CN104701809A - LED constant-voltage power supply with self-locking protecting circuit - Google Patents
LED constant-voltage power supply with self-locking protecting circuit Download PDFInfo
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- CN104701809A CN104701809A CN201510145192.XA CN201510145192A CN104701809A CN 104701809 A CN104701809 A CN 104701809A CN 201510145192 A CN201510145192 A CN 201510145192A CN 104701809 A CN104701809 A CN 104701809A
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Abstract
The invention provides an LED constant-voltage power supply with a self-locking protecting circuit. The LED constant-voltage power supply comprises a power conversion circuit, load, a voltage detection comparing circuit, a comparing circuit and a self-locking circuit; the power conversion circuit comprises a power chip and a current detecting circuit and used for converting 220V AC into constant voltage DC; the output end of the power conversion circuit is connected with the load; the current detecting circuit is used for detecting current flowing through the load; two ends of the current detecting circuit are respectively connected to two input ends of the comparing circuit; the comparing circuit is used for comparing voltage of two ends of the current detecting circuit; if the input voltage of the load is less than the voltage at the other end of the current detecting circuit, a control signal can be outputted to the self-locking circuit; the voltage detection comparing circuit is used for detecting the voltage of the end without being connected in series with the load, of the current detecting circuit; if the detecting voltage exceeds the set value, the control signal can be outputted to the self-locking circuit; the self-locking circuit is used for controlling the output of the power chip according to the outputs of the comparing circuit and the voltage detection comparing circuit.
Description
[technical field]
The present invention relates to technical field of LED illumination, be specifically related to a kind of LED constant voltage source with defencive function.
[background technology]
LED is because having environmental protection, energy-efficient, the advantages such as long-life, obtains applying more and more widely at lighting field.And stablize, reliable, efficiently LED power be that to realize LED lamp energy-efficient, safe and reliable basis.Particularly existing LED power is in overvoltage, can not protect immediately during overcurrent, causes the damage of LED lamp.
[summary of the invention]
In view of this, the invention provides a kind of LED constant voltage source with defencive function, the defect of LED constant voltage source in prior art can be overcome.
The present invention adopts following technical scheme, the LED constant voltage source of structural belt self-locking protective circuit, and it comprises power converting circuit and load, voltage detecting comparison circuit, comparison circuit, latching circuit; Power converting circuit, comprises power supply chip and current detection circuit, and export for 220V alternating current being converted to constant voltage DC electricity, its output connects load; Current detection circuit, for detecting the electric current flowing through load, its to be located in power-switching circuit and and load in series, and its two ends connect two inputs of comparison circuit respectively; Comparison circuit, for comparing the voltage at current detection circuit two ends, as being less than the voltage of the current detection circuit other end with load input voltage, will export control signal to latching circuit; Voltage detecting comparison circuit, for detect current detection circuit not with the voltage of that one end of load in series, as detected voltage higher than set point, control signal will be exported to latching circuit; Latching circuit, according to the output of comparison circuit and voltage detecting comparison circuit, controls the output of power supply chip, and its output connects the closedown pin of power supply chip.
Preferably, described voltage detecting comparison circuit comprises Zener diode ZD1, and the negative electrode of ZD1 connects the input of load, and anode connects the input of latching circuit.
Preferably, the power supply input pin of described comparison circuit connects independent DC power supply, and the input of self-locking protective circuit connects the positive pole of storage capacitor, and storage capacitor is attempted by DC power supply two ends.
Advantageous Effects of the present invention is: the LED constant voltage source of band self-locking protective circuit of the present invention, possesses overcurrent and overvoltage measuring ability simultaneously, when load overcurrent and overvoltage, and the output of the automatic powered-down chip of energy; Self-locking resistance is provided with storage capacitor as stand-by power supply, therefore must restart at power cut-off and after overcurrent and overvoltage disappear, power supply could normally export, and this power safety performance is high.
[accompanying drawing explanation]
The circuit composition frame chart of the LED constant voltage source of the band self-locking protective circuit in Fig. 1 embodiment one;
The circuit theory diagrams of the LED constant voltage source of the band self-locking protective circuit in Fig. 2 embodiment one.
[embodiment]
In order to make the technical scheme of this patent and technique effect clearly, be described in detail below in conjunction with the embodiment of drawings and Examples to this patent.
Embodiment one:
As Fig. 1, the LED constant voltage source of the band self-locking protective circuit in the present embodiment, comprises power converting circuit, power supply chip, current detection circuit, voltage detecting comparison circuit, comparison circuit, latching circuit.
