CN103533696A - LED constant-current driving circuit - Google Patents
LED constant-current driving circuit Download PDFInfo
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- CN103533696A CN103533696A CN201210225627.8A CN201210225627A CN103533696A CN 103533696 A CN103533696 A CN 103533696A CN 201210225627 A CN201210225627 A CN 201210225627A CN 103533696 A CN103533696 A CN 103533696A
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Abstract
Disclosed in the invention is an LED constant-current driving circuit comprising a first comparator, a second comparator, a first resistor, a first triode and a light-emitting diode group. The light-emitting diode group includes a plurality of light-emitting diodes connected in series; and each light-emitting diode in the light-emitting diode group is connected in parallel with a reversed connected voltage-stabilizing tube. One terminal of the first resistor is connected to an inverted input terminal of the first comparator; and the other terminal is connected with a circuit between an output terminal of the first comparator and a non-inverting input terminal of the second comparator. An output terminal of the second comparator is connected with a base electrode of the first triode; and an inverted input terminal of second comparator is connected with an emitter of the first triode. A direct-current voltage input line and a trigger voltage input line are connected to the first comparator; an output terminal of the light-emitting diode group is connected with a collector of the first triode; and an input terminal of the light-emitting diode group is connected to the direct-current voltage input line. With the structure, the cost is low and the size is small; and reliability of the circuit during application can be improved.
Description
Technical field
The present invention relates to a kind of drive circuit, specifically LED constant-current drive circuit.
Background technology
LED has that volume is little, low cost and other advantages, so people's input for some systems by LED usually, and by LED lamp, whether lights to judge in system, whether signal is connected when system testing.As a semiconductor device that is operated in low-voltage, direct current, LED need work under constant electric current environment.Conventional mains-supplied during general system power supply, if need LED luminous when system detects, needs, by drive circuit, alternating voltage is carried out to rectification and controls afterwards for LED.Electrology characteristic from LED, the mean forward current of LED is along with the increase of forward voltage presents significantly linear growth, the change of LED its forward voltage after forward conduction is given birth to very large variation by causing that LED powers on to miscarry, and electric current is very large on the impact of LED junction temperature, excessive electric current is easy to cause LED to damage because junction temperature raises.For fear of LED, damage and the accuracy of impact test the defect such as existing LED constant-current drive circuit exists complex structure, components and parts are many, cost is high and reliability is low.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, provide a kind of simple in structure, cost is low, and the high LED constant-current drive circuit of reliability.
Object of the present invention is achieved through the following technical solutions: LED constant-current drive circuit, comprise the first comparator, the second comparator, the first resistance, the first triode and light-emitting diode group, described light-emitting diode group comprises the light-emitting diode of a plurality of series connection, and in light-emitting diode group, on each light-emitting diode, is all parallel with the voltage-stabiliser tube of a reversal connection, the output of described the first comparator is connected with the in-phase input end of the second comparator, described first resistance one end is connected on the inverting input of the first comparator, connection between its other end and the first comparator output terminal and the second comparator in-phase input end, the output of described the second comparator is connected with the base stage of the first triode, the inverting input of the second comparator is connected with the first transistor emitter, on the first comparator, connect direct voltage input line, on the first comparator in-phase input end, be connected with trigger voltage input line, the output of described light-emitting diode group is connected with the collector electrode of the first triode, the input of light-emitting diode group is connected on direct voltage input line.Direct voltage input line is specifically connected on the forward voltage input of the first comparator, and the present invention is in when application, direct voltage input line external direct current power supply, the system power supply voltage after the external rectification conversion of trigger voltage input line.
LED constant-current drive circuit, also comprises the second resistance and the 3rd resistance, and described second resistance one end is connected on the circuit between the first comparator inverting input and the first resistance, its other end ground connection; Described second resistance one end connects on the circuit between the second comparator inverting input and the first transistor emitter, its other end ground connection.
Described the first resistance is adjustable resistance.
Described the first triode is NPN type triode.
As preferably, described light-emitting diode group comprises the light-emitting diode of three series connection.
Compared with prior art, the present invention has following beneficial effect: (1) the present invention includes the first comparator, the second comparator, the first resistance, the first triode and light-emitting diode group, overall structure is simple, be convenient to realize, components and parts used are few, cost is low, wherein, on the first comparator, connect direct voltage input line, on the first comparator in-phase input end, be connected with trigger voltage input line, when the present invention is used for system testing, voltage by treating examining system is as trigger voltage of the present invention, the direct voltage ability of inputting on direct voltage input line is as the supply power voltage of light-emitting diode, make the supply power voltage of lumination of light emitting diode stable, thereby can not damage because variation in voltage on light-emitting diode causes light-emitting diode, improved reliability when the present invention applies.
(2) light-emitting diode group of the present invention comprises the light-emitting diode of a plurality of series connection, and in light-emitting diode group, on each light-emitting diode, be all parallel with the voltage-stabiliser tube of a reversal connection, so, when the present invention applies, the branch road that on each light-emitting diode, voltage-stabiliser tube in parallel forms forms protective circuit of the present invention, when the lamp pearl of certain light-emitting diode is opened circuit, the voltage-stabiliser tube in parallel with it devoted oneself to work, thereby can avoid circuit to open circuit, the present invention can avoid single light-emitting diode to damage and the erroneous judgement that causes in when application, further improved reliability when the present invention applies.
Accompanying drawing explanation
Fig. 1 is the structural representation of the embodiment of the present invention.
