LED lamp and control circuit thereof

Abstract

The invention relates to the technical field of automobile lamp control, in particular to an LED lamp and a control circuit thereof. The control circuit comprises an open-short circuit logic control module, an LED light source module, a power supply input module and an LED driving module, the open-short circuit logic control module controls connection and disconnection between the power supply input module and the LED driving module by diagnosing an electric signal between the LED light source module and the LED driving module, and the open-short circuit logic control module is composed of discrete devices. The LED lamp provided by the invention comprises the LED lamp control circuit. According to the circuit, LED open and short circuit diagnosis can be realized, and when a single LED is in an open circuit or a plurality of LEDs are in an open circuit, and when one LED is in a short circuit or a plurality of LEDs are in a short circuit, other LED particles can be turned off, so that all the LED particles are extinguished. The elements used in the invention are discrete elements, so that the cost is low and the reliability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile lamp control, and in particular to an LED lamp and a control circuit thereof. Background Art

[0002] like Figure 1 As shown, in conventional designs, discrete components are often only capable of diagnosing single LED open circuits or multiple LEDs with multiple channels. These limited diagnostic capabilities cannot meet the needs of both LED open circuit and LED short circuit diagnosis. To meet the requirements for both LED open circuit and LED short circuit diagnosis, the design requires a driver chip with these capabilities. However, typical LED driver chips only provide LED open circuit diagnosis and output channel short circuit to GND diagnosis. Driver chips capable of both single LED short circuit diagnosis are relatively rare, and most are foreign brands. Therefore, driver chips with both LED open circuit and short circuit diagnosis capabilities are relatively costly, and the limited variety of models contributes to the high cost. If chip production capacity is limited, replacement chips may be unavailable. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: In order to overcome the above technical problems, the present invention provides an LED lamp and its control circuit, which uses discrete devices to build a module with open circuit and short circuit logic control, which can meet the diagnosis requirements of a single open circuit or a single short circuit of an LED, optimize the design scheme, and reduce the cost of the lamp.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an LED lamp control circuit, including an open-short circuit logic control module, an LED light source module, a power input module and an LED driver module, the power input module supplies power to the LED light source module, the open-short circuit logic control module and the LED driver module, the LED driver module is used to drive the LED light source module, the LED light source module includes at least two LED lamp beads, the open-short circuit logic control module controls the on and off between the power input module and the LED driver module by diagnosing the electrical signal between the LED light source module and the LED driver module, and the open-short circuit logic control module is composed of discrete components.

[0005] The power input module is connected to at least two LED light source modules, and there is no upper limit on the number of LED light source modules. The LED driver module includes a voltage stabilizing module and a switch current limiting module. The output of the voltage stabilizing module controls the on / off of the switch current limiting module. Each LED light source module is connected to a switch current limiting module, and each switch current limiting module is connected to the same voltage stabilizing module. The open-short circuit logic control module includes an open-short circuit diagnostic module and a switch control module. The output of the open-short circuit diagnostic module controls the on / off of the switch control module. Each LED light source module is connected to a corresponding open-short circuit diagnostic module. The open-short circuit diagnostic module corresponding to each LED light source module is connected to the input of the switch control module, and the output of the switch control module is connected to the voltage stabilizing module of the LED driver module.

[0006] The voltage stabilizing module includes a first resistor R1 and a voltage stabilizing diode D2, one end of the first resistor R1 is connected to the positive electrode of the voltage stabilizing diode D2, the other end of the first resistor R1 is connected to the output end of the power input module, the first resistor R1 is connected in series with the voltage stabilizing diode D2 and then grounded, the switching current limiting module includes a power transistor and a sampling resistor, the LED driving module is connected to the LED light source module through the collector of the power transistor, the emitter of the power transistor is connected in series with the voltage stabilizing diode D2 and then grounded, the base of the power transistor is connected to the positive electrode of the voltage stabilizing diode D2, and the emitter of the power transistor is grounded through the sampling resistor.

[0007] The open-short circuit diagnostic module includes a differential comparator, which includes a first transistor and a second transistor. The bases of the first transistor and the second transistor are respectively connected to the low-level end and the high-level end of the same LED light source module. The emitter of the first transistor is connected to the base of the second transistor and then grounded through a voltage-dividing resistor. The voltage-dividing resistor is connected in series with a pull-up resistor and connected to the output end of the power input module. The collector of the first transistor is connected to the collector of the second transistor through a current-limiting resistor, and the emitter of the second transistor is connected to the base of the first transistor. The switch control module includes a switch transistor Q7. The collector of the switch transistor Q7 is connected to the base of the power transistor, and the base of the switch transistor Q7 is connected to the collector of the first transistor.

[0008] A current limiting resistor R9 is connected in series between the base and emitter of the switching transistor Q7.

[0009] The power input module is connected to two LED light source modules, the LED driving module includes a voltage stabilizing module and two switch current limiting modules, the two LED light source modules are respectively connected to a switch current limiting module, and the two switch current limiting modules are connected to the same voltage stabilizing module, the open-short circuit logic control module includes two open-short circuit diagnostic modules and a switch control module, each LED light source module is respectively connected to one open-short circuit diagnostic module, the open-short circuit diagnostic modules corresponding to the two LED light source modules are both connected to the input end of the switch control module, and the output end of the switch control module is connected to the LED driving module.

[0010] Each LED light source module has two LED lamp beads.

[0011] The power input module includes a voltage source VCC, an anti-reverse diode D1 and a TVS tube T1. The voltage source VCC is grounded through the TVS tube T1. The voltage source VCC outputs voltage through the anti-reverse diode D1. The anti-reverse diode D1, the LED light source module, the power transistor and the sampling resistor are connected in series and then grounded.

[0012] The TVS tube T1 is connected in parallel with a protection capacitor C1 to perform filtering protection function.

[0013] An LED lamp of the present invention includes the LED lamp control circuit of the present invention.

[0014] The beneficial effects of the present invention are that the LED lamp and its control circuit in the field of automobile light control technology have the following advantages:

[0015] (1) The circuit of the present invention can realize LED open circuit diagnosis. When a single LED or multiple LEDs are open circuit, the circuit control module can shut down other LED particles and turn off all of them.

[0016] (2) The circuit of the present invention can realize a circuit control module that can shut down the other LED particles and extinguish all of them when one LED or multiple LEDs are short-circuited.

[0017] (3) The circuit of the present invention has a constant current effect, ensuring that when the operating voltage at both ends of the LED fluctuates, the brightness of the LED will not be affected by the voltage change.

[0018] (4) The components used in the present invention are all discrete components, which are low in cost and high in reliability. They are not limited to certain special chips or components and are highly substitutable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and examples.

[0020] Figure 1 This is a block diagram of an LED diagnostic control circuit in the prior art.

[0021] Figure 2 This is a principle block diagram of the LED lamp control circuit of the present invention.

[0022] Figure 3 It is a circuit diagram of the LED lamp control circuit of the present invention.

[0023] In the figure, 1-1 is the open and short circuit diagnosis module, 1-2 is the switch control module, 2-1 is the voltage regulation module, 2-2 is the switch current limiting module, and 3 is the power input module. DETAILED DESCRIPTION

[0024] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0025] like Figure 2 As shown, an LED lamp control circuit of the present invention includes an open-short circuit logic control module, an LED light source module, a power input module 3 and an LED driver module. The power input module 3 supplies power to the LED light source module, the open-short circuit logic control module and the LED driver module. The LED driver module is used to drive the LED light source module. The LED light source module includes at least two LED lamp beads. The open-short circuit logic control module controls the on-off between the power input module 3 and the LED driver module by diagnosing the electrical signal between the LED light source module and the LED driver module. The open-short circuit logic control module is composed of discrete components.

[0026] The power input module 3 is connected to at least two LED light source modules. Generally, in an automotive LED lamp, the power input module 3 is connected to 8-10 LED light source modules.

[0027] The LED driver module includes a voltage stabilizing module 2-1 and a switch current limiting module 2-2. The output of the voltage stabilizing module 2-1 controls the on and off of the switch current limiting module 2-2. Each LED light source module is respectively connected to a switch current limiting module 2-2, and each switch current limiting module 2-2 is connected to the same voltage stabilizing module 2-1. The open-short circuit logic control module includes an open-short circuit diagnostic module 1-1 and a switch control module 1-2. The output of the open-short circuit diagnostic module 1-1 controls the on and off of the switch control module 1-2. Each LED light source module is respectively connected to a corresponding open-short circuit diagnostic module 1-1. The open-short circuit diagnostic module 1-1 corresponding to each LED light source module is connected to the input end of the switch control module 1-2, and the output end of the switch control module 1-2 is connected to the voltage stabilizing module 2-1 of the LED driver module.

[0028] Figure 3In a specific embodiment, the power input module 3 is connected to two LED light source modules, each of which has two LED lamp beads, namely L1, L2, L3 and L4. The LED driver module includes a voltage stabilizing module 2-1 and two switch current limiting modules 2-2. The two LED light source modules are respectively connected to one switch current limiting module 2-2, and the two switch current limiting modules 2-2 are connected to the same voltage stabilizing module 2-1. The open-short circuit logic control module includes two open-short circuit diagnostic modules 1-1 and one switch control module 1-2. Each LED light source module is respectively connected to one open-short circuit diagnostic module 1-1. The open-short circuit diagnostic modules 1-1 corresponding to the two LED light source modules are both connected to the input end of the switch control module 1-2, and the output end of the switch control module 1-2 is connected to the LED driver module.

[0029] The voltage stabilization module 2-1 includes a first resistor R1 and a Zener diode D2. One end of the first resistor R1 is connected to the anode of the Zener diode D2, and the other end of the first resistor R1 is connected to the output of the power input module 3. The first resistor R1 and the Zener diode D2 are connected in series and then to ground. The switching current limiting module 2-2 includes power transistors Q1 and Q2 and sampling resistors R2 and R3. The LED driver module is connected to the LED light source module via the collector of the power transistor. The emitter of the power transistor is connected in series with the Zener diode D2 and then to ground. The base of the power transistor is connected to the anode of the Zener diode D2, and the emitter of the power transistor is grounded via the sampling resistor.

[0030] Figure 3In the example, the open-short circuit diagnosis module 1-1 includes a differential comparator, which includes a first transistor Q3, Q5 and a second transistor Q4, Q6. The bases of the first transistor and the second transistor are respectively connected to the low-level end and the high-level end of the same LED light source module. The emitter of the first transistor is connected to the base of the second transistor and then grounded through a voltage-dividing resistor R5, R8. The voltage-dividing resistor is connected in series with a pull-up resistor R4, R7 to connect to the output end of the power input module 3. The collector of the first transistor is connected to the collector of the second transistor through a current-limiting resistor R6, R10. The emitter of the second transistor is connected to the base of the first transistor. The switch control module 1-2 includes a switch transistor Q7. The collector of the switch transistor Q7 is connected to the base of the power transistor, and the base of the switch transistor Q7 is connected to the collector of the first transistor. The bases of the first transistors Q3, Q5, and the second transistors Q4, Q6 are connected to signals of different voltage levels. These signals convert the analog voltage across the LED light source module into digital logic levels. By comparing the differences, these signals drive the control logic of the subsequent switch control module 1-2. The base of the switching transistor Q7 receives the logic signal from the preceding open-circuit and short-circuit diagnosis module 1-1 via resistor R9. When the base voltage of the switching transistor Q7 is sufficiently high, the switching transistor Q7 saturates and conducts, closing the collector-emitter path and driving the LED. When the base voltage of the switching transistor Q7 falls below the threshold, the switching transistor Q7 turns off, disconnecting the LED.

[0031] A current limiting resistor R9 is connected in series between the base and emitter of the switching transistor Q7.

[0032] The power input module 3 includes a voltage source VCC, an anti-reverse diode D1, and a TVS diode T1. The voltage source VCC is grounded through the TVS diode T1, and the voltage source VCC outputs a voltage through the anti-reverse diode D1. The anti-reverse diode D1, the LED light source module, the power transistor, and the sampling resistor are connected in series and then grounded. The TVS diode T1 is a bidirectional TVS diode. A protective capacitor C1 is connected in parallel to the TVS diode T1 to provide filtering protection.

[0033] Figure 3 In the figure, GND represents ground, VS represents the output of the power input module 3, and N-1 represents the output of the open-short circuit diagnosis module 1-1.

[0034] An LED lamp of the present invention includes the LED lamp control circuit of the present invention, and can also feed back the functional status of the lamp to the vehicle body control.

[0035] The LED lamp and its control circuit of the present invention can effectively control the failure diagnosis problem of LED open circuit or short circuit: it can meet the requirements of single LED open circuit diagnosis and multiple or multi-channel LED open circuit diagnosis; it can meet the requirements of single LED short circuit diagnosis and multiple or multi-channel LED path diagnosis. The anti-reverse diode D1, LED light source module, power transistor and sampling resistor are connected in series in sequence as the main circuit. The main circuit has the characteristic of constant current. When the input voltage changes, the amplitude of current change is small. The power transistors Q1 and Q2 in the switch current limiting module 2-2 realize the control of LED current; the switch transistor Q7 of the switch control module 1-2 realizes the switching and open and short circuit diagnosis functions of the circuit.

