CN207939800U - A LED Linear Constant Current Control Circuit Based on Discrete Components - Google Patents

Abstract

The utility model discloses a L ED linear constant current control circuit based on discrete component, this L ED linear constant current control circuit based on discrete component include input, rectifier module, linear constant current module and L ED lamp pearl module that mutual electric connection is in the same place, linear constant current module is including connecting MOS pipe Q1 and MOS pipe Q2 between this rectifier module and L ED lamp pearl module, biasing resistance R1 and mutual parallel connection's current sampling resistance R2 and current sampling resistance R3 the utility model discloses L ED linear constant current control circuit simple structure adjusts the electric current that flows through the lamp pearl, reaches constant current's effect, need not special constant current control chip, uses the voltage source drive of technology maturity, can have good constant current precision under the broad voltage, and the suitability is strong, makes the utility model discloses extremely strong market competition has.

Description

A LED Linear Constant Current Control Circuit Based on Discrete Components

Technical field:

The utility model relates to the technical field of car lamp products, in particular to an LED linear constant current control circuit based on discrete components.

Background technique:

Car lights are various traffic lights installed on cars to ensure safe driving, which are divided into two types: lighting lights and signal lights. As the "eyes" of a car, whether it is dim or bright is not only related to the external image of a car owner, but also the safety guarantee for driving at night or in bad weather. Car lights with poor lighting effects can easily cause driver eye fatigue, and cannot provide the driver with effective illumination brightness and area. Good car lights can provide drivers with higher brightness and better vision, and can also improve driving comfort. Sex and safety, ensure driving safety, make driving full of confidence. Therefore, the bright lights of the car lights are an important guarantee for the driver's driving safety.

Tungsten-halogen bulbs are commonly used in car lights at present. Halogen-tungsten bulbs are gas-filled incandescent bulbs that contain some halogen elements or halides in the filling gas. The luminous efficiency is 20Lm/W, the color temperature is 3000K, and the service life is about 2000 hours. It can be seen intuitively that this tungsten-halogen bulb not only has a short service life, but also has high energy consumption. In addition, the brightness of the tungsten-halogen bulb will gradually decrease during use, resulting in light decay. Today, when resources are scarce and energy conservation and emission reduction are vigorously advocated, the use of this tungsten-halogen bulb obviously cannot meet the needs of the times.

For this reason, LED car lights have appeared on the market, and LED car lights have the following advantages:

1. Energy saving: It is directly converted from electric energy to light energy by light-emitting diodes. Compared with ordinary car bulbs, the power consumption is only equivalent to 1/10 of traditional lights, which can better save fuel consumption and protect car circuits from being burned by excessive load current. Bad.

2. Environmental protection: There are no ultraviolet and infrared rays in the spectrum, low heat generation, no radiation, small glare, and waste can be recycled, no pollution, no mercury, and safe to touch. It is a typical green lighting led light source.

3. Long service life: There is no loose part in the lamp body, and there are no shortcomings such as filament luminescence and easy burning, heat deposition, and light decay. Under appropriate current and voltage, the service life can reach 80,000 to 100,000 hours, which is longer than traditional light sources. more than 10 times longer. (with the characteristics of one-time replacement and lifetime use)

Four, high brightness, high temperature resistance. (Electrical energy is directly converted into light energy, with low heat generation, completely touchable by hand, safe and secure)

Five, small size. Designers can change the lighting mode at will to make the car look more diverse. Car manufacturers favor LED, which is entirely determined by the advantages of LED itself.

6. Good stability, strong anti-seismic performance of LED: resin package, not easy to break, easy to store and transport.

7. The luminous purity is high, the color is clear and bright, no need for lampshade filtering, and the light wave error is within 10 nanometers.

8. The response speed is fast, no hot start time is required, and the light can be emitted within microseconds, while the traditional glass bulb has a delay of 0.3 seconds, which can prevent rear-end collisions and ensure driving safety.

LED lights are suitable for various lighting applications in automotive electronics, including headlights (high and low beams), fog lights, tail lights, brake lights, turn signals, daytime running lights, pedal lights, instrument lights, license plates Lamps, door lights, interior lights, width indicator lights, navigation, entertainment systems, backlights and indicator lights, etc.