In accompanying drawing, the corresponding name of Reference numeral is called: A1-the first comparator, A2-the second comparator, R1-the first resistance, R2-the second resistance, R3-three resistance, Q1-the first triode, LED1-the first light-emitting diode, LED2-the second light-emitting diode, LED3-three light-emitting diode, DW1-the first voltage-stabiliser tube, DW2-the second voltage-stabiliser tube, DW3-three voltage-stabiliser tube, 1-trigger voltage input line, 2-direct voltage input line.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this.
Embodiment:
As shown in Figure 1, LED constant-current drive circuit, comprise the first comparator A1, the second comparator A2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3, the first triode Q1 and light-emitting diode group, the first resistance R 1 is adjustable resistance, the first triode Q1 is NPN type triode, light-emitting diode group comprises the light-emitting diode of three series connection, three light-emitting diodes are respectively the first LED 1, the second LED 2 and the 3rd LED 3, on three light-emitting diodes, be parallel with respectively the first voltage-stabiliser tube DW1 of reversal connection, the second voltage-stabiliser tube DW2 and the 3rd voltage-stabiliser tube DW3.The output of the first comparator A1 is connected with the in-phase input end of the second comparator A2, first resistance R 1 one end is connected on the inverting input of the first comparator A1, the connection between its other end and the first comparator A1 output and the second comparator A2 in-phase input end.The output of the second comparator A2 is connected with the base stage of the first triode Q1, the inverting input of the second comparator A2 is connected with the first triode Q1 emitter, the upper direct voltage input line 2 connecting for external direct current power supply of the first comparator A1, on the first comparator A1 in-phase input end, be connected with trigger voltage input line 1, trigger voltage input line 1 is for receiving the voltage input after system rectification to be tested.The output of light-emitting diode group is connected with the collector electrode of the first triode Q1, and light-emitting diode group input is connected on direct voltage input line 2.As preferably, in the present embodiment, the first comparator A1 and the second comparator A2 all adopt LM358.
As mentioned above, can well realize the present invention.
Claims (5)
1.LED constant-current drive circuit, it is characterized in that: comprise the first comparator (A1), the second comparator (A2), the first resistance (R1), the first triode (Q1) and light-emitting diode group, described light-emitting diode group comprises the light-emitting diode of a plurality of series connection, and in light-emitting diode group, on each light-emitting diode, is all parallel with the voltage-stabiliser tube of a reversal connection, the output of described the first comparator (A1) is connected with the in-phase input end of the second comparator (A2), described the first resistance (R1) one end is connected on the inverting input of the first comparator (A1), connection between its other end and the first comparator (A1) output and the second comparator (A2) in-phase input end, the output of described the second comparator (A2) is connected with the base stage of the first triode (Q1), the inverting input of the second comparator (A2) is connected with the first triode (Q1) emitter, the upper direct voltage input line (2) that connects of the first comparator (A1), on the first comparator (A1) in-phase input end, be connected with trigger voltage input line (1), the output of described light-emitting diode group is connected with the collector electrode of the first triode (Q1), the input of light-emitting diode group is connected on direct voltage input line (2).
2. LED constant-current drive circuit according to claim 1, it is characterized in that: also comprise the second resistance (R2) and the 3rd resistance (R3), described the second resistance (R2) one end is connected on the circuit between the first comparator (A1) inverting input and the first resistance (R1), its other end ground connection; Described the second resistance (R2) one end connects on the circuit between the second comparator (A2) inverting input and the first triode (Q1) emitter, its other end ground connection.
3. LED constant-current drive circuit according to claim 1, is characterized in that: described the first resistance (R1) is adjustable resistance.
4. LED constant-current drive circuit according to claim 1, is characterized in that: described the first triode (Q1) is NPN type triode.
5. according to any LED constant-current drive circuit described in claim 1～4, it is characterized in that: described light-emitting diode group comprises the light-emitting diode of three series connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210225627.8A CN103533696A (en) | 2012-07-03 | 2012-07-03 | LED constant-current driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210225627.8A CN103533696A (en) | 2012-07-03 | 2012-07-03 | LED constant-current driving circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103533696A true CN103533696A (en) | 2014-01-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210225627.8A Pending CN103533696A (en) | 2012-07-03 | 2012-07-03 | LED constant-current driving circuit |
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| CN (1) | CN103533696A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2146003Y (en) * | 1992-07-31 | 1993-11-10 | 申文龙 | Self-stabilizing D.C-D.C conversion milli-ohmmeter and million-ohmmeter |
| US7215127B1 (en) * | 2006-01-13 | 2007-05-08 | Advanced Semiconductor Engineering, Inc. | Detecting fixture and method thereof for detecting capacitors |
| CN102149241A (en) * | 2011-05-11 | 2011-08-10 | 罗宏基 | LED (light-emitting diode) electrifying luminescence circuit |
| CN202652655U (en) * | 2012-07-03 | 2013-01-02 | 成都市宏山科技有限公司 | Led constant current drive circuit |
-
2012
- 2012-07-03 CN CN201210225627.8A patent/CN103533696A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2146003Y (en) * | 1992-07-31 | 1993-11-10 | 申文龙 | Self-stabilizing D.C-D.C conversion milli-ohmmeter and million-ohmmeter |
| US7215127B1 (en) * | 2006-01-13 | 2007-05-08 | Advanced Semiconductor Engineering, Inc. | Detecting fixture and method thereof for detecting capacitors |
| CN102149241A (en) * | 2011-05-11 | 2011-08-10 | 罗宏基 | LED (light-emitting diode) electrifying luminescence circuit |
| CN202652655U (en) * | 2012-07-03 | 2013-01-02 | 成都市宏山科技有限公司 | Led constant current drive circuit |
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Application publication date: 20140122 |