Overvoltage protection LED lamp panel circuit for camera

Abstract

The utility model discloses an overvoltage protection LED lamp panel circuit used on a camera, comprising a complete machine power supply input VBAT, an overvoltage protection circuit connected with the complete machine power supply input VBAT, and an LED voltage-dividing current-limiting and switch control circuit connected with the overvoltage protection circuit. According to the utility model, low cost and low power consumption are realized, and related advantage functions of overvoltage protection and the like are realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of protection circuit, especially a kind of overvoltage protection LED lamp panel circuit for camera. BACKGROUND

[0002] Under the drive of big data, artificial intelligence, 5G, Internet of Things and other technologies, camera monitoring is no longer a simple video input device, and new features are shown in product form, performance and function. In terms of product form, cameras have shifted from fixed form to rotatable form. Pan-tilt cameras have become the mainstream of the home camera market, and gun camera also plays an important role in the field of industrial security. In terms of product performance, camera display indicators are also improving year by year. With consumers demanding higher quality pictures, camera pixels have also been upgraded, with 4 million pixel cameras showing the most obvious growth.

[0003] In terms of product function, video recording, storage and night vision have become the standard configuration of cameras. More than 80% of monitoring cameras have video recording, remote viewing and cloud storage functions. Through the cloud and remote, the use of cameras is no longer limited by time and place, making it more convenient and ensuring the security of the content. 97% of cameras support night vision, and are gradually evolving towards color. The share of day and night full-color cameras increased from 20% in January 2022 to 31% in December.

[0004] With the dramatic increase in demand for camera industry market, LED backlight design has become the mainstream of market demand. Good circuit design makes LED backlight more secure, energy-saving, efficient, power protection and other advantages, making its function more abundant and performance more perfect. The cost should also be reduced.

[0005] The intelligent light compensation of LED backlight design makes the image quality of the camera clearer in various weather and lightless conditions. Low color temperature intelligent control LED can reduce the irritation to the human eye and improve the monitoring distance and range of the camera to the surrounding environment. The introduction of intelligent light sensing makes the LED lamp panel widely used in intelligent control in camera light compensation design.

[0006] As Figures 1-4As shown, taking the existing conventional camera LED power board circuit design system as an example, the existing camera LED lamp board circuit design generally adopts the whole machine power input system to input the power V_BAT, then adopts the DC-DC step-down chip to convert the voltage, obtains the target voltage VCC_LED of the LED lamp board, then outputs the constant voltage / constant current DC-DC driving chip for the LED continuous voltage LED+ and LED-, so that the LED lamp forms a pressure difference between the positive and negative electrodes to drive the LED to emit light, and the circuit controls and adjusts the LED-voltage through the control signal IR_LED, so that the light emitting diode obtains the switching control effect, and realizes the related lamp board switching control function.

[0007] This scheme adopts two power-related chips to convert the whole machine voltage, the cost is high, the input voltage does not add the overvoltage protection function, the power efficiency is low, and the energy consumption is serious. The utility model discloses a kind of overvoltage protection LED lamp board circuits for camera, which is low in cost, low in power consumption, and realizes overvoltage protection and other related advantages.

[0008] To solve the problems in the prior art, the utility model aims to provide an overvoltage protection LED lamp board circuit for a camera.

[0009] To achieve the above object, the utility model adopts the technical scheme: an overvoltage protection LED lamp board circuit for a camera, comprising a whole machine power input V_BAT, an overvoltage protection circuit connected with the whole machine power input V_BAT, and an LED voltage division current limiting and switching control circuit connected with the overvoltage protection circuit.

[0010] As a further improvement of the utility model, the overvoltage protection circuit comprises a voltage stabilizing tube D3, MOS tubes Q1, Q2 and Q3, the cathode of the voltage stabilizing tube D3 is connected with the whole machine power input V_BAT, the anode of the voltage stabilizing tube D3 is connected with the source of the MOS tube Q2, the drain of the MOS tube Q2 is grounded, the gate of the MOS tube Q2 is connected with the whole machine power input V_BAT, the gate of the MOS tube Q1 is connected with the common terminal of the whole machine power input V_BAT and the voltage stabilizing tube D3, the source of the MOS tube Q1 is connected with the whole machine power input V_BAT, the drain of the MOS tube Q1 is connected with the gate of the MOS tube Q3, the source of the MOS tube Q3 is connected with the whole machine power input V_BAT, the drain of the MOS tube Q3 is connected with the power input end VCC_LED of the LED voltage division current limiting and switching control circuit, and a resistor R155 is connected between the gate and the source of the MOS tube Q3, and the gate of the MOS tube Q3 is further connected with the anode of the voltage stabilizing tube D3 through a resistor R156.

