Single-segment linear constant-power LED driving circuit and method

A single-segment linear constant-power LED driving circuit, characterized in that the single-segment linear constant-power LED driving circuit at least comprises:

• a voltage input module, an LED load, a power switch tube, a sampling resistor, a current control module, a comparison module and an over-voltage control module;
• wherein
• the voltage input module is configured to provide an input voltage;
• the LED load is connected to an output terminal of the voltage input module and is powered by the voltage input module;
• a drain terminal of the power switch tube is connected to an output terminal of the LED load, and the control of constant current of the LED load is realized by turning on and turning off the power switch tube;
• one terminal of the sampling resistor is connected to a source terminal of the power switch tube, and another terminal of the sampling resistor is grounded for sampling and converting the current flowing through the power switch tube into a sampling voltage;
• the over-voltage control module is connected to the drain terminal of the power switch tube so as to detect a drain terminal voltage of the power switch tube, and when the voltage at the drain terminal of the power switch tube is greater than a set high voltage, the over-voltage control module outputs a turn-off signal to turn off the current flowing through the LED load;
• the current control module is connected to a compensation capacitor, and another terminal of the compensation capacitor is grounded;
• the current control module receives the sampling voltage and integrates the compensation capacitor to generate a control signal to limit the peak current flowing through the power switch tube, thereby achieving a constant current average value in different input voltage periods;
• meanwhile, the turn-off signal is received to turn off the current flowing through the LED load when the turn-off signal is enabled, thereby reducing power consumption;
• the comparison module is connected to the sampling resistor and the current control module, and compares the sampling voltage with the control signal to generate a switching signal of the power switch tube so as to realize the control of constant current of the LED load.