Anti-overshoot current and voltage circuit

Abstract

The anti-overshoot current and voltage circuit comprises a signal input end, a first MOS tube, a first resistor, an electrolytic capacitor, an LED light source, a first power supply signal input end and a second power supply signal input end, and the first MOS tube serves as a switch of the anti-overshoot current and voltage circuit and is used for controlling on and off of the LED light source. Compared with the prior art, the output end of the LED light source is connected in parallel with the electrolytic capacitor, the problem of over-voltage at two ends of the LED light source when the LED light source is turned on can be effectively solved by utilizing the fact that the voltage at two ends of the electrolytic capacitor cannot be suddenly changed, so that the problem of current overshoot is solved, and the service life of the LED light source is obviously prolonged.

Description

Technical Field

[0001] The utility model is applicable to the field of LED technology, and particularly relates to an anti-overcurrent and overvoltage circuit. Background Art

[0002] In the field of high-speed developing multimedia display technology today, LED light sources have gradually become the mainstream choice in scenarios such as business presentations, home entertainment, and education and training due to their significant advantages such as high brightness, energy conservation, and environmental protection.

[0003] However, the voltage output by the driving power supply of existing LED light sources is often higher than the voltage of the LED light source. When the switch is turned on, it causes overcharging current in the LED light source, affecting the service life of the LED light source.

[0004] Therefore, there is an urgent need for a new anti-overcurrent and overvoltage circuit to solve the above problems. Summary of the Utility Model

[0005] The utility model provides an anti-overcurrent and overvoltage circuit, aiming to solve the problem of current overshoot caused by overvoltage at both ends when the LED light source is turned on, and improve the service life of the LED light source.

[0006] The utility model provides an anti-overcurrent and overvoltage circuit for an LED drive output switch. The anti-overcurrent and overvoltage circuit includes a signal input terminal, a first MOS transistor, a first resistor, an electrolytic capacitor, an LED light source, a first power signal input terminal, and a second power signal input terminal. The first MOS transistor serves as the switch of the anti-overcurrent and overvoltage circuit to control the conduction and cut-off of the LED light source.

[0007] The first power signal input terminal is respectively connected to the first end of the first resistor, the positive electrode of the electrolytic capacitor, and the first end of the LED light source. The second end of the first resistor, the negative electrode of the electrolytic capacitor, and the second end of the LED light source are respectively connected to the drain of the first MOS transistor. The gate of the first MOS transistor is connected to the signal input terminal, and the source of the first MOS transistor is connected to the second power signal input terminal.

[0008] Preferably, the anti-overcurrent and overvoltage circuit further includes a second resistor. The first end of the second resistor is connected to the signal input terminal, and the second end of the second resistor is connected to the gate of the first MOS transistor.

[0009] Preferably, the anti-overcurrent and overvoltage circuit further includes a third resistor. The first end of the third resistor is connected to the gate of the first MOS transistor, and the second end of the third resistor is connected to the source of the first MOS transistor.

[0010] Preferably, the first MOS transistor is an NMOS transistor.

[0011] Compared with the prior art, the anti-overcurrent and overvoltage circuit of the present utility model includes a signal input terminal, a first MOS transistor, a first resistor, an electrolytic capacitor, an LED light source, a first power signal input terminal, and a second power signal input terminal. The first MOS transistor serves as the switch of the anti-overcurrent and overvoltage circuit to control the conduction and cut-off of the LED light source. The first power signal input terminal is respectively connected to the first end of the first resistor, the positive electrode of the electrolytic capacitor, and the first end of the LED light source. The second end of the first resistor, the negative electrode of the electrolytic capacitor, and the second end of the LED light source are respectively connected to the drain of the first MOS transistor. The gate of the first MOS transistor is connected to the signal input terminal, and the source of the first MOS transistor is connected to the second power signal input terminal. In the present utility model, an electrolytic capacitor is connected in parallel at the output end of the LED light source. By utilizing the fact that the voltage across the electrolytic capacitor cannot change suddenly, the overvoltage at both ends of the LED light source during turn-on can be effectively solved, thereby solving the problem of current overshoot and significantly improving the service life of the LED light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present utility model will be described in detail below with reference to the drawings. Through the detailed description in conjunction with the following drawings, the above or other aspects of the present utility model will become clearer and easier to understand. In the drawings:

[0013] Figure 1 is a schematic structural diagram of the anti-overcurrent and overvoltage circuit provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] In order to make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0015] Please refer to Figure 1, the present utility model provides an anti-overcurrent and overvoltage circuit for an LED drive output switch. The anti-overcurrent and overvoltage circuit includes a signal input terminal DR, a first MOS transistor Q1, a first resistor R1, an electrolytic capacitor EC1, an LED light source CN1, a first power signal input terminal VO+, and a second power signal input terminal VO-. The first MOS transistor Q1 serves as the switch of the anti-overcurrent and overvoltage circuit to control the conduction and cutoff of the LED light source CN1. The first power signal input terminal VO+ and the second power signal input terminal VO- are the input terminals of the built-in power supply of the LED projector. The signal input terminal DR inputs the control signal of the LED projector control board to control the switch of the first MOS transistor Q1. When the LED projector is powered on, the signal input terminal DR is at a high level, and when it is powered off, the signal input terminal DR is at a low level. The first resistor R1 is the discharge resistor of the electrolytic capacitor EC1 when the LED light source CN1 is off.

