CN202026505U

CN202026505U - Light emitting diode (LED) constant current source

Info

Publication number: CN202026505U
Application number: CN2011200784843U
Authority: CN
Inventors: 方友维
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-23
Filing date: 2011-03-23
Publication date: 2011-11-02
Anticipated expiration: 2021-03-23

Abstract

The utility model discloses a light emitting diode (LED) constant current source which comprises an input end of a power grid, a rectifying circuit, a surge protecting unit, a voltage converting unit and a driving output end; a first charging loop formed by connecting a first resistor and a first charging capacitor in series is connected between the output ends of the rectifying circuit, a second charging loop formed by connecting a second resistor and a second capacitor in series is also connected between the output ends of the rectifying circuit, one end and the conducting control end of a crystal switching tube are connected to both ends of the first capacitor, and the other end and the conducting control end of the crystal switching tube are connected to both ends of the second capacitor; and both ends of the first capacitor are respectively connected with a discharging resistor and a voltage clamping diode in parallel. According to the LED constant current source, the technical problems of damage of a component because the surge current is too large, larger loss because of larger resistance value existing in a thermistor, failure of a current surge preventing function under the state of a heat engine when a power supply is powered off and powered down and the supply of power is restored in a short time and the like, which exist in a traditional thermistor surge preventing mode, can be solved.

Description

A kind of LED constant-current source

Technical field

The utility model designs a kind of driving power of LED lighting.

Background technology

In recent years; along with the LED develop rapidly; semiconductor lighting---this be called as the revolution of throwing light on for the third time after naked light and incandescent lamp industry be closely connected in the application of China and be in the same place with national strategic aims such as energy-saving and emission-reduction, environmental protection; advance the semiconductor lighting industry development to become will of the state; particularly the industry development of implementing at global financial crisis in China in the works, semiconductor lighting also is used as and promotes conventional industries, cultivates one of major fields of new industry.In rural infrastructure development, based on the transformation of the infrastructure construction of railway, highway, airport, water conservancy etc. and supporting illumination, upgrading.Major part has all taked LED as lighting source.

But because the environment of outwork is abominable, LED has been driven into the fast-developing bottleneck of restriction LED illumination.Because of driving the illuminating engineering quality accident that causes, LED emerges in an endless stream.

Though the LED light fixture is energy-conservation more a lot of than conventional lamp, the driving of conventional lamp belongs to resistive/inductive load.But LED drives and belongs to the capacitive load characteristic, and electrical network needs the big electric capacity of input that drives is charged during start, and therefore when multi-lamp started work simultaneously, quite electrical network was simultaneously to a lot of the also electric capacity chargings of the United Nations General Assembly.The mains supply ability that moment needs is much larger than traditional lighting.Moment surge current by each power supply 40A calculates; when many large-power lamps are started shooting simultaneously to supply line; transformer has proposed high requirement, the existing picture of overload such as the electrical network tripping operation that usually can occur starting shooting, and the electrical network saltus step also can produce destruction to other electrical equipment with electrical network.

The anti-surge mode of traditional thermistor adopts the mode of serial connection thermistor in current supply circuit.Its deficiency is as follows: at first, rectifier bridge and precharge diode often damage because of surge current is excessive; Secondly, the work back is bigger than big resistance so loss because of thermistor also exists, especially when the low pressure input current is big; The 3rd, when power supply shutdown, power down, the short time, because of the hysteresis that thermistor temp descends, resistance did not also revert to the high value state when restoring electricity, therefore anti-current surge disabler under the hot machine state.

Along with the illumination and the proposition of Internet of Things notion as required, but the intellectuality of remote monitoring is thrown light on as required and is also become the developing direction of LED illumination.

Summary of the invention

The purpose of this utility model provides a kind of LED constant-current source, exist big resistance so loss big and with damages because of surge current the is excessive device, thermistor that solves that the anti-surge mode of traditional thermistor exists when power supply shuts down, power down, short time is when restoring electricity, technical problem such as anti-current surge disabler under the hot machine state.

