CN217849732U

CN217849732U - Protection circuit for automobile lamp and automobile lamp with protection circuit

Info

Publication number: CN217849732U
Application number: CN202221937194.4U
Authority: CN
Inventors: 徐悦
Original assignee: Changzhou Xingyu Automotive Lighting Systems Co Ltd
Current assignee: Changzhou Xingyu Automotive Lighting Systems Co Ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2022-11-18
Anticipated expiration: 2032-07-25

Abstract

The utility model relates to an automobile lamp technical field especially relates to an automobile lamp who is used for automobile lamp's protection circuit and has this protection circuit, and protection circuit includes that power protection module's output is connected with undervoltage protection module's input, and undervoltage protection module's output is connected with LED function control module's input. The utility model provides a protection circuit for car lamps and lanterns, when transient low pressure or short-term voltage fall to 0V appear, can be automatic and quick with the input circuit disconnection, protect the components and parts of back stage circuit, in the normal input voltage scope that rises to when voltage, lamps and lanterns resume normal work again, have guaranteed the security of car light in the use, and then have improved the security and the stability of circuit.

Description

Protection circuit for automobile lamp and automobile lamp with protection circuit

Technical Field

The utility model relates to an automobile lamp technical field especially relates to a automobile lamp who is used for automobile lamp's protection circuit and has this protection circuit.

Background

The light in the current car generally adopts LED lamps and lanterns, when the unstable condition appears in automobile body power supply system, for example when appearing instantaneous low voltage, perhaps when short-term voltage drops to 0V, when not having undervoltage protection, can reduce circuit performance, influences automobile lamps and lanterns's protection circuit life.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is: when not having under-voltage protection in order to solve current LED lamps and lanterns, can reduce circuit performance, influence circuit life's technical problem, the utility model provides a protection circuit for car lamps and lanterns, when transient low pressure or short-term voltage drop to 0V appear, can be automatic and quick with the input circuit disconnection, protect the components and parts of back level circuit, in voltage rises to normal input voltage scope, lamps and lanterns resume normal work again, guaranteed the security of car light in the use, and then improved the security and the stability of circuit.

The utility model provides a technical scheme that its technical problem adopted is: a protection circuit for an automotive lamp, comprising: the LED power supply comprises a power supply protection module, an under-voltage protection module and an LED function control module; the output end of the power supply protection module is connected with the input end of the under-voltage protection module, and the output end of the under-voltage protection module is connected with the input end of the LED function control module;

wherein, the undervoltage protection module includes: the circuit comprises a first voltage-stabilizing diode D2, a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, a first capacitor C4, a second capacitor C5, a first switch MOS tube Q2 and a first triode Q3; the utility model discloses a power protection module, including first switch MOS pipe Q2, first zener diode D2's negative pole, first electric capacity C4's one end third resistance R7 and first switch MOS pipe Q2's source electrode all with power protection module's output is connected, first zener diode D2's positive pole with first resistance R5's one end is connected, second resistance R6 with second electric capacity C5 parallel connection, the one end after the connection is connected respectively first resistance R5's the other end and first triode Q3's base, the other end after the connection with first triode Q3's projecting pole all is connected with public ground, first triode Q3's collecting electrode with fourth resistance R8's one end is connected, first electric capacity C4's the other end with public ground connects, third resistance R7's the other end with fourth resistance R8's the other end all with first switch MOS pipe Q2's grid is connected, first switch MOS pipe Q2's drain electrode is the output of MOS under-voltage protection module.

Further, specifically, the power protection module includes a transient diode T1, a third capacitor C1, a fourth capacitor C2, a fifth capacitor C3, a fifth resistor R1, a sixth resistor R2, a seventh resistor R3, an eighth resistor R4, a second switching MOS transistor Q1, and a second voltage regulator diode D1; the transient diode T1, the third capacitor C1, the fifth resistor R1, the fourth capacitor C2 and the fifth capacitor C3 are connected in parallel, one connected end and the drain electrode of the second switch MOS tube Q1 are connected with a vehicle body power supply, the other connected end is connected with the public ground end, the seventh resistor R3, the second voltage stabilizing diode D1 and the eighth resistor R4 are connected in parallel, the connected end is connected with the source electrode of the second switch MOS tube Q1, the connected other end is connected with the grid electrode of the second switch MOS tube Q1 and one end of the sixth resistor R2, the other end of the sixth resistor R2 is connected with the public ground end, and the source electrode of the second switch MOS tube Q1 is the output end of the power supply protection module.

