LED light strip with over-temperature protection

Abstract

The utility model discloses a kind of LED lamp strips with over-temperature protection, LED lamp string is connected in series by several LED light sources, the anode of first LED light source of LED lamp string is electrically connected with LED driving power line VCC, the cathode of last LED light source of LED lamp string is electrically connected with ground wire GND;LED lamp string is connected with thermistor PTC1, when lamp strip is still in winding state, direct power test or use, lamp strip along with temperature rise, the internal resistance of thermistor PTC1 increases with temperature rise, circuit total resistance increases, current reduces, lamp strip power reduces, to suppress temperature further rise;Z1 is connected in parallel at the two ends of thermistor PTC1, when thermistor PTC1 internal resistance rises to certain time, two end voltage rises to breakdown voltage of stabilivolt diode Z1, stabilivolt diode Z1 is turned on, when this thermistor PTC1 two ends voltage is clamped at stabilizing value, ensure that lamp strip always maintains certain brightness, will not be completely extinguished, avoid LED light source damage.

Description

Technical Field

[0001] This utility model relates to a lighting device, and more particularly to an LED light strip. Background Technology

[0002] Existing LED light strips typically employ a circuit structure consisting of LED chips connected in series with a current-limiting resistor. For ease of storage, transportation, and sales, the light strips are usually wound onto a plastic spool at the factory. In practical applications, users need to unwind and straighten the light strip before powering it on. However, some users often neglect to power on or use the light strip while it is still wound. The heat dissipation area of ​​the light strip is significantly reduced when wound, making it easy for heat to accumulate and causing the internal temperature to rise rapidly. As the power-on time increases, the accumulated high temperature can easily reach the ignition point of the plastic spool or the light strip substrate material, igniting the light strip and surrounding materials and causing a serious fire safety accident. Utility Model Content

[0003] In order to overcome the shortcomings of the prior art, this utility model provides an LED light strip with over-temperature protection.

[0004] The technical solution adopted by this utility model to solve its technical problem is: An LED light strip with over-temperature protection includes an LED driver power line VCC, a ground line GND, and an LED light string composed of several LED light sources connected in series. The positive terminal of the first LED light source in the LED light string is electrically connected to the LED driver power line VCC, and the negative terminal of the last LED light source in the LED light string is electrically connected to the ground line GND. The LED light string is connected in series with an over-temperature protection circuit, which includes a thermistor PTC1, and a Zener diode Z1 is connected in parallel across the thermistor PTC1.

[0005] This application incorporates a thermistor PTC1 connected in series within the LED strip. When the LED strip is still wound and directly powered on for testing or use, as the temperature of the strip rises, the internal resistance of the thermistor PTC1 increases, leading to an increase in the total circuit resistance, a decrease in current, and a reduction in the strip's power, thereby suppressing further temperature increases. If the internal resistance of the thermistor PTC1 continues to increase, positive feedback is formed, ultimately causing the LED strip to turn off. A Zener diode Z1 is connected in parallel across the thermistor PTC1. When the internal resistance of the thermistor PTC1 rises to a certain level, the voltage across it rises to the breakdown voltage of the Zener diode Z1, causing Z1 to conduct. At this point, the voltage across the thermistor PTC1 is clamped at a regulated value, preventing the thermistor PTC1 from completely blocking the current due to positive feedback. This ensures that the LED strip maintains a certain brightness and does not completely turn off, thus preventing damage to the LED light source.

[0006] As a further improvement of this utility model, the positive terminal of the Zener diode Z1 and one end of the thermistor PTC1 are simultaneously connected to the negative terminal of the light-emitting diode LED1, and the other end of the Zener diode Z1 and the thermistor PTC1 are simultaneously connected to the positive terminal of the light-emitting diode LED2.

[0007] As a further improvement of this utility model, the LED light strip is composed of at least one LED light string connected in series.

[0008] As a further improvement of this utility model, the LED light string also includes several current-limiting resistors, which are connected in series between adjacent LED light sources.

[0009] As a further improvement of this utility model, the thermistor PTC1 is a thermistor with a positive temperature coefficient.

[0010] The beneficial effects of this utility model are as follows: A thermistor PTC1 is connected in series within the LED strip. When the LED strip is still in a wound state and is directly powered on for testing or use, as the temperature of the LED strip rises, the internal resistance of the thermistor PTC1 increases, increasing the total circuit resistance, decreasing the current, and reducing the power of the LED strip, thereby suppressing further temperature increases. If the internal resistance of the thermistor PTC1 continues to increase, positive feedback is formed, eventually causing the LED strip to turn off. A Zener diode Z1 is connected in parallel across the thermistor PTC1. When the internal resistance of the thermistor PTC1 rises to a certain level, the voltage across it rises to the breakdown voltage of the Zener diode Z1, causing the Zener diode Z1 to conduct. At this time, the voltage across the thermistor PTC1 is clamped at the regulated value, ensuring that the LED strip always maintains a certain brightness and will not completely turn off, thus avoiding damage to the LED light source. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0014] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0015] The following describes some embodiments of the present invention with reference to the accompanying drawings.