As shown in Figure 1, it is the drive circuit in the LED car light. Usually the nominal rated voltage of the car battery is DC 12V, so the manufacturer uses DC12V as a reference when designing and testing, but according to the actual measurement, when driving normally The voltage of the LED lamp bead is between 10-14.4V. Since the voltage of the LED lamp bead is constant, the resistance value of the LED current-limiting resistor R10 is constant, and the voltage added to both ends of the LED current-limiting resistor R10 increases or decreases, resulting in the The current will rise or fall proportionally. When the current of the LED lamp bead rises, the temperature of the LED lamp bead and the power consumption of the LED current limiting resistor R10 will increase rapidly, which will affect the life and stability of the lamp; and when the current of the LED lamp bead drops, The luminous flux and illuminance of the car lights cannot meet the design requirements.

In view of this, the inventor proposes the following technical solutions.

Utility model content:

The purpose of the utility model is to overcome the deficiencies of the prior art and provide an LED linear constant current control circuit based on discrete components.

In order to solve the above technical problems, the utility model adopts the following technical scheme: the LED linear constant current control circuit based on discrete components includes: an input terminal electrically connected to each other, a rectifier module, a linear constant current module and LED lamp beads module, the linear constant current module includes a MOS tube Q1 and a MOS tube Q2 connected between the rectifier module and the LED lamp bead module, a bias resistor R1, and a current sampling resistor R2 and a current sampling resistor connected in parallel R3.

Further, in the above technical solution, one end of the bias resistor R1 is connected to the positive pole of the LED lamp bead module, and the other end is connected to the G pole of the MOS transistor Q1; the D pole of the MOS transistor Q1 is connected to the pole of the LED lamp bead module. Negative pole; the G pole of the MOS transistor Q2 is connected to the S pole of the MOS transistor Q1, the D pole of the MOS transistor Q2 is connected to the G pole of the MOS transistor Q1, the S pole of the MOS transistor Q2 is connected to the negative pole of the rectifier module, and the current sampling resistor R2 and the current sampling resistor R3 are both connected between the S pole and the G pole of the MOS transistor Q2.

Further, in the above technical solution, the input terminal is an AC/DC input terminal, and its input voltage is 10-15V.

Furthermore, in the above technical solution, the LED bead module is composed of a plurality of LED bead connected in series and parallel.

Further, in the above technical solution, the rectification module includes a rectification bridge composed of interconnected common cathode diode D1 and common anode diode D2, the negative pole of the rectification bridge is connected to the S pole of the MOS transistor Q2; the positive pole of the rectification bridge is Connect the positive electrode in the LED lamp bead module.

After adopting the above technical scheme, the utility model has the following beneficial effects compared with the prior art: the utility model LED linear constant current control circuit has a simple structure, adjusts the current flowing through the lamp bead, and achieves the function of constant current, without special constant current The control chip is driven by a voltage source with mature technology, which can have good constant current accuracy under a wide voltage range and has strong applicability, which makes the utility model have strong market competitiveness.

Description of drawings:

Fig. 1 is the circuit diagram of the driving circuit in the prior art LED car lamp;

Fig. 2 is a schematic block diagram of the utility model;

Fig. 3 is a circuit diagram of the utility model.

Detailed ways:

Below in conjunction with specific embodiment and accompanying drawing, the utility model is further described.

As shown in Figures 2 and 3, it is a LED linear constant current control circuit based on discrete components, which includes: an input terminal 1 electrically connected to each other, a rectifier module 2, a linear constant current module 3 and an LED lamp bead mold Group 4, characterized in that: the linear constant current module 3 includes a MOS transistor Q1 and a MOS transistor Q2 connected between the rectifier module 2 and the LED lamp bead module 4, a bias resistor R1 and a current connected in parallel Sampling resistor R2 and current sampling resistor R3. The LED linear constant current control circuit of the utility model is simple in structure, does not need a special constant current control chip, is driven by a voltage source with mature technology, can have good constant current accuracy under a wide voltage, and has strong applicability, which makes the utility model extremely Strong market competitiveness.

One end of the bias resistor R1 is connected to the positive pole of the LED lamp bead module 4, and the other end is connected to the G pole of the MOS transistor Q1; the D pole of the MOS transistor Q1 is connected to the negative pole of the LED lamp bead module 4; the G pole of the MOS transistor Q2 is The S pole of the MOS transistor Q1 is connected to the S pole of the MOS transistor Q1, the D pole of the MOS transistor Q2 is connected to the G pole of the MOS transistor Q1, the S pole of the MOS transistor Q2 is connected to the negative pole of the rectifier module 2, and the current sampling resistor R2 and the current sampling resistor R3 are both Connected between S pole and G pole of MOS transistor Q2.

