CN201860479U - LED constant-current supply with high efficiency and high precision - Google Patents
LED constant-current supply with high efficiency and high precision Download PDFInfo
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- CN201860479U CN201860479U CN2010202219148U CN201020221914U CN201860479U CN 201860479 U CN201860479 U CN 201860479U CN 2010202219148 U CN2010202219148 U CN 2010202219148U CN 201020221914 U CN201020221914 U CN 201020221914U CN 201860479 U CN201860479 U CN 201860479U
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Abstract
The utility model relates to an LED constant-current supply with high efficiency and high precision, which comprises a rectification circuit chip DB (Data Base) 1 and a constant-current circuit chip U1, and is characterized in that the output end of a rectification circuit is connected with an output open circuit protective circuit via a PPFC (Power Factor Correction) Circuit; a plurality of divider resistors connected with corresponding LED loads are connected onto the output end of the constant-current supply; and the divider resistors are connected with a contact pin or a socket. Since an EMI (Electro-Magnetic Interference) resistance circuit, the PPFC, the output open circuit protective circuit, an optimized circuit of the constant-current chip, an output voltage-dividing constant-current circuit and the contact pin are additionally arranged on the circuit, the system can operate under a constant-current mode with high efficiency and high precision. By perfecting the plurality of unit circuits and combining the plurality of protective circuits, the constant-current has high efficiency and high precision.
Description
Technical field
The utility model relates to supply unit, specifically is a kind of high efficiency high accuracy LED constant-current supply.
Background technology
At present, in the typical application circuit of LED constant current chip BP2808, exist more defective and deficiency, wherein, owing to do not have EMI electromagnetic compatibility Anti-interference Design, APFC circuit of power factor correction, load open circuit unprotected circuit, when having one or more LED luminous tubes to damage in the load, just can't all press; In addition, the power drives plate is consolidated the power drives plate on the lamp bar with gelling with general employing that be connected between the lamp bar (a plurality of light emitting diode string compose in parallel), the mode of connecting with the mains then and getting final product is easy in processes such as transportation, installation because of dropping opening circuit of causing being electrically connected.
Owing to there are the problems referred to above, make that existing LED constant-current supply efficient is low, precision is low.
Summary of the invention
The purpose of this utility model is to provide a kind of high efficiency high accuracy LED constant-current supply.
It is such that the utility model adopts technical scheme: promptly a kind of high efficiency high accuracy LED constant-current supply comprises: rectification circuit chip DB1, constant-current circuit chip U1; It is characterized in that: rectification circuit output be connected with the output open circuit protective circuit by power factor correction circuit; Be connected with some divider resistances that connect with corresponding LED load respectively at the constant-current supply output, described divider resistance is connected with contact pin or socket;
Described open loop protection circuit comprises triode Q2 and Q3, wherein, the emitter of Q2 by resistance R 7 be connected with the output of constant-current supply, base stage is passed through resistance R 8, R6 is connected with the output of constant-current supply; The collector electrode of triode is connected with the base stage of triode Q3, collector electrode by triode Q3 is connected with the brightness adjustment control end DIM of constant-current circuit chip, and, be parallel with resistance R 9 and capacitor C 4 between the collector electrode of triode Q3 and the ground, grounded emitter by capacitor C 5 ground connection; When power supply is opened a way, the B of triode Q2, the conducting of the E utmost point, the B of triode Q 3, the conducting of E pole tension greater than 0.7V, the brightness adjustment control end DIM of constant-current circuit chip resistance over the ground is infinitely small, the output current of constant-current supply is zero;
Described power factor correction circuit is by capacitor C E1 and CE2, three diode D1, D2 and D3, three inductance RP1, RP2, RP3 constitutes, wherein be connected in parallel on the output of rectification circuit after the series connection of capacitor C E1 and diode D1 forward section, be connected in parallel on the output of rectification circuit after inductance RP2, diode D2 and the inductance RP3 series connection, diode D3 and the output that is connected in rectification circuit after capacitor C E2 connects, capacitor C E1 also passes through diode D2, inductance SP1 and is connected with electric capacity RP 3.
