A kind of temperature control soft starting circuit
[technical field]
The present invention relates to the technical field of soft starting circuit, the temperature control provided especially for LED constant current driving power is soft to be opened
The technical field of dynamic circuit.
[background technique]
Soft start is one of the starting protection of most critical in all kinds of power supplys, and when circuit start, quick start is in power supply
Portion's element bring electrical impact and thermal shock can be bigger, will lead to power-fail or the lost of life when excessive.In order to
The harm of quick start bring is further decreased at high temperature, and this patent proposes a kind of circuit that the starting time varies with temperature.
Majority soft startup of electric power technology is started using non-temperature association at present, therefore soft start reliable at normal temperature
Design is possible to still less reliable at high temperature.
[summary of the invention]
The object of the invention is to solve the problems of the prior art, a kind of temperature control soft starting circuit is proposed, when soft start
Between length with temperature height variation circuit, can preferably play a protective role to circuit, improve the work of soft starting circuit
Stability and reliability.
To achieve the above object, the invention proposes a kind of temperature control soft starting circuits, including soft starting circuit, control feedback
Loop, constant-current switch power source route, LED light, inspection leakage resistance, one output end of constant-current switch power source route connect LED light and inspection stream
Resistance is grounded again, and another output end connection control feedback control loop of constant-current switch power source route, control feedback control loop connects soft start
Circuit;The soft starting circuit includes capacitor C1, diode D1, triode Q1, resistance R1, resistance R3 and thermistor R2, soft
Start-up circuit connects supply voltage Vcc, and supply voltage Vcc passes through the resistance R1 and thermistor R2 of capacitor C1 connection parallel connection, and
The resistance R1 and thermistor R2 of connection are grounded;The collector of the supply voltage Vcc connecting triode Q1, the base stage of triode Q1
It is connected with the cathode of capacitor C1, tie point is equipped with the first test point;The emitter of the triode Q1 connects diode D1, and two
The cathode of pole pipe D1 is equipped with the second test point, diode D1 series resistance R3, and resistance R3 connection controls feedback control loop;The control
Feedback control loop includes optocoupler, first switch source current ring, second switch source current ring.
Preferably, the first switch source current ring connects resistance R4, resistance R4 series LED lamp.
Preferably, the resistance R3 connection first switch source current ring, constant-current switch power source connection optocoupler, light
Coupling connects second switch source current ring, and second switch source current ring connects first switch source current ring.
Preferably, the constant-current switch power source line-to-ground connection.
Beneficial effects of the present invention: LED constant current driving power of the present invention has the process of one section of starting after connecting, soft to open
Dynamic length of time can preferably play a protective role to circuit with the circuit of temperature height variation.To protect electronic product not
It is hit, guarantees the normal work of circuit, improve the job stability and reliability of soft starting circuit.
Feature and advantage of the invention will be described in detail by embodiment combination attached drawing.
[Detailed description of the invention]
Fig. 1 is a kind of connection circuit diagram of temperature control soft starting circuit of the present invention.
In figure: the first test point of 1-, the second test point of 2-, 3- soft starting circuit, 4- control feedback control loop, 5- constant current switch
Power circuit, 6-LED lamp, 7- diode D1,8- triode Q1,9- capacitor C1,10- resistance R1,11- thermistor R2,12- electricity
It hinders R3,13- and examines leakage resistance, 14- resistance R4,15- first switch source current ring, 16- second switch source current ring, 17- light
Coupling.
[specific embodiment]
Refering to fig. 1, of the invention, including soft starting circuit 3, control feedback control loop 4, constant-current switch power source route 5, LED light
6, leakage resistance 13 is examined, 5 one output end of constant-current switch power source route connection LED light 6 and inspection leakage resistance 13 are grounded again, constant current switch electricity
Another output end of source route 5 connection control feedback control loop 4, control feedback control loop 4 connect soft starting circuit 3;The soft start electricity
Road 3 includes capacitor C1 9, diode D1 7, triode Q1 8, resistance R1 10, resistance R3 12 and thermistor R2 11, soft to open
Dynamic circuit 3 connects supply voltage Vcc, and supply voltage Vcc connects resistance R1 10 and thermistor R2 in parallel by capacitor C1 9
11, resistance R1 10 in parallel and thermistor R2 11 are grounded;The collector of the supply voltage Vcc connecting triode Q1 8,
The base stage of triode Q1 8 is connected with the cathode of capacitor C1 9, and tie point is equipped with the first test point 1;The triode Q1's 8
Emitter connects diode D1 7, and the cathode of diode D1 7 is equipped with the second test point 2,7 series resistance R3 12 of diode D1,
The connection of resistance R3 12 controls feedback control loop 4;The control feedback control loop 4 include optocoupler 17, first switch source current ring 15,
Second switch source current ring 16.The first switch source current ring connects resistance R4 14,14 series LED lamp 6 of resistance R4.
The connection first switch source current of resistance R3 12 ring 15, constant-current switch power source route 5 connect optocoupler 17, and optocoupler 17 connects
Second switch source current ring 16, second switch source current ring 16 connect first switch source current ring 15.The constant current is opened
Close 5 grounding connection of power circuit.
The course of work of the present invention:
During the work time, when power supply is switched on, the first test point 1 is because of capacitor C1 for a kind of temperature control soft starting circuit of the present invention
9 voltages be 0, export close to Vcc high level, thus the voltage of the second test point 2 namely cathode of diode D1 7 compared with
Height injects after feedback control loop, and the output electric current of power supply is minimum.As Vcc is thermistor pair by R1 10 and R2 11
C1 9 charges, and the voltage of the first test point 1 gradually decreases, and causes 2 voltage of the second test point also to reduce, to inject feedback control loop
Signal it is smaller and smaller.Driving power output electric current constantly increases in this way, and after final C1 9 is fully charged, Q1 8 ends, two poles
Pipe D1 7 is also switched off, and such soft starting circuit does not just have an impact power supply after power initiation work.Here power initiation
Time is to determine the time charged by C1 9, and the RC network time constant that this time is made of C1 9, R1 10, R2 11
It determines, only R2 11 is variable here, and temperature is higher, and 11 resistance value of R2 is bigger, therefore the starting time is longer, thus to power supply
Impact is also just smaller.
The present invention, LED constant current driving power have the process of one section of starting after connecting, soft-start time length is with temperature
The circuit of height variation, can preferably play a protective role to circuit.To protect electronic product not to be hit, guarantee circuit
It works normally, improves the job stability and reliability of soft starting circuit.
Above-described embodiment is the description of the invention, is not limitation of the invention, after any pair of simple transformation of the present invention
Scheme all belong to the scope of protection of the present invention.