CN102946676B

CN102946676B - Constant voltage and constant current power supply of light-emitting diode (LED) lamp

Info

Publication number: CN102946676B
Application number: CN201210484429.3A
Authority: CN
Inventors: 戴文良
Original assignee: NINGBO AISHI ELECTRIC EQUIPMENT CO Ltd
Current assignee: NINGBO AISHI ELECTRIC EQUIPMENT CO Ltd
Priority date: 2012-11-23
Filing date: 2012-11-23
Publication date: 2015-01-07
Anticipated expiration: 2032-11-23
Also published as: CN102946676A

Abstract

The invention provides a constant voltage and constant current power supply of a light-emitting diode (LED) lamp, belongs to the field of power circuits and solves the problems that the existing constant voltage and constant current power supply of the LED lamp is not high in control accuracy. The constant voltage and constant current power supply of the LED lamp comprises an input module, a power conversion module, a ramp generator, a voltage comparator, a blocking oscillator, a constant voltage deviation amplifying circuit, a phase shift pulse-width modulation (PWM) module, a duty ratio control module and a plurality of parallel-connection LED circuits. The constant voltage and constant current power supply of the LED lamp obtains error signals through a comparison circuit, enables the phase shift PWM module to conveniently adjust phase difference of all voltage output to all the LED circuits according to square signals formed through error signal conversion, and accordingly can control a plurality of LED lamps accurately and stably.

Description

A kind of LED constant voltage constant current power

Technical field

The present invention relates to power circuit field, particularly relate to a kind of LED constant voltage constant current power.

Background technology

The effect of LED constant voltage constant current power is that alternating current is converted to direct current for LED.The LED constant voltage constant current power of prior art comprises input module, rectification module, power conversion module, output rectification module, output module and control module.But existing LED constant voltage constant current power in use, alternating current voltage due to external world's input there are differences and existing LED constant voltage constant current power control mode is simple, LED control precision for multiple parallel connection or series connection is inadequate, and the fluctuation of its electric current and voltage exporting to each LED is larger.

Summary of the invention

The technical problem to be solved in the present invention is to provide that a kind of control precision is high, dynamic property good and can controls the LED constant voltage constant current power of multiple LED.

The technical scheme that the present invention solves the employing of its technical problem is, a kind of LED constant voltage constant current power is proposed, it comprises input module, alternating current is converted to galvanic power conversion module, ramp generator, the LED circuit of voltage comparator, blocking oscillator, constant voltage deviation amplifying circuit, PWM phase-shift PWM module, duty cycle control module and multiple parallel connection; the d. c. voltage signal of power conversion module conversion inputs to ramp generator, voltage comparator is exported to after ramp generator is level and smooth by d. c. voltage signal, the sampled voltage signal of multiple LED circuit exports constant voltage deviation amplifying circuit to, sampled voltage signal after constant voltage deviation amplifying circuit amplifies exports voltage comparator to, voltage comparator outputs control signals to blocking oscillator after comparing the d. c. voltage signal of ramp generator input and the sampled voltage signal of constant voltage deviation amplifying circuit input, blocking oscillator exports PWM phase-shift PWM module and duty cycle control module to after this control signal is become square-wave signal, described duty cycle control module is according to the d. c. voltage signal exported after the conversion of this square wave signal controlling power conversion module, described PWM phase-shift PWM module adjusts its voltage-phase exporting each LED circuit to according to this square-wave signal and makes the voltage-phase difference of adjacent LED circuit be 360 °/N, wherein N is the number of LED circuit in parallel.

Further, described blocking oscillator comprises the first resistance, the second resistance, the 3rd resistance, the 4th resistance, transformer, diode, triode, the first electric capacity, the second electric capacity; First resistance one end access voltage comparator output, accesses primary first end after the first resistance other end accesses the second resistance; First electric capacity one end is accessed between the first resistance and the second resistance, other end ground connection; Primary second termination enters transistor base, transistor collector access transformer secondary output first end, transformer secondary output and the second electric capacity and diodes in parallel are arranged, and transistor emitter is by connecting with voltage comparator output after the 3rd resistance, the 4th resistance step-down; Second electric capacity is connected with PWM phase-shift PWM module and duty cycle control module respectively.