Obviously, under the situation of the non-loaded i.e. open circuit of power supply, when power supply is exported busbar voltage more than or equal to 360V, the B of Q2; the conducting of the E utmost point, the B of Q3, the E pole tension enters saturation condition greater than 0.7V; crossing current chip 8 pin are infinitely small to the ground resistance, and output current is zero, thereby plays a protective role.Because dividing potential drop current-sharing protection is arranged; when certain paths of LEDs had open circuit or certain LEDs short circuit, curtage loaded on the resistance, thereby played the effect of voltage stabilizing current-sharing because an antidetonation socket or contact pin are arranged; make power panel by contact pin and the welding of lamp bar, compact reliable, the anti-damage of falling of such connection.
Description of drawings
Accompanying drawing 1 is the circuit block diagram of LED constant-current supply of the prior art;
Accompanying drawing 3 is the circuit theory diagrams of LED constant-current supply of the prior art;
Accompanying drawing 4 is the circuit theory diagrams of the utility model embodiment.
Embodiment
Referring to accompanying drawing 1,3, the typical application circuit of existing LED constant current chip BP2808 comprises rectification chip, constant current chip and output circuit.
Referring to accompanying drawing 2,4, high efficiency high accuracy LED constant-current supply described in the utility model comprises: rectification circuit chip DB1, constant-current circuit chip U1; It is characterized in that: rectification circuit output be connected with the output open circuit protective circuit by power factor correction circuit;
Described open loop protection circuit comprises triode Q2 and Q3, wherein, the emitter of Q2 by resistance R 7 be connected with the output head anode of constant-current supply, base stage passes through resistance R 8 and is connected with the negative pole of output end of constant-current supply; The collector electrode of triode is connected with the base stage of another triode Q3, collector electrode by triode Q3 is connected with the brightness adjustment control end DIM of constant-current circuit chip, and, be parallel with resistance R 9 and capacitor C 4 between the collector electrode of triode Q3 and the ground, grounded emitter by capacitor C 5 ground connection; When power source loads is opened a way, the B of triode Q2, the conducting of the E utmost point, the B of Q3, E pole tension be greater than 0.7V, the Q3 conducting, the brightness adjustment control end DIM of constant-current circuit chip resistance over the ground is infinitely small, output current is zero, thereby plays a protective role.
Described power factor correction circuit is by capacitor C E1, CE2 and C1, three diode D1, D2 and D3, three inductance RP1, RP2 and RP3 constitute, wherein be connected in parallel on the output of rectification circuit after the series connection of capacitor C E1 and diode D1 forward section, be connected in parallel on the output of rectification circuit after inductance RP2, diode D2 and the inductance RP3 series connection, diode D3 and the output that is connected in rectification circuit after capacitor C E2 connects, C1 is connected in parallel on the output of rectification circuit, and capacitor C E1 also is connected with electric capacity RP3 by diode D2, inductance SP1.
PPFC Active PFC principle: above-mentioned CE1, CE2, D1, D2, D3, RP1, RP2, RP3 constitutes the PFC correcting circuit, and voltage is by CE1 process D2, RP1 gives CE1, and the CE2 charging provides electric current to load simultaneously, its charging constant is very little, and the charging interval is very fast, because of CE1, the CE2 capacitance equates, so two pressure drops equate the D2 conducting, and D1 and D3 reverse biased and by, after CE1 charging is complete, D2 by, D1 and D3 forward bias and conducting, CE1, electric charge on the CE2 is respectively by D1, and the D3 parallel circuits discharges, and the electric current of keeping in the load is constant.
In an embodiment, the model of rectification circuit chip is selected DB107 for use, and its input is connected with the anti-electromagnetic interference circuit of EMI: the anti-electromagnetic interference circuit of described EMI comprises the electromagnetism anti-jamming circuit that exchanges a low pass filter between the inlet wire separate port and be made of piezo-resistance VZ1 and another differential mode capacitor device CX1 that is made of differential mode inductance coil LD1 and LD2 and differential mode capacitor device CX2; Wherein differential mode inductance coil LD1, the LD2 in the low pass filter is connected with zero line side with the live wire end of rectification circuit input end respectively, on differential mode inductance coil LD1 and LD2, be parallel with inductance RD1 and RD2 respectively, VZ1 and differential mode capacitor CX1 are connected in parallel on LD1, the input of LD2, CX2 and at LD1, the LD2 output.
