CN202475873U - LED energy-saving lamp circuit - Google Patents

Abstract

The utility model discloses an LED (light emitting diode) energy-saving lamp circuit comprising a rectification filter circuit, a starting circuit, an oscillating circuit, a follow current circuit, a constant current control circuit and an output circuit, wherein the rectification filter circuit is connected with the starting circuit and the oscillating circuit respectively; the oscillating circuit is connected with the output circuit; the follow current circuit is connected with the oscillating circuit; and the constant current control circuit is connected with the starting circuit, the oscillating circuit and the output circuit. The LED energy-saving lamp circuit has the benefits of simple and compact structure, less elements, low manufacturing cost, stable performance, low energy consumption, high efficiency, safe and reliable work, long service life, extensive use, and constant current-controlled switch power.

Description

LED energy-saving lamp circuit

technical field

The utility model relates to a lighting lamp circuit, in particular to an LED energy-saving lamp circuit.

Background technique

With the continuous development of my country's economy and the continuous improvement of people's living standards, people's demand for lighting fixtures has also increased rapidly, and at the same time, more attention has been paid to the quality and effect of lighting fixtures. As a new type of light source, LED energy-saving lamps have the advantages of long service life, low energy consumption, hygiene and environmental protection, and the scope of use is rapidly expanding. However, most of the driving power sources of LED energy-saving lamps sold on the market are used for low voltage. If they are used for 220v AC, an additional ballast is required, which is huge and complicated, and inconvenient to use. It can be used for 220v AC, most of which are driven by resistance-capacity current-limiting power supply or resistance current-limiting power supply, without constant current function. Although it is simple, it has low efficiency and unstable performance, and cannot meet the requirements of LED energy-saving lamps.

Contents of the invention

The purpose of the utility model is to overcome the deficiencies of the prior art and provide an LED energy-saving lamp circuit with high efficiency and stable performance.

The purpose of this utility model is to be realized through the following technical solutions:

An LED energy-saving lamp circuit, comprising a rectification and filtering circuit, a starting circuit, an oscillation circuit, a freewheeling circuit, a constant current control circuit and an output circuit; the rectification and filtering circuit is respectively connected to the starting circuit and the oscillation circuit, and the oscillation circuit is connected to the output circuit , the freewheeling circuit is connected with the oscillating circuit, and the constant current control circuit is respectively connected with the starting circuit, the oscillating circuit and the output circuit.

The rectification and filtering circuit is composed of a bridge rectifier D1 and a filter capacitor C1, and pins 1 and 4 of the bridge rectifier D1 are respectively connected to the positive and negative poles of the filter capacitor C1; the starting circuit is composed of a starting resistor R1; the oscillation The circuit is composed of switching tube Q1, switching transformer T1 and feedback resistor R2. The e pole of switching tube Q1 is connected to pin 1 of switching transformer T1. One end of feedback resistor R2 is connected to b pole of switching tube Q1, and the other end is connected to switching transformer T1. The 2-pin connection; the freewheeling circuit is made up of the freewheeling diode D2; the constant current control circuit is made up of the signal amplifier transistor Q3, the control transistor Q2, the sampling resistor R3, the b pole of the control transistor Q2 and the signal amplifier transistor Q3 The c pole is connected, and the two ends of the sampling resistor R3 are respectively connected with the e pole and the b pole of the signal amplifying transistor Q3; the output circuit is composed of a filter capacitor C2 and a load LED1.

The beneficial effects of the utility model are:

1. The structure is simple and compact, the components are few, and the production cost is low.

2. Switching power supply plus constant current control, stable performance, meeting the working requirements of LED energy-saving lamps.

3. Low energy consumption, high efficiency, safe and reliable work, and long service life.

Description of drawings

Fig. 1 is the circuit block diagram of the present utility model.

Fig. 2 is the schematic circuit diagram of the utility model.

The marks in the figure are: 1-rectification and filtering circuit, 2-starting circuit, 3-oscillating circuit, 4-freewheeling circuit, 5-constant current control circuit, 6-output circuit.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail:

The utility model LED energy-saving lamp circuit block diagram as shown in Figure 1, comprises rectification filter circuit 1, starting circuit 2, oscillation circuit 3, freewheeling circuit 4, constant current control circuit 5 and output circuit 6; Said rectification filter circuit 1 They are respectively connected to the starting circuit 2 and the oscillating circuit 3, the oscillating circuit 3 is connected to the output circuit 6, the freewheeling circuit 4 is connected to the oscillating circuit 3, and the constant current control circuit 5 is connected to the starting circuit 2, the oscillating circuit 3 and the output circuit 6 respectively.