Further, described PWM phase-shift PWM module comprises two CD4046 chips and a LM311 comparator, a described CD4046 chip input accesses described square-wave signal, output access comparator LM311 first end, LM311 second termination enters to the power supply of its power supply, LM311 output access the 2nd CD4046 chip input, the 2nd CD4046 chip output accesses each LED circuit.

The present invention obtains error signal by adopting comparison circuit, and error signal is converted to square-wave signal and is convenient to PWM phase-shift PWM module and exports the voltage phase difference of each LED circuit to according to the adjustment of this square-wave signal, thus make constant voltage constant current power of the present invention can control multiple LED and control is more accurate and stable.

Accompanying drawing explanation

Fig. 1 is the schematic block circuit diagram of LED constant voltage constant current power of the present invention;

Fig. 2 is the circuit diagram of blocking oscillator in Fig. 1;

Fig. 3 is the circuit block diagram of PWM phase-shift PWM module in Fig. 1.

Embodiment

Be below specific embodiments of the invention and by reference to the accompanying drawings, technical scheme of the present invention is further described, but the present invention be not limited to these embodiments.

Please refer to Fig. 1, Fig. 1 is the schematic block circuit diagram of LED constant voltage constant current power of the present invention.In Fig. 1, LED constant voltage constant current power of the present invention comprises input module 10, alternating current is converted to galvanic power conversion module 11, ramp generator 12, the LED circuit 18 of voltage comparator 13, blocking oscillator 14, constant voltage deviation amplifying circuit 15, PWM phase-shift PWM module 16, duty cycle control module 17 and multiple parallel connection.

The d. c. voltage signal that power conversion module 11 is changed inputs to ramp generator 12, voltage comparator 13 is exported to after ramp generator 12 is level and smooth by d. c. voltage signal, the sampled voltage signal of multiple LED circuit 18 exports constant voltage deviation amplifying circuit 15 to, sampled voltage signal after constant voltage deviation amplifying circuit 15 amplifies exports voltage comparator 13 to, voltage comparator 13 outputs control signals to blocking oscillator 14 after comparing the d. c. voltage signal of ramp generator 12 input and the sampled voltage signal of constant voltage deviation amplifying circuit 15 input, blocking oscillator 14 exports PWM phase-shift PWM module 16 and duty cycle control module 17 to after this control signal is become square-wave signal, described duty cycle control module 17 changes the d. c. voltage signal of rear output according to this square wave signal controlling power conversion module 11, described PWM phase-shift PWM module 16 adjusts its voltage-phase exporting each LED circuit 18 to according to this square-wave signal and makes the voltage-phase difference of adjacent LED circuit 18 be 360 °/N, wherein N is the number of LED circuit in parallel.In Fig. 1, draw 3 LED circuits in parallel altogether, then now N value is 3 and the voltage-phase difference of adjacent LED circuit is 120 °.

The d. c. voltage signal that the present invention adopts ramp generator 12 preliminary treatment to export voltage comparator 13 to makes the comparative effectiveness of comparator more accurate.

Use PWM phase-shift PWM module to make the current impulse in each LED circuit saltus step can not occur, the magnitude of voltage now exported by duty cycle control module modulation power modular converter 11 again can guarantee that the electric current of each bar LED circuit is all equal simultaneously.

PWM phase-shift PWM module 16 and duty cycle control module 17 all need input square-wave signal effectively to modulate, and the control signal that traditional voltage comparator exports is not square-wave signal.The present invention is converted to square-wave signal by adopting blocking oscillator 14 control signal that makes voltage comparator 13 export, thus is that PWM phase-shift PWM module 16 and duty cycle control module 17 phase modulation or voltage become possibility.

Further, the circuit diagram of blocking oscillator 14 of the present invention as shown in Figure 2.In Fig. 2, the electronic component that blocking oscillator 14 mainly comprises has: the first resistance R1, the second resistance R2, the 3rd resistance R3, the 4th resistance R4, transformer T, diode D, triode V, the first electric capacity C1, the second electric capacity C2.First resistance R1 one end access voltage comparator 13 output, access the elementary first end of transformer T after the first resistance R1 other end accesses the second resistance R2, first electric capacity C1 one end is accessed between the first resistance R1 and the second resistance R2, other end ground connection; Elementary second termination of transformer T enters triode V base stage, triode V collector electrode access transformer T level first end, transformer T level and the second electric capacity C2 and diode D are arranged in parallel, and triode V emitter is by accessing voltage comparator 13 output after the 3rd resistance R3, the 4th resistance R4 step-down; Second electric capacity C2 accesses PWM phase-shift PWM module 16 and duty cycle control module 17.

