【 中文摘要 】本发明公开了一种共阴LED驱动电路构建方法，采用基于共低侧电流采样电阻的恒流驱动方式，所构建的共阴LED驱动电路包括电源，输入滤波电容，PMOS开关，续流二极管，储能滤波电感，输出滤波电容，LED构成的双色或三色共阴LED，电流采样电阻和驱动信号控制器；将输入滤波电容、PMOS开关，续流二极管，储能滤波电感、输出滤波电容、LED分别与电流采样电阻组成降压LED驱动器；驱动信号控制器通过反馈信号的变化对驱动信号进行调节以确保流经LED的电流恒定；调整采样电阻的阻值便能调节LED的最大工作电流；通过控制PWM信号的脉冲宽度可调节双色共阴LED的工作电流，从而调节双色或三色共阴LED的亮度。

【 英文摘要 】The invention discloses a method for constructing a common cathode LED driving circuit. Adopting a constant current driving manner based on a common low side current sampling resistor, the constructed common cathode LED driving circuit comprises a power supply, an input filter capacitor, a PMOS switch, a freewheeling diode, an energy storage filter inductor, an output filter capacitor, a double-color or three-color common cathode LED composed of an LED, a current sampling resistor and a driving signal controller; The input filter capacitor, the PMOS switch, the freewheeling diode, the energy storage filter inductor, the output filter capacitor and the LED are respectively combined with the current sampling resistor to form a step-down LED driver; The driving signal controller adjusts the driving signal according to the change of the feedback signal to ensure that the current flowing through the LED is constant; The maximum working current of the LED can be adjusted by adjusting the resistance of the sampling resistor; The working current of the two-color common-cathode LED can be adjusted by controlling the pulse width of the PWM signal, so that the brightness of the two-color or three-color common-cathode LED can be adjusted.

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