A drive circuit and switching power supply

Abstract

The application discloses a driving circuit and a switching power supply. The driving circuit coupled to a light source comprises a pulse trigger circuit, a transformer and a relay. A first input terminal of the transformer is connected to a power supply voltage; a second input terminal of the transformer is connected with the pulse trigger circuit; a first output terminal of the transformer is connected with a first end of the relay; a second output terminal of the transformer is connected with a second end of the relay; a first end of a light source is connected with the second output terminal of the transformer; and a second end of the light source is coupled to the first output terminal of the transformer. When the light source works, the relay is connected and the working current of the light source flows through the relay. Therefore, the circuit loss can be reduced and the conversion efficiency can be improved; the volume and weight as well as the cost of the driving circuit canbe reduced to realize miniaturization; and a problem that the transformer makes audio noises due to the low-frequency commutation is solved.

Description

technical field [0001] The present application relates to the technical field of switching power supplies, in particular to a driving circuit and a switching power supply. Background technique [0002] With the increasing shortage of power resources, the traditional light bulb mode has failed to achieve the purpose of energy saving and emission reduction. In this case, HID lamps and other light sources are more and more widely used. HID light is an excellent light source with high efficiency and energy saving, but it has a defect, that is, it takes about 2-3 minutes to turn on the power under normal circumstances before the light can slowly light up, sometimes when there is a sudden power failure and the power supply is restored immediately It takes 10-20 minutes to light up again, and it cannot be turned on at one point like incandescent lamps and halogen lamps, which is very unsuitable for occasions that require instant start lighting. [0003] The inventor of the present...

AI Technical Summary

Problems solved by technology

HID light is an excellent light source with high efficiency and energy saving, but it has a defect, that is, it takes about 2-3 minutes to turn on the power under normal circumstances before the light can slowly light up, sometimes when there is a sudden power failure and the power supply is restored immediately It takes 10-20 minutes to light up again, and it cannot be turned on at one point like incandescent lamps and halogen lamps, which is very unsuitable for occasions that require instant start lighting

[0003] The inventor of the present application found in the long-term research and development process that in the prior art, in order to increase the lighting speed of the HID lamp, the lighting circuit of the ballast is usually used, that is, the driving circuit, while the traditional low frequency (tens of Hz to hundreds of Hz) ) The lighting circuit of HID ballast mostly adopts the pulse transformer starting method, but this method has many disadvantages: 1) Due to the large number of turns of the high-voltage side winding of the pulse transformer, the loss is large and the conversion efficiency of the whole machine is low; 2 ) During the low-frequency commutation of the light source current, the pulse transformer will generate audio noise; 3) In order to improve the conversion efficiency or light source power, the high-voltage side winding of the pulse transformer needs to use thicker wires, which will increase the volume and weight of the transformer large, increased cost

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