When voltage comparator 13 exports high level, the first electric capacity C1 starts charging, triode V conducting, produces collector current, and primary is serially connected in triode V base loop formation positive feedback and makes triode saturated, and transformer T is elementary saturated simultaneously.Transformer T elementary saturated after, transformer T secondary voltage declines, thus transistor collector electric current is declined, and triode V exits saturation condition; Then repeat said process, thus on the second electric capacity C2, form the process of charging back and forth to export square-wave signal to PWM phase-shift PWM module 16 and duty cycle control module 17.

Please refer to Fig. 3, PWM phase-shift PWM module of the present invention comprises two CD4046 chips and a LM311 comparator, a described CD4046 chip input accesses described square-wave signal, output access comparator LM311 first end, LM311 second termination enters to the power supply of its power supply, LM311 output access the 2nd CD4046 chip input, the 2nd CD4046 chip output accesses each LED circuit.

CD4046 is general CMOS phase-locked loop intergrated circuit, and LM311 is also comparatively conventional comparator.One CD4046 exports the sawtooth waveforms with square-wave signal same frequency, this sawtooth waveforms and square-wave signal are output to LM311, the comparative level of LM311 changes, comparator output signal Front movement, comparator output signal export to the 2nd CD4046 carry out phase-locked after, an input signal then in advance part thus realize Phasing is compared in the signal leading edge that the 2nd CD4046 exports.

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendment or supplement or adopt similar mode to substitute to described specific embodiment, but can't depart from spirit of the present invention or surmount the scope that appended claims defines.

Claims

1. a LED constant voltage constant current power, it is characterized in that, comprise input module, alternating current is converted to galvanic power conversion module, ramp generator, the LED circuit of voltage comparator, blocking oscillator, constant voltage deviation amplifying circuit, PWM phase-shift PWM module, duty cycle control module and multiple parallel connection; the d. c. voltage signal of power conversion module conversion inputs to ramp generator, voltage comparator is exported to after ramp generator is level and smooth by d. c. voltage signal, the sampled voltage signal of multiple LED circuit exports constant voltage deviation amplifying circuit to, sampled voltage signal after constant voltage deviation amplifying circuit amplifies exports voltage comparator to, voltage comparator outputs control signals to blocking oscillator after comparing the d. c. voltage signal of ramp generator input and the sampled voltage signal of constant voltage deviation amplifying circuit input, blocking oscillator exports PWM phase-shift PWM module and duty cycle control module to after this control signal is become square-wave signal, described duty cycle control module is according to the d. c. voltage signal exported after the conversion of this square wave signal controlling power conversion module, described PWM phase-shift PWM module adjusts its voltage-phase exporting each LED circuit to according to this square-wave signal and makes the voltage-phase difference of adjacent LED circuit be 360 °/N, wherein N is the number of LED circuit in parallel,

Described blocking oscillator comprises the first resistance, the second resistance, the 3rd resistance, the 4th resistance, transformer, diode, triode, the first electric capacity, the second electric capacity; First resistance one end access voltage comparator output, accesses primary first end after the first resistance other end accesses the second resistance; First electric capacity one end is accessed between the first resistance and the second resistance, other end ground connection; Primary second termination enters transistor base, transistor collector access transformer secondary output first end, transformer secondary output and the second electric capacity and diodes in parallel are arranged, and transistor emitter is by connecting with voltage comparator output after the 3rd resistance, the 4th resistance step-down; Second electric capacity is connected with PWM phase-shift PWM module and duty cycle control module respectively.

2. LED constant voltage constant current power according to claim 1, it is characterized in that, described PWM phase-shift PWM module comprises two CD4046 chips and a LM311 comparator, a described CD4046 chip input accesses described square-wave signal, output access comparator LM311 first end, LM311 second termination enters to the power supply of its power supply, and LM311 output access the 2nd CD4046 chip input, the 2nd CD4046 chip output accesses each LED circuit.