Lighting switching control circuit

Abstract

The utility model discloses an illumination switching control circuit, comprising a switch unit comprising a first diode and an MOS tube, the anode of the first diode is connected with a bias voltage, the cathode of the first diode is connected with the control end of the MOS tube, the first end of the MOS tube is connected with a first control node, and the second end of the MOS tube is connected with the first end of a second illumination unit; the control unit comprises a voltage division circuit and a transistor, the voltage division circuit is used for generating divided voltage based on the bias voltage, a base electrode of the transistor receives the divided voltage, an emitter electrode of the transistor is connected with the second control node, and a collector electrode of the transistor is connected with an anode of the first diode. According to the utility model, on and off of the switch unit are controlled through the control unit based on the connection relation between the first control node and the reference potential and between the second control node and the reference potential, thereby realizing illumination switching. The current is prevented from flowing backwards through the first diode, the potential of the first control node is prevented from being lowered, and the lighting unit is prevented from being lighted slightly under the requirement of closing the lighting unit.

Description

TECHNICAL FIELD

[0001] The utility model belongs to control circuit technical field, specifically about a lighting switching control circuit. BACKGROUND

[0002] The vehicle light switching circuit is part of the vehicle light control circuit, which is used for controlling the on-off of the high beam and low beam of the vehicle. Most of the existing vehicle lights connect the high beam and low beam in series. When it is necessary to turn off the high beam, a control signal is applied to the control circuit, so that the control circuit shorts the high beam module, thereby turning off the high beam. Due to the simple structure of the control circuit, only one MOS tube is usually used as a switch tube, so that only a small control signal is needed to turn on the MOS tube. The circuit is easy to be triggered by mistake, the switching control of the vehicle light is not stable enough, and when it is necessary to turn off the high beam and low beam at the same time, the light may be slightly bright.

[0003] Therefore, in view of the above technical problems, it is necessary to provide a lighting switching control circuit. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims at providing a lighting switching control circuit, which can solve the problems of unstable lighting switching control and slight brightness of the lighting unit.

[0005] In order to achieve the above-mentioned purpose, the technical scheme provided by a specific embodiment of the utility model is as follows:

[0006] A lighting switching control circuit is used for controlling a lighting unit, the lighting unit includes a first lighting unit and a second lighting unit, the first end of the first lighting unit is connected with a first power supply voltage, the second end of the first lighting unit and the first end of the second lighting unit are connected with a second power supply voltage, and the lighting switching control circuit includes:

[0007] A switching unit includes a first diode and a MOS tube, the anode of the first diode is connected with a bias voltage, the cathode is connected with the control end of the MOS tube, the first end of the MOS tube is connected with the second end of the second lighting unit and a first control node, and the second end of the MOS tube is connected with the first end of the second lighting unit;

[0008] A control unit includes a voltage dividing circuit and a transistor, the voltage dividing circuit is used for voltage dividing the bias voltage and generating a divided voltage, the base of the transistor is used for receiving the divided voltage, the emitter of the transistor is connected with a second control node, and the collector of the transistor is connected with the anode of the first diode;

[0009] In the first state, the first control node is connected with a reference potential, and the first lighting unit is turned on.

[0010] In the second state, the first control node and the second control node are connected to a reference potential, and the first lighting unit and the second lighting unit are turned on.

[0011] In the third state, the second control node is connected to the reference potential, and the first lighting unit and the second lighting unit are turned off.

[0012] In one or more embodiments of the utility model, the switch unit further includes a first voltage stabilizing unit, the first voltage stabilizing unit includes a first voltage stabilizing diode, the anode of the first voltage stabilizing diode is connected to the first control node, and the cathode is connected to the control end of the MOS tube.

[0013] In one or more embodiments of the utility model, the first voltage stabilizing unit further includes a first resistor and a first capacitor, the first end of the first resistor and the first end of the first capacitor are both connected to the control end of the MOS tube, and the second end of the first resistor and the second end of the first capacitor are both connected to the first control node.