Further, specifically, the LED function control module includes a driving module and an LED light emitting module, an input end of the driving module is connected to an output end of the under-voltage protection module, and an output end of the driving module is connected to the LED light emitting module.

Further, specifically, the driving module is a linear chip driving module, a linear constant current driving module, or a switching power supply driving module.

Further, specifically, the first switching MOS transistor Q2 and the second switching MOS transistor Q1 are both P-type MOS transistors.

Further, specifically, the first transistor Q3 is an NPN transistor.

An automotive light fixture comprising a protection circuit for an automotive light fixture as described above.

The beneficial effects of the utility model are that, the utility model discloses a protection circuit for car lamps and lanterns, input and automobile body power through power protection module are connected, the magnitude of voltage when automobile body power is less than the lower limit value of the normal operating voltage of LED function control module or when the magnitude of voltage of automobile body power is 0V suddenly, the undervoltage protection module switches on and closes LED function control module fast, keep apart between power protection module and undervoltage protection module and the LED function control module, components and parts among the protection circuit can not receive instantaneous current impact, and then the security and the stability of circuit have been improved, the security of car lamps and lanterns in the use has been guaranteed.

Drawings

The present invention will be further described with reference to the accompanying drawings and examples.

Fig. 1 is a schematic structural diagram of the preferred embodiment of the present invention.

Fig. 2 is a circuit diagram of the power protection module according to the preferred embodiment of the present invention.

Fig. 3 is a circuit diagram of the undervoltage protection module according to the preferred embodiment of the present invention.

Fig. 4 is a circuit diagram of the LED function control module according to the preferred embodiment of the present invention.

In the figure 1, a power supply protection module; 2. an undervoltage protection module; 3. an LED function control module; 31. a drive module; 32. and the LED light-emitting control module.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention and to simplify the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as a specific case by those skilled in the art.

As shown in fig. 1, it is the best embodiment of the present invention, a protection circuit for automotive lamp, which is characterized by comprising: the LED lamp comprises a power supply protection module 1, an under-voltage protection module 2 and an LED function control module 3; the output end of the power supply protection module 1 is connected with the input end of the under-voltage protection module 2, and the output end of the under-voltage protection module 2 is connected with the input end of the LED function control module 3; the input of power protection module 1 is connected with the automobile body power, the magnitude of voltage when the automobile body power is less than the lower limit value of the normal operating voltage of LED function control module 3 or the magnitude of voltage of automobile body power is 0V suddenly, undervoltage protection module 2 switches on and closes LED function control module 3 fast, keep apart between power protection module 1 and undervoltage protection module 2 and LED function control module 3, components and parts among the protection circuit can not receive instantaneous current impact, and then the security and the stability of circuit have been improved, the security of car lamps and lanterns in the use has been guaranteed.

In the embodiment of the present invention, as shown in fig. 2, the power protection module 1 includes a transient diode T1, a third capacitor C1, a fourth capacitor C2, a fifth capacitor C3, a fifth resistor R1, a sixth resistor R2, a seventh resistor R3, an eighth resistor R4, a second switching MOS transistor Q1, and a second voltage regulator diode D1; transient diode T1, third electric capacity C1, fifth resistance R1, fourth electric capacity C2 and fifth electric capacity C3 parallel connection, the drain electrode of the one end and second switch MOS pipe Q1 after connecting all is connected with automobile body power, the other end and the public ground after connecting are connected, seventh resistance R3, second zener diode D1 and eighth resistance R4 parallel connection, the one end and the source electrode of second switch MOS pipe Q1 after connecting, the grid of second switch MOS pipe Q1 and the one end of sixth resistance R2 are connected to the other end after connecting, the other end and the public ground of sixth resistance R2 are connected, the source electrode of second switch MOS pipe Q1 is the output of power protection module 1.