The anti-interference principle of EMI: differential mode inductance coil LD1, LD2 and differential mode capacitor device CX2 constitute a low pass filter that exchanges between the inlet wire separate port, are used for suppressing to exchange the differential mode interference noise on the inlet wire, prevent that power-supply device is disturbed by it.
The AC rectification that rectification circuit DB1 brings EMI is a direct voltage.
It is such that the peripheral circuit of constant current chip U1 connects: resistance R 1-R3 series connection is between the positive pole of constant-current supply output cathode and voltage-stabiliser tube DZ1, the DZ1 minus earth, resistance R 4 is connected in parallel on the DZ1, capacitor C 3 is connected on R2 and ground, capacitor C 2 and on DZ1, diode D4 positive pole connects output cathode, and the D4 negative pole is connected on the grid of field effect transistor Q1, and the source electrode of Q1 is connected with LM2 with 4 pin (output) of U1 respectively with drain electrode; Diode D5 is connected on 3 pin (power input) of constant current chip U1, resistance R 5 is in parallel with D5,1 pin (signal) of constant current chip is connected with the constant-current supply output negative pole, 2 pin are connected with resistance R 2, and 3 pin are connected with diode D5 negative pole, and 5 pin are empty, 6 pin meet sampling resistor RS1, RS2 is to ground, and 7 pin connecting resistance RT1 are to ground, and 8 pin connect the collector electrode of Q3.
In the output circuit: filter capacitor C01 is connected in parallel on the output both positive and negative polarity, and inductance L M1, LM2 go into end and be in series, and bleed off resistance R 6 is connected in parallel on the output both positive and negative polarity.
The constant current chip circuit: 1 pin of chip U1 is the internal electrical seedbed, 2 pin 12V voltage stabilizing light ZD1 are the line voltage compensation of peak threshold, voltage between sampling LN and the VDD, 3 pin power inputs, in-line power is provided, the drain terminal of 4 pin internal power switches, also be output, the source end by the external power switch outputs to last 5 pin of LM1 for empty, 6 pin current sample ends, sampling resistor RS1, RS2 is connected between CS and the GND end, and resistance value is more little, and electric current is big more, 7 pin setting chip work turn-off times, the resistance that is connected RT chip 7 pin is set the turn-off time of Q1.In each cycle, Q1 opens up to inductive current and rises to peak value.At this moment Q1 turn-offs.Spent the turn-off time of setting, Q1 opens again, goes round and begins again like this
8 pin light modulations can be with simulating two kinds of light modulation and PWM light modulations.For the simulation light modulation, only need the potentiometer of an external 150K just can test the 0-100% light modulation.For the PWM light modulation, the light modulation of suggestion is 270Hz frequently.In no situation, as long as unsettled.Open-circuit-protection is exactly to utilize this principle to accomplish the protection of no current output
The explanation of chip U1
| Number of pins | The pin title | Describe |
| 1 | GND | Signal and |
| 2 | LN | The line voltage compensation of peak threshold, the voltage between sampling LN and the |
| 3 | VDD | Power input must connect shunt capacitance nearby |
| 4 | OUT | The drain terminal of internal power switch, the source end of external power switch |
| 5 | NC | Unsettled |
| 6 | CS | Current sample end, sampling resistor are connected between CS and the GND |
| 7 | RT | The setting chip work turn-off |
| 8 | DIM | Switch enable, simulation and PWM light modulation end |
As seen table from scheming in the contrast, and the 8th pin of the chip U1 in the LED constant-current supply of the prior art is that DIM holds formula unsettled, and is to utilize this end as control end in the utility model, controls the output of 4 pin.
It is dividing potential drop current-sharing protection that the utility model is further optimized: promptly be connected with some divider resistances that are connected with the LED load respectively on the power supply output cathode; be convenient to like this when certain paths of LEDs has open circuit or certain LEDs short circuit; curtage loads on the resistance, thereby plays the effect of voltage stabilizing current-sharing.Referring to the divider resistance R10-R15 in the accompanying drawing 4.
Further, constant-current supply output of the present utility model connects at least one antidetonation socket or contact pin.Latter linked two antidetonation socket J1 and J2 referring to divider resistance in the accompanying drawing 4.This structure makes power panel by contact pin and the welding of lamp bar, compact reliable, the anti-damage of falling of such connection.