[0014] In one or more embodiments of the utility model, the switch unit further includes a second resistor and a second diode, the anode of the second diode is connected to the bias voltage, the cathode is connected to the first end of the first resistor, and the second end of the first resistor is connected to the anode of the first diode.

[0015] In one or more embodiments of the utility model, the switch unit further includes a third voltage stabilizing unit, the third voltage stabilizing unit includes a third capacitor and a fourth capacitor, the first end of the third capacitor and the first end of the fourth capacitor are connected to the second power supply voltage, the second end of the third capacitor is connected to the control end of the MOS tube, and the second end of the fourth capacitor is connected to the ground voltage.

[0016] In one or more embodiments of the utility model, the voltage dividing circuit includes at least two voltage dividing resistors connected in series between the bias voltage and the second control node.

[0017] In one or more embodiments of the utility model, the control unit includes a second voltage stabilizing unit, the second voltage stabilizing unit includes a second voltage stabilizing diode; wherein,

[0018] The cathode of the second voltage stabilizing diode is connected to the base of the transistor, and the anode of the second voltage stabilizing diode is connected to the second control node.

[0019] In one or more embodiments of the utility model, the second voltage stabilizing unit further includes a second capacitor, the first end of the second capacitor is connected to the base of the transistor, and the second end of the second capacitor is connected to the emitter of the transistor.

[0020] In one or more embodiments of the utility model, the control unit further includes a third diode, the anode of the third diode is connected with the bias voltage, and the cathode is connected with the voltage dividing circuit.

[0021] Compared with the prior art, the lighting switching control circuit of the utility model, through the control unit based on the connection relationship between the first control node and the second control node and the reference potential, controls the opening and closing of the switch unit, realizes the effect of lighting switching. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the technical personnel of the present disclosure better understand the technical solutions in the present disclosure, the following will be briefly introduced the drawings needed to be used in the embodiment or the prior art description, obviously, the drawings in the following description are only some embodiments in the present disclosure, for those skilled in the art, without creative labor, other drawings can also be obtained according to these drawings.

[0023] Figure 1 The switch unit structure diagram of the lighting switching control circuit in an embodiment of the utility model;

[0024] Figure 2 The control unit structure diagram of the lighting switching control circuit in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] In order to make the technical personnel of the present disclosure better understand the technical solutions in the present disclosure, the following will be briefly introduced the drawings needed to be used in the embodiment or the prior art description, obviously, the drawings in the following description are only some embodiments in the present disclosure, for those skilled in the art, without creative labor, other drawings can also be obtained according to these drawings.

[0026] Unless otherwise specifically indicated, throughout the specification and claims, the term "comprise" or variations such as "comprises" or "comprising" will be understood to imply the inclusion of a stated element or group of elements but not the exclusion of any other element or group of elements.

[0027] The "coupling" or "connection" or "linking" in the description includes both direct connection and indirect connection. The indirect connection is the connection through an intermediate medium, such as the connection through an electrically conductive medium, which can have a parasitic inductance or a parasitic capacitance; the indirect connection can also include the connection through other active devices or passive devices on the basis of achieving the same or similar functional purposes, such as the connection through a circuit or component such as a switch, a follow-up circuit, etc. In addition, in the utility model, words such as "first", "second" and the like are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply a certain actual relationship, quantity or order between the technical features.

[0028] As shown in Figure 1 and Figure 2 , the utility model discloses a kind of lighting switching control circuit in an embodiment, for control lighting unit, lighting unit includes first lighting unit L1 and second lighting unit L2, the first end of first lighting unit L1 is connected with first power supply voltage L_LED+, the second end of first lighting unit L1, the first end of second lighting unit L2 is connected with second power supply voltage H_LED+.

