Control circuit for realizing output current adjustability

Abstract

The utility model relates to the technical field of control circuits, in particular to a control circuit for realizing adjustable output current, which comprises a main power circuit, a switching tube control circuit and a constant current loop control circuit which are connected in sequence, the main power circuit comprises a switching tube Q9, a switching tube Q10, a triode Q5, a triode Q6 and a resistor RS1, and the switching tube Q9 and the switching tube Q10 are connected with the resistor RS1; the switching tube control circuit comprises an optocoupler U2-A, an optocoupler U2-B, a chip OT1 and a feedback voltage FB, the chip OT1 is connected with the optocoupler U2-B, one end of the chip OT1 is connected with the feedback voltage FB, and the optocoupler U2-A is connected with one end of the constant current control circuit; the constant current control circuit comprises an input voltage U1, a chip U6-A, a resistor R1, a chip U9-B, a reference voltage U2 and a voltage IADJ; one end of the voltage IADJ is connected with one end of the chip U6-A, the other end of the chip U6-A is connected with the resistor R1 and the chip U9-B, one end of the chip U9-B is connected with the reference voltage U2, and the input voltage U1 is connected with the resistor R1 and the chip U9-B. According to the output current adjustable control circuit, the output current IO can be adjusted by changing the resistor R1 and the reference voltage U2.

Description

TECHNICAL FIELD

[0001] The utility model relates to control circuit technical field, concretely relates to a kind of output current adjustable control circuit. BACKGROUND

[0002] Under the background of the rapid development of today's LED power supply, it is often necessary to realize luminous brightness adjustable. In order to control the luminous flux, it is actually to control the output current adjustable of LED power supply. In order to realize output current adjustable, the common method is to control through software, but through this way, MCU control chip needs to be added, and host computer software also needs to be increased, which needs tedious process to adjust output current, so as to cause cost increase.

[0003] Therefore, it is the inevitable demand of LED power supply industry to design a kind of output current adjustable control circuit. UTILITY MODEL CONTENT

[0004] In order to overcome the defects of prior art, the purpose of the utility model is to provide a kind of output current adjustable control circuit.

[0005] In order to achieve the purpose, the technical scheme of the utility model is as follows: a kind of output current adjustable control circuit, including main power circuit, switch tube control circuit and constant current loop control circuit connected in turn,

[0006] The main power circuit includes switch tube Q9, switch tube Q10, triode Q5, triode Q6 and resistance RS1, and the switch tube Q9 and switch tube Q10 are connected with resistance RS1 through triode Q5 and triode Q6.

[0007] The switch tube control circuit includes photoelectric coupler U2-A, photoelectric coupler U2-B, chip OT1 and feedback voltage FB, the chip OT1 is connected with photoelectric coupler U2-B, one end of the chip OT1 is connected with feedback voltage FB, and one end of photoelectric coupler U2-A is connected with constant current control circuit.

[0008] The constant current control circuit includes input voltage U1, chip U6-A, resistance R1, chip U9-B, reference voltage U2 and voltage IADJ, one end of the chip U6-A is connected with one end of the chip U6-A, the other end of the chip U6-A is connected with resistance R1 and chip U9-B, one end of the chip U9-B is connected with reference voltage U2, and input voltage U1 is connected with resistance R1 and chip U9-B.

[0009] Preferably, one end of the chip U6-A is connected with resistance R165, resistance R106 and resistance R61, and the calculation formula of the output current IO of the adjustable control circuit is as follows:

[0010] Output current

[0011] Preferably, one end of the resistor R1 is also connected with a resistor R74, a resistor R73, a resistor R50,

[0012] The calculation formula of the reference voltage U2 is:

[0013]

[0014] Preferably, the resistor R1 includes a resistor R58, a resistor R59 and a resistor VR1,

[0015] The calculation formula of the resistor R1 is:

[0016]

[0017] The beneficial effects of the utility model are:

