Control circuit for reducing light attenuation of constant-voltage power supply

Abstract

The utility model discloses a constant voltage power supply light attenuation reduction control circuit comprising a sampling module used for sampling an electric signal of an LED lamp strip to obtain a sampling signal; the input end of the amplification module is electrically connected with the sampling module so as to amplify the sampling signal; the main control module comprises a difference value calculation unit, a comparison unit and a storage unit in which a preset difference value is stored, the output end of the amplification module is electrically connected with the difference value calculation unit, and the difference value calculation unit can calculate the difference value of the sampling signals sampled twice. The difference value calculation unit and the storage unit are electrically connected with the comparison unit, and the comparison unit can compare the difference value of the sampling signals with the preset difference value; and the driving module is used for adjusting the magnitude of the output voltage.

Description

Technical Field

[0001] The utility model relates to the technical field of LED control circuits, in particular to a constant voltage power supply for reducing light decay control circuit. Background Art

[0002] When a constant voltage power supply drives a constant voltage LED load, the output voltage of the power supply is fixed, and the lamp beads rely on resistors to limit the current. When the lamp beads work, the temperature will continue to rise (eventually reaching thermal equilibrium). When the temperature is high, the luminous efficiency of the LED chip will decrease, and the color temperature will shift. If the voltage is reduced, the current will increase, the power on the resistor will increase, the heat generated by the resistor will increase, and the resistance value will become smaller (the chip carbon film resistor is 200 - 300 PPM / °C). When dozens or hundreds of resistors work in parallel, the change amount will increase, and the LED light decay is obvious. This patent utilizes the tiny temperature change coefficient of the resistor to detect this change voltage and compare whether to reduce the heat generation to protect the LED light decay. Content of the Utility Model

[0003] The purpose of the utility model is to at least solve one of the technical problems existing in the prior art, and provide a constant voltage power supply for reducing light decay control circuit that can extend the service life of the light source.

[0004] According to the constant voltage power supply for reducing light decay control circuit of the embodiment of the utility model, it includes a sampling module for sampling the electrical signal of the LED light strip to obtain a sampling signal; an amplification module, the input end of the amplification module is electrically connected to the sampling module to amplify the sampling signal; a main control module, the main control module includes a difference calculation unit, a comparison unit and a storage unit storing a preset difference, the output end of the amplification module is electrically connected to the difference calculation unit, the difference calculation unit can calculate the difference between the sampling signals of two consecutive samplings, the difference calculation unit and the storage unit are respectively electrically connected to the comparison unit, and the comparison unit can compare the size of the difference between the sampling signals with the preset difference; a driving module, the driving module is used to adjust the size of the output voltage, the main control module is electrically connected to the driving module, and controls the working state of the driving module according to the size relationship between the difference of the sampling signals and the preset difference to adjust the size of the output voltage.

[0005] According to some embodiments of the utility model, the sampling module includes a sampling resistor R1, one end of the sampling resistor R1 is electrically connected to the LED light strip, and the other end of the sampling resistor R1 is grounded.

[0006] According to some embodiments of the present utility model, the amplification module includes a comparator U1, a resistor R2, a resistor R3, and a capacitor C1. One end of the resistor R2 is electrically connected to one end of the sampling resistor R1. The other end of the resistor R2 is respectively electrically connected to the positive input terminal of the comparator U1 and one end of the capacitor C1. One end of the resistor R3 is grounded. The other end of the resistor R3 is respectively electrically connected to the negative input terminal of the comparator U1 and the other end of the capacitor C1. The output terminal of the comparator U1 is electrically connected to the main control module.

[0007] According to some embodiments of the present utility model, it includes a power module. The main control module includes a main control chip U2, a resistor R4, and a capacitor C2. An ADC unit, the difference calculation unit, a comparison unit, and a storage unit are integrated in the main control chip U2. The ADC unit is used to convert the sampling signal into a digital signal. One end of the resistor R4 is electrically connected to the output terminal of the comparator U1. The other end of the resistor R4 is respectively electrically connected to the input terminal of the main control chip U2 and the capacitor C2. The output terminal of the main control chip U2 is electrically connected to the power module.

[0008] According to some embodiments of the present utility model, the power module includes a resistor R5 and a triode Q1. The output terminal of the main control chip U1 is electrically connected to the base of the triode Q1 through the series-connected resistor R5. The collector of the triode Q1 is grounded. The emitter of the triode Q1 is electrically connected to the load to control the output voltage.

