Overcurrent protection circuit and LED module

Abstract

The utility model discloses an overcurrent protection circuit and an LED module, relates to the technical field of display, and provides the overcurrent protection circuit which consists of a power switch module, a detection switch module and a controller and is used for managing and controlling the overcurrent risk of the LED module in real time, the controller can collect the current value of the LED module in real time when the power switch module and the detection switch module are switched on and the power voltage at the power voltage end is transmitted to the LED module, and the controller can judge whether the LED module has an overcurrent risk or not at the moment according to the current value. And the conduction speed of the power switch module and the on-off state of the detection switch module are adjusted in real time according to the judgment result, so that the existing over-current risk is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an overcurrent protection circuit and an LED module. BACKGROUND

[0002] With the rapid development of display technology, LED (Light Emitting Diode) modules are increasingly widely used in various electronic devices. An LED module usually includes a display screen, a driving circuit, a connector, and related electronic components. In actual applications, an LED module needs to withstand the continuous change of current, especially under the trend of high-definition display and large-size screens, the current demand increases significantly.

[0003] However, the conventional LED module has certain overcurrent risk under long-time operation or specific working conditions, which can cause display abnormalities of the LED module, and even component damage, which is extremely detrimental to the safe use of the LED module. Therefore, there is an urgent need for a method capable of real-time management and control of the overcurrent risk of the LED module.

[0004] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. UTILITY MODEL CONTENT

[0005] The main purpose of the present application is to provide an overcurrent protection circuit and an LED module, aiming to solve the technical problem of the overcurrent risk of the current LED module.

[0006] To achieve the above-mentioned purpose, the present application provides an overcurrent protection circuit, which is provided with an LED module. The overcurrent protection circuit comprises:

[0007] A power switch module, an input end of the power switch module is connected with a power voltage end, and an output end of the power switch module is connected with a first end of the LED module;

[0008] The power switch module is used for connecting the power voltage on the power voltage end and transmitting the connected power voltage to the first port of the LED module;

[0009] A detection switch module, an input end of the detection switch module is connected with a second end of the LED module, and an output end of the detection switch module is connected with a ground end;

[0010] The detection switch module is used for controlling the first end of the LED module to be connected with the ground end when being in a conduction state, and the power voltage on the second end of the LED module transmitted via the power switch module is circulated in the LED module;

[0011] A controller, the controller is connected with a control end of the power switch module and a control end of the detection switch module, respectively.

[0012] The controller is configured to collect a current value of the power supply voltage when the power supply voltage flows through the LED module, and adjust a turn-on speed of the power supply switch module and detect a switch state of the switch module according to the current value.

[0013] In an embodiment, the controller is provided with a pulse signal output port.

[0014] The pulse signal output port is configured to output a pulse signal to control the turn-on speed of the power supply switch module.

[0015] In an embodiment, the power supply switch module is provided with a first analog switch.

[0016] The control end of the first analog switch is connected to the pulse signal output port, the input end of the first analog switch is connected to the power supply voltage end, and the output end of the first analog switch is connected to the first end of the LED module.

[0017] In an embodiment, the first analog switch comprises a first switch device.

[0018] The control end of the first switch device is connected to the pulse signal output port, the input end of the first switch device is connected to the power supply voltage end, and the output end of the first switch device is connected to the first end of the LED module.

[0019] In an embodiment, the controller is provided with an analog signal output end.

[0020] The analog signal output end is configured to output an analog signal corresponding to the current value on the LED module to control the switch state of the switch module.

[0021] In an embodiment, the switch module is provided with a second analog switch and a constant current circuit.

[0022] The first control end of the second analog switch is connected to the pulse signal output port, the second control end of the second analog switch is connected to the analog signal output end, and the output end of the second analog switch is connected to the control end of the constant current circuit.

[0023] The input end of the constant current circuit is connected to the second end of the LED module, and the output end of the constant current circuit is connected to the ground end.

[0024] In an embodiment, the second analog switch comprises a second switch device and a control device.

[0025] The control end of the second switch device is connected to the pulse signal output port, the input end of the second switch device is connected to the level recognition pin of the control device, and the output end of the second switch device is connected to the ground end.

[0026] The input end of the control device is connected with the analog signal output end, and the output pin of the control device is connected with the control end of the constant current circuit.

[0027] In an embodiment, the constant current circuit comprises an operational amplifier and a third switching device.

[0028] The non-inverting input end of the operational amplifier is connected with the output pin of the control device, and the output end of the operational amplifier is connected with the control end of the third switching device.

