LED system and power supply protection circuit

Abstract

The utility model provides an LED system and a power supply protection circuit. The circuit is characterized in that the output end of a power supply module is connected with the input end of electric equipment through a sampling resistor and a switch unit in sequence; the current detection module collects an electric signal of the sampling resistor and outputs the signal to the first end of the driving control module; the second end of the driving control module is connected with the electric equipment; the driving control module controls the working state of the switch unit; when over-current or short-circuit grounding occurs and a power supply is short-circuited or over-voltage occurs, the switch unit is controlled to be in a turn-off state, and the connection between the power supply module and the electric equipment is cut off, namely, the problem of over-voltage and over-current caused by misplug of a plug-in and the electric equipment is solved. A pure hardware power supply protection circuit is used for protecting the power supply module and the electric equipment, so that the response speed is high; the circuit does not need to consider the range of input and output voltage and current, can set a protection threshold by setting a resistance value and the like, and is wide in application range, simple in current detection mode and low in cost.

Description

Technical Field

[0001] This utility model belongs to the field of power electronics technology, and more specifically, it relates to an LED system and a power supply protection circuit. Background Technology

[0002] With the development of technology, the need for LED (Light Emitting Diode) technology is increasing in various fields, such as its growing application in automotive lighting systems. As the number of LEDs increases, LED systems become more complex, making the circuitry that powers them particularly important. A DC / DC (Direct Current to Direct Current) chip can be used to power the LED modules, converting the 12V or 24V from the vehicle battery to 5V for output to the LED modules.

[0003] Since LED modules are connected to the DC / DC chip's power supply circuit by operators, manual operation is prone to errors, such as reversed connectors, short circuits to the power supply, or short circuits to ground, which can lead to damage to the DC / DC chip or LED module. Therefore, protection circuits are needed to protect the DC / DC chip and LED module. A high-side driver chip can be added between the DC / DC chip and LED module for protection, but the different input and output voltages and currents of the circuit make the selection of the high-side driver chip difficult, limiting its application and increasing its cost. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide an LED system and power supply protection circuit that can be used to set protection thresholds by setting resistance values ​​without considering the range of input and output voltage and current. It has a wide range of applications, simple current detection method, and low cost.

[0005] The first aspect of this application discloses a power supply protection circuit, which is disposed between a power supply module and an electrical device. The power supply protection circuit includes: a current detection module, a sampling resistor, a drive control module, and a switching unit.

[0006] One end of the input terminal of the current detection module is connected to one end of the sampling resistor, and the connection point is connected to the output terminal of the power supply module.

[0007] The other end of the input terminal of the current detection module is connected to the other end of the sampling resistor, the first end of the drive control module, and the input terminal of the switching unit, respectively.

[0008] The output terminal of the current detection module is connected to the second terminal of the drive control module;

[0009] The output terminal of the drive control module is connected to the control terminal of the switch unit;

[0010] The output terminal of the switching unit is connected to the third terminal of the drive control module and the positive terminal of the input terminal of the electrical equipment, respectively.

[0011] Optionally, the current detection module includes: a current monitoring chip and a first voltage divider unit;

[0012] The two ends of the current monitoring chip serve as the two ends of the current detection module, respectively.

[0013] The output terminal of the current monitoring chip is connected to the first terminal of the first voltage divider unit;

[0014] The second terminal of the first voltage divider unit is grounded;

[0015] The output terminal of the first voltage divider unit serves as the output terminal of the current detection module.

[0016] Optionally, the first voltage divider unit includes: a first voltage divider resistor and a second voltage divider resistor;

[0017] One end of the first voltage divider resistor serves as the first end of the first voltage divider unit;

[0018] The other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor, and the connection point serves as the output terminal of the first voltage divider unit.

[0019] The other end of the second voltage divider resistor serves as the second end of the first voltage divider unit.

[0020] Optionally, the switching unit includes: a first switching transistor, a second switching transistor, and a second resistor;

[0021] The first terminal of the first switching transistor serves as the input terminal of the switching unit;

[0022] The second terminal of the first switching transistor is connected to the second terminal of the second switching transistor and the first terminal of the second resistor, respectively.

[0023] The first terminal of the second switching transistor serves as the output terminal of the switching unit;

[0024] The control terminal of the first switching transistor is connected to the control terminal of the second switching transistor and the other end of the second resistor, and the connection point serves as the control terminal of the switching unit.

[0025] Optionally, the drive control module includes: a drive unit, a freewheeling unit, and a second voltage divider unit;

[0026] The output terminal of the drive unit serves as the output terminal of the drive control module.

[0027] The control terminal of the drive unit is connected to the output terminal of the freewheeling unit;

[0028] The positive input terminal of the drive unit serves as the first terminal of the drive control module.

[0029] The first input terminal of the freewheeling unit serves as the second terminal of the drive control module;

[0030] The second input terminal of the freewheeling unit is connected to the output terminal of the second voltage divider unit;

[0031] The first terminal of the second voltage divider unit serves as the third terminal of the drive control module;

[0032] The negative terminal of the input of the driving unit and the second terminal of the second voltage divider unit are both grounded.