The circuit schematic diagram of the utility model is shown in Figure 2, the rectification filter circuit 1 is composed of a bridge rectifier D1 and a filter capacitor C1; the starting circuit 2 is composed of a starting resistor R1; the oscillation circuit 3 is composed of a switching tube Q1 , switching transformer T1 and feedback resistor R2; the freewheeling circuit 4 is made up of a freewheeling diode D2; the constant current control circuit 5 is made up of a signal amplifier transistor Q3, a control transistor Q2, and a sampling resistor R3; the output circuit 6 is composed of filter capacitor C2 and load LED1. Circuit connection:

Pin 2 of the bridge rectifier D1 is connected to one input end of the mains, and pin 3 of the bridge rectifier D1 is connected to the other input end of the mains; pin 1 of the bridge rectifier D1 is respectively connected to the positive pole of the filter capacitor C1 and the starting resistor One end of R1 is connected to the c-pole of the switch tube Q1; the 4-pin of the bridge rectifier D1, the negative pole of the filter capacitor C1, the e-pole of the control transistor Q2, the negative pole of the LED1, the negative pole of the filter capacitor C2, and the positive pole of the freewheeling diode D2 Connect to the ground; the other end of the starting resistor R1 is respectively connected to the b pole of the switching tube Q1, one end of the feedback resistor R2 and the c pole of the control transistor Q2; the e pole of the switching tube Q1 is respectively connected to the negative pole of the freewheeling diode D2 and the switching transformer Pin 1 of T1 is connected; pin 2 of switching transformer T1 is connected with the other end of feedback resistor R2; pin 3 of switching transformer T1 is respectively connected with one end of sampling resistor R3, the positive pole of filter capacitor C2 and the e pole of signal amplifying transistor Q3; The c pole of the signal amplifying transistor Q3 is connected with the b pole of the control transistor Q2; the b pole of the signal amplifying transistor Q3 is respectively connected with the other end of the sampling resistor R3 and the anode of the LED1.

The working principle of this LED energy-saving lamp circuit:

The 220-volt mains is rectified by the bridge rectifier D1 and filtered by the filter capacitor C1 to obtain a smooth direct current all the way to the collector of the switch tube Q1, and then shunted by the start-up resistor R1 to the base of the switch tube Q1 to start the oscillation circuit. After the tube Q1 is started by the starting resistor R1, a weak current flows out from the emitter. This current flows into the 1 pin of the switching transformer T1 and flows out from its 3 pin. The 1 pin and 3 pin of the switching transformer T1 are primary windings, and the 1 pin and Pin 2 is the feedback winding. At this time, the feedback winding of the switching transformer T1 generates a feedback current that is input to the base of the switching tube Q1 through the feedback resistor R2 to form positive feedback, so that the switching tube Q1 is quickly saturated and turned on, and the switching tube Q1 is saturated and turned on. The current through the primary winding of the switching transformer T1 increases from small to maximum, and the rate of change of the current decreases at this time, so the feedback current generated by the feedback winding of the switching transformer T1 also decreases and reversely causes the switching tube Q1 to withdraw from saturation conduction and quickly cutoff, thus completing one oscillation cycle. Next, the switch tube Q1 enters the next oscillation cycle after being started by the start-up resistor R1. When the switching tube Q1 is turned off, the energy stored in the switching transformer T1 is freewheeled by the freewheeling diode D2 and then transmitted to the load LED1 through the primary winding of the switching transformer T1 to be released. The pulse current flowing from pin 3 of the switching transformer T1 is filtered by the filter capacitor C2 and then flows to the sampling resistor R3. The signal of the output current change is taken out through the sampling resistor R3 and then output to the load LED1 from the other end. The load LED1 is composed of one or several Composed of light-emitting diodes. The signal taken out from the sampling resistor R3 is amplified by the signal amplifier transistor Q3 and then reaches the base of the control transistor Q2, and the control transistor Q2 controls the switch tube Q1 to achieve the purpose of constant current output.

The advantage of placing the switch transformer T1 behind the switch tube Q1 in the circuit of the utility model is: the freewheeling winding is omitted, and the switch tube Q1 does not bear the high voltage generated by the switch transformer T1 when it is cut off, so that the switch tube Q1 is cut off. The energy stored in the switching transformer T1 is fully released to the load LED1.

Claims (2)

1. A kind of LED energy-saving lamp circuit, it is characterized in that: comprise rectifying and filtering circuit, starting circuit, oscillation circuit, freewheeling circuit, constant current control circuit and output circuit; Described rectifying and filtering circuit is connected with starting circuit and oscillation circuit respectively, The oscillating circuit is connected with the output circuit, the freewheeling circuit is connected with the oscillating circuit, and the constant current control circuit is respectively connected with the starting circuit, the oscillating circuit and the output circuit. 2. The LED energy-saving lamp circuit according to claim 1, characterized in that: the rectification filter circuit is composed of a bridge rectifier D1 and a filter capacitor C1, and pins 1 and 4 of the bridge rectifier D1 are respectively connected to the filter capacitor C1. The positive pole is connected to the negative pole; the starting circuit is composed of a starting resistor R1; the oscillating circuit is composed of a switching tube Q1, a switching transformer T1 and a feedback resistor R2, and the e pole of the switching tube Q1 is connected to pin 1 of the switching transformer T1, and the feedback resistor One end of R2 is connected to the b pole of the switching tube Q1, and the other end is connected to the 2 pin of the switching transformer T1; the freewheeling circuit is composed of a freewheeling diode D2; the constant current control circuit is composed of a signal amplifier transistor Q3 and a control transistor Q2 , sampling resistor R3, the b pole of the control triode Q2 is connected to the c pole of the signal amplifying transistor Q3, and the two ends of the sampling resistor R3 are respectively connected to the e pole and b pole of the signal amplifying transistor Q3; the output circuit is composed of a filter capacitor C2 And load LED1 composition.

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