[0029] The input end of the third switching device is connected with the second end of the LED module, and the output end of the second switching device is connected with the ground end.

[0030] In an embodiment, the controller is further provided with an analog signal receiving port, and the detection switching module further comprises a current adjusting module.

[0031] The input end of the current adjusting module is connected with the output end of the constant current circuit, and the output end of the current adjusting module is connected with the analog signal receiving port.

[0032] In addition, to achieve the above object, the application further provides an LED module, which comprises the overcurrent protection circuit as described above.

[0033] The one or more technical solutions provided by the application have at least the following technical effects:

[0034] The application provides an overcurrent protection circuit, which comprises an LED module, and the overcurrent protection circuit comprises: a power switching module, the input end of the power switching module is connected with a power voltage end, and the output end of the power switching module is connected with a first end of the LED module; the power switching module is used for connecting the power voltage on the power voltage end and transmitting the connected power voltage to the first port of the LED module; a detection switching module, the input end of the detection switching module is connected with a second end of the LED module, and the output end of the detection switching module is connected with a ground end; the detection switching module is used for controlling the first end of the LED module to be connected with the ground end when being in a conduction state, and the power voltage on the second end of the LED module transmitted via the power switching module flows in the LED module; a controller, the controller is connected with the control end of the power switching module and the control end of the detection switching module respectively; and the controller is used for collecting a current value when the power voltage flows in the LED module, and adjusting the conduction speed of the power switching module and the switching state of the detection switching module according to the current value.

[0035] That is, the application provides an overcurrent protection circuit for real-time management and control of overcurrent risk of an LED module, which comprises a power switch module, a detection switch module and a controller, wherein the controller can collect the current value on the LED module when the power voltage on a power voltage terminal is transmitted to the LED module when the power switch module and the detection switch module are turned on, and the controller can determine whether overcurrent risk exists in the LED module according to the current value, so as to adjust the turn-on speed of the power switch module and the switching state of the detection switch module according to the determination result, so as to avoid the overcurrent risk. BRIEF DESCRIPTION OF DRAWINGS

[0036] The drawings incorporated in the specification and forming a part thereof illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0038] Figure 1 A module schematic diagram of the overcurrent protection circuit of the present application;

[0039] Figure 2 A detailed module structure schematic diagram of the overcurrent protection circuit of the present application;

[0040] Figure 3 A detailed circuit structure schematic diagram of the overcurrent protection circuit of the present application.

[0041] Explanation of reference numerals:

[0042] 10, power switch module; 101, first analog switch; Q1, first switching device;

[0043] 20, detection switch module; 201, second analog switch; 202, constant current circuit; Q2, second switching device; U1, control device; OP1, operational amplifier; Q3, third switching device;

[0044] MCU, controller; PWM, pulse signal output port; DAC, analog signal output terminal; ADC, analog signal receiving port;

[0045] R, resistor; C, capacitor; D, voltage stabilizing diode; Ro, voltage dividing resistor string; VCC, power voltage terminal.

[0046] The object implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0048] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0049] In addition, if the embodiments of the present application involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel solutions are included, for example, "A and / or B" includes A solution, or B solution, or A and B solutions are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person of ordinary skill in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection claimed by the present application.

[0050] Based on this, the present application provides an overcurrent protection circuit, referring to Figure 1 , Figure 1 is a schematic diagram of the modules of the overcurrent protection circuit of the present application.

[0051] The overcurrent protection circuit is provided with an LED module, and the overcurrent protection circuit comprises: a power switch module 10, an input end of the power switch module 10 is connected with a power voltage end VCC, and an output end of the power switch module 10 is connected with a first end of the LED module; the power switch module 10 is used for connecting the power voltage on the power voltage end VCC and transmitting the connected power voltage to the first port of the LED module.

[0052] The detection switch module 20 is connected with the second end of the LED module, and the output end of the detection switch module 20 is connected with the ground. When the detection switch module 20 is in the on state, the first end of the LED module is connected with the ground, and the power supply voltage on the second end of the LED module is circulated in the LED module through the power switch module 10.

[0053] The controller MCU is connected with the control end of the power switch module 10 and the control end of the detection switch module 20 respectively. The controller MCU is used for collecting the current value of the power supply voltage circulating in the LED module, and adjusting the on speed of the power switch module 10 and the switching state of the detection switch module 20 according to the current value.