[0011] As a further improvement of the utility model, the LED voltage division current limiting and switch control circuit includes one or multiple parallel LED lamp panels, each of which includes a MOS tube and at least one or multiple LED lamp beads connected in series, the anode of each of the LED lamp beads is provided with a current limiting resistor between the power input end VCC_LED, the cathode of each of the LED lamp beads is connected with the drain of the corresponding MOS tube, the gate of each of the MOS tubes is connected with the control level IR_LED, and the source of each of the MOS tubes is grounded.

[0012] The utility model adopts overvoltage protection input circuit, cooperates relevant voltage division current limiting and control circuit, realizes camera LED lamp panel light supplementing relevant function, this scheme has low cost, low power consumption, and realizes overvoltage protection and other relevant advantage function.

[0013] The utility model has the advantages that:

[0014] 1. The utility model provides a low-cost and low-power LED lamp panel circuit design.

[0015] 2. The circuit related to the utility model has a camera LED lamp panel load overvoltage protection function related circuit design.

[0016] 3. The LED lamp panel related to the utility model has a current limiting, voltage division, control and other multifunctional circuit functions.

[0017] 4. The innovative circuit used in the utility model replaces the conventional voltage reduction, constant current / constant voltage chip lamp panel power supply circuit design, and the design of the camera LED light supplementing panel circuit is more simple, and the application and expansion field are more extensive. DRAWINGS

[0018] Figure 1 It is a system block diagram of the existing LED lamp panel circuit.

[0019] Figure 2 It is a voltage reduction conversion circuit diagram of the existing LED lamp panel circuit.

[0020] Figure 3 It is an LED constant voltage / constant current voltage output circuit diagram of the existing LED lamp panel circuit.

[0021] Figure 4 It is an LED voltage division / current limiting control circuit diagram of the existing LED lamp panel circuit.

[0022] Figure 5 It is a system block diagram of the embodiment of the utility model.

[0023] Figure 6 For the overvoltage protection circuit diagram in the embodiment of the utility model;

[0024] Figure 7 For the LED voltage division current limiting and switch control circuit diagram in the embodiment of the utility model. DETAILED DESCRIPTION

[0025] The embodiments of the utility model will be described in detail below with reference to the drawings.

[0026] EMBODIMENT

[0027] As Figure 5 shown, an overvoltage protection LED lamp plate circuit for camera, including whole machine power input V_BAT, still include with overvoltage protection circuit of whole machine power input V_BAT connection, and with the LED voltage division current limiting and switch control circuit of overvoltage protection circuit connection.

[0028] As Figure 6 shown, the overvoltage protection circuit includes voltage stabilizing tube D3, MOS tube Q1, MOS tube Q2 and MOS tube Q3, the cathode of voltage stabilizing tube D3 is connected with whole machine power input V_BAT, voltage stabilizing tube D3's anode is connected with the source electrode of MOS tube Q2, the drain electrode of MOS tube Q2 is grounded, the grid of MOS tube Q2 is connected with whole machine power input V_BAT, the grid of MOS tube Q1 is connected with the common terminal of whole machine power input V_BAT and voltage stabilizing tube D3, the source electrode of MOS tube Q1 is connected with whole machine power input V_BAT, the drain electrode of MOS tube Q1 is connected with the grid of MOS tube Q3, the source electrode of MOS tube Q3 is connected with whole machine power input V_BAT, the drain electrode of MOS tube Q3 is connected with the power input terminal VCC_LED of the LED voltage division current limiting and switch control circuit, and the grid and source electrode of MOS tube Q3 are connected with resistance R155, and the grid of MOS tube Q3 is also connected with the anode of voltage stabilizing tube D3 through resistance R156.

[0029] As Figure 7 shown, the LED voltage division current limiting and switch control circuit includes one or more parallel LED lamp plates, each LED lamp plate includes MOS tube and at least one or more LED lamp beads in series, the positive pole of each LED lamp bead is provided with current-limiting resistor between power input terminal VCC_LED, the negative pole of each LED lamp bead is connected with the drain electrode of the corresponding MOS tube of this path, the grid of each MOS tube is connected with control level IR_LED, and the source electrode of each MOS tube is grounded.

[0030] The embodiment realizes a low-cost LED lamp panel circuit design with short circuit protection. When the whole machine power is connected, V_BAT input is lower than 12V related voltage. VCC_LED end normally outputs 12V to LED series / parallel circuit power supply, when V_BAT is greater than 12V, the protection circuit VCC_LED output is 0V, at this time the load LED series / parallel circuit is off, therefore the input LED lamp panel circuit plays a protection role. The VCC_LED series / parallel circuit selects the LED lamp voltage drop and the rated current, and adopts the IR_LED control level to implement the light supplement switch control of each road LED.

