CN-122028255-A - LED driver and operation method thereof

CN122028255ACN 122028255 ACN122028255 ACN 122028255ACN-122028255-A

Abstract

The present disclosure provides an LED driver and a method of operating the same, the LED driver including a plurality of conversion circuits and a control circuit. The plurality of conversion circuits are respectively coupled with the plurality of LED light sources and supply power to the plurality of LED light sources. The control circuit is used for setting the conversion circuit to generate output current and output voltage, calculating to obtain the output power of the conversion circuit, summing the output power of all the conversion circuits to obtain total output power, and setting at least one conversion circuit to regulate the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits when the total output power is judged to be larger than the upper power limit so as to reduce the total output power to be smaller than or equal to the upper power limit.

Inventors

ZHOU QINGHE
LU YONGQUAN
XIE MINGLUN
LIN JIANTING

Assignees

台达电子工业股份有限公司

Dates

Publication Date: 20260512
Application Date: 20250515
Priority Date: 20241108

Claims (10)

1. An LED driver for driving a plurality of LED light sources according to an input voltage, comprising: A plurality of conversion circuits having a plurality of output terminals respectively coupled to the plurality of LED light sources for supplying power to the plurality of LED light sources, the plurality of conversion circuits forming a first stage circuit and a second stage circuit, the first stage circuit comprising an input terminal for receiving the input voltage, the second stage circuit comprising an input terminal coupled to an output terminal of the first stage circuit, and The control circuit is coupled with the plurality of conversion circuits and is used for setting each of the plurality of conversion circuits to generate an output current and an output voltage at the output end; wherein the control circuit calculates an output power of each of the plurality of conversion circuits according to the output current and the output voltage of each of the plurality of conversion circuits; the control circuit sums the output powers of the plurality of conversion circuits to obtain a total output power, and When the control circuit judges that the total output power is larger than a power upper limit, the control circuit sets at least one of the plurality of conversion circuits to regulate down the output current according to the power upper limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the power upper limit.
2. The LED driver of claim 1, wherein the control circuit determines a scaling ratio according to a difference between the total output power and the upper power limit, and sets each of the plurality of conversion circuits to scale down the output current by the scaling ratio.
3. The LED driver of claim 1, wherein the control circuit determines a plurality of adjustment ratios according to the upper power limit and at least one of the total output power and the output power of the respective conversion circuit, and sets each of the plurality of conversion circuits to adjust the output current according to one of the plurality of adjustment ratios.
4. The LED driver of claim 1, wherein the control circuit determines a plurality of adjustment ratios according to the upper power limit and at least one of the total output power and the output power of the respective conversion circuits, and sets a portion of the plurality of conversion circuits to adjust the output current according to one of the plurality of adjustment ratios, respectively.
5. The LED driver of claim 1, wherein the plurality of conversion circuits comprises a first conversion circuit group and a second conversion circuit group; the control circuit is also used for controlling the first conversion circuit group to start and comparing the total output power with the upper power limit; The control circuit judges that the total output power is larger than the upper power limit, and sets at least one of the plurality of conversion circuits in the first conversion circuit group to regulate down the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the upper power limit; after the control circuit judges that the total output power is less than or equal to the upper power limit, the control circuit controls the second conversion circuit group to start and compares the total output power with the upper power limit The control circuit judges that the total output power is larger than the upper power limit, and sets at least one of the plurality of conversion circuits to regulate down the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the upper power limit.
6. An operation method of an LED driver, wherein the LED driver is configured to drive a plurality of LED light sources according to an input voltage, and includes a plurality of conversion circuits and a control circuit, a plurality of output terminals of the plurality of conversion circuits are respectively coupled to the plurality of LED light sources to supply power to the plurality of LED light sources, the plurality of conversion circuits form a first stage circuit and a second stage circuit, the first stage circuit includes an input terminal for receiving the input voltage, the second stage circuit includes an input terminal coupled to an output terminal of the first stage circuit, and the control circuit is coupled to the plurality of conversion circuits, the operation method includes the steps of: (a) Setting the control circuit to set each of the plurality of conversion circuits to generate an output current and an output voltage at the output end; (b) Setting the control circuit to calculate an output power of each of the plurality of conversion circuits according to the output current and the output voltage of each of the plurality of conversion circuits; (c) Setting the control circuit to sum the output powers of the conversion circuits to obtain a total output power, and (D) When the total output power is judged to be larger than a power upper limit, the control circuit is set to set at least one of the plurality of conversion circuits to regulate down the output current according to the power upper limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the power upper limit.
7. The method of claim 6, wherein in the step (d), the control circuit determines an adjustment ratio according to a difference between the total output power and the upper power limit, and sets each of the plurality of converting circuits to adjust the output current by the adjustment ratio.
8. The method of claim 6, wherein in the step (d), the control circuit determines a plurality of adjustment ratios according to the upper power limit and at least one of the total output power and the output power of the respective conversion circuits, and sets each of the plurality of conversion circuits to adjust the output current according to one of the plurality of adjustment ratios.
9. The method of claim 6, wherein in the step (d), the control circuit determines a plurality of adjustment ratios according to the upper power limit and at least one of the total output power and the output power of the respective conversion circuits, and sets a portion of the plurality of conversion circuits to reduce the output current according to one of the plurality of adjustment ratios.
10. The method of claim 6, wherein the plurality of switching circuits comprises a first switching circuit group and a second switching circuit group, the method further comprising: Setting the control circuit to control the first conversion circuit group to start, and setting the control circuit to compare the total output power with the upper power limit; When the control circuit judges that the output power of the first conversion circuit group is larger than the upper power limit, the control circuit is arranged to regulate down the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits, so as to reduce the total output power to be smaller than or equal to the upper power limit; When the control circuit judges that the output power of the first conversion circuit group is less than or equal to the upper power limit, the control circuit is set to control the second conversion circuit group to start and set the control circuit to compare the total output power with the upper power limit When the control circuit judges that the total output power is larger than the upper power limit, the control circuit is set to set at least one of the plurality of conversion circuits to regulate down the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the upper power limit.