[0054] The overcurrent protection circuit comprises the power switch module 10, the detection switch module 20 and the controller MCU. Figure 1 It can be seen that the overcurrent protection circuit comprises the power switch module 10, the detection switch module 20 and the controller MCU.

[0055] Specifically, when the power switch module 10 is in the on state, the power supply voltage at the power supply voltage end VCC flows into the first port of the LED module through the on power switch module 10. In order to ensure that the driving current can be generated in the LED module, the power supply current corresponding to the power supply voltage at the first port of the LED module needs to flow into the second port of the LED module. Therefore, the detection switch module 20 connected with the second port of the LED module needs to be controlled to enter the on state at this time. At this time, the power supply current at the first port of the LED module flows to the second port of the LED module, and then flows into the ground through the on detection switch module 20 from the second port, so as to realize the loop closure between the power supply voltage end VCC and the ground, and make the power supply current flow in the LED module, and the flowing direction is the first end of the LED module→the second end of the LED module.

[0056] Because the controller MCU is connected with the power switch module 10 and the detection switch module 20 respectively, when the power switch module 10 and the detection switch module 20 are both on, and the driving current exists in the LED module to display the state, the controller MCU can obtain the current value of the driving current in the LED module through the detection switch module 20 at this time, and judge whether there is an overcurrent risk in the LED module according to the current value. According to the judgment result of whether there is an overcurrent risk, the on speed of the power switch module 10 is dynamically adjusted, so as to dynamically reduce the current value of the power supply current transmitted to the LED module, avoid the overcurrent phenomenon of the LED module caused by the too large power supply current, and dynamically adjust the switching state of the detection switch module 20, so as to cut off the on loop of the LED module, and avoid the overcurrent phenomenon caused by the continuous large current in the LED module, so as to cause the display abnormality and the component damage.

[0057] For the convenience of illustration, the module structure of the overcurrent protection circuit is described in combination with Figure 2 the drawing.

[0058] The controller MCU is provided with a pulse signal output port PWM, which is used to output a pulse signal to control the conduction speed of the power switch module 10.

[0059] The power switch module 10 is provided with a first analog switch 101, the control end of which is connected with the pulse signal output port PWM, the input end of which is connected with the power voltage end VCC, and the output end of which is connected with the first end of the LED module.

[0060] That is, in a feasible implementation structure, the power switch module 10 proposed in the embodiment can be provided with the first analog switch 101. Among them, the first analog switch 101 is connected between the pulse signal output port PWM and the LED module, which is used to adjust the conduction speed according to the input pulse signal, and the power current input from the power voltage end VCC is transmitted into the LED module according to the conduction speed, so as to avoid the rapid flow of the power current into the LED module, thereby causing the overcurrent risk of the LED module.

[0061] Meanwhile, the controller MCU is provided with an analog signal output end DAC, which is used to output an analog signal corresponding to the current value on the LED module, and control the switching state of the detection switch module 20.

[0062] The detection switch module 20 is provided with a second analog switch 201 and a constant current circuit 202; the first control end of the second analog switch 201 is connected with the pulse signal output port PWM, the second control end of the second analog switch 201 is connected with the analog signal output end DAC, and the output end of the second analog switch 201 is connected with the control end of the constant current circuit 202; the input end of the constant current circuit 202 is connected with the second end of the LED module, and the output end of the constant current circuit 202 is connected with the ground end.

[0063] In a feasible implementation structure, the detection switch module 20 proposed in this embodiment may include a second analog switch 201 and a constant current circuit 202. The second analog switch 201 is connected between the PWM output port of the controller MCU and the constant current circuit 202, and between the analog signal output port DAC and the constant current circuit 202. It is used to switch on and off according to the level of the input pulse signal. In the on state, it transmits the analog signal to the constant current circuit 202. The constant current circuit 202 is connected between the second analog switch 201 and the second terminal of the LED module to ensure that the current of the analog signal remains constant, providing a reliable power current output to the load. In the off state, it cuts off the analog signal transmitted to the constant current circuit 202, thus preventing the LED module from being connected to ground. That is, the LED module cannot normally receive the power current through the first analog switch 101. This cuts off the power current flowing into the LED module in the event of an overcurrent risk, thereby avoiding the potential overcurrent risk.

[0064] Specifically, the similar circuit structures of the first analog switch 101, the second analog switch 201, and the constant current circuit 202 can be as follows: Figure 3 The circuit structure shown is shown.