[0009] The constant voltage power supply light decay control circuit according to the embodiments of the present utility model has at least the following beneficial effects: The temperature change causes the current of the LED light strip to change. The changed current forms a sampling signal after passing through the sampling module. The sampling signal is amplified by the amplification module and then input into the main control module. The difference calculation unit subtracts the two sampling signals before and after. The comparison unit compares the difference with a preset difference. If the difference exceeds the preset difference, the main control module outputs a control signal to control the driving module to act to adjust the output voltage, reduce the power, reduce the heat generation, thereby reducing the light decay and protecting the LED light source (there is research data showing that assuming the light emission of the LED chip at a junction temperature of 25 °C is 100%, then when the junction temperature rises to 60 °C, its light emission amount is only 90%; when the junction temperature reaches 100 °C, it will drop to 80%; at 140 °C, it is only 70%. It can be seen that improving the heat dissipation and controlling the junction temperature is very important for improving its light emission efficiency), and improving the service life of the LED light strip.

[0010] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present utility model. Description of the Drawings

[0011] The following further describes the specific embodiments of the present utility model in conjunction with the drawings;

[0012] Figure 1 It is the circuit schematic diagram of the constant voltage power supply for reducing light decay control circuit. Specific embodiments

[0013] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description of the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention. However, it should not be construed as a limitation on the protection scope of the present invention.

[0014] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the present invention.

[0015] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is two or more. Understand greater than, less than, exceeding, etc. as not including the present number, and understand above, below, within, etc. as including the present number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0016] Refer to Figure 1, a constant voltage power supply for reducing light decay control circuit of the utility model, includes a sampling module, an amplification module 11, a main control module 12 and a driving module 13. The sampling module is used to sample the electrical signal of the LED light strip to obtain a sampling signal; the input end of the amplification module 11 is electrically connected to the sampling module to amplify the sampling signal; the main control module 12 includes a difference calculation unit, a comparison unit and a storage unit storing a preset difference. The output end of the amplification module 11 is electrically connected to the difference calculation unit. The difference calculation unit can calculate the difference between the sampling signals of two consecutive samplings. The difference calculation unit and the storage unit are respectively electrically connected to the comparison unit. The comparison unit can compare the size of the difference of the sampling signal with the preset difference; the driving module 13 is used to adjust the size of the output voltage. The main control module 12 is electrically connected to the driving module 13, and controls the working state of the driving module 13 according to the size relationship between the difference of the sampling signal and the preset difference to adjust the size of the output voltage. The temperature change causes the current of the LED light strip to change. The changed current forms a sampling signal after passing through the sampling module. The sampling signal is amplified by the amplifier module and then input into the main control module 12. The difference calculation unit subtracts the two consecutive sampling signals. The comparison unit compares the difference with the preset difference. If the difference exceeds the preset difference, the main control module 12 outputs a control signal to control the driving module 13 to act to adjust the output voltage, reduce the power, reduce the heat generation, thereby reducing the light decay and protecting the LED light source (there is research data showing that assuming the light emission of the LED chip at a junction temperature of 25°C is 100%, then when the junction temperature rises to 60°C, its light emission is only 90%; when the junction temperature reaches 100°C, it will drop to 80%; 140°C is only 70%. It can be seen that improving heat dissipation and controlling the junction temperature is very important for improving its luminous efficiency), and improving the service life of the LED light strip.

[0017] Further, the sampling module includes a sampling resistor R1. One end of the sampling resistor R1 is electrically connected to the LED light strip, and the other end of the sampling resistor R1 is grounded. The amplification module 11 includes a comparator U1, a resistor R2, a resistor R3 and a capacitor C1. One end of the resistor R2 is electrically connected to one end of the sampling resistor R1. The other end of the resistor R2 is respectively electrically connected to the positive input end of the comparator U1 and one end of the capacitor C1. One end of the resistor R3 is grounded. The other end of the resistor R3 is respectively electrically connected to the negative input end of the comparator U1 and the other end of the capacitor C1. The output end of the comparator U1 is electrically connected to the main control module 12. The temperature change causes the current of the LED light strip to change. The changed current forms a sampling signal after passing through the sampling resistor R1. The sampling signal is amplified by the comparator U1 and then input into the main control module 12.

