Driving circuit for LED lamp, LED lamp containing same and method for operating driving circuit

#The present application relates to Light Emitting Diode (LED) illumination technology, and particularly relates to a driving circuit for an LED lamp and the LED lamp containing the same, and the driving circuit is configured to perform three-stage dimming control on an LED load of the LED lamp.

#A three-stage dimming driving circuit of a related LED lamp adopts three-wire inputs in which two wires are live wires, and one wire is a zero wire, there is a three-stage selection switching circuit between the three-wire inputs and the three-stage dimming driving circuit. With the three-stage selection switching circuit, two-wire connection of one live wire and one zero wire may be selected, or connection of two live wires and one zero wire is selected. The related three-stage dimming control circuit is capable of adjusting a current level output from the driving circuit to an LED load by connecting two live wires to switching action pins DET1 and DET2 of a constant current control chip in the driving circuit respectively, thereby achieving three-stage dimming. This scheme requires a special constant current control chip which needs to have the switching action pins DET1 and DET2 and to withstand a high voltage, so that the constant current control chip has a high cost, a small circuit design space and low flexibility.

#A main object of the present disclosure is to provide a driving circuit capable of performing three-stage dimming control on an LED lamp and the LED lamp containing the driving circuit, in order to solve problems in the prior art that a constant current control chip is high in cost and poor in platform compatibility, thereby achieving the driving circuit with the low cost and good platform compatibility without switching action pins DET1 and DET2 of the constant current control chip, so that a circuit design space is larger.

#Drawings of the description for constituting a part of the present application are used to provide further understanding of the present disclosure, exemplary embodiments of the present disclosure and description thereof are used to explain the present disclosure, rather than constituting improper limitation to the present disclosure. In the drawings:

#FIG. 1 is a simplified circuit diagram of a three-stage dimming control operating principle of a driving circuit for an LED load according to the present disclosure.

#FIG. 2 is a curve diagram for describing a relation between maximum on-time of a constant current control chip of the driving circuit for the LED load and a resistance of a resistor connected to a maximum on-time pin.

#It is to be noted that in the case without conflicting, embodiments in the present application and features in the embodiments may be mutually combined. The present disclosure is described in detail below with reference to the drawings and in combination with the embodiments.

#It is to be noted that unless otherwise specified, all technical and scientific terms used in the present application have the same meanings as commonly understood by those of ordinary skill in the art of the present application.

#In the present disclosure, in the case without contrary description, orientation words used such as “up, down, top and bottom” usually refer to directions as shown in the drawings, or refer to upright, vertical or gravitational directions of a component itself; similarly, in order to understand and describe conveniently, “inner and outer” refer to the inner and outer relative to an outline of each component itself, but the above orientation words are not used to limit the present disclosure.