Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A method of filtering a ripple can include: (i) generating, by a sampling circuit, a sense voltage signal that represents an output current flowing through a load; (ii) generating, by a filter circuit, a filter voltage signal by filtering the sense voltage signal, where the filter circuit includes a switch capacitor circuit and a filter capacitor; and (iii) generating, by an error amplifying circuit, an error compensation signal by amplifying a difference between the sense voltage signal and the filter voltage signal, where the error compensation signal is configured to compensate and regulate the output current flowing through the load by controlling a power switch that is coupled to the load and the sampling circuit.

Abstract: The present disclosure relates to an LED driving circuit and method using a single inductor. A constant current controller controls a power stage circuit to provide a constant output signal, and thus to provide a constant current signal for an LED load. A dimming controller regulates luminance of the LED load. A constant voltage generating circuit receives the current signal at an output terminal of the power stage circuit and a reserve supply voltage for providing a supply voltage for the dimming controller. Compared with the prior art, the present disclosure does not need an independent power supply chip, and reduces components such as inductors and rectifying transistors. Thus, a peripheral circuit is simplified, and an overall size of the system is reduced.

Abstract: A method of filtering a ripple can include: (i) generating, by a sampling circuit, a sense voltage signal that represents an output current flowing through a load; (ii) generating, by a filter circuit, a filter voltage signal by filtering the sense voltage signal, where the filter circuit includes a switch capacitor circuit and a filter capacitor; and (iii) generating, by an error amplifying circuit, an error compensation signal by amplifying a difference between the sense voltage signal and the filter voltage signal, where the error compensation signal is configured to compensate and regulate the output current flowing through the load by controlling a power switch that is coupled to the load and the sampling circuit.

Abstract: An LED driving circuit for driving an LED load including N LED strings, where N is a positive integer no less than 2, can include: (i) a power converter having a power switch; (ii) a constant current control circuit that controls a switching operation of the power switch such that the power converter generates a driving current for the LED load; (iii) N control switches respectively coupled in series to the N LED strings; (iv) a PWM signal generator configured to generate N color tuning PWM signals; and (v) a color tuning control circuit configured to output N switching control signals according to the N color tuning PWM signals, to control switching operations of the N control switches, to regulate a ratio of a current through each LED string of the LED load to the driving current, and to regulate the color temperature of the LED load.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: The present disclosure relates to an LED driving circuit and method using a single inductor. A constant current controller controls a power stage circuit to provide a constant output signal, and thus to provide a constant current signal for an LED load. A dimming controller regulates luminance of the LED load. A constant voltage generating circuit receives the current signal at an output terminal of the power stage circuit and a reserve supply voltage for providing a supply voltage for the dimming controller. Compared with the prior art, the present disclosure does not need an independent power supply chip, and reduces components such as inductors and rectifying transistors. Thus, a peripheral circuit is simplified, and an overall size of the system is reduced.

Abstract: A method of filtering a ripple can include: (i) generating, by a sampling circuit, a sense voltage signal that represents an output current flowing through a load; (ii) generating, by a filter circuit, a filter voltage signal by filtering the sense voltage signal, where the filter circuit includes a switch capacitor circuit and a filter capacitor; and (iii) generating, by an error amplifying circuit, an error compensation signal by amplifying a difference between the sense voltage signal and the filter voltage signal, where the error compensation signal is configured to compensate and regulate the output current flowing through the load by controlling a power switch that is coupled to the load and the sampling circuit.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A multichannel constant current LED controlling circuit can include: (i) a control loop configured to generate a first control signal in accordance with a current feedback signal that represents a driving current flowing through an LED load, where the LED load comprises a plurality of LED strings coupled in series; (ii) a loop steady state network comprising a plurality of steady state holding components configured to hold a plurality of steady state control signals that correspond to a plurality of load states of the LED load, where when a state of the LED load varies, at least one of the steady state holding components is selected by the control loop to generate the first control signal; and (iii) a power switching transistor of a power stage circuit configured to generate a pseudo-constant output current to drive the LED load.