[0018] Further, the main control module 12 includes a main control chip U2, a resistor R4, and a capacitor C2. An ADC unit, a difference calculation unit, a comparison unit, and a storage unit are integrated in the main control chip U2. The ADC unit is used to convert the sampling signal into a digital signal. One end of the resistor R4 is electrically connected to the output end of the comparator U1, and the other end of the resistor R4 is respectively electrically connected to the input end of the main control chip U2 and the capacitor C2. The output end of the main control chip U2 is electrically connected to the power module. The main control chip U2 is a prior art, and the specific model is not described herein. The difference calculation unit calculates the difference between the previous and current sampling signals, and the comparison unit compares the difference with a preset difference. If the difference exceeds the preset difference, the main control chip U2 outputs a control signal to control the operation of the drive module 13 to adjust the output voltage, reduce the power, reduce the heat generation, thereby reducing the light decay and protecting the LED light source.

[0019] Further, the power module includes a resistor R5 and a triode Q1. The output end of the main control chip U1 is electrically connected to the base of the triode Q1 through the series-connected resistor R5. The collector of the triode Q1 is grounded, and the emitter of the triode Q1 is electrically connected to the load to control the output voltage. The control signal output by the main control chip U2 directly controls the on / off of the triode Q1, thereby controlling the magnitude of the output voltage supplied to the load, reducing the power, reducing the heat generation, thereby reducing the light decay and protecting the LED light source.

[0020] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above preferred modes can be freely combined and superimposed.

[0021] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the description and drawings of the present invention under the inventive concept of the present invention, or directly or indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A constant voltage power supply light attenuation reduction control circuit, characterized in that: include: A sampling module, used for sampling the electrical signal of the LED light strip to obtain a sampling signal; an amplifying module (11), wherein an input end of the amplifying module (11) is electrically connected to the sampling module to amplify the sampling signal; A main control module (12), the main control module (12) comprising a difference calculation unit, a comparison unit and a storage unit storing a preset difference value, the output end of the amplification module (11) is electrically connected to the difference calculation unit, the difference calculation unit is capable of calculating the difference between the sampling signals of two consecutive samplings, the difference calculation unit and the storage unit are electrically connected to the comparison unit respectively, and the comparison unit is capable of comparing the difference between the sampling signals and the preset difference value; A driving module (13), the driving module (13) being used to adjust the magnitude of an output voltage, the main control module (12) being electrically connected to the driving module (13), and controlling the working state of the driving module (13) according to the magnitude relationship between the difference of the sampling signal and the preset difference to adjust the magnitude of the output voltage.

2. The constant voltage power supply light attenuation reduction control circuit according to claim 1, characterized in that: The sampling module includes a sampling resistor R1 , one end of the sampling resistor R1 is electrically connected to the LED light strip, and the other end of the sampling resistor R1 is grounded.

3. The constant voltage power supply light attenuation reduction control circuit according to claim 2, characterized in that: The amplification module (11) comprises a comparator U1, a resistor R2, a resistor R3 and a capacitor C1, one end of the resistor R2 is electrically connected to one end of the sampling resistor R1, the other end of the resistor R2 is electrically connected to the positive input end of the comparator U1 and one end of the capacitor C1 respectively, one end of the resistor R3 is grounded, the other end of the resistor R3 is electrically connected to the negative input end of the comparator U1 and the other end of the capacitor C1 respectively, and the output end of the comparator U1 is electrically connected to the main control module (12).

4. The constant voltage power supply light attenuation reduction control circuit according to claim 3, characterized in that: The invention comprises a power module, wherein the main control module (12) comprises a main control chip U2, a resistor R4, and a capacitor C2. The main control chip U2 is integrated with an ADC unit, the difference calculation unit, a comparison unit, and a storage unit. The ADC unit is used to convert the sampling signal into a digital signal. One end of the resistor R4 is electrically connected to the output end of the comparator U1, and the other end of the resistor R4 is electrically connected to the input end of the main control chip U2 and the capacitor C2 respectively. The output end of the main control chip U2 is electrically connected to the power module.

5. The constant voltage power supply light attenuation reduction control circuit according to claim 4, characterized in that: The power module includes a resistor R5 and a transistor Q1. The output end of the main control chip U1 is electrically connected to the base of the transistor Q1 via the series resistor R5. The collector of the transistor Q1 is grounded. The emitter of the transistor Q1 is electrically connected to the load to control the output voltage.

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