The utility model realizes that the technical scheme of above-mentioned purpose is that this LED constant-current source comprises electrical network input, rectification circuit, surge protection unit, voltage transformation module and drive output; It is characterized in that the surge protection unit is connected between the input of the output of rectification circuit and voltage transformation module, this surge protection unit is made up of crystal switch pipe, charging capacitor and charging and discharging circuit; Between rectification circuit output end, be connected with first charge circuit that composes in series by first resistance and first charging capacitor, between rectification circuit output end, also be connected with second charge circuit of forming by second resistance and second capacitance series, one end of described crystal switch pipe and conducting control end are connected on the two ends of described first electric capacity, and the other end of crystal switch pipe and conducting control end are connected on the two ends of second resistance; The two ends of first electric capacity respectively and be connected with discharge resistance, voltage clamp diode; The capacitance of described first electric capacity is less than second electric capacity; The charge circuit that the charge constant of the charge circuit of being made up of first resistance, first charging capacitor is made up of second resistance and second charging capacitor greatly.

Described crystal switch pipe adopts the gold oxygen semiconductor field effect transistor.

Between voltage transformation module and drive output, be connected to intelligent control unit.

Voltage transformation module, voltage sample unit, current sampling unit, power supply temperature sampling unit, lamp temperatures sampling unit, voltage-regulation/feedback unit and protection and switching on and shutting down control unit that intelligent control unit comprises a computer module, is connected with output with the data acquisition of computer module, this computer module realizes communicating by letter connection by level conversion and RJ485 signal transmitting and receiving unit with Surveillance center.

The utility model improves by circuit and has greatly reduced start, surge current when restarting, avoids surge to cause damage of product and avoids causing electric net overload, tripping operation because of surge; Can realize the Long-distance Control of road lamp management and illumination as required; Greatly improved the reliability of LED street lamp, the convenience of energy-saving effect and road lamp management.

Description of drawings

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

Fig. 2 is the LED constant-current source circuit figure of band power factor correction of the present utility model.

Fig. 3 is of the present utility model not with the LED constant-current source circuit figure of power factor correction.

Fig. 4 is the schematic block circuit diagram of intelligent control unit of the present utility model.

Fig. 5 is the schematic block circuit diagram of the RS485 communication modes of intelligent control unit of the present utility model.

Fig. 6 is the schematic block circuit diagram of the wireless communication mode of intelligent control unit of the present utility model.

Embodiment

The technical solution of the utility model is: adopted MOSFET to replace in the driving power input circuit part and traditional realized preventing the surge function with the thermistor current limliting.And realization start soft start charging modes.Power supply is gathered output voltage current signal and temperature signal at the integrated microcontroller of output, realizes remote monitoring by A/D conversion and coding back by holding wire output digital signal.And accept the Long-distance Control that external control signal is realized lamp, light modulation, regularly.

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

Among Fig. 1, led drive circuit comprises: anti-surge unit, voltage transformation module, intelligent control unit.Before anti-surge unit was rectification circuit.

Among Fig. 2,3, anti-surge part A is made of resistance R 1, R2, R3, voltage clamp diode Z1, gold oxygen semiconductor field effect transistor Q1, capacitor C 3.Between rectification circuit D1 output, be connected with first charge circuit that composes in series by first resistance R 1 and the first charging capacitor C3, between rectification circuit D1 output, also be connected with second charge circuit that composes in series by second resistance R 3 and second capacitor C 2, the end of described gold oxygen semiconductor field effect transistor Q1 and conducting control end are connected on the two ends of described first capacitor C 3, and the other end of gold oxygen semiconductor field effect transistor Q1 and conducting control end are connected on the two ends of second resistance R 3; The two ends of first capacitor C 3 respectively and be connected with discharge resistance R2, voltage clamp diode Z1; The capacitance of described first capacitor C 3 is less than second capacitor C 2; The charge circuit that the charge constant of the charge circuit of being made up of first resistance R 1, the first charging capacitor C3 is made up of second resistance R 3 and the second charging capacitor C2 greatly.In Fig. 2, form circuit of power factor correction by inductance L 1, diode D2, D3.

C3 does not also have charging during start, and Q1 is not open-minded, and electrical network charges to big electric capacity by R3.(several ohm-tens ohm of R3 values), because of R1 to the charge constant of C3 more than R3 during to the charging of C2 constant big, when the C3 charging level reaches when Q1 is opened, big capacitor C 2 has charged to line voltage.And Q1 is with the C3 charging voltage, and it is open-minded gradually to rise, and presents soft opening state.Therefore the surge current of starting shooting is very little.R3 is by bypass after Q1 opens.Because of the Q1 conduction impedance is very little, so loss is very little during operate as normal.Make circuit reach the function of anti-surge, also reduced loss simultaneously, reduced the temperature rise that drives.