[0029] First lighting unit L1 in an embodiment is low beam unit, including one or more light emitting diode LED1, second lighting unit L2 is high beam unit, including one or more light emitting diode LED2. Optionally, in another embodiment, first lighting unit L1 is high beam unit, including one or more light emitting diode LED2, second lighting unit L2 is low beam unit, including one or more light emitting diode LED1.

[0030] As shown in Figure 1 , switch unit 10 includes first diode D1 and MOS tube M1, the anode of first diode D1 is directly or indirectly connected with bias voltage VCC, cathode is connected with the control end of MOS tube M1, the first end of MOS tube M1 is connected with the second end of second lighting unit L2 and first control node LB-, the second end of MOS tube M1 is connected with the first end of second lighting unit L2 and second power supply voltage H_LED+. Bias voltage VCC in an embodiment refers to power supply anode. MOS tube M1 in an embodiment is N channel MOS tube M1, and the first end of MOS tube M1 is source, and the second end is drain, and control end is gate.

[0031] As shown in Figure 2As shown, the control unit 20 includes a voltage divider circuit 21 and a transistor Q1. The voltage divider circuit 21 is used to divide the bias voltage VCC and generate a divided voltage. The base of the transistor Q1 is used to receive the divided voltage. The emitter of the transistor Q1 is connected to the second control node HB-, and the collector of the transistor Q1 is connected to the anode of the first diode D1. In one embodiment, the transistor Q1 is an NPN transistor Q1.

[0032] When the bias voltage VCC is in the power supply state:

[0033] In the first state, the first control node LB- is connected to the reference potential, and the MOS transistor M1 is turned on under the control of the bias voltage VCC, so the second lighting unit L2 is short-circuited and the first lighting unit L1 is turned on. In one embodiment, the reference potential refers to the ground voltage or the negative pole of the power supply.

[0034] In the second state, the first control node LB- and the second control node HB- are connected to the reference potential, the transistor Q1 is turned on under the control of the bias voltage VCC, and the gate voltage of the MOS transistor M1 is pulled down, causing the MOS transistor M1 to be turned off and the first lighting unit L1 and the second lighting unit L2 to be turned on.

[0035] In the third state, the second control node HB- is connected to the reference potential, and the first lighting unit L1 and the second lighting unit L2 are turned off. It is understood that when both the first control node LB- and the second control node HB- are not connected to the reference potential, the first lighting unit L1 and the second lighting unit L2 are turned off.

[0036] In other embodiments, the transistor Q1 may be a PNP transistor Q1 and the MOS transistor M1 may be a P-channel MOS transistor, and the connection method of the above devices may be adaptively modified.

[0037] like Figure 1 As shown, in one embodiment, the switch unit 10 further includes a first voltage stabilizing unit, which includes a first voltage stabilizing diode Z1, a first resistor R1, and a first capacitor C1. Specifically, the anode of the first voltage stabilizing diode Z1 is connected to the first terminal of the MOS transistor M1 and the first control node LB-, and the cathode is connected to the control terminal of the MOS transistor M1. The first terminal of the first resistor R1 and the first terminal of the first capacitor C1 are both connected to the control terminal of the MOS transistor M1, and the second terminal of the first resistor R1 and the second terminal of the first capacitor C1 are both connected to the first terminal of the MOS transistor M1 and the first control node LB-. The first voltage stabilizing diode Z1, the first resistor R1, and the first capacitor C1 all function to stabilize the voltage.

[0038] like Figure 1As shown, the switch unit 10 further comprises a second resistor R2 and a second diode D2. The anode of the second diode D2 is connected to the bias voltage VCC, the cathode is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is connected to the anode of the first diode D1. The second diode D2 is used to prevent current from flowing backward.

