KR200389959Y1 - Steady-Output temperature compensation device for LED traffic signal and LED Lamp - Google Patents

Abstract

The designed constant output temperature compensation device for LED traffic light and LED lamp is designed for LED lamps or LED traffic signals that use high-brightness LED elements that react sensitively to changes in ambient temperature such as seasonal changes and day and night temperature differences. The purpose is to keep the output characteristics constant. The light output of the LED changes according to the change of the ambient temperature, and the purpose is to maintain the constant light output (within a specified value) by controlling the output voltage to compensate for the light output change.

The temperature compensation circuit designed for this purpose is connected to the pulse width controller (PWM controller) on the primary side of the transformer in the power supply device (SMPS) to control the duty ratio of the switching transistor. In the circuit configuration, two NTCs and resistors are connected to each NTC in parallel to control the duty ratio of the switching transistor, and the duty ratio of the transistor is directly controlled according to the change of the ambient temperature. It is characterized by being able to compensate for variations in light output due to temperature changes.

Description

Steady-Output temperature compensation device for LED traffic signal and LED Lamp}

The present invention relates to a power supply device (SMPS) with a built-in temperature compensation circuit, and more particularly to a high-power LED driving power supply (SMPS) used in LED traffic lights or LED lamps.

Recently, due to the development of semiconductor technology, the production of high brightness LEDs (High Bright Light Emitting Diodes) has been diversified, and it is now tending to replace general light bulbs, which have been used in existing vehicle and pedestrian traffic lights. Conventional light bulbs consume a lot of power and are difficult to manage and maintain due to their short lifespan. On the other hand, in the case of LED lamps or traffic lights using high-brightness LEDs, the power consumption is only 1/10. In the case of using a general bulb, a separate power supply was not necessary because the commercial power of 220V was used as it is, but in the case of LED traffic lights, a high-power LED is operated by a DC power source, and a separate power supply device (SMPS) is required.

 In the case of high-brightness LEDs currently on the market, the characteristics of brightness change with temperature vary according to color, type, and grade. That is, when the temperature rises above the reference temperature (25 ℃), the power consumption increases and the light intensity increases or decreases.When the temperature falls below the reference temperature (25 ℃), the power consumption decreases but the light intensity decreases. There are various characteristics that increase and decrease. In addition, even in the same product, the amount of light change with temperature change is markedly different according to the grade.

Therefore, the temperature compensator must be designed and controlled according to the characteristics, types, colors, and grades of LEDs of each company, but the time and cost are very large.

In order to solve the problem of light output change due to temperature change, the designed circuit is connected to the pulse width control part (PWM control part) of the transformer primary side in the power supply device (SMPS), and the configuration controls the duty ratio of the switching transistor. By connecting two NTCs and resistors to each NTC in parallel to directly control the duty ratio of the transistor according to the change of ambient temperature, the output voltage of the secondary side (lamp side) is changed to change the light output according to the temperature change. It is characterized by being able to compensate.

In other words, by controlling the voltage of the primary side of the transformer by using a resistor and NTC to maintain a constant light output of the load side (lamp side) according to the temperature change.

In order to achieve the above object, the LED traffic signal lamp and the LED lamp power supply device of the present invention have induced a DC voltage from the primary coil part to the secondary coil part according to the switching operation of the transistor in the pulse width controller (PWM controller part). 1 is a detailed circuit diagram of a power supply device with a designed temperature compensation circuit, and FIG. 2 is a block diagram of FIG. 1. The following is a description of the configuration device and the operation principle on the basis of the accompanying drawings.

 Power supply for LED traffic light and LED lamp for the present invention is largely configured as shown in Figure 2 and the detailed circuit is shown in Figure 1. The designed power supply unit protects the power supply device from the overcurrent and overvoltage of the AC power input and reduces the noise terminal voltage. The power supply and EMI filter unit 10, which is composed of a fuse, a varistor, a line filter, and an AC voltage In order to convert to DC voltage, rectifier 20 consisting of a bridge diode and smoothing capacitor generates a pulse width modulated (PWM) signal based on the switching operation of the primary transistor and converts the input rectified voltage to the secondary side and changes the ambient temperature. Pulse width control unit 40 including a temperature compensating circuit 30 for varying the output voltage with respect to the load which varies according to the control, maintaining the constant light intensity, and maintaining the output of the secondary side constantly, And a constant voltage circuit part 50 for transmitting a control signal to a pulse width control part controlling the operation of the switching transistor on the transformer primary side.