The input terminal 1 is an AC/DC input terminal, and its input voltage is 10-15V.

The LED lamp bead module 4 is composed of a plurality of LED lamp beads connected in series and parallel.

The rectification module 2 includes a rectification bridge composed of interconnected common cathode diodes D1 and common anode diodes D2, the cathode of the rectification bridge is connected to the S pole of the MOS transistor Q2; the anode of the rectification bridge is connected to the LED lamp bead module 4 in the positive pole.

The LED lamp bead module 4 adopts 3020 LED lamp beads or 3030 LED lamp beads.

The working principle of the utility model is: the input terminal 1 inputs the AC/DC voltage, and the bias current is provided to the gate (G pole) of the MOS transistor Q1 by the bias resistor R1, the MOS transistor Q1 is turned on, and the positive voltage of the rectifier module 2 is passed through The positive pole of the LED lamp bead module 4 flows in, then flows out from the negative pole of the LED lamp bead module 4, flows into the drain (D pole) of the MOS transistor Q1, and flows out from the source (S pole) of the MOS transistor Q1, and then flows into the current sampling Resistors R2, R3, and then to the negative pole of the rectifier module 2 form a current loop. At this time, since the gate (G pole) of the MOS transistor Q2 is also connected to the current sampling resistors R1 and R2, it is at the same potential as R1 and R2, and the MOS The gate-source (G-S pole) of the tube Q2 has a turn-on threshold voltage, which is a relatively fixed voltage value, so the voltage across the current sampling resistors R2 and R3 is equivalent to a reference voltage. When the input voltage rises or falls At this time, the voltage of the D pole and the S pole of the MOS transistor Q2 is correspondingly reduced or increased, and the voltage of the G pole of the MOS transistor Q1 is adjusted, and then the current flowing through the LED lamp bead module 4 is adjusted to achieve a constant current effect. It can be known from this that the constant current of this solution is only related to the G electrode voltage of the MOS transistor Q2, and has little to do with the level of the input voltage, which can well solve the problems existing in the existing solution.

Of course, the above descriptions are only specific embodiments of the utility model, and are not intended to limit the implementation scope of the utility model. Should be included in the utility model patent scope.

Claims (5)

1. A LED linear constant current control circuit based on discrete components, which includes: an input terminal (1), a rectifier module (2), a linear constant current module (3) and an LED lamp bead module electrically connected together (4), characterized in that: the linear constant current module (3) includes a MOS transistor Q1 and a MOS transistor Q2 connected between the rectifier module (2) and the LED lamp bead module (4), and a bias resistor R1 and the current sampling resistor R2 and the current sampling resistor R3 connected in parallel. 2. The LED linear constant current control circuit based on discrete components according to claim 1, wherein one end of the bias resistor R1 is connected to the positive pole of the LED lamp bead module (4), and the other end is connected to The G pole of the MOS tube Q1; the D pole of the MOS tube Q1 is connected to the negative pole of the LED lamp bead module (4); the G pole of the MOS tube Q2 is connected to the S pole of the MOS tube Q1, and the D pole of the MOS tube Q2 is connected to the MOS tube Q1 The G pole and the S pole of the MOS transistor Q2 are connected to the negative pole of the rectification module (2), and the current sampling resistor R2 and the current sampling resistor R3 are both connected between the S pole and the G pole of the MOS transistor Q2. 3. A LED linear constant current control circuit based on discrete components according to claim 1, characterized in that: said input terminal (1) is an AC/DC input terminal, and its input voltage is 10-15V. 4. The LED linear constant current control circuit based on discrete components according to claim 1, characterized in that: the LED lamp bead module (4) is composed of a plurality of LED lamp beads connected in series and parallel. 5. A LED linear constant current control circuit based on discrete components according to any one of claims 1-4, characterized in that: the rectification module (2) includes a common cathode diode D1 and a common anode connected to each other A rectification bridge composed of a diode D2, the cathode of the rectification bridge is connected to the S pole of the MOS transistor Q2; the anode of the rectification bridge is connected to the anode of the LED lamp bead module (4).