When a signal is turned on for an automobile lamp, a voltage VIN input by an automobile body power supply firstly passes through a transient diode T1 in a power supply protection module 1 to inhibit the impact of transient pulse, and then is filtered by a third capacitor C1 and a fourth capacitor C2, a fifth resistor R1 is used for absorbing static current in a circuit, and a fifth capacitor C3 is a ground capacitor of a drain electrode of a second switch MOS transistor Q1 and is used for filtering a high-frequency interference signal; the second voltage stabilizing diode D1 is connected between the grid electrode and the source electrode of the second switch MOS tube Q1, when the stable voltage value of the second voltage stabilizing diode D1 is VD1, the grid electrode of the second switch MOS tube Q1 starts threshold voltage VGS (th), and when VD1 is larger than VGS (th), the second switch MOS tube Q1 is conducted, namely the switch is closed. When VIN is less than VD1, the gate-source voltage VGSS of the second switch MOS transistor Q1 is equal to the voltage drop across the seventh resistor R3 after the seventh resistor R3 and the sixth resistor R2 are connected in series, i.e., the voltage of VGSS = [ R3/(R3 + R2) ] -VIN input, and when VGSS is less than VGS (th), the second switch MOS transistor Q1 is turned off, i.e., the switch is turned off. When VIN is larger than or equal to VD1, VGSS = VD1 at the moment, namely, the reverse connection prevention protection function is realized in the power protection module 1 by the second switch MOS tube Q1, when the forward voltage input by the vehicle body power supply is, the second switch MOS tube Q1 is conducted, and when the vehicle body power supply is reversely connected, the second switch MOS tube Q1 is cut off.

As shown in fig. 3, the undervoltage protection module 2 includes: the circuit comprises a first voltage-stabilizing diode D2, a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, a first capacitor C4, a second capacitor C5, a first switch MOS tube Q2 and a first triode Q3; the cathode of the first voltage-stabilizing diode D2, one end of the first capacitor C4, one end of the third resistor R7 and the source of the first switching MOS transistor Q2 are all connected with the output end of the power protection module 1, the anode of the first voltage-stabilizing diode D2 is connected with one end of the first resistor R5, the second resistor R6 and the second capacitor C5 are connected in parallel, the connected end is respectively connected with the other end of the first resistor R5 and the base of the first triode Q3, the connected other end and the emitter of the first triode Q3 are both connected with a common ground, the collector of the first triode Q3 is connected with one end of the fourth resistor R8, the other end of the first capacitor C4 is connected with the common ground, the other end of the third resistor R7 and the other end of the fourth resistor R8 are both connected with the gate of the first switching MOS transistor Q2, and the drain of the first switching MOS transistor Q2 is the output end of the under-voltage protection module 2.

After the voltage VIN input by the vehicle body power supply passes through the power protection module 1, the voltage VD2 of the cathode end of the first voltage stabilizing diode D2= VIN-IIN × RDS (on), where IIN is an input current, RDS (on) is a static drain-source resistance on-state resistance of the switching MOS transistor Q1, and the first resistor R5 and the first voltage stabilizing diode D2 are connected in series for current limiting and voltage dividing. When the first voltage stabilizing diode D2 works normally, when the voltage applied to the first voltage stabilizing diode D2 and the first resistor R5 changes, the voltage on the first voltage stabilizing diode D2 is unchanged, the changed voltage is transmitted to the first resistor R5, and the first resistor R5 limits current to be large, so that the first voltage stabilizing diode D2 is prevented from being burnt out. The first resistor R5 is used for protecting the first zener diode D2 from working normally. The second resistor R6 is a base bias resistor of the first triode Q3, and provides a base voltage for the first triode Q3, the first capacitor C4 is a source-to-ground capacitor of the switch MOS transistor Q1, and the voltage of the third resistor R7 is a gate-to-source voltage of the first switch MOS transistor Q2. The second capacitor C5 is a base electrode ground capacitor of the first triode Q3 and is used for high-frequency filtering and improving the anti-interference capability, and when high-frequency alternating noise interference comes, the second capacitor C5 can carry out short circuit on the base electrode ground, so that the interference is eliminated, and the anti-interference capability of the protection circuit is improved. The fourth resistor R8 is a protection resistor of the collector of the first triode Q3, and enhances the conduction capability of the first triode Q3, so that the first switching MOS transistor Q2 is quickly turned on, and the LED function control module 3 is quickly turned off.