[0018] The utility model relates to a kind of output current adjustable control circuit, mainly including main power circuit, switch tube control circuit and constant current loop control circuit, wherein, the role of switch tube Q9 and switch tube Q10 is: the size of output current IO is controlled by the length of control switch tube conduction time;The role of chip OT1 is: the conduction length of switch tube Q9 and switch tube Q10 is controlled;The role of resistor RS1 is: the size of output current IO is sampled;The role of chip U9-B is: the size of reference voltage U2 is controlled;The role of chip U6-A is: the size of control voltage IADJ is controlled by comparing with reference voltage U2;The role of photoelectric coupler U2-A, photoelectric coupler U2-B is: the luminous quantity size of photoelectric coupler U2-A is influenced by the size of IADJ, to control the on-voltage size of U2-B, determine the size of feedback voltage FB, the size of feedback voltage FB determines the conduction length of chip OT1 control switch tube Q9 and switch tube Q10.By changing resistor R1 and reference voltage U2, the adjustable output current IO can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] In the drawings:

[0020] Fig. 1 It is the circuit diagram of the main power circuit of the utility model;

[0021] Fig. 2 It is the circuit diagram of the switch tube control circuit of the utility model;

[0022] Fig. 3 It is the circuit diagram of a kind of output current adjustable control circuit of the utility model. DETAILED DESCRIPTION

[0023] The utility model will make further detailed instructions combining with the drawings and examples, obviously, the described example is only a part of the utility model example, is not all examples. In the case of no conflict, the example in this application and the features in the example can be combined with each other. Based on the example in the utility model, all other examples obtained by the ordinary skill in the art without creative labor belong to the scope of the utility model protection.

[0024] It should be noted that if the utility model example has involved directionality indication (such as up, down, left, right, front, back……), the directionality indication is only used to explain the relative position relationship, movement condition etc. between components in a certain specific posture (as shown in the drawings), if the specific posture changes, then the directionality indication also changes accordingly.

[0025] In addition, "a plurality of" means two or more. In addition, the technical solutions of each example can be combined with each other, but it must be based on the realization of the ordinary skill in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the utility model.

[0026] Please refer to the drawings in the description Figs. 1-3 The utility model provides a kind of realization output current adjustable control circuit, including main power circuit, switch tube control circuit and constant current loop control circuit connected in turn,

[0027] Main power circuit includes switch tube Q9, switch tube Q10, triode Q5, triode Q6 and resistance RS1, switch tube Q9 and switch tube Q10 are connected resistance RS1 by triode Q5 and triode Q6;

[0028] Switch tube control circuit includes optocoupler U2-A, optocoupler U2-B, chip OT1 and feedback voltage FB, chip OT1 is connected optocoupler U2-B, one end of chip OT1 is connected feedback voltage FB, and one end of optocoupler U2-A is connected constant current control circuit;

[0029] Constant current control circuit includes input voltage U1, chip U6-A, resistance R1, chip U9-B, reference voltage U2 and voltage IADJ;One end of voltage IADJ is connected one end of chip U6-A, and the other end of chip U6-A is connected resistance R1 and chip U9-B, one end of chip U9-B is connected reference voltage U2, and input voltage U1 is connected resistance R1 and chip U9-B.

[0030] One end of chip U6-A is connected with resistance R165, resistance R106 and resistance R61, and the calculation formula of the output current IO of this adjustable control circuit is as follows:

[0031] Output current

[0032] One end of the resistance R1 is also connected with the resistance R74, the resistance R73, the resistance R50, the resistance R1 includes the resistance R58, the resistance R59 and the resistance VR1,

[0033] The calculation formula of the reference voltage U2 is as follows:

[0034]

[0035] The calculation formula of the resistance R1 is as follows:

[0036]