The inventive device of FIG. 1 configured as described above is used to drive a lamp product using all kinds of high-brightness LEDs regardless of color, type, and grade, and detailed operation is as follows.

(1) AC power input and EMI filter unit 10 of [FIGS. 1 and 2], which protect the power supply from overvoltage and overcurrent that can be input through commercial current and fuses to reduce noise terminal voltage. It includes a varistor, a line filter consisting of a coil and a capacitor, and supplies commercial power to the SMPS.

(2) Rectification circuit section 20 of Figs. 1 and 2, which rectifies the commercial AC power input through 10 into a DC voltage using a bridge diode and a smoothing capacitor.

(3) Pulse width control unit 40 shown in Figs. 1 and 2, which drives the pulse width controller U1 using the DC voltage of the rectifying unit, generates a PWM waveform, induces a secondary waveform on the secondary side, and subsequently a photodiode on the secondary side. By receiving the signal of U2, the duty ratio of the switching transistor is controlled so as to output a constant voltage by controlling the adjustment pulse width, and is operated including a temperature compensation circuit to be described later.

(4) Constant voltage controller 50 of [Fig. 1 and 2]: This generates a constant output voltage through the diode and the smoothing circuit induced voltage on the secondary side, and if the output voltage is changed according to the load change in the future The turn-on time of the controller U3 is changed and the turn-on time of the photodiode U2 is also changed to operate as a constant voltage controller for controlling the pulse width by applying a signal to the pulse width controller and maintaining a constant output voltage.

(5) Temperature compensation circuit section of [30] and [Fig. 3] of [FIGS. 1 and 2], which separates the output voltage so that the brightness can be adjusted according to the temperature change of the LED lamp separately from the operation of the SMPS which maintains the constant voltage. It is a circuit that operates to maintain the constant light output of the LED lamp by forcibly increasing or decreasing it according to the temperature of the LED, to compensate the following light output characteristics of the LED.

If there is no temperature compensation circuit in the SMPS autonomy, the light output characteristic of the LED lamp is changed when the temperature is changed, and thus the light output of the LED lamp cannot be kept constant.

 In order to solve this problem, a thermistor device whose resistance value is changed in accordance with the change of temperature is composed of the pulse head control part of the transformer primary side. In particular, by connecting each NTC in series and connecting resistors in parallel, it is possible to control by adjusting the resistance when you want to obtain different output according to temperature change. That is, the temperature compensation circuit is designed to finely adjust the magnitude of the pulse width required to control the duty ratio of the switching transistor connected to the primary side of the transformer using a resistance value connected in parallel with the NTC.

The light output characteristics of LED lamps that change with temperature are designed to maintain a constant light output by controlling the output power according to the temperature compensation circuit.

3 is a detailed view showing a temperature compensation circuit and operates as follows.

The temperature compensation circuit unit 30 operates as follows according to the magnitude of the synthesis resistance of one part (the resistance and thermistor are connected in parallel) or the resistance of the two parts of the star.

(1) When the combined resistance of one part increases more than two parts when the ambient temperature changes-The output voltage of the secondary side supplied to the lamp (load _ decreases, and the load when the combined resistance of one part decreases more than two parts The output voltage on the secondary side supplied to the circuit increases.

(2) When two parts of the combined resistance increases than one part-The output voltage of the secondary side supplied to the load increases, and when the two parts of the combined resistance decreases than one part, the output voltage supplied to the load decreases. . This is because the reference voltage V _REF of the pulse tip control unit changes according to the change in the synthesis resistance, and the reference voltage value is higher than the reference voltage in comparison with the reference voltage inside the pulse width controller U1 of the pulse tip controller. The output voltage supplied to the load (secondary side) is reduced by decreasing the ON time of the transistor, and when it is low, the output voltage supplied to the load (secondary side) is increased by increasing the ON time of the transistor on the primary side.

