LED protection circuit

Abstract

The utility model relates to the technical field of illumination, and provides an LED light emitting diode protection circuit, which comprises a bidirectional transient suppression diode used for preventing voltage abrupt change or current peak, a filter circuit used for filtering ripple voltage, a current limiting and rectifying circuit used for preventing overlarge current and voltage reverse connection, and an LED light emitting diode. The bidirectional transient suppression diode is connected between the positive electrode and the negative electrode of input voltage; the input end of the filter circuit is connected with the bidirectional transient suppression diode, and the output end of the filter circuit is connected with the input end of the current limiting and rectifying circuit; and the output end of the current limiting and rectifying circuit is connected with the LED. The protection circuit designed by the utility model can prevent adverse effects on the LED caused by voltage abrupt change, ripple voltage, overlarge current and reverse voltage connection, and improves the stability and reliability of the LED.

Description

Technical Field

[0001] The utility model relates to the technical field of lighting, in particular to an LED light emitting diode protection circuit. Background Art

[0002] As a new type of light source, LED light emitting diodes are widely used due to their high reliability, long service life, low power consumption, energy saving and environmental protection, etc., and play an extremely important role in the application of existing electronic products. However, in the actual use of light emitting diodes, factors such as overvoltage, overcurrent, ripple voltage, reverse voltage, etc. will have an adverse effect on the stability and reliability of LED light emitting diodes and even damage the LED light emitting diodes. Utility Model Content

[0003] The utility model aims to overcome the adverse effects of overvoltage, overcurrent, ripple voltage in DC voltage, excessive current and excessive reverse voltage on LED light emitting diodes, improve the stability and reliability of LED light emitting diodes, and provide an LED light emitting diode protection circuit.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] An LED light emitting diode protection circuit, characterized in that it comprises:

[0006] Buffer circuits to prevent voltage surges or current spikes;

[0007] A filter circuit for filtering out ripple voltage;

[0008] Rectification circuit for preventing voltage reverse connection;

[0009] Current limiting circuit to prevent excessive current;

[0010] LED light emitting diode;

[0011] The rectifying circuit and the current limiting circuit constitute a current limiting and rectifying module;

[0012] The buffer circuit is connected between the positive and negative poles of the input voltage; the input end of the filter circuit is connected to the buffer circuit, the output end of the filter circuit is connected to the input end of the current limiting and rectification module, and the output end of the current limiting and rectification module is connected to the LED light-emitting diode.

[0013] As a preferred solution of the utility model, the buffer circuit includes a bidirectional transient suppression diode, and the bidirectional transient suppression diode is connected between the positive and negative electrodes of the input voltage.

[0014] As a preferred embodiment of the utility model, the filtering circuit includes a capacitor C2, a resistor R11, a common-mode inductor T1, a resistor R3 and a capacitor C1; the first end and the second end of the capacitor C2 are respectively connected to the first end and the second end of the bidirectional transient suppression diode; the capacitor C2 and the resistor R11 are connected in parallel, and the resistor R10 and the capacitor C1 are connected in parallel; the first end and the second end of the common-mode inductor are respectively connected to the first end and the second end of the resistor R11, and the third end and the fourth end of the common-mode inductor are respectively connected to the first end and the second end of the resistor R10.

[0015] As a preferred solution of the present utility model, the rectifier circuit includes a rectifier bridge formed by a diode D1, a diode D2, a diode D3, and a diode D4.

[0016] As a preferred solution of the utility model, the diodes D1, D2, D3 and D4 are Schottky diodes. Schottky diodes, also known as Schottky barrier diodes (SBD for short), are low-power, ultra-high-speed semiconductor devices with extremely short reverse recovery time.

[0017] As a preferred solution of the utility model, the current limiting circuit includes: a resistor R7, a resistor R16, a resistor R1 and a resistor R2;

[0018] The resistor R7, the resistor R16, the resistor R1, the resistor R2 and the rectifier bridge form a current limiting and rectifying module;

[0019] The first end of the resistor R7 and the first end of the resistor R16 are connected to the first end and the second end of the capacitor C1 respectively.

[0020] The second end of the resistor R7 and the second end of the resistor R16 are connected to the first end and the second end of the rectifier bridge respectively.

[0021] The third end and the fourth end of the rectifier bridge are connected to the first end of the resistor R1 and the first end of the resistor R2 respectively.

[0022] The second end of the resistor R1 and the second end of the resistor R2 are connected to the cathode and anode of the LED, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The utility model discloses a circuit principle diagram of an LED light emitting diode protection circuit. DETAILED DESCRIPTION

[0024] The utility model is described in detail below in conjunction with the accompanying drawings.

[0025] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0026] Example 1

[0027] like Figure 1 As shown, in this embodiment, a light-emitting diode LED protection circuit includes a buffer circuit for preventing voltage mutation or current spike, a filter circuit for filtering ripple voltage, a current limiting circuit for preventing excessive current, a rectifier circuit and a light-emitting diode LED1 for preventing voltage reverse connection; the current limiting circuit and the rectifier circuit constitute a current limiting and rectification module; the buffer circuit is connected between the positive and negative poles of the input voltage; the input end of the filter circuit is connected to the buffer circuit, and the output end of the filter circuit is connected to the input end of the current limiting circuit; the current limiting circuit is connected to the rectifier circuit and the LED light-emitting diode.