Current detection circuit, for detecting the electric current flowing through load LED, its two ends all connect two voltage input ends of comparison circuit, and the input of voltage detecting comparison circuit connects the input of current detection circuit; The output of comparison circuit connects the input of latching circuit, and the output of latching circuit connects the closedown pin of power supply chip.
As Fig. 2, current detection circuit is made up of resistance RS1, and for detecting the electric current flowing through load, because RS1 and load LED strip join, the current value flowing through RS1 is equal with the current value of load LED.The voltage of RS1 front and back ends is inputed to the 5th pin and the 6th pin of LM358; Wherein after RS1, terminal voltage is the magnitude of voltage at load LED two ends, is also the output of power converting circuit.
Voltage detecting comparison circuit forms primarily of Zener diode ZD1, for detecting load LED both end voltage, as exceeded set point, will export control signal to latching circuit.
Comparison circuit forms primarily of comparator LM358, and for the size of the voltage and load LED both end voltage that compare RS1 front end, the voltage as RS1 front end is greater than load LED both end voltage, will export control signal to latching circuit.Comparison circuit has independent power supply Vdd to power, and this power supply is connected to the positive pole of storage capacitor EC4 after several resistance.
Latching circuit, according to the output of comparison circuit and voltage detecting comparison circuit, control the output of power supply chip, primarily of NPN type triode Q1 and PNP type triode Q2 composition, the base stage of Q1 connects the collector electrode of Q2, and the collector electrode of Q1 connects the base stage of Q2, connects the closedown pin of power supply chip after the emitter series limiting resistor R12 of Q1, the base stage of Q2 connects the output of voltage detecting comparison circuit and the output of comparison circuit simultaneously, i.e. the 7th pin of LM358.Play the resistance of miscellaneous function in this circuit, diode will not repeat at this.
The voltage of the LED constant voltage source energy stable output of self-locking protective circuit in the present embodiment, power supply chip is the part in power converting circuit, and it adopts model to be the integrated circuit of KA3525, and the 10th pin of this chip is power-off pin.
The operation principle of the LED constant voltage source of the self-locking protective circuit in the present embodiment is as follows:
220V alternating current is through the direct voltage 12V of power converting circuit conversion stable output.
During load LED overcurrent, the electric current that resistance RS1 passes through increases, and the voltage 12VS of RS1 front end uprises, the 5th pin voltage of comparator LM258 uprises, 6 pin load voltage 12V because of electric power output voltage constant, therefore voltage remains unchanged, when voltage ratio the 6th pin of the 5th pin is high time, 7th pin of LM258 exports a high potential, Q2 conducting, Q2 current collection very low level, Q1 conducting, the transmitting very electronegative potential of Q1, the closedown pin of power supply chip is electronegative potential, and power supply chip is closed.Therefore, power supply chip does not work, thus does not export, thus protects power supply and load LED.LM258 has accessory power supply Vdd to power always, and EC4 has voltage to exist always, Q1 and Q2 self-locking work always, and the closedown pin of power supply chip is low level always, until load overcurrent Failure elimination, is energized after power-off again, and power supply just can normal work.
When output voltage exceedes the voltage 14V of Zener diode ZD1; Zener diode ZD1 conducting; the base stage of Q2 is high potential, Q2 conducting, the current collection very electronegative potential of Q2; Q1 conducting; the transmitting very electronegative potential of Q1, the closedown pin of power supply chip is electronegative potential, and power supply chip is closed; power supply does not export, thus protects power supply and load LED.LM258 has accessory power supply Vdd to power always, and EC4 has voltage to exist always, Q1 and Q2 self-locking work always, and the closedown pin of power supply chip is low level always, until load overcurrent Failure elimination, is energized after power-off again, and power supply just can normal work.
When output current is in normal range (NR), ON/OFF pin is high potential, and the closedown pin of power supply chip is also high potential, and now power supply chip normally works, the reliable load voltage 12V of LED constant voltage source energy stable output of the band self-locking protective circuit in the present embodiment.
The foregoing is only the preferred embodiment of this patent, be not limited to this patent, for a person skilled in the art, this patent can have various modifications and variations.Within all spirit at this patent and principle, any amendment done, equivalent replacement, improvement etc., within the protection range that all should be included in this patent.