[0039] The switch unit 10 further comprises a third voltage stabilizing unit, which comprises a third capacitor C3 and a fourth capacitor C4. The first end of the third capacitor C3 and the first end of the fourth capacitor C4 are connected to the second power supply voltage H_LED+, the second end of the third capacitor C3 is connected to the control end of the MOS transistor M1, and the second end of the fourth capacitor C4 is connected to the ground voltage. Both the third capacitor C3 and the fourth capacitor C4 are used to stabilize the voltage by charging and discharging, so as to avoid overshoot current caused by too fast power-on, which damages the MOS transistor M1 or other devices.

[0040] As shown, the control unit 20 comprises a second voltage stabilizing unit, which comprises a second voltage stabilizing diode Z2 and a second capacitor C2. The cathode of the second voltage stabilizing diode Z2 is connected to the base of the transistor Q1, and the anode of the second voltage stabilizing diode Z2 is connected to the emitter of the transistor Q1 and the second control node HB-. The first end of the second capacitor C2 is connected to the base of the transistor Q1, and the second end of the second capacitor C2 is connected to the emitter of the transistor Q1 and the second control node HB-. Both the second voltage stabilizing diode Z2 and the second capacitor C2 have the function of stabilizing voltage. Figure 2

[0041] Based on the size of the bias voltage VCC, the resistance values of the first voltage dividing resistor R3 and the second voltage dividing resistor R4 are selected. In an embodiment, the resistance value of the first voltage dividing resistor R3 is selected to be 20KΩ, and the resistance value of the second voltage dividing resistor R4 is selected to be 1.2KΩ. The model of the transistor Q1 is bc846b, and its opening voltage is about 0.6V-0.7V. At this time, the bias voltage VCC is 12V, which is commonly used in control circuits, and the voltage dividing voltage can be approximately (12V-0.7)*1.2KΩ / 20KΩ=0.639V, which is enough to open the transistor Q1 completely, so that the transistor Q1 is in a saturated state and can completely pull down the gate voltage of the MOS transistor M1.

[0042] In an embodiment, the control unit 20 comprises a second voltage stabilizing unit, which comprises a second voltage stabilizing diode Z2 and a second capacitor C2. The cathode of the second voltage stabilizing diode Z2 is connected to the base of the transistor Q1, and the anode of the second voltage stabilizing diode Z2 is connected to the emitter of the transistor Q1 and the second control node HB-. The first end of the second capacitor C2 is connected to the base of the transistor Q1, and the second end of the second capacitor C2 is connected to the emitter of the transistor Q1 and the second control node HB-. Both the second voltage stabilizing diode Z2 and the second capacitor C2 have the function of stabilizing voltage.

[0043] In an embodiment, the control unit 20 further comprises a third diode D3, the anode of the third diode D3 is connected to the bias voltage VCC, and the cathode is connected to the voltage dividing circuit 21. The third diode D3 is used to prevent current from flowing backward. ​

[0044] The switch unit 10 and the control unit 20 of the lighting switching control circuit of the application share a power supply positive pole (i.e. bias voltage VCC), and the lighting switching is controlled by controlling the connection relationship between the first control node LB- and the second control node HB- and the power supply negative pole (i.e. reference potential). When the bias voltage VCC is supplied and only the second control node HB- is connected to the reference potential, the transistor Q1 is turned on, and due to the existence of the first voltage stabilizing diode Z1, the potential LB- of the first control node LB- is also pulled down at this time, i.e. the current flows in the direction of the first control node LB-~the first voltage stabilizing diode Z1~the transistor Q1~the second control node HB-. At this time, the first lighting unit L1 and the second lighting unit L2 form a loop, and the first lighting unit L1 and the second lighting unit L2 may appear dim. The application prevents the current from flowing from the first control node LB- to the second control node HB- based on the first diode D1, avoids the dimming of the first lighting unit L1 and the second lighting unit L2, and realizes stable control of lighting switching.