When normally working, VD2 is when normal operating voltage scope the embodiment of the utility model provides an in, select suitable withstand voltage's first zener diode D2 and third resistance R7 according to input voltage VIN's scope for when third resistance R7's voltage is greater than first switch MOS pipe Q2's grid and opens threshold voltage VGS (th), first switch MOS pipe Q2 switches on, and the switch is closed promptly. At this time, the drain output voltage VDSS = VD2 of the first switching MOS transistor Q2. When VD2 is less than the lower limit value of normal working voltage or the voltage value of the vehicle body power supply is suddenly 0V, the voltage of the third resistor R7 is less than the grid opening threshold voltage VGS (th) of the first switch MOS tube Q2, the first switch MOS tube Q2 is cut off, the VD2 value is equal to 0V, the switch is closed, the under-voltage protection function is realized, no influence is caused on the function control module and the components at the later stage, and the safety and the stability of the circuit are improved.

Note that, in the whole circuit implementation, when selecting the first zener diode D2, attention is paid to the value of the regulated voltage VZ, and the maximum value of the regulated voltage needs to be considered, and the value changes slightly according to the operating current and the temperature. And stabilizing the current IZ value, wherein the IZ value at the maximum environmental temperature needs to be calculated, and IZmin is more than or equal to IZz and less than or equal to IZmax. The dynamic resistance RZ, the ratio of voltage change and current change of two ends of a voltage stabilizing diode, the rated power consumption PZ, the PZ under the maximum environment temperature, the temperature coefficient alpha and the relative change quantity of the voltage of two ends of the voltage stabilizing tube caused by the temperature change of 1 ℃ are required to be calculated, VZ = VZnom + alpha TJ-Tnom considers that the temperature coefficient alpha is smaller, and the influence of the temperature coefficient on the VZ can be ignored.

The utility model discloses in the embodiment, first switch MOS pipe Q2 and second switch MOS pipe Q1 are P type MOS pipe, and first triode Q3 is NPN type triode.

The embodiment of the utility model provides an in, LED function control module 3 includes drive module 31 and LED luminescence module 32, and drive module 31's input is connected with undervoltage protection module 2's output, and drive module 31's output is connected with LED luminescence module 32, and drive module 31 is used for driving LED luminescence module 32 and lights. The driving module 31 is, but not limited to, a linear chip driving module, a linear constant current driving module, or a switching power supply driving module.

In a specific embodiment of the present invention, the driving module 31 is a linear constant current driving module, as shown in fig. 4, specifically, the linear constant current driving module includes: the circuit comprises a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a bipolar diode D3, a third zener diode D4, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a second triode Q4 and a third triode Q5. One end of a ninth resistor R9 is connected with the output end of the undervoltage protection module 2, a bipolar diode D3 is connected with a sixth capacitor C6 in parallel, the other end of the ninth resistor R9 and the base of the second triode Q4 are both connected with one end after being connected in parallel, the other end after being connected in parallel is connected with a common ground end, one end of a seventh capacitor C7 is connected with the base of the second triode Q4, one end of a thirteenth resistor R13 is connected with the emitter of the second triode Q4, one end of an eighth capacitor C8 is connected with the base of the third triode Q5, one end of a fourteenth resistor R14 is connected with the emitter of the third triode Q5, the other end of the seventh capacitor C7, the other end of the thirteenth resistor R13, the other end of the eighth capacitor C8 and the other end of the fourteenth resistor R14 are both connected with the common ground end, the base of the second triode Q4 is also connected with the base of the third triode Q5, the collector of the second triode Q4 is also connected with the collector of the third triode Q5, a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12 are connected with the cathode of the anode of the third diode D4, and the cathode of the light-emitting diode D4 are connected in parallel and the output end of the light-stabilizing diode D4, and the light-emitting diode D-diode.

The LED light-emitting module is driven by the second triode Q4 and the third triode Q5, the ninth resistor R9 is a current-limiting resistor and plays a role in overcurrent protection for the bipolar diode D3, the sixth capacitor C6 is mainly used for filtering isolation, the bipolar diode D3 provides a reference voltage source and provides a reference base voltage (1.4V) for the second triode Q4, and the third voltage-stabilizing diode D4 is used for consuming the voltage of the circuit, so that when current passes through the light-emitting diode in the LED light-emitting module, components in the protection circuit are protected, and instantaneous high current can be prevented from being broken down. The tenth resistor R10, the eleventh resistor R11, and the twelfth resistor R12 are used for shunt in parallel in the circuit, and play a role of buffering. The thirteenth resistor R13 is a sampling resistor of the second transistor Q4, and the fourteenth resistor R14 is a sampling resistor of the third transistor Q5, through which the current of the emitter is set. The seventh capacitor C7 and the eighth capacitor C8 are bypass capacitors, and when the base current increases, the amount of change in the current is reduced, so as to keep the driving module 31 in a stable state.

