Low-cost NTC control circuit

Abstract

The utility model provides a low cost NTC control circuit, including voltage stabilizing circuit, NTC down current circuit and LED drive constant current circuit, the voltage stabilizing circuit includes resistor R1, capacitor C1 and Zener diode ZD1, the capacitor C1 and Zener diode ZD1 are connected in parallel and then connected to the one end of resistor R1, the NTC down current circuit includes adjustable resistor RT1, resistor R2, resistor R3, resistor R4, capacitor C3 and triode Q2, the adjustable resistor RT1, resistor R2, resistor R3, resistor R4, capacitor C3 and triode Q2 are connected in parallel and then connected to the one end of resistor R1. The adjustable resistor RT1 is connected with the resistor R3 in series, one end of the adjustable capacitor RT1 is connected to one end of a voltage stabilizing diode ZD1 of the voltage stabilizing circuit, the resistor R3 is connected with a base electrode of the triode Q2, the resistor R4 is connected with the capacitor C3 in parallel, one end of the R4 is connected with the base electrode of the triode Q2, and the other end of the R4 is connected with GND. The low-cost square wave generator circuit provided by the utility model is simple in circuit, meets the requirements of customers, also meets the requirement of reducing the cost, and is relatively simple to process and manufacture.

Description

Technical Field

[0001] The utility model relates to the technical field of automotive parts, in particular to a low-cost NTC control circuit. Background Art

[0002] With the continuous development of the automotive market, the industrial chain has become increasingly globalized and production has further shifted to emerging markets. New energy vehicles are a new chapter in the automotive industry. In recent years, new energy vehicles have developed rapidly in China, with strong market demand and increasingly rich configurations. However, the prices of new cars are getting cheaper and cheaper. This requires that under the condition of not reducing functions and regulations, LED current reduction uses MCU adjustment.

[0003] So far, to achieve current reduction circuit control for automotive headlight LEDs, MCU is basically used. The manufacturing of MCU itself is difficult, and the skill requirements for personnel are relatively high. At the same time, the use of MCU is relatively complex and requires professional technical personnel to operate, which increases the overall manufacturing cost of the vehicle. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the problem that to achieve current reduction circuit control for existing automotive headlight LEDs, MCU is basically used. The manufacturing of MCU itself is difficult, the skill requirements for personnel are relatively high, and the use of MCU is relatively complex and requires professional technical personnel to operate, which increases the overall manufacturing cost of the vehicle, and to provide a low-cost NTC control circuit.

[0005] To achieve the above technical purpose and reach the above technical effect, the utility model is realized through the following technical solutions:

[0006] The utility model provides a low-cost NTC control circuit, including a voltage stabilization circuit, an NTC current reduction circuit, and an LED driving constant current circuit. The voltage stabilization circuit includes a resistor R1, a capacitor C1, and a voltage stabilizing diode ZD1. The capacitor C1 is connected in parallel with the voltage stabilizing diode ZD1 and then connected to one end of the resistor R1. The NTC current reduction circuit includes a variable resistor RT1, resistors R2, R3, R4, a capacitor C3, and a triode Q2. The variable resistor RT1 is connected in series with the resistor R3. One end of the variable capacitor RT1 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilization circuit. The resistor R3 is connected to the base of the triode Q2. The resistor R4 is connected in parallel with the capacitor C3. One end of the R4 is connected to the base of the triode Q2 and the other end is connected to GND. One end of the resistor R2 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilization circuit and the other end is connected to the emitter of the triode Q2.

[0007] Preferably, the LED driving constant current circuit includes a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a capacitor C4, a triode Q3, a triode Q4 and a triode Q5. The base of the triode Q3 is connected to the emitter of the triode Q2. The base of the triode Q3 is respectively connected to the emitters of the triode Q4 and the triode Q5 through the resistor R8. The bases of the triode Q4 and the triode Q5 are respectively connected to the collector of the triode Q3 through the resistors R6 and R7.

[0008] Preferably, it further includes a power supply circuit, and the power supply circuit includes a diode D1, a capacitor C2 and a voltage protection device TV1. One end of the capacitor C2 is connected to the cathode of the diode D1, and the other end is connected to GND. The voltage protection device TV1 is connected to both ends of the power supply.

[0009] Preferably, it further includes an LED light source, and the cathode of the LED light source is connected to the emitters of the triode Q4 and the triode Q5.