[0033] Optionally, the driving unit includes: a pull-up resistor, a fourth resistor, a third switch, a fourth switch, and a pull-down resistor;

[0034] The first terminal of the third switch is connected to one terminal of the fourth resistor;

[0035] The control terminal of the third switch is connected to one end of the pull-up resistor and the first end of the fourth switch, respectively.

[0036] The control terminal of the fourth switch is connected to one end of the pull-down resistor, and the connection point serves as the control terminal of the drive unit.

[0037] The second terminal of the third switch, the second terminal of the fourth switch, and the other terminal of the pull-down resistor are grounded;

[0038] The other end of the fourth resistor serves as the output terminal of the driving unit.

[0039] The other end of the pull-up resistor is connected to the common terminal of the switching unit and the sampling resistor.

[0040] Optionally, the freewheeling unit includes: a first diode and a second diode;

[0041] The anode of the first diode serves as the first input terminal of the freewheeling unit;

[0042] The anode of the second diode serves as the second input terminal of the freewheeling unit;

[0043] The cathodes of the first diode and the second diode are connected, and the connection point serves as the output terminal of the freewheeling unit.

[0044] Optionally, the second voltage divider unit includes: a third voltage divider resistor and a fourth voltage divider resistor;

[0045] One end of the third voltage divider resistor serves as the first end of the second voltage divider unit;

[0046] The other end of the third voltage divider resistor is connected to one end of the fourth voltage divider resistor, and the connection point serves as the output terminal of the second voltage divider unit.

[0047] The other end of the fourth voltage divider resistor serves as the second end of the second voltage divider unit.

[0048] Optionally, it may also include: an ADC acquisition module connected to the output terminal of the current detection module, and / or a control module connected to the control terminal of the drive control module.

[0049] The second aspect of this application discloses an LED system, including: a power module, an LED module, and a power supply protection circuit as described in any of the first aspects of this application;

[0050] The power supply protection circuit is located between the power supply module and the LED module.

[0051] As can be seen from the above technical solution, the power supply protection circuit provided by this utility model is set between the power supply module and the electrical equipment, including: the output terminal of the power supply module is connected to the input terminal of the electrical equipment in sequence through a sampling resistor and a switching unit; the current detection module collects the electrical signal of the sampling resistor and outputs the signal to the first terminal of the drive control module; the second terminal of the drive control module is connected to the electrical equipment; the drive control module controls the working state of the switching unit; and when an overcurrent or short grounding occurs on the power supply module side, or when a short circuit or overvoltage occurs on the electrical equipment side, the control switch unit is in the off state, disconnecting the connection between the power supply module and the electrical equipment. That is, for problems such as incorrect plug-in insertion and overvoltage and overcurrent caused by the electrical equipment itself, the power supply protection circuit protects the power supply module and the electrical equipment without software intervention. The pure hardware circuit has a fast response speed. This circuit does not need to consider the range of input and output voltage and current. The protection threshold can be set by setting the resistance value, etc. It has a wide range of applications, a simple current detection method, and low cost. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of a power supply protection circuit provided in an embodiment of the present utility model;

[0054] Figure 2 This is a schematic diagram of another power supply protection circuit provided in an embodiment of the present utility model;

[0055] Figure 3 This is a schematic diagram of another power supply protection circuit provided in an embodiment of the present utility model;

[0056] Figure 4 This is a schematic diagram of another power supply protection circuit provided in an embodiment of the present utility model;

[0057] Figure 5 This is a schematic diagram of another power supply protection circuit provided in an embodiment of the present utility model;

[0058] Figure 6 This is a schematic diagram of another power supply protection circuit provided in an embodiment of the present utility model;

[0059] Figure 7 This is a schematic diagram of another power supply protection circuit provided in an embodiment of this utility model. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0061] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Furthermore, the terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data used can be interchanged where appropriate so that embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0062] This application provides a power supply protection circuit to solve the problem in the prior art where the input and output voltages and currents of the circuits are different, which makes it difficult to select high-side driver chips, limits the application conditions, and results in high costs.

[0063] like Figure 1 As shown, the power supply protection circuit is located between the power supply module and the electrical equipment.

[0064] Specifically, the power supply protection circuit's power supply terminal is connected to the output terminal of the power module; the device terminal of the power supply protection circuit is connected to the power interface of the electrical equipment.

[0065] The power supply protection circuit can be integrated with the power module as a power supply device; of course, the power supply protection circuit can also be integrated with the electrical equipment as an electrical device; the power supply protection circuit can also be used independently. No specific limitation is made here, depending on the actual situation, and all of these are within the protection scope of this application.

[0066] The electrical equipment can be connected to the power module via the power supply protection circuit in the form of a plug-in, or other forms, which will not be elaborated here. It depends on the actual situation and is all within the protection scope of this application.

[0067] The power module can be a DC / DC module, which may include at least one DC / DC chip; the power module can be integrated on the motherboard, for example, the power module is an onboard DