Low-cost LED power supply circuit with overvoltage protection
By using an overvoltage protection circuit and a constant current drive circuit composed of transistors and MOSFETs in the vehicle headlight power supply circuit, the problem of increased cost of voltage regulator chips and constant current chips in the prior art is solved, realizing low-cost voltage regulation and constant current power supply, and improving the stability and safety of the circuit.
Patent Information
- Application Number
- CN202422864875.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-22
AI Technical Summary
The use of voltage regulator chips and constant current chips in existing vehicle lighting power supply modules increases production costs. A low-cost power supply circuit is needed to provide stable voltage and constant current while reducing costs.
An overvoltage protection circuit and a constant current drive circuit composed of transistors and MOSFETs are used. The voltage is reduced by transistor T103 and resistor R303, the current stability is controlled by transistor T302, and the current threshold is controlled by MOSFETs T301 and T102, which simplifies the use of the chip.
It achieves regulated constant current power supply, reduces production costs, improves circuit stability and safety, and reduces the probability of LED light damage.
Smart Images
Figure CN223515074U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vehicle lighting power supply technology, specifically to a low-cost LED power supply circuit with overvoltage protection. Background Technology
[0002] In recent years, the automotive industry has faced fierce competition, with most automakers reducing overall vehicle production costs by cutting costs on various components. Existing automotive lighting power supply modules typically include voltage regulator modules and constant current modules. These modules utilize voltage regulator chips and constant current chips, respectively, to automatically adjust the output current of the power supply, improving current and voltage stability. However, the use of voltage regulator chips and constant current chips significantly increases the production cost of automotive lights. Utility Model Content
[0003] In view of this, the problem to be solved by this utility model is to provide a low-cost LED power supply circuit with overvoltage protection, which can provide stable voltage and constant current power supply while saving the production cost of vehicle lights.
[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0005] A low-cost LED power supply circuit with overvoltage protection includes a positive terminal and a negative terminal for outputting electrical energy, wherein an overvoltage protection circuit is provided between the positive terminal and the negative terminal.
[0006] The overvoltage protection circuit includes a transistor T103, with its emitter and negative terminal connected. A resistor R102 and a capacitor C102 are connected in series between the base and positive terminal of the transistor T103. The collector of the transistor T103 is connected to pin 2 of a dual-input diode D104. A resistor R104 is connected in series between pin 3 of the dual-input diode D104 and its positive terminal. A resistor R303 is connected in series between the positive terminal and the LED.
[0007] Furthermore, pin 3 of the dual-input diode D104 is connected to the gate of the MOSFET T101, the source of the MOSFET T101 is connected to the negative terminal, and a resistor R103 is connected in series between the drain of the MOSFET T101 and the base of the transistor T103.
[0008] Furthermore, a resistor R105 is connected in series between pin 1 of the dual-input diode D104 and its positive terminal, and a capacitor C104 is connected in series between the resistor R105 and its negative terminal.
[0009] Furthermore, pin 1 of the dual-input diode D104 is connected to the gate of the MOSFET T102, the source and negative terminals of the MOSFET T102 are connected, and a constant current drive circuit is connected in series between the drain and positive terminals of the MOSFET T102.
[0010] Furthermore, the constant current driving circuit includes a transistor T302. The transistor T302 is connected in series between the LED and the resistor R303. The emitter of the transistor T302 is connected to the resistor R303. Several LEDs are connected in series between the collector of the transistor T302 and the drain of the MOSFET T102. A forward-biased diode D301 and a capacitor C301 are connected in series between the base and the positive terminal of the transistor T302, respectively.
[0011] Furthermore, the constant current driving circuit includes a MOSFET T301, the source of which is connected to the drain of a MOSFET T102, a resistor R302 connected in series between the drain of the MOSFET T301 and the base of the MOSFET T302, and a capacitor C302 and a resistor R30 connected in series between the gate and the source of the MOSFET T301, respectively.
[0012] Furthermore, the constant current driving circuit includes a MOSFET T301, the source of which is connected to the drain of a MOSFET T102 and the output terminal of the LED, a resistor R302 is connected in series between the drain of the MOSFET T301 and the base of the transistor T302, and a capacitor C302 and a resistor R30 are connected in series between the gate and the source of the MOSFET T301.
[0013] Furthermore, a capacitor C101, a resistor R101, and a transient pulse suppressor D101 are connected in series between the positive and negative terminals, respectively.
[0014] The advantages and positive effects of this utility model are:
[0015] (1) An overvoltage protection circuit is set up, which includes a transistor T103 and a resistor R303. The transistor T103 is used to shunt current to reduce the current flowing through the resistor R303 and stabilize the voltage of the power supply. A constant current drive circuit is set up, which includes a transistor T302. By controlling the current flowing through the transistor T302, the stability of the power supply current is ensured.
[0016] (2) Both the overvoltage protection circuit and the constant current drive circuit are built from simple electronic components, saving the use of chips and reducing production costs. Attached Figure Description
[0017] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:
[0018] Figure 1 This is an overall system diagram of a low-cost LED power supply circuit with overvoltage protection according to this utility model;
[0019] Figure 2 This is an overvoltage protection circuit diagram of a low-cost LED power supply circuit with overvoltage protection according to this utility model;
[0020] Figure 3 This is a constant current drive circuit diagram of a low-cost LED power supply circuit with overvoltage protection according to this utility model. Detailed Implementation
[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0023] This invention provides a low-cost LED power supply circuit with overvoltage protection, such as... Figure 1 As shown, the device includes a power supply module that provides electrical energy. The output terminal of the power supply module has a positive terminal and a negative terminal for outputting electrical energy. In one embodiment of this application, the negative terminal is grounded. An overvoltage protection circuit for stabilizing the voltage and a constant current drive circuit for stabilizing the current are connected in series between the positive and negative terminals, respectively.
[0024] like Figure 2 As shown, the overvoltage protection circuit includes a transistor T103. The emitter and cathode of transistor T103 are connected together. A resistor R102 and a capacitor C102 are connected in series between the base and anode of transistor T103. A forward-biased diode D103 is connected in series between resistor R102 and the anode. A capacitor C103 is connected in series between the base and cathode of transistor T103. The collector of transistor T103 is connected to pin 2 of a dual-input diode D104. A resistor R104 is connected in series between pin 3 of dual-input diode D104 and its anode.
[0025] The function of transistor T103 is as follows: A resistor R303 is connected in series between the positive terminal and the LED to reduce voltage. When the positive output voltage is higher than the threshold, the transistor is controlled to conduct or the current flowing through the transistor is changed, which can effectively reduce the voltage input to the LED and reduce the probability of LED damage.
[0026] The overvoltage protection circuit includes a MOSFET T101, with a resistor R103 connected in series between the drain of the MOSFET T101 and the base of the transistor T103. The gate of the MOSFET T101 is connected to pin 3 of the dual-input diode D104, and the source of the MOSFET T101 is connected to the negative terminal.
[0027] The control process of MOSFET T101 is as follows: when the voltage output from the positive terminal is higher than the threshold / increases, MOSFET T101 is turned on / the opening degree of MOSFET T101 increases, the base voltage of transistor T103 is pulled down / changed, and the transistor T103 is turned on / changed in terms of current flow.
[0028] A resistor R105 is connected in series between pin 1 of the dual-input diode D104 and its positive terminal to form a backup circuit, ensuring that the transistor T103 is turned on.
[0029] An overvoltage protection circuit and a constant current drive circuit are connected in series between the positive and negative terminals, respectively. To ensure that the overvoltage protection circuit is always operational when the constant current drive circuit is in use, a MOSFET T102 is installed within the overvoltage protection circuit. The source of MOSFET T102 is connected to the negative terminal, and the gate of MOSFET T102 is connected to pin 1 of the dual-input diode D104. A capacitor C104 is connected in series between the source and gate of MOSFET T102. MOSFET T102 will only conduct after current has flowed through the overvoltage protection circuit, allowing the constant current drive circuit to operate normally.
[0030] like Figure 3 As shown, the constant current drive circuit includes a transistor T302, which is connected in series between a resistor R303 and an LED. The emitter of transistor T302 is connected to resistor R303, and several LEDs are connected in series between the collector of transistor T302 and the drain of MOSFET T102. A forward-biased diode D301 and a capacitor C301 are connected in series between the base and anode of transistor T302, a capacitor C310 is connected in series between the emitter and base of transistor T302, and a capacitor C309 is connected in series between the base and collector of transistor T302.
[0031] The working principle of transistor T302 is as follows: by controlling the base voltage of transistor T302, the magnitude of the current flowing through transistor T302 is changed, thereby ensuring the stability of the current flowing through the LED.
[0032] The constant current drive circuit includes a MOSFET T301 for controlling the current flowing through the transistor T302. The drain of the MOSFET T302 is connected to the source of the MOSFET T301. A resistor R302 is connected in series between the drain of the MOSFET T301 and the base of the transistor T302. A capacitor C304 is connected in series between the drain and source of the MOSFET T301. A capacitor C302 and a resistor R301 are connected in series between the gate and source of the MOSFET T301, respectively. A capacitor C303 is connected in series between the gate and drain of the MOSFET T301.
[0033] The control process of MOSFET T301 is as follows: the current flowing through the LED lamp flows through MOSFET T102 and returns to the negative terminal. When the current exceeds the current threshold, the current through the current-carrying resistor R301 increases, the gate voltage of MOSFET T301 increases, the conduction degree of MOSFET T301 increases, which changes the base voltage of transistor T302, changes the opening degree of transistor T302, and thus changes the current flowing through transistor T302.
[0034] A capacitor C101, a resistor R101, and a transient pulse suppressor D101 are connected in series between the positive and negative terminals to improve the stability of the electrical energy between them.
[0035] The embodiments of this utility model have been described in detail above, but the content described is only a preferred embodiment of this utility model and should not be considered as limiting the scope of implementation of this utility model. All equivalent changes and improvements made within the scope of this utility model should still fall within the scope of this patent.
Claims
1. A low-cost LED power supply circuit with overvoltage protection, characterized in that, It includes a positive and a negative terminal for outputting electrical energy, and an overvoltage protection circuit is provided between the positive and negative terminals; The overvoltage protection circuit includes a transistor T103, with its emitter and negative terminal connected. A resistor R102 and a capacitor C102 are connected in series between the base and positive terminal of the transistor T103. The collector of the transistor T103 is connected to pin 2 of a dual-input diode D104. A resistor R104 is connected in series between pin 3 of the dual-input diode D104 and its positive terminal. A resistor R303 is connected in series between the positive terminal and the LED.
2. The low-cost LED power supply circuit with overvoltage protection according to claim 1, characterized in that, Pin 3 of the dual-input diode D104 is connected to the gate of the MOSFET T101. The source and negative terminals of the MOSFET T101 are connected. A resistor R103 is connected in series between the drain of the MOSFET T101 and the base of the transistor T103.
3. The low-cost LED power supply circuit with overvoltage protection according to claim 1, characterized in that, A resistor R105 is connected in series between pin 1 of the dual-input diode D104 and its positive terminal, and a capacitor C104 is connected in series between the resistor R105 and its negative terminal.
4. The low-cost LED power supply circuit with overvoltage protection according to claim 1, characterized in that, Pin 1 of the dual-input diode D104 is connected to the gate of the MOSFET T102. The source and negative terminals of the MOSFET T102 are connected, and a constant current drive circuit is connected in series between the drain and positive terminals of the MOSFET T102.
5. A low-cost LED power supply circuit with overvoltage protection according to claim 4, characterized in that, The constant current driving circuit includes a transistor T302. The transistor T302 is connected in series between the LED and the resistor R303. The emitter of the transistor T302 is connected to the resistor R303. Several LEDs are connected in series between the collector of the transistor T302 and the drain of the MOSFET T102. A forward-biased diode D301 and a capacitor C301 are connected in series between the base and the positive terminal of the transistor T302, respectively.
6. A low-cost LED power supply circuit with overvoltage protection according to claim 5, characterized in that, The constant current driving circuit includes a MOSFET T301. The source of the MOSFET T301 is connected to the drain of the MOSFET T102 and the output terminal of the LED. A resistor R302 is connected in series between the drain of the MOSFET T301 and the base of the transistor T302. A capacitor C302 and a resistor R30 are connected in series between the gate and the source of the MOSFET T301.
7. A low-cost LED power supply circuit with overvoltage protection according to claim 1, characterized in that, A capacitor C101, a resistor R101, and a transient pulse suppressor D101 are connected in series between the positive and negative terminals, respectively.