[0031] As shown in the figure, the overvoltage protection circuit principle is as follows: Figure 6

[0032] Wherein V_BAT is the LED lamp panel power supply, generally input is between 9V-12V; the following describes the operation principle of the load protection circuit:

[0033] When V_BAT>12V, the voltage stabilizing tube D3 is in a stable state, the MOS tube Q1 gate voltage is 12V, the source voltage is greater than 12V, Vgs<0, since the MOS tube Q1 is PMOS, the MOS tube Q1 is in a conductive state, therefore the MOS tube Q3 part of the gate voltage is 12V, the MOS tube Q3 source voltage is 12V, the MOS tube Q3 is PMOS, therefore the MOS tube Q3 is cut off, VCC_LED output is 0V (no voltage output), the LED lamp panel circuit plays a protection role.

[0034] When VBAT<=12V, the voltage stabilizing tube D3 is in a cut-off state, at this time the MOS tube Q1 gate voltage is 12V, the source voltage is also 12V, Vgs=0, therefore the MOS tube Q1 is cut off, the current flows through the resistor R155 to the gate of the MOS tube Q3, and the voltage is divided with the resistor R156, at this time the MOS tube Q3 gate voltage is about 6V, the source voltage is 12V, therefore Vgs<0, therefore the MOS tube Q3 is turned on, VBAT=VCC_LED voltage, the camera LED lamp panel power supply circuit load works normally.

[0035] As shown in the figure, the LED voltage division / current limiting / control circuit is detailed: Figure 7

[0036] Wherein V_BAT input voltage is about 9-12V, according to the conventional LED lamp bead maximum current is about Imax<75mA, therefore the size of the current limiting resistor is greater than 2K ohms according to the design of 4 parallel 3 series circuit, according to the LED lamp bead voltage drop in 2.5V-3V voltage drop and the LED lamp bead saturation current in 12mA-20mA evaluation, therefore the optimized current limiting resistor configuration is 6.1K ohm. ​​

[0037] When the control signal IR_LED is high (greater than 0.7v), MOS Q4, MOS Q5, MOS Q6, MOS Q7, MOS Q8 are NMOS, Vgs>0, and the LED emits light normally. Conversely, when the control signal IR_LED is low (less than 0.7v), NMOS Vgs<0, and the circuit is cut off, thus completing the related functions of the LED light plate through current limiting, voltage dividing, and control.

[0038] Compared with the conventional camera light plate circuit, the low-cost LED light plate has more advantages in voltage protection, voltage dividing / current limiting / control design, avoids the consumption of the chip on the current, saves the cost of the related product design, and improves the safety performance of the product.

[0039] The above-described embodiments only express the specific implementation of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application.

Claims

1. An overvoltage protection LED light board circuit for a camera, comprising a system power input V_BAT, characterized in that, The overvoltage protection circuit is connected with the whole machine power input V_BAT, and the LED voltage division current limiting and switch control circuit is connected with the overvoltage protection circuit; the overvoltage protection circuit comprises a stabilizing tube D3, MOS tubes Q1, Q2 and Q3, the cathode of the stabilizing tube D3 is connected with the whole machine power input V_BAT, the anode of the stabilizing tube D3 is connected with the source of the MOS tube Q2, the drain of the MOS tube Q2 is grounded, the gate of the MOS tube Q2 is connected with the whole machine power input V_BAT, the gate of the MOS tube Q1 is connected with the common terminal of the whole machine power input V_BAT and the stabilizing tube D3, the source of the MOS tube Q1 is connected with the whole machine power input V_BAT, the drain of the MOS tube Q1 is connected with the gate of the MOS tube Q3, the source of the MOS tube Q3 is connected with the whole machine power input V_BAT, the drain of the MOS tube Q3 is connected with the power input terminal VCC_LED of the LED voltage division current limiting and switch control circuit, and the gate and the source of the MOS tube Q3 are connected with the resistor R155, and the gate of the MOS tube Q3 is further connected with the anode of the stabilizing tube D3 through the resistor R156.

2. The overvoltage protection LED light panel circuit for use on a camera head of claim 1, wherein, The LED voltage division current limiting and switch control circuit comprises one or more parallel LED lamp panels, each of the LED lamp panels comprises a MOS tube and at least one or more LED lamp beads connected in series, the anode of each of the LED lamp beads is provided with a current limiting resistor between the power input terminal VCC_LED, the cathode of each of the LED lamp beads is connected with the drain of the corresponding MOS tube, the gate of each of the MOS tubes is connected with the control level IR_LED, and the source of each of the MOS tubes is grounded.

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