(3) According to the above operation, the output voltage of the secondary side supplied to the load can be changed according to the change of one part and two parts of the synthesis resistance part of the temperature control part. The resistance value of is fixed and maintains a constant output voltage according to the constant voltage control signal. Therefore, by selecting the NTC suitable for one part and two parts and the appropriate parallel resistance for detailed adjustment according to the temperature increase and decrease, the output voltage can be adjusted for any characteristic of temperature change, so the temperature compensation circuit can be easily designed. .

4 is a diagram showing a temperature compensation circuit and a pulse width control unit. The change in temperature causes a change in the resistance value of the temperature compensating circuit part, and accordingly, the magnitude of the voltage applied to each resistor part is different, and the pulse width of the pulse width control part is output differently according to the voltage value transmitted to the microprocessor. It is possible to control the ON time of.

5 and 6, the synthetic resistor connection part of the temperature compensation circuit part of FIG. 3 is slightly changed.

FIG. 5 is a case where only one part is used in the synthetic resistor part of FIG. 3, and two parts are replaced with a fixed resistor, and as the temperature increases, the value of NTC connected to the composite resistor 1 decreases and is supplied to the load. Secondary output voltage increases proportionally and can be used when it is necessary to continuously increase the current value as the temperature increases.

FIG. 6 is a case in which only two parts are used in the composite resistor section of FIG. 3, and one part is replaced by a fixed resistor. As the temperature increases, the value of NTC connected to the composite resistor section 2 decreases. The output voltage of the secondary side to be supplied decreases in proportion to it, so it can be used when it is necessary to continuously reduce the current value as the temperature increases.

5 and 6, the use of PTC instead of NTC will yield the opposite.

1. The designed temperature compensator keeps the light output characteristic of LED lamp or traffic signal which is sensitive to the change of the surrounding temperature constantly (within the specified value).

2. Regardless of the high-brightness LED used, if only the LED change characteristic is determined by temperature, the light output characteristic can be compensated within the desired temperature range by replacing the resistance value connected with NTC.

3. It can be easily applied to all high-brightness LED products except LED lamps and traffic lights.

4. Applicable to loads other than LED applications sensitive to temperature characteristics.

1 is a diagram illustrating a first embodiment of a power supply device (SMPS) incorporating a constant output temperature compensation circuit for an LED traffic light and an LED lamp according to the present invention.

FIG. 2 is a block diagram of FIG. 1.

3 is an exemplary view of a second embodiment of the constant output temperature compensation circuit according to the present invention.

3-1 is a constant output temperature compensation circuit and a pulse width control unit according to the present invention.

4 is a third exemplary embodiment of a constant output temperature compensation circuit according to the present invention.

5 is an exemplary view of a fourth embodiment of the constant output temperature compensation circuit according to the present invention.

Claims (4)

In power supply devices used for traffic signals and LED lamps that use high-brightness LEDs as light sources, commercial AC power flows from the EMI filter unit to the rectifier circuit unit converting to direct current, the transformer unit converting to low voltage, and the secondary coil unit from the primary coil unit to the secondary coil unit. Constant voltage circuit for supplying a constant voltage to the LED lamp side (secondary side), and pulse width controlling the voltage of the primary transformer by controlling the ON time of the switching transistor according to the change of the resistance value according to the temperature change. A power supply consisting of a control unit, a thermistor element whose resistance changes with temperature change, and a resistor connected in parallel with the thermistor, and a temperature compensation circuit unit located at the input of the pulse width controller. The power supply device of claim 1, wherein the power supply device controls the voltage on the secondary side by controlling the voltage value on the primary side of the transformer so that the change in light output according to the temperature of the high-brightness LED can be maintained at a constant (within a prescribed value) state. A power supply comprising a temperature compensation circuit comprising two NTCs and a resistor connected in parallel to each NTC, The power supply device of claim 1, wherein the power compensation device replaces the elements of the two parts of the synthetic resistor section with a fixed resistor in the temperature compensation circuit section of claim 2, and the temperature compensation circuit and PTC continuously increase the current value as the temperature increases. A power supply comprising a temperature compensation circuit that reverses its characteristics, The power supply apparatus according to claim 1, wherein the power supply device uses a temperature compensation circuit and a PTC that replaces one part of the synthesis resistor section with a fixed resistor in the temperature compensation circuit section of claim 2 and continuously decreases the current value as the temperature increases. A power supply comprising a temperature compensation circuit that reverses characteristics