[0028] Specifically, voltage mutation or current spike may cause thermal breakdown or electrical breakdown of LED light emitting diode, thus damaging the LED light emitting diode. Transient suppression diode is mainly used to protect the circuit from transient events such as overvoltage and overcurrent. Among them, bidirectional transient suppression diode is more suitable for protecting bipolar circuit. Therefore, bidirectional transient suppression diode D13 is connected between the positive and negative poles of the input voltage as a buffer circuit to prevent voltage mutation or current spike from damaging the circuit.

[0029] Specifically, in an industrial production environment, the input DC voltage usually contains an AC component of the industrial frequency, i.e., a ripple voltage. The ripple voltage will have an adverse effect on the display performance, stability, and life of the LED light-emitting diode, and a filter circuit needs to be designed to filter the ripple voltage. The filter circuit in the utility model includes a capacitor C2, a resistor R11, a common-mode inductor T1, a resistor R3, and a capacitor C1; the first end and the second end of the capacitor C2 are respectively connected to the first end and the second end of the bidirectional transient suppression diode D13; the capacitor C2 and the resistor R11 are connected in parallel, and the resistor R10 and the capacitor C1 are connected in parallel; the first end and the second end of the common-mode inductor T1 are respectively connected to the first end and the second end of the resistor R11, and the third end and the fourth end of the common-mode inductor T1 are respectively connected to the first end and the second end of the resistor R10.

[0030] Specifically, if the circuit current exceeds the rated current of the LED light-emitting diode, the LED light-emitting diode will be damaged. If the input voltage is reversed, the LED light-emitting diode may also be reversely broken down. The utility model designs a current limiting and rectification circuit to prevent excessive current and reverse voltage.

[0031] The rectifier circuit includes a rectifier bridge composed of four Schottky diodes, diode D1, diode D2, diode D3, and diode D4. The rectifier bridge uses the unidirectional conduction characteristics of the diodes so that when the input voltage is reversed, the current still flows from the positive electrode of the LED light-emitting diode to the negative electrode, thereby maintaining a normal working state.

[0032] The current limiting circuit includes: a resistor R7, a resistor R16, a resistor R1 and a resistor R2; the first end of the resistor R7 and the first end of the resistor R16 are connected to the first end and the second end of the capacitor C1 respectively, the second end of the resistor R7 and the second end of the resistor R16 are connected to the first end and the second end of the rectifier bridge respectively, the third end and the fourth end of the rectifier bridge are connected to the first end of the resistor R1 and the first end of the resistor R2 respectively, and the second end of the resistor R1 and the second end of the resistor R2 are connected to the cathode and anode of the LED light emitting diode respectively. The current limiting circuit avoids excessive current and damage to the rectifier bridge and the light emitting diode by introducing a current limiting resistor.

[0033] During the actual application of this embodiment, the resistor R11, the resistor R10, the capacitor C1, the capacitor C2 and the common-mode inductor T1 can be calculated and configured according to the frequency of the AC component in the input voltage that needs to be filtered out to achieve filtering of AC voltages of different frequencies; the resistors R7 and R16 can be calculated and configured according to the rated current parameters of the diodes of the rectifier bridge used, and the resistors R1 and R2 can be calculated and configured according to the rated current parameters of the light-emitting diode LED1.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A LED light emitting diode protection circuit, characterized in that: include: Buffer circuits to prevent voltage surges or current spikes; A filter circuit for filtering out ripple voltage; Rectification circuit for preventing voltage reverse connection; Current limiting circuit to prevent excessive current; LED light emitting diode; The rectifying circuit and the current limiting circuit constitute a current limiting and rectifying module; The buffer circuit is connected between the positive and negative poles of the input voltage; the input end of the filter circuit is connected to the buffer circuit, the output end of the filter circuit is connected to the input end of the current limiting and rectification module, and the output end of the current limiting and rectification module is connected to the LED light-emitting diode.

2. The LED protection circuit according to claim 1, characterized in that: The buffer circuit includes a bidirectional transient suppression diode connected between the positive and negative electrodes of the input voltage.

3. The LED protection circuit according to claim 2, characterized in that: The filtering circuit includes a capacitor C2, a resistor R11, a common-mode inductor T1, a resistor R3 and a capacitor C1; the first end and the second end of the capacitor C2 are respectively connected to the first end and the second end of the bidirectional transient suppression diode; the capacitor C2 and the resistor R11 are connected in parallel, and the resistor R10 and the capacitor C1 are connected in parallel; the first end and the second end of the common-mode inductor are respectively connected to the first end and the second end of the resistor R11, and the third end and the fourth end of the common-mode inductor are respectively connected to the first end and the second end of the resistor R10.

4. The LED protection circuit according to claim 3, characterized in that: The rectifier circuit includes a rectifier bridge formed by a diode D1 , a diode D2 , a diode D3 , and a diode D4 .

5. The LED protection circuit according to claim 4, characterized in that: The diode D1 , the diode D2 , the diode D3 , and the diode D4 are Schottky diodes.

6. The LED protection circuit according to claim 4, characterized in that: The current limiting circuit includes: a resistor R7, a resistor R16, a resistor R1 and a resistor R2; The resistor R7, the resistor R16, the resistor R1, the resistor R2 and the rectifier bridge form a current limiting and rectifying module; The first end of the resistor R7 and the first end of the resistor R16 are connected to the first end and the second end of the capacitor C1 respectively. The second end of the resistor R7 and the second end of the resistor R16 are connected to the first end and the second end of the rectifier bridge respectively. The third end and the fourth end of the rectifier bridge are connected to the first end of the resistor R1 and the first end of the resistor R2 respectively. The second end of the resistor R1 and the second end of the resistor R2 are connected to the cathode and anode of the LED, respectively.

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