LED (light-emitting diode) constant-current drive circuit, constant-current dimming circuit and control method of LED (light-emitting diode) constant-current dimming circuit

The invention discloses an LED (light-emitting diode) constant-current dimming circuit. The dimming circuit comprises a switching power supply module, a voltage sampling module, a current sampling module, a control module and a voltage regulation and feedback module, wherein the switching power supply module is used for supplying power to an LED load; the voltage sampling module is used for acquiring the output voltage; the current sampling module is used for acquiring the output current; the control module is connected with the voltage sampling module and the current sampling module; the voltage regulation and feedback module is connected with the control module and the switching power supply module; the control module is used for regulating the reference voltage output to the voltage regulation and feedback module according to the output voltage from the voltage sampling module and the output current from the current sampling module; the voltage regulation and feedback module is used for generating a corresponding voltage regulation signal according to the reference voltage and feeding the voltage regulation signal back to the switching power supply module so that the switching power supply module regulates the output voltage. The output voltage is regulated in real time by detecting the output current to achieve the function of setting the maximum constant current of the LED. The circuit has a simple structure and higher efficiency. Meanwhile, the invention also provides the corresponding LED constant current dimming circuit and a control method thereof.