurate current measurement and control.
Customization: Adaptive charging is achieved through big data analysis and artificial intelligence algorithms.
Conclusion
The application of the current control mode in the power adapter has significantly improved the performance and reliability of the bracket. With the continuous development of technology, the current control mode will play an increasingly important role in the power adapter.