Claims (3)
1. the LED constant voltage source with self-locking protective circuit, comprises power converting circuit and load, it is characterized in that: it also comprises voltage detecting comparison circuit, comparison circuit, latching circuit;
Power converting circuit, comprises power supply chip and current detection circuit, and export for 220V alternating current being converted to constant voltage DC electricity, its output connects load;
Current detection circuit, for detecting the electric current flowing through load, its to be located in power-switching circuit and and load in series, and its two ends connect two inputs of comparison circuit respectively;
Comparison circuit, for comparing the voltage at current detection circuit two ends, as being less than the voltage of the current detection circuit other end with load input voltage, will export control signal to latching circuit;
Voltage detecting comparison circuit, for detect current detection circuit not with the voltage of that one end of load in series, as detected voltage higher than set point, control signal will be exported to latching circuit;
Latching circuit, according to the output of comparison circuit and voltage detecting comparison circuit, controls the output of power supply chip, and its output connects the closedown pin of power supply chip.
2. the LED constant voltage source of band self-locking protective circuit as claimed in claim 1, is characterized in that: described voltage detecting comparison circuit comprises Zener diode ZD1, and the negative electrode of ZD1 connects the input of load, and anode connects the input of latching circuit.
3. the LED constant voltage source of band self-locking protective circuit as claimed in claim 1; it is characterized in that: the power supply input pin of described comparison circuit connects independent DC power supply; the input of self-locking protective circuit connects the positive pole of storage capacitor, and storage capacitor is attempted by DC power supply two ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510145192.XA CN104701809B (en) | 2015-03-30 | 2015-03-30 | A kind of LED constant voltage source with self-locking protective circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510145192.XA CN104701809B (en) | 2015-03-30 | 2015-03-30 | A kind of LED constant voltage source with self-locking protective circuit |
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| Publication Number | Publication Date |
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| CN104701809A true CN104701809A (en) | 2015-06-10 |
| CN104701809B CN104701809B (en) | 2019-03-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201510145192.XA Expired - Fee Related CN104701809B (en) | 2015-03-30 | 2015-03-30 | A kind of LED constant voltage source with self-locking protective circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105048404A (en) * | 2015-07-13 | 2015-11-11 | 山东超越数控电子有限公司 | Power supply overvoltage protection method based on triode latch circuit |
| CN108399904A (en) * | 2018-04-27 | 2018-08-14 | 深圳市华星光电半导体显示技术有限公司 | Liquid crystal panel drive circuit |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103139968A (en) * | 2011-11-30 | 2013-06-05 | 海洋王照明科技股份有限公司 | Light-emitting diode (LED) driving circuit and LED lamp |
| CN203423827U (en) * | 2013-07-23 | 2014-02-05 | 从兴技术有限公司 | LED street lamp control apparatus |
| US20140232295A1 (en) * | 2013-02-19 | 2014-08-21 | Princeton Technology Corporation | Led driving device |
| CN104219842A (en) * | 2014-08-29 | 2014-12-17 | 深圳市奋勇光电有限公司 | LED constant-current unit |
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2015
- 2015-03-30 CN CN201510145192.XA patent/CN104701809B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103139968A (en) * | 2011-11-30 | 2013-06-05 | 海洋王照明科技股份有限公司 | Light-emitting diode (LED) driving circuit and LED lamp |
| US20140232295A1 (en) * | 2013-02-19 | 2014-08-21 | Princeton Technology Corporation | Led driving device |
| CN203423827U (en) * | 2013-07-23 | 2014-02-05 | 从兴技术有限公司 | LED street lamp control apparatus |
| CN104219842A (en) * | 2014-08-29 | 2014-12-17 | 深圳市奋勇光电有限公司 | LED constant-current unit |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105048404A (en) * | 2015-07-13 | 2015-11-11 | 山东超越数控电子有限公司 | Power supply overvoltage protection method based on triode latch circuit |
| CN108399904A (en) * | 2018-04-27 | 2018-08-14 | 深圳市华星光电半导体显示技术有限公司 | Liquid crystal panel drive circuit |
| CN108399904B (en) * | 2018-04-27 | 2020-02-18 | 深圳市华星光电半导体显示技术有限公司 | Liquid crystal panel driving circuit |
| US11087704B2 (en) | 2018-04-27 | 2021-08-10 | Shenzhen China Star Optoelectronics Semiconductor Display Technology Co., Ltd. | Liquid crystal panel driving circuit and liquid crystal panel |
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| CN104701809B (en) | 2019-03-01 |
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