An automotive lamp comprising a protection circuit for an automotive lamp as described above.

The beneficial effects of the utility model are that, the utility model discloses a protection circuit for car lamps and lanterns, input and automobile body power through power protection module 1 are connected, when the magnitude of voltage of automobile body power is less than the lower limit value of the normal operating voltage of LED function control module 3 or the magnitude of voltage of automobile body power is 0V suddenly, undervoltage protection module 2 switches on and closes LED function control module 3 fast, keep apart between power protection module 1 and undervoltage protection module 2 and the LED function control module 3, components and parts among the protection circuit can not receive instantaneous current impact, and then the security and the stability of circuit have been improved, the security of car lamps and lanterns in the use has been guaranteed.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A protection circuit for an automotive light fixture, comprising: the LED power supply comprises a power supply protection module (1), an under-voltage protection module (2) and an LED function control module (3);

the output end of the power supply protection module (1) is connected with the input end of the under-voltage protection module (2), and the output end of the under-voltage protection module (2) is connected with the input end of the LED function control module (3);

wherein the undervoltage protection module (2) comprises: the circuit comprises a first voltage-stabilizing diode D2, a first resistor R5, a second resistor R6, a third resistor R7, a fourth resistor R8, a first capacitor C4, a second capacitor C5, a first switch MOS tube Q2 and a first triode Q3;

the negative pole of first zener diode D2, the one end of first electric capacity C4, the one end of third resistance R7 and the source electrode of first switch MOS pipe Q2 all with the output of power protection module (1) is connected, first zener diode D2's positive pole with the one end of first resistance R5 is connected, second resistance R6 with second electric capacity C5 parallel connection, the one end after the connection is connected respectively the other end of first resistance R5 and the base of first triode Q3, the other end after the connection with the projecting pole of first triode Q3 all is connected with public ground, the collecting electrode of first triode Q3 with the one end of fourth resistance R8 is connected, the other end of first electric capacity C4 with public ground connects, the other end of third resistance R7 with the other end of fourth resistance R8 all with the grid of first MOS pipe Q2 is connected, the drain electrode of first switch MOS pipe Q2 is the output of undervoltage protection module (2).

2. The protection circuit for the automobile lamp according to claim 1, wherein the power protection module (1) comprises a transient diode T1, a third capacitor C1, a fourth capacitor C2, a fifth capacitor C3, a fifth resistor R1, a sixth resistor R2, a seventh resistor R3, an eighth resistor R4, a second switching MOS transistor Q1, and a second zener diode D1;

the transient diode T1, the third capacitor C1, the fifth resistor R1, the fourth capacitor C2 and the fifth capacitor C3 are connected in parallel, one connected end and the drain electrode of the second switch MOS tube Q1 are connected with a vehicle body power supply, the other connected end is connected with the common ground end, the seventh resistor R3, the second voltage stabilizing diode D1 and the eighth resistor R4 are connected in parallel, the connected end is connected with the source electrode of the second switch MOS tube Q1, the connected other end is connected with the grid electrode of the second switch MOS tube Q1 and one end of the sixth resistor R2, the other end of the sixth resistor R2 is connected with the common ground end, and the source electrode of the second switch MOS tube Q1 is the output end of the power supply protection module (1).

3. Protection circuit for automotive lamps as claimed in claim 1, characterized in that said LED function control module (3) comprises a driving module (31) and an LED lighting module (32), the input of said driving module (31) being connected with the output of said undervoltage protection module (2), the output of said driving module (31) being connected with said LED lighting module (32).

4. The protection circuit for automotive lamps of claim 3, characterized in that the driving module (31) is a linear chip driving module, a linear constant current driving module or a switching power supply driving module.

5. The protection circuit for an automotive lamp according to claim 2, wherein the first switching MOS transistor Q2 and the second switching MOS transistor Q1 are both P-type MOS transistors.

6. The protection circuit for an automotive lamp of claim 1, wherein the first transistor Q3 is an NPN transistor.

7. An automotive lamp, characterized in that it comprises a protection circuit for an automotive lamp as described in any one of claims 1 to 6.