Because the constant current chip is in original application; serious defective and deficiency are arranged; through above-mentioned improvement; promptly in circuit, add the anti-electromagnetic interference circuit of EMI; the PPFC power factor correction circuit, output open circuit protective circuit, the optimization circuit of constant current chip; output dividing potential drop flow equalizing circuit, contact pin connection etc. lets the system operate in the mode of operation of high-efficiency high-accuracy constant current.By improving and the combination of a plurality of protective circuits of above a plurality of element circuits, allow this power supply reach efficiently high-precision constant current.
Claims (2)
1. a high efficiency high accuracy LED constant-current supply comprises: rectification circuit DB1, constant-current circuit chip U1; It is characterized in that: the output of rectification circuit is connected with the output open circuit protective circuit by power factor correction circuit; Be connected with some divider resistances that connect with corresponding LED load respectively at the constant-current supply output, described divider resistance is connected with contact pin or socket;
Described open loop protection circuit comprises triode Q2 and another triode Q3, wherein, the emitter of triode Q2 by resistance R 7 be connected with the output plus terminal of constant-current supply, base stage passes through resistance R 8 and is connected with the output negative terminal of constant-current supply; The collector electrode of triode Q2 is connected with the base stage of another triode Q3, collector electrode by triode Q3 is connected with the brightness adjustment control end DIM of constant-current circuit chip, and, be parallel with resistance R 9 and capacitor C 4 between the collector electrode of triode Q3 and the ground, grounded emitter by capacitor C 5 ground connection;
Described power factor correction circuit is by capacitor C E1 and CE2, three diode D1, D2 and D3, three inductance RP1, RP2, RP3 constitutes, wherein be connected in parallel on the output of rectification circuit after the series connection of capacitor C E1 and diode D1 forward section, be connected in parallel on the output of rectification circuit after inductance RP2, diode D2 and the inductance RP3 series connection, diode D3 and the output that is connected in rectification circuit after capacitor C E2 connects, capacitor C E1 also passes through diode D2, inductance SP1 and is connected with electric capacity RP3.
2. high efficiency high accuracy LED constant-current supply according to claim 1, it is characterized in that: the input of described rectification circuit is connected with the anti-electromagnetic interference circuit of EMI, and the anti-electromagnetic interference circuit of described EMI comprises the electromagnetism anti-jamming circuit that exchanges a low pass filter between the inlet wire separate port and be made of piezo-resistance VZ1 and another differential mode capacitor device CX1 that is made of differential mode inductance coil LD1 and LD2 and differential mode capacitor device CX2; Wherein differential mode inductance coil LD1, the LD2 in the low pass filter is connected with zero line side with the live wire end of rectification circuit input end respectively, on differential mode inductance coil LD1 and LD2, be parallel with inductance RD1 and RD2 respectively, VZ1 and differential mode capacitor CX1 are connected in parallel on LD1, the input of LD2, CX2 and at LD1, the LD2 output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202219148U CN201860479U (en) | 2010-06-10 | 2010-06-10 | LED constant-current supply with high efficiency and high precision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010202219148U CN201860479U (en) | 2010-06-10 | 2010-06-10 | LED constant-current supply with high efficiency and high precision |
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| Publication Number | Publication Date |
|---|---|
| CN201860479U true CN201860479U (en) | 2011-06-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010202219148U Expired - Fee Related CN201860479U (en) | 2010-06-10 | 2010-06-10 | LED constant-current supply with high efficiency and high precision |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201860479U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104049192A (en) * | 2013-03-15 | 2014-09-17 | 海洋王（东莞）照明科技有限公司 | Low-power LED test apparatus and multipath constant current output circuit thereof |
-
2010
- 2010-06-10 CN CN2010202219148U patent/CN201860479U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104049192A (en) * | 2013-03-15 | 2014-09-17 | 海洋王（东莞）照明科技有限公司 | Low-power LED test apparatus and multipath constant current output circuit thereof |
| CN104049192B (en) * | 2013-03-15 | 2016-12-28 | 海洋王（东莞）照明科技有限公司 | A kind of low-power LED test device and multiple constant current output circuit thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: Chongqing Xiaocao Technology Co., Ltd. Assignor: Gan Guorui Contract record no.: 2012500000083 Denomination of utility model: LED constant-current supply with high efficiency and high precision Granted publication date: 20110608 License type: Exclusive License Record date: 20120905 |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110608 Termination date: 20140610 |