[0065] (1) When the pulse signal output by the PWM output port of the controller MCU is at a high level, both the first switching device Q1 in the first analog switch 101 and the second switching device Q2 in the second analog switch 201 are in the on state. The on first switching device Q1 is connected to the power supply current on the power supply voltage terminal VCC, and the power supply current is transmitted to the first terminal of the LED module. At the same time, the second switching device Q2 in the second analog switch 201 is on, and the connected pulse signal is transmitted to the controller U1 in the second analog switch 201. The level recognition pin of the controller U1 (i.e. Figure 3 The S pin of the controller U1, based on the high-level pulse signal received, controls the input terminal (i.e., the input of the controller U1) Figure 3 An analog signal is input to pin B2 of the control device U1 and passed to the operational amplifier OP1 in the constant current circuit. Operational amplifier OP1 compares the current value corresponding to the analog signal with a preset current value. If the current value is lower than the preset current value, it outputs a low level, and the third switching device Q3 in the constant current circuit 202 turns on, connecting the LED module to ground. This allows the power supply current at the first port of the LED module to flow to the second port, enabling the LED module to enter normal display mode. The preset current value is the maximum current that the LED module can withstand.

[0066] It should be noted that, because the detection switch module 20 is also provided with a signal conditioning circuit and a sampling resistor Ro as shown in Figure 2 and Figure 3 , the current amplitude signal S1 of the analog signal is mainly sampled by the sampling resistor Ro and converted into a corresponding voltage signal V1, and then the voltage signal V1 is output to the analog signal receiving port ADC of the controller MCU through the signal conditioning circuit, realizing real-time monitoring of the current intensity of the analog signal, and according to the monitoring result, the controller MCU adjusts the voltage value of the output analog signal in real time, so that it can reflect the current value flowing in the LED module in real time. At the same time, the controller MCU can also adjust the output frequency and duty cycle of the output pulse signal according to the input voltage signal V1, so that it can better meet the demand of the current value of the LED module, and when it is judged by the voltage signal V1 that there is an overcurrent risk in the LED module, the output frequency and duty cycle of the pulse signal are adjusted to reduce the conduction speed of the first switching device Q1 or change the conduction state of the first switching device Q1 and the second switching device Q2 to the off state, so as to cut off the power current flowing into the LED module, thereby avoiding the overcurrent risk.

[0067] Specifically, the sampling resistor Ro in the embodiment can be as shown in the voltage dividing resistor string Ro in Figure 3 , because of the operational amplifier OP1, the operational amplifier OP1 will control the current flowing through the two resistors in the voltage dividing resistor string Ro by adjusting the voltage at the output end. The current flowing through the voltage dividing resistor string Ro is equal to the voltage of the first analog signal divided by the resistance R in the voltage dividing resistor string Ro, so the controller MCU can calculate the current intensity flowing into the LED module at this time according to the current of the voltage dividing resistor string Ro reflected by the input voltage signal and the resistance R in the voltage dividing resistor string Ro, and then judge whether there is an overcurrent phenomenon in the LED module at this time.

[0068] (2) When the level state of the pulse signal output by the pulse signal output port PWM of the controller MCU is low, the first switching device Q1 in the first analog switch 101 and the second switching device Q2 in the second analog switch 201 are both in the off state. The first switching device Q1 in the off state does not access the power current on the power voltage end VCC, and the second switching device Q2 in the second analog switch 201 is off, and the input pulse signal does not access, so that the level recognition pin of the controller device U1 cannot receive any pulse signal. At this time, the output pin of the controller device U1 is connected to another input end (i.e. B1 in Figure 3 ), and this section is connected to the ground pin (i.e. GND in Figure 3The controller U1 is grounded through the GND pin of the controller U1), the controller U1 is in the off state, and thus no voltage is input to the non-inverting input terminal of the operational amplifier OP1 in the constant current circuit 202, and the operational amplifier OP1 cannot perform comparison and amplification, and thus the third switching device Q3 has no effect on the control terminal of the third switching device Q3, and the third switching device Q3 is in the off state, and thus the second end of the LED module cannot be connected to the ground, and the LED module is in the shutdown state.