[0016] The first power signal input terminal VO+ is respectively connected to the first end of the first resistor R1, the positive electrode of the electrolytic capacitor EC1, and the first end of the LED light source CN1. The second end of the first resistor R1, the negative electrode of the electrolytic capacitor EC1, and the second end of the LED light source CN1 are respectively connected to the drain of the first MOS transistor Q1. The gate of the first MOS transistor Q1 is connected to the signal input terminal DR, and the source of the first MOS transistor Q1 is connected to the second power signal input terminal VO-.

[0017] Specifically, after the power supply is started, the signal input terminal DR drives the first MOS transistor Q1 to conduct at a high level. At this time, the electrolytic capacitor EC1 has no voltage, and the first power signal input terminal VO+ outputs a signal to charge the electrolytic capacitor EC1. When the voltage of the electrolytic capacitor EC1 reaches the conduction voltage of the LED light source CN1, the LED light source CN1 lights up, and the voltage continues to rise until the current of the LED light source CN1 reaches the constant current value. The electrolytic capacitor EC1 plays a role in voltage smoothing at the moment of turning on, preventing the overcurrent phenomenon that the LED power supply voltage is greater than the voltage of the LED light source CN1 during conduction, and effectively improving the reliability of the LED light source CN1.

[0018] In this embodiment, the anti-overcurrent and overvoltage circuit further includes a second resistor R2. The first end of the second resistor R2 is connected to the signal input terminal DR, and the second end of the second resistor R2 is connected to the gate of the first MOS transistor Q1. The second resistor R2 serves as the drive resistor of the first MOS transistor Q1 to adjust the switching speed of the first MOS transistor Q1.

[0019] In this embodiment, the overshoot current and voltage circuit further includes a third resistor R3. The first end of the third resistor R3 is connected to the gate of the first MOS transistor Q1, and the second end of the third resistor R3 is connected to the source of the first MOS transistor Q1. The third resistor R3 serves as a discharge resistor for the driving pin of the first MOS transistor Q1 to prevent electrostatic damage to the first MOS transistor Q1.

[0020] In this embodiment, the first MOS transistor Q1 is an NMOS transistor.

[0021] Compared with the prior art, the utility model includes a signal input terminal, a first MOS transistor, a first resistor, an electrolytic capacitor, an LED light source, a first power signal input terminal, and a second power signal input terminal in the overshoot current and voltage circuit. The first MOS transistor serves as a switch of the overshoot current and voltage circuit to control the conduction and cut-off of the LED light source. The first power signal input terminal is respectively connected to the first end of the first resistor, the positive electrode of the electrolytic capacitor, and the first end of the LED light source. The second end of the first resistor, the negative electrode of the electrolytic capacitor, and the second end of the LED light source are respectively connected to the drain of the first MOS transistor. The gate of the first MOS transistor is connected to the signal input terminal, and the source of the first MOS transistor is connected to the second power signal input terminal. The utility model connects an electrolytic capacitor in parallel at the output end of the LED light source. By utilizing the fact that the voltage across the electrolytic capacitor cannot change suddenly, it can effectively solve the problem of overvoltage at both ends of the LED light source during turn-on, thereby solving the problem of current overshoot and significantly improving the service life of the LED light source.

[0022] It should be noted that in this article, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0023] The embodiments of the utility model have been described above in conjunction with the accompanying drawings. What is disclosed is only the preferred embodiments of the utility model. However, the utility model is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the utility model, those of ordinary skill in the art can still make many equivalent changes in form without departing from the purpose of the utility model and the scope protected by the claims, and all of them belong to the protection scope of the utility model.

Claims

1. An anti-overshoot current and voltage circuit for LED drive output switch, characterized in that: The anti-overshoot current and voltage circuit includes a signal input terminal, a first MOS transistor, a first resistor, an electrolytic capacitor, an LED light source, a first power signal input terminal, and a second power signal input terminal. The first MOS transistor serves as a switch of the anti-overshoot current and voltage circuit to control the on and off of the LED light source. The first power signal input terminal is respectively connected to the first end of the first resistor, the positive electrode of the electrolytic capacitor and the first end of the LED light source, the second end of the first resistor, the negative electrode of the electrolytic capacitor and the second end of the LED light source are respectively connected to the drain of the first MOS tube, the gate of the first MOS tube is connected to the signal input terminal, and the source of the first MOS tube is connected to the second power signal input terminal.

2. The anti-overshoot current and voltage circuit according to claim 1, characterized in that: The anti-overshoot current voltage circuit also includes a second resistor, a first end of the second resistor is connected to the signal input end, and a second end of the second resistor is connected to the gate of the first MOS tube.

3. The anti-overshoot current and voltage circuit according to claim 1, characterized in that: The anti-overshoot current voltage circuit also includes a third resistor, a first end of the third resistor is connected to the gate of the first MOS tube, and a second end of the third resistor is connected to the source of the first MOS tube.

4. The anti-overshoot current and voltage circuit according to claim 1, characterized in that: The first MOS tube is an NMOS tube.

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