[0036] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. An LED lamp control circuit, characterized in that: It includes an open-short circuit logic control module, an LED light source module, a power input module and an LED driver module. The power input module supplies power to the LED light source module, the open-short circuit logic control module and the LED driver module. The LED driver module is used to drive the LED light source module. The LED light source module includes at least two LED lamp beads. The open-short circuit logic control module controls the on-off between the power input module and the LED driver module by diagnosing the electrical signal between the LED light source module and the LED driver module. The open-short circuit logic control module is composed of discrete components.

2. The LED lamp control circuit according to claim 1, wherein: The power input module is connected to at least two LED light source modules, the LED driving module includes a voltage stabilizing module and a switch current limiting module, the output of the voltage stabilizing module controls the on and off of the switch current limiting module, each LED light source module is respectively connected to a switch current limiting module, and each switch current limiting module is connected to the same voltage stabilizing module, the open-short circuit logic control module includes an open-short circuit diagnostic module and a switch control module, the output of the open-short circuit diagnostic module controls the on and off of the switch control module, each LED light source module is respectively connected to a corresponding open-short circuit diagnostic module, the open-short circuit diagnostic module corresponding to each LED light source module is connected to the input end of the switch control module, and the output end of the switch control module is connected to the voltage stabilizing module of the LED driving module.

3. The LED lamp control circuit according to claim 2, wherein: The voltage stabilizing module includes a first resistor R1 and a voltage stabilizing diode D2, one end of the first resistor R1 is connected to the positive electrode of the voltage stabilizing diode D2, the other end of the first resistor R1 is connected to the output end of the power input module, the first resistor R1 is connected in series with the voltage stabilizing diode D2 and then grounded, the switching current limiting module includes a power transistor and a sampling resistor, the LED driving module is connected to the LED light source module through the collector of the power transistor, the emitter of the power transistor is connected in series with the voltage stabilizing diode D2 and then grounded, the base of the power transistor is connected to the positive electrode of the voltage stabilizing diode D2, and the emitter of the power transistor is grounded through the sampling resistor.

4. The LED lamp control circuit according to claim 3, wherein: The open-short circuit diagnostic module includes a differential comparator, which includes a first transistor and a second transistor. The bases of the first transistor and the second transistor are respectively connected to the low-level end and the high-level end of the same LED light source module. The emitter of the first transistor is connected to the base of the second transistor and then grounded through a voltage-dividing resistor. The voltage-dividing resistor is connected in series with a pull-up resistor and connected to the output end of the power input module. The collector of the first transistor is connected to the collector of the second transistor through a current-limiting resistor, and the emitter of the second transistor is connected to the base of the first transistor. The switch control module includes a switch transistor Q7. The collector of the switch transistor Q7 is connected to the base of the power transistor, and the base of the switch transistor Q7 is connected to the collector of the first transistor.

5. The LED lamp control circuit according to claim 4, wherein: A current limiting resistor R9 is connected in series between the base and emitter of the switching transistor Q7.

6. The LED lamp control circuit according to claim 4, wherein: The power input module is connected to two LED light source modules, the LED driving module includes a voltage stabilizing module and two switch current limiting modules, the two LED light source modules are respectively connected to a switch current limiting module, and the two switch current limiting modules are connected to the same voltage stabilizing module, the open-short circuit logic control module includes two open-short circuit diagnostic modules and a switch control module, each LED light source module is respectively connected to one open-short circuit diagnostic module, the open-short circuit diagnostic modules corresponding to the two LED light source modules are both connected to the input end of the switch control module, and the output end of the switch control module is connected to the LED driving module.

7. The LED lamp control circuit according to claim 6, wherein: Each LED light source module has two LED lamp beads.

8. The LED lamp control circuit according to claim 4, wherein: The power input module includes a voltage source VCC, an anti-reverse diode D1 and a TVS tube T1. The voltage source VCC is grounded through the TVS tube T1. The voltage source VCC outputs voltage through the anti-reverse diode D1. The anti-reverse diode D1, the LED light source module, the power transistor and the sampling resistor are connected in series and then grounded.

9. The LED lamp control circuit according to claim 8, wherein: The TVS tube T1 is connected in parallel with a protection capacitor C1.

10. An LED lamp, characterized in that: The invention comprises the LED lamp control circuit as described in claims 1-9.

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