Z1 is to prevent the VGS limiting value of C3 charging voltage greater than Q1 as voltage clamp.

R2 is used for discharge loop, and C3 discharges by R2 when input disconnects, and Q1 turn-offs behind several power frequency periods.Then recover the function of anti-surge when starting shooting once more immediately.

If instant power-down does not then also have fully by load discharge because of C2 electric capacity.Therefore input does not have big surge current.

Fig. 4. described the formation of intelligent control unit, mainly constituted by computer module 9 (DSP/MCU) and peripheral voltage, electric current, temperature sampling circuit.Peripheral voltage, electric current, temperature sampling circuit comprise voltage transformation module 1, voltage sample unit 2, current sampling unit 3.

Drive output and gather the voltage and current signal of power supply output (LED light fixture), by certain communication protocol data are fed back to the control of outside central authorities, monitoring unit 11 by computer module 9 inner A/D conversions and coding back by voltage sample functional block 2 and current sampling unit 3.To judge the power and the malfunction of power source voltage/electric current, electric current/LED lamp.Simultaneously sampled signal and computer module 9 inner setting benchmark are relatively formed the control of power supply loop by voltage-regulation/feedback unit 6 in the back.

The temperature of power supply temperature inside and light fixture relatively realizes temperature-compensating and overheat protector function to power supply, light fixture in the back by power supply temperature sampling unit 4,5 samplings of lamp temperatures sampling unit with computer module 9 inner setting values.Be sent to the temperature regime of outside Surveillance center after simultaneously sampled signal being changed by A/D with monitoring driving and light fixture.

Can carry out subregion to the LED lamp by the outer monitoring centring system, divide circuit, grouping management.And as required, by time, place switch lamp and regulate the brightness of LED lamp, energy-conservation and prolong life-span of LED light fixture.The realization light fixture is patrolled and examined/functions such as automatic failure alarm automatically.

Among Fig. 57 is protection and switching on and shutting down control; The 8th, drive output/light fixture; The 9th, comprise computer modules such as data sampling, loop control, A/D converting unit; The 10th, level conversion and RJ485 signal transmitting and receiving unit, the 11st, outer monitoring/control system.

Fig. 5,6 has described the communication modes of intelligent LED driving with Surveillance center, can adopt the mode of RS485 communication or wireless telecommunications.

The utility model does not relate to the part prior art that maybe can adopt all same as the prior art to be realized.

Claims

1. LED constant-current source, it comprises electrical network input, rectification circuit, surge protection unit, voltage transformation module and drive output; It is characterized in that the surge protection unit is connected between the input of the output of rectification circuit and voltage transformation module, this surge protection unit is made up of crystal switch pipe, charging capacitor and charging and discharging circuit; Between rectification circuit output end, be connected with first charge circuit that composes in series by first resistance and first charging capacitor, between rectification circuit output end, also be connected with second charge circuit of forming by second resistance and second capacitance series, one end of described crystal switch pipe and conducting control end are connected on the two ends of described first electric capacity, and the other end of crystal switch pipe and conducting control end are connected on the two ends of second resistance; The two ends of first electric capacity respectively and be connected with discharge resistance, voltage clamp diode; The capacitance of described first electric capacity is less than second electric capacity; The charge circuit that the charge constant of the charge circuit of being made up of first resistance, first charging capacitor is made up of second resistance and second charging capacitor greatly.

2. a kind of LED constant-current source according to claim 1 is characterized in that described crystal switch pipe adopts the gold oxygen semiconductor field effect transistor.

3. a kind of LED constant-current source according to claim 1 is characterized in that being connected to intelligent control unit between voltage transformation module and drive output.

4. a kind of LED constant-current source according to claim 3; it is characterized in that voltage transformation module, voltage sample unit, current sampling unit, power supply temperature sampling unit, lamp temperatures sampling unit, voltage-regulation/feedback unit and protection and switching on and shutting down control unit that intelligent control unit comprises a computer module, is connected with output with the data acquisition of computer module, this computer module realizes communicating by letter connection by level conversion and RJ485 signal transmitting and receiving unit with Surveillance center.