[0069] It should be noted that the resistor R in the first analog switch 101 is used to stabilize the control of the first switching device Q1, the resistor connected to the control terminal of the second switching device Q2 is used for voltage reduction, the capacitor connected to the power input terminal of the controller U1 (i.e. Figure 3 The resistor R and the capacitor C connected between the output terminal and the non-inverting input terminal of the operational amplifier OP1 are used for filtering, the operational amplifier OP1 further includes a positive power terminal for providing a 5V positive power supply to the operational amplifier OP1, and the capacitor C connected to the positive power terminal is mainly used for voltage reduction, the resistor R connected between the output terminal of the operational amplifier OP1 and the control terminal of the third switching device Q3 is used for voltage reduction to prevent the output voltage from being too large to damage the control terminal, and further, in order to protect the operational amplifier OP1, a zener diode D is connected to the inverting input terminal of the operational amplifier OP1 for stabilizing the positive power supply and ensuring the working stability and precision of the operational amplifier OP1, and a resistor R is further connected between the inverting input terminal of the operational amplifier OP1 and the output terminal of the third switching device Q3 to prevent self-oscillation and provide a stable bias current.

[0070] The embodiment of the present application further provides an LED module, which comprises the overcurrent protection circuit.

[0071] It can be understood that, since the overcurrent protection circuit is used in the LED module, the embodiment of the LED module comprises all the technical solutions of all the embodiments of the overcurrent protection circuit, and the same technical effects are achieved, and thus no further description is given herein.

[0072] The above only describes some embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made according to the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. An overcurrent protection circuit, characterized by comprising: The overcurrent protection circuit is provided with an LED module, and the overcurrent protection circuit comprises: a power switch module, an input end of the power switch module being connected with a power voltage end, and an output end of the power switch module being connected with a first end of the LED module; the power switch module is used for connecting with a power voltage on the power voltage end and transmitting the connected power voltage to a first port of the LED module; a detection switch module, an input end of the detection switch module being connected with a second end of the LED module, and an output end of the detection switch module being connected with a ground end; the detection switch module is used for controlling the first end of the LED module to be connected with the ground end when being in a conduction state, and a power voltage on the second end of the LED module transmitted via the power switch module to flow in the LED module; a controller, the controller being connected with a control end of the power switch module and a control end of the detection switch module respectively; the controller is used for collecting a current value when the power voltage flows on the LED module and adjusting a conduction speed of the power switch module and a switch state of the detection switch module according to the current value.

2. The overcurrent protection circuit of claim 1, wherein, the controller is provided with a pulse signal output port; the pulse signal output port is used for outputting a pulse signal to control the conduction speed of the power switch module.

3. The overcurrent protection circuit of claim 2, wherein, the power switch module is provided with a first analog switch; a control end of the first analog switch is connected with the pulse signal output port, an input end of the first analog switch is connected with the power voltage end, and an output end of the first analog switch is connected with the first end of the LED module.

4. The overcurrent protection circuit of claim 3, wherein, the first analog switch comprises a first switch device; a control end of the first switch device is connected with the pulse signal output port, an input end of the first switch device is connected with the power voltage end, and an output end of the first switch device is connected with the first end of the LED module.

5. The overcurrent protection circuit of claim 4, wherein, the controller is provided with an analog signal output end; the analog signal output end is used for outputting an analog signal corresponding to the current value on the LED module to control the switch state of the detection switch module.

6. The overcurrent protection circuit of claim 5, wherein, the detection switch module is provided with a second analog switch and a constant current circuit; a first control end of the second analog switch is connected with the pulse signal output port, a second control end of the second analog switch is connected with the analog signal output end, and an output end of the second analog switch is connected with a control end of the constant current circuit; an input end of the constant current circuit is connected with the second end of the LED module, and an output end of the constant current circuit is connected with the ground end.

7. The overcurrent protection circuit of claim 6, wherein, the second analog switch comprises a second switch device and a control device; a control end of the second switch device is connected with the pulse signal output port, an input end of the second switch device is connected with a level identification pin of the control device, and an output end of the second switch device is connected with a ground end; an input end of the control device is connected with the analog signal output end, and an output pin of the control device is connected with the control end of the constant current circuit.

8. The overcurrent protection circuit of claim 7, wherein, the constant current circuit comprises an operational amplifier and a third switch device; The non-inverting input terminal of the operational amplifier is connected with the output pin of the control device, and the output terminal of the operational amplifier is connected with the control terminal of the third switch device; The input terminal of the third switch device is connected with the second end of the LED module, and the output terminal of the second switch device is connected with the ground.

9. The overcurrent protection circuit of claim 8, wherein, The controller is further provided with an analog signal receiving port, and the detection switch module further comprises a current adjusting module. The input terminal of the current adjusting module is connected with the output terminal of the constant current circuit, and the output terminal of the current adjusting module is connected with the analog signal receiving port.

10. An LED module, characterized in that The LED module comprises the overcurrent protection circuit according to any one of claims 1 to 9.

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