Description

LED driver and operation method thereof Technical Field The present disclosure relates to a light-emitting diode (LED) driver and an operating method thereof, and more particularly, to an LED driver with a total power limiting protection function and an operating method thereof. Background In LED lighting applications, LED drivers are typically used to provide the appropriate voltage and current for the LED light source to operate stably and efficiently. The LED driver may include a plurality of voltage converters to provide power requirements for different LED light sources. The voltage converters are respectively connected with a front-stage PFC (power factor correction ) circuit to receive the power factor corrected electric energy from the PFC circuit. In addition, the voltage converters are also respectively coupled to the LED light sources to respectively supply power to the different LED light sources. Although each voltage converter has an over-power protection function, so as to automatically adjust or close when the output power exceeds a safety range, thereby avoiding damage caused by overload, from the perspective of the whole system, the PFC circuit needs to bear the power supply of the whole system, and the heat dissipation capability of the PFC circuit and the LED lamp also affects the stability and the operation efficiency of the whole system. Because each voltage converter does not operate at the maximum power at the same time, if the design is directly performed by adding up the maximum power of each voltage converter, the product size is too large and the power density is low, which may not meet the specific product specification. If the maximum power summation of each voltage converter is not considered, the situation that the total output power of the LED driver and the generated heat energy exceed the bearable range of the whole system may occur, thereby affecting the operation stability and the service life of the LED driver. In addition, in applications such as plant illumination, the LED driver may supply power to the LED light sources such as red light, far infrared light, blue light, white light, etc., respectively, and it is required to be able to more flexibly adjust the power of each LED light source so as to meet the illumination requirements of various different applications. Therefore, how to develop an LED driver and an operation method thereof that can improve the above prior art is an urgent need. Disclosure of Invention An object of the present disclosure is to provide an LED driver and an operating method thereof, so as to solve the foregoing technical problems. In order to achieve the above object, the present disclosure provides an LED driver for driving a plurality of LED light sources according to an input voltage, and comprising a plurality of conversion circuits and a control circuit. The plurality of output ends of the plurality of conversion circuits are respectively coupled to the plurality of LED light sources to supply power to the plurality of LED light sources, and the plurality of conversion circuits form a first-stage circuit and a second-stage circuit, wherein the first-stage circuit comprises an input end for receiving input voltage, and the second-stage circuit comprises an input end coupled to the output end of the first-stage circuit. The control circuit is coupled to the plurality of conversion circuits and is used for setting each of the plurality of conversion circuits to generate output current and output voltage at the output end. The control circuit calculates the output power of each of the plurality of conversion circuits according to the output current and the output voltage of each of the plurality of conversion circuits. The control circuit sums the output powers of the plurality of conversion circuits to obtain a total output power. When the control circuit judges that the total output power is larger than the upper power limit, the control circuit sets at least one of the plurality of conversion circuits to reduce the output current according to the upper power limit and at least one of the total output power and the output power of the individual conversion circuits so as to reduce the total output power to be smaller than or equal to the upper power limit. In order to achieve the above objective, the present disclosure further provides an operation method of an LED driver, wherein the LED driver is configured to drive a plurality of LED light sources according to an input voltage, and includes a plurality of conversion circuits and a control circuit. The plurality of output ends of the plurality of conversion circuits are respectively coupled with the plurality of LED light sources to supply power to the plurality of LED light sources, and the plurality of conversion circuits form a first-stage circuit and a second-stage circuit. The first stage circuit includes an input terminal for receiving an input voltage, and the second stage cir