[0016] Reference Figure 1 An LED light strip with over-temperature protection includes an LED driver power line VCC, a ground line GND, and an LED string composed of several LED light sources connected in series. The positive terminal of the first LED light source in the LED string is electrically connected to the LED driver power line VCC, and the negative terminal of the last LED light source in the LED string is electrically connected to the ground line GND. An over-temperature protection circuit is connected in series to the LED string. The over-temperature protection circuit includes a thermistor PTC1, and a Zener diode Z1 is connected in parallel across the thermistor PTC1. In this embodiment, the first LED light source is the first LED light source forming the LED string. Figure 1 LED1 is a light-emitting diode, and the last LED light source is the last one that makes up the LED string, such as... Figure 1 LED4 is a light-emitting diode.

[0017] This invention incorporates a thermistor PTC1 connected in series within the LED strip. When the strip is still wound and directly powered on for testing or use, as the temperature rises, the internal resistance of the thermistor PTC1 increases, leading to an increase in the total circuit resistance, a decrease in current, and a reduction in the strip's power. This suppresses further temperature increases and achieves over-temperature protection. If the internal resistance of the thermistor PTC1 continues to increase, positive feedback will form, eventually causing the strip to turn off. Therefore, a Zener diode Z1 is connected in parallel across the thermistor PTC1. When the internal resistance of the thermistor PTC1 rises to a certain level, the voltage across it increases to the breakdown voltage of the Zener diode Z1, causing Z1 to conduct. At this point, the voltage across the thermistor PTC1 is clamped at a regulated value, ensuring the strip maintains a certain brightness and does not completely turn off, allowing the strip to continue to be used and preventing damage to the LED light source.

[0018] The positive terminal of the Zener diode Z1 and one end of the thermistor PTC1 are simultaneously connected to the negative terminal of the light-emitting diode LED1. The other end of the negative terminal of the Zener diode Z1 and the thermistor PTC1 are simultaneously connected to the positive terminal of the light-emitting diode LED2. In this embodiment, the Zener diode Z1 is a commonly used device with a Zener voltage of 30V.

[0019] The LED light strip is composed of at least one LED string connected in series, and can be extended arbitrarily as needed.

[0020] The LED string also includes several current-limiting resistors, which are connected in series between adjacent LED light sources, such as... Figure 1 The current-limiting resistors R1 and R2 are used for overcurrent protection.

[0021] The thermistor PTC1 is a positive temperature coefficient thermistor, specifically model SMD1206E005SF60V. Its core parameters are: holding current 0.05A, rated voltage 60V, and core electrical parameters (25℃): holding current 0.05A (maximum current during normal operation without tripping); trip current approximately 0.15A (minimum current to activate protection); rated voltage DC 60V (maximum withstand voltage); maximum current 100A (maximum withstand current during short circuit); initial resistance 3.6Ω (minimum resistance value at 25℃); maximum resistance 50Ω. The operating temperature range is -40℃ to +85℃. Specifically, the current of the thermistor PTC1 is 0.074A at -40℃, 0.066A at -20℃, 0.058A at 0℃, 0.05A at 25℃, 0.0425A at 40℃, 0.0375A at 50℃, 0.035A at 60℃, 0.03A at 70℃, and 0.0275A at 85℃. This shows that as the temperature increases, the current gradually decreases, reducing the power of the LED strip and thus preventing further temperature rise.

[0022] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An LED light strip with over-temperature protection, characterized in that... include: The LED driver power supply line VCC, the ground line GND, and an LED light string consisting of several LED light sources connected in series, wherein the positive terminal of the first LED light source in the LED light string is electrically connected to the LED driver power supply line VCC, and the negative terminal of the last LED light source in the LED light string is electrically connected to the ground line GND; the LED light string is connected in series with an over-temperature protection circuit, which includes a thermistor PTC1, and a Zener diode Z1 is connected in parallel across the thermistor PTC1.

2. The LED light strip with over-temperature protection according to claim 1, characterized in that... The positive terminal of the Zener diode Z1 and one end of the thermistor PTC1 are simultaneously connected to the negative terminal of the light-emitting diode LED1, and the other end of the Zener diode Z1 and the thermistor PTC1 are simultaneously connected to the positive terminal of the light-emitting diode LED2.

3. The LED light strip with over-temperature protection according to claim 1, characterized in that... The LED light strip is composed of at least one LED string connected in series.

4. The LED light strip with over-temperature protection according to claim 1, characterized in that... The LED string also includes several current-limiting resistors, which are connected in series between adjacent LED light sources.

5. The LED light strip with over-temperature protection according to claim 1, characterized in that... The thermistor PTC1 is a thermistor with a positive temperature coefficient.

Images