[0010] In summary, the present invention provides a low-cost NTC control circuit, a voltage stabilizing circuit, an NTC current reduction circuit and an LED driving constant current circuit. The voltage stabilizing circuit includes a resistor R1, a capacitor C1 and a voltage stabilizing diode ZD1. The capacitor C1 and the voltage stabilizing diode ZD1 are connected in parallel and then connected to one end of the resistor R1. The NTC current reduction circuit includes a variable resistor RT1, a resistor R2, a resistor R3, a resistor R4, a capacitor C3 and a triode Q2. The variable resistor RT1 is connected in series with the resistor R3. One end of the variable capacitor RT1 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilizing circuit. The resistor R3 is connected to the base of the triode Q2. The resistor R4 is connected in parallel with the capacitor C3. One end of the R4 is connected to the base of the triode Q2 and the other end is connected to GND. One end of the resistor R2 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilizing circuit and the other end is connected to the emitter of the triode Q2. By changing the resistance value of the RT1 resistor, the base current of the diode Q2 is changed, and the triode Q2 works in the conduction state to control the base current of the constant current circuit Q3 to achieve the function of current reduction. The present invention realizes the function of current reduction through the NTC current reduction circuit and the LED driving constant current circuit. The circuit is simple. While meeting the requirements of customers, it also meets the need for cost reduction, and the processing and manufacturing are relatively simple. Description of the Drawings

[0011] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0012] Figure 1 is the overall structural schematic diagram of the present invention;

[0013] Description of reference numerals in the figure: 1 - Oscillation circuit, 2 - Square wave output circuit, 3 - NTC current reduction circuit, 4 - LED drive constant current circuit, 5 - LED light source. Specific embodiments

[0014] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0015] Please refer to Figure 1 , the present invention provides a low-cost NTC control circuit, which is characterized in that: it includes a voltage stabilizing circuit, an NTC current reduction circuit, and an LED drive constant current circuit. The voltage stabilizing circuit includes a resistor R1, a capacitor C1, and a voltage stabilizing diode ZD1. The capacitor C1 is connected in parallel with the voltage stabilizing diode ZD1 and then connected to one end of the resistor R1. The NTC current reduction circuit includes a variable resistor RT1, resistors R2, R3, R4, a capacitor C3, and a triode Q2. The variable resistor RT1 is connected in series with the resistor R3. One end of the variable capacitor RT1 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilizing circuit. The resistor R3 is connected to the base of the triode Q2. The resistor R4 is connected in parallel with the capacitor C3. One end of the R4 is connected to the base of the triode Q2 and the other end is connected to GND. One end of the resistor R2 is connected to one end of the voltage stabilizing diode ZD1 of the voltage stabilizing circuit and the other end is connected to the emitter of the triode Q2.

[0016] The LED drive constant current circuit includes resistors R4, R5, R6, R7, resistors R8, R9, R10, a capacitor C4, triodes Q3, Q4, and Q5. The base of the triode Q3 is connected to the emitter of the triode Q2. The base of the triode Q3 is respectively connected to the emitters of the triodes Q4 and Q5 through the resistor R8. The bases of the triodes Q4 and Q5 are respectively connected to the collector of the triode Q3 through the resistors R6 and R7.

[0017] Power supply circuit, the power supply circuit includes a diode D1, a capacitor C2, and a voltage protection device TV1. One end of the capacitor C2 is connected to the cathode of the diode D1 and the other end is connected to GND. The voltage protection device TV1 is connected to both ends of the power supply.

[0018] LED light source, the cathode of the LED light source is connected to the emitters of the triodes Q4 and Q5.

[0019] The basic principle, main features and advantages of the present utility model have been shown and described above. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and all these changes and improvements fall within the scope of the present utility model claimed.

Claims

1. A low-cost NTC control circuit, characterized in that: It includes a voltage stabilizing circuit, an NTC current reduction circuit, and an LED driving constant current circuit. The voltage stabilizing circuit includes a resistor R1, a capacitor C1, and a zener diode ZD1. The capacitor C1 is connected in parallel with the zener diode ZD1 and then connected to one end of the resistor R1. The NTC current reduction circuit includes a variable resistor RT1, resistors R2, R3, R4, a capacitor C3, and a triode Q2. The variable resistor RT1 is connected in series with the resistor R3. One end of the variable resistor RT1 is connected to one end of the zener diode ZD1 of the voltage stabilizing circuit. The resistor R3 is connected to the base of the triode Q2. The resistor R4 is connected in parallel with the capacitor C3. One end of the R4 is connected to the base of the triode Q2 and the other end is connected to GND. One end of the resistor R2 is connected to one end of the zener diode ZD1 of the voltage stabilizing circuit and the other end is connected to the emitter of the triode Q2.

2. The low-cost NTC control circuit according to claim 1, wherein The LED driving constant current circuit includes resistors R4, R5, R6, R7, resistor R8, resistors R9, R10, a capacitor C4, triodes Q3, Q4, and Q5. The base of the triode Q3 is connected to the emitter of the triode Q2. The base of the triode Q3 is respectively connected to the emitters of the triodes Q4 and Q5 through the resistor R8. The bases of the triodes Q4 and Q5 are respectively connected to the collector of the triode Q3 through the resistors R6 and R7.

3. The low-cost NTC control circuit according to claim 1, characterized in that: It also includes a power supply circuit. The power supply circuit includes a diode D1, a capacitor C2, and a voltage protection device TV1. One end of the capacitor C2 is connected to the cathode of the diode D1 and the other end is connected to GND. The voltage protection device TV1 is connected across the power supply.

4. The low-cost NTC control circuit according to claim 1, wherein: It also includes an LED light source. The cathode of the LED light source is connected to the emitters of the triodes Q4 and Q5.

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