[0037] The utility model discloses a kind of output current adjustable control circuit, wide application range, it can be widely applied in power industry field, it mainly includes main power circuit, switch tube control circuit and constant current loop control circuit connected in turn, wherein, main power circuit and switch tube control circuit are existing control circuit, constant current loop control circuit is the core adjustable circuit of the application required protection. Among them, the role of switch tube Q9 and switch tube Q10 is: the size of output current IO is controlled by the length of switch tube conduction time;The role of chip OT1 is: the conduction length of switch tube Q9 and switch tube Q10 is controlled;The role of resistance RS1 is: the size of output current IO is sampled;The role of chip U9-B is: the size of reference voltage U2 is controlled;The role of chip U6-A is: the size of voltage IADJ is controlled by comparing with reference voltage U2;The role of photoelectric coupler U2-A and photoelectric coupler U2-B is: the luminous quantity size of photoelectric coupler U2-A is influenced by the size of IADJ, so as to control the on-voltage size of U2-B, determine the size of feedback voltage FB, the conduction length of switch tube Q9 and switch tube Q10 controlled by chip OT1 is determined by the size of feedback voltage FB.

[0038] The core technical point of the adjustable control circuit is: the size of reference voltage U2 is controlled as variable, causes each component in main power circuit, switch tube control circuit and constant current loop control circuit to react, so as to realize that output circuit IO is adjustable according to reference voltage U2, the relationship between output current IO and reference voltage U2 is further explained by the calculation formula of output current IO, the calculation formula of reference voltage U2 and the calculation formula of resistance R1, how reference voltage U2 changes influences output current IO.

[0039] From the calculation formula of output current IO, to change output current IO, reference voltage U2 must be changed;From the calculation formula of reference voltage U2, to change reference voltage U2, resistance R1 must be changed;From the calculation formula of resistance R1, to change resistance R1, resistance VR1 must be changed.

[0040] For example, when U1=10V, resistance VR1=20KΩ, R1=10.02KΩ; U2=10.01V; output current IO=9.34A;

[0041] When U1=10V, resistance VR1=10KΩ, R1=6.71KΩ; U2=8.36V; output current IO=7.8A.

[0042] It can be seen that only an adjustable resistance VR1 is added to the original constant current loop control circuit, the output current can be adjusted.

[0043] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control circuit for realizing adjustable output current, characterized in that: The main power circuit, the switch tube control circuit and the constant current loop control circuit are connected in sequence, The main power circuit comprises a switch tube Q9, a switch tube Q10, a triode Q5, a triode Q6 and a resistor RS1, the switch tube Q9 and the switch tube Q10 are connected with the resistor RS1 through the triode Q5 and the triode Q6; The switch tube control circuit comprises an optical coupler U2-A, an optical coupler U2-B, a chip OT1 and a feedback voltage FB, the chip OT1 is connected with the optical coupler U2-B, one end of the chip OT1 is connected with the feedback voltage FB, and one end of the optical coupler U2-A is connected with the constant current control circuit; The constant current control circuit comprises an input voltage U1, a chip U6-A, a resistor R1, a chip U9-B, a reference voltage U2 and a voltage IADJ, one end of the voltage IADJ is connected with one end of the chip U6-A, the other end of the chip U6-A is connected with the resistor R1 and the chip U9-B, one end of the chip U9-B is connected with the reference voltage U2, and the input voltage U1 is connected with the resistor R1 and the chip U9-B.

2. The output current adjustable control circuit according to claim 1, wherein, One end of the chip U6-A is connected with a resistor R165, a resistor R106 and a resistor R61, and the calculation formula of the output current IO of the adjustable control circuit is:

3. The output current adjustable control circuit according to claim 1, wherein, One end of the resistor R1 is also connected with a resistor R74, a resistor R73 and a resistor R50, The calculation formula of the reference voltage U2 is:

4. The output current adjustable control circuit according to claim 1, wherein, The resistor R1 comprises a resistor R58, a resistor R59 and a resistor VR1, The calculation formula of the resistor R1 is:

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