[0045] From the above technical solutions, the utility model has the following beneficial effects:

[0046] The control unit controls the opening and closing of the switch unit based on the connection relationship between the first control node and the second control node and the reference potential, thereby realizing the effect of lighting switching. Meanwhile, the first diode prevents the current from flowing backward, avoids the potential of the first control node being pulled down by the control unit, and further prevents the lighting unit from appearing dim in the demand of turning off the lighting unit.

[0047] For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be realized in other specific forms without departing from the spirit or basic characteristics of the utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the utility model is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the utility model. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0048] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A lighting switching control circuit for controlling a lighting unit, wherein the lighting unit comprises a first lighting unit and a second lighting unit, wherein a first end of the first lighting unit is connected to a first power supply voltage, and a second end of the first lighting unit and a first end of the second lighting unit are connected to a second power supply voltage, characterized in that: The illumination switching control circuit comprises: a switching unit comprising a first diode and a MOS tube, an anode of the first diode being connected to a bias voltage, a cathode of the first diode being connected to a control end of the MOS tube, a first end of the MOS tube being connected to a second end of a second illumination unit and a first control node, a second end of the MOS tube being connected to a first end of the second illumination unit; a control unit comprising a voltage dividing circuit and a transistor, the voltage dividing circuit being configured to divide the bias voltage and generate a divided voltage, a base of the transistor being configured to receive the divided voltage, an emitter of the transistor being connected to the second control node, and a collector of the transistor being connected to the anode of the first diode; in the first state, the first control node is connected to a reference potential, and the first illumination unit is turned on; in the second state, the first control node and the second control node are connected to the reference potential, and the first illumination unit and the second illumination unit are turned on; in the third state, the second control node is connected to the reference potential, and the first illumination unit and the second illumination unit are turned off.

2. The illumination switching control circuit according to claim 1, characterized by The switching unit further comprises a first voltage stabilizing unit, the first voltage stabilizing unit comprising a first voltage stabilizing diode, an anode of the first voltage stabilizing diode being connected to the first control node, and a cathode of the first voltage stabilizing diode being connected to the control end of the MOS tube.

3. The illumination switching control circuit according to claim 2, characterized in that, The first voltage stabilizing unit further comprises a first resistor and a first capacitor, a first end of the first resistor and a first end of the first capacitor being connected to the control end of the MOS tube, and a second end of the first resistor and a second end of the first capacitor being connected to the first control node.

4. The illumination switching control circuit according to claim 1, characterized by The switching unit further comprises a second resistor and a second diode, an anode of the second diode being connected to the bias voltage, and a cathode of the second diode being connected to the first end of the first resistor, and a second end of the first resistor being connected to the anode of the first diode.

5. The illumination switching control circuit according to claim 1, characterized by The switching unit further comprises a third voltage stabilizing unit, the third voltage stabilizing unit comprising a third capacitor and a fourth capacitor, a first end of the third capacitor and a first end of the fourth capacitor being connected to a second bias voltage, a second end of the third capacitor being connected to the control end of the MOS tube, and a second end of the fourth capacitor being connected to a ground voltage.

6. The illumination switching control circuit according to claim 1, characterized by The voltage dividing circuit comprises at least two voltage dividing resistors connected in series between the bias voltage and the second control node.

7. The illumination switching control circuit according to claim 1, characterized by The control unit comprises a second voltage stabilizing unit, the second voltage stabilizing unit comprising a second voltage stabilizing diode; wherein, a cathode of the second voltage stabilizing diode is connected to the base of the transistor, and an anode of the second voltage stabilizing diode is connected to the second control node.

8. The illumination switching control circuit according to claim 7, characterized in that, The second voltage stabilizing unit further comprises a second capacitor, a first end of the second capacitor being connected to the base of the transistor, and a second end of the second capacitor being connected to the emitter of the transistor.

9. The illumination switching control circuit according to claim 1, characterized by The control unit further comprises a third diode, an anode of the third diode being connected to the bias voltage, and a cathode of the third diode being connected to the voltage dividing circuit.

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