LED power supply with hot plug protection

Abstract

The invention discloses an LED power supply with hot plug protection. The LED power supply comprises a control chip U1, a power device Q2, resistors RV1-RV2, a capacitor EC1, a switch tube Q1 and a resistor RS1, a first pin of the control chip U1 is connected with a control end of the power device Q2, a positive electrode of the power device Q2 is connected with one end of the capacitor EC1, one end of the resistor RV1 and a positive electrode of the LED module, the other end of the resistor RV1 is connected with a second pin of the control chip U1 and one end of the resistor RV2, a third pin of the control chip U1 is connected with a control end of the switch tube Q1, and the other end of the switch tube Q1 is connected with a negative electrode of the power device Q2. The input end of the switch tube Q1 is connected with one end of the resistor RS1 and the negative electrode of the LED module. The grounding pin of the control chip U1, the negative electrode of the power device Q2, the resistor RV2, the output end of the switch tube Q1 and the other end of the resistor RS1 are connected with a GND end. Through the circuit, the reliability of the power supply and the LED module under special conditions can be enhanced, and the power supply or the LED module is prevented from being damaged.

Description

Technical Field

[0001] The present invention relates to the field of LED switching power supplies, and in particular to an LED power supply with hot-swap protection. Background Art

[0002] Traditional LED constant-current output switching power supplies are designed to be used only after the power supply output terminal is securely connected to the LED module before AC power is applied. If AC power is applied without first properly connecting the power supply output cable to the LED module as required, the switching power supply will output a no-load protection voltage higher than the maximum load voltage due to its no-load output. If an LED module is connected at this time, the voltage on the internal EC capacitor of the power supply will be much higher than the voltage of the LED module. The EC capacitor will force discharge the LED module, resulting in a strong discharge surge current in the LED module, which can damage or even destroy the LED chip within the LED module. It may also damage the semiconductor IC and other components within the power supply. Therefore, an LED power supply with hot-swap protection is urgently needed to solve this problem. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides an LED power supply with hot-swap protection.

[0004] An embodiment of the present invention adopts a technical solution to solve its technical problem: an LED power supply with hot-swap protection, including a control chip U1, a power device Q2, resistors RV1-RV2, a capacitor EC1, a switch tube Q1 and a resistor RS1; the first pin of the control chip U1 is connected to the control end of the power device Q2, the positive electrode of the power device Q2 is respectively connected to one end of the capacitor EC1, one end of the resistor RV1 and the positive electrode of the LED module, the other end of the resistor RV1 is respectively connected to the second pin of the control chip U1 and one end of the resistor RV2, the third pin of the control chip U1 is connected to the control end of the switch tube Q1, the input end of the switch tube Q1 is respectively connected to one end of the resistor RS1 and the negative electrode of the LED module, the ground pin of the control chip U1, the negative electrode of the power device Q2, the resistor RV2, the output end of the switch tube Q1 and the other end of the resistor RS1 are connected to the GND end.

[0005] As one of the preferred embodiments of the present invention, the control chip U1 has a fourth pin for feeding a DIM signal.

[0006] As one of the preferred embodiments of the present invention, the switch tube Q1 is configured as a MOS tube.

[0007] The beneficial effects of the present invention are as follows: an LED power supply with hot-swap protection includes a control chip U1, a power device Q2, resistors RV1-RV2, a capacitor EC1, a switch tube Q1, and a resistor RS1; a first pin of the control chip U1 is connected to the control end of the power device Q2, the positive electrode of the power device Q2 is respectively connected to one end of the capacitor EC1, one end of the resistor RV1, and the positive electrode of the LED module, the other end of the resistor RV1 is respectively connected to the second pin of the control chip U1 and one end of the resistor RV2, the third pin of the control chip U1 is connected to the control end of the switch tube Q1, the input end of the switch tube Q1 is respectively connected to one end of the resistor RS1 and the negative electrode of the LED module, the ground pin of the control chip U1, the negative electrode of the power device Q2, the resistor RV2, the output end of the switch tube Q1, and the other end of the resistor RS1 are connected to the GND end; the above circuit can enhance the reliability of the power supply and the LED module under special conditions and prevent damage to the power supply or the LED module. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which: Figure 1 The following is a circuit diagram of an LED power supply with hot-swap protection. DETAILED DESCRIPTION

[0009] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0010] In the description of this invention, "above," "below," and "within" are understood to be exclusive of the number indicated. The terms "first" and "second" are used solely to distinguish technical features and are not to be construed as indicating or implying relative importance, or as implicitly specifying the number or order of the technical features indicated.

[0011] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0012] In the present invention, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection; and internal communication between two components or interaction between two components. Those skilled in the art can reasonably determine the specific meanings of these terms in the present invention based on the specific content of the technical solution.

[0013] Reference Figure 1 , an LED power supply with hot-swap protection, including a control chip U1, a power device Q2, resistors RV1-RV2, a capacitor EC1, a switch tube Q1 and a resistor RS1; The first pin of the control chip U1 is connected to the control end of the power device Q2, the positive electrode of the power device Q2 is respectively connected to one end of the capacitor EC1, one end of the resistor RV1 and the positive electrode of the LED module, the other end of the resistor RV1 is respectively connected to the second pin of the control chip U1 and one end of the resistor RV2, the third pin of the control chip U1 is connected to the control end of the switch tube Q1, the input end of the switch tube Q1 is respectively connected to one end of the resistor RS1 and the negative electrode of the LED module, the ground pin of the control chip U1, the negative electrode of the power device Q2, the resistor RV2, the output end of the switch tube Q1 and the other end of the resistor RS1 are connected to the GND end; wherein, the switch tube Q1 is preferably a MOS tube; the control chip U1 also has a fourth pin for feeding a DIM signal, which can realize dimming of the LED module.

[0014] The working principle of the present invention is as follows: 1. During normal use, first connect the power output port to the LED module and then connect the power input line to the power grid; the output voltage of the control signal line Control (the third pin) of the control chip U1 is high, turning on the switch tube Q1, and then the first pin of the control chip U1 outputs the I-ADJ signal representing the brightness to the power device Q2. The power device Q2 starts to output current, and the voltage on the capacitor EC1 in parallel with the power port gradually increases. After reaching the operating voltage of the LED module, the output voltage stabilizes at the total LED-VF voltage and operates stably.

[0015] 2. If the power input line is connected to the power grid without first firmly connecting the power output port to the LED module, the output voltage of the control signal line Control of the control chip U1 is still high after power is turned on, turning on the switch tube Q1. Then, the first pin of the control chip U1 outputs the I-ADJ signal representing the brightness to the power device Q2, and the power device Q2 starts to output current. The voltage on the capacitor EC1 connected in parallel with the power port gradually rises. However, since the output port is not connected to the LED module, the output voltage continues to rise to the maximum voltage value, which is equal to the no-load protection voltage. At this time, the divided voltage of the resistors RV1 and RV2 will be higher than the voltage limit under normal circumstances. The second pin of the control chip U1 detects that the voltage is greater than the voltage limit and determines that the power output port is not connected to the LED module load. It immediately changes the output voltage of the control signal line Control to a low level, turning off the switch tube Q1. At the same time, the first pin of the control chip U1 adjusts the I-ADJ signal representing the brightness to the minimum brightness value and outputs it to the power device Q2, which is now in the protection state.

[0016] If the LED module is subsequently connected to the output port of the power supply, the operating state at this time becomes that the voltage on capacitor EC1 is applied to the two-unit series network consisting of the LED module and resistor RS1. According to the maximum transient current value of the LED module, a suitable resistance value is calculated and applied to resistor RS1. The voltage on capacitor EC1 then gradually becomes a low voltage through discharge, close to the LED operating voltage. The divided voltage of resistors RV1 and RV2 will be lower than the voltage limit under normal circumstances. The second pin of the control chip U1 detects that it is less than the voltage limit, then determines that the power output port has been connected to the LED module, and immediately changes the output voltage of the control signal line Control to a high level, turning on the switch tube Q1. At the same time, the first pin of the control chip U1 adjusts the brightness-representing I-ADJ signal to the normal operating brightness value and outputs it to the power device Q2. The power device Q2 begins to increase the output current, and the voltage on the capacitor EC1 connected in parallel with the power port gradually rises. After reaching the LED operating voltage, the output voltage stabilizes at the total LED-VF voltage and operates stably.

[0017] 3. During normal use, if the LED module is disconnected from the power output port, the voltage on the capacitor EC1 will quickly rise to the no-load protection voltage value. At this time, the voltage divided by the resistors RV1 and RV2 will be higher than the voltage limit under normal circumstances. The second pin of the control chip U1 detects that the voltage is greater than the voltage limit, and it is determined that the power output port is not connected to the LED module at this time. The output voltage of the control signal line Control is immediately changed to a low level, and the switch tube Q1 is turned off. At the same time, the first pin of the control chip U1 adjusts the I-ADJ signal representing the brightness to the minimum brightness value and outputs it to the power device Q2. At this time, it is in the protection state.

[0018] If the LED module is subsequently connected to the power output port, the operation will proceed according to the working principle in point 2 above.

[0019] The advantages of the present invention are: simple circuit, easy implementation, able to enhance the reliability of the power supply and LED module under special conditions, prevent damage to the power supply or LED module, can support operation in various situations, and has good application effects.

[0020] Of course, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. An LED power supply with hot-swap protection, characterized in that: It includes a control chip U1, a power device Q2, resistors RV1-RV2, a capacitor EC1, a switch tube Q1 and a resistor RS1; the first pin of the control chip U1 is connected to the control end of the power device Q2, the positive electrode of the power device Q2 is respectively connected to one end of the capacitor EC1, one end of the resistor RV1 and the positive electrode of the LED module, the other end of the resistor RV1 is respectively connected to the second pin of the control chip U1 and one end of the resistor RV2, the third pin of the control chip U1 is connected to the control end of the switch tube Q1, the input end of the switch tube Q1 is respectively connected to one end of the resistor RS1 and the negative electrode of the LED module, and the ground pin of the control chip U1, the negative electrode of the power device Q2, the resistor RV2, the output end of the switch tube Q1 and the other end of the resistor RS1 are connected to the GND end.

2. The LED power supply with hot-swap protection according to claim 1, characterized in that: The control chip U1 has a fourth pin for feeding a DIM signal.

3. The LED power supply with hot-swap protection according to claim 1, characterized in that: The switch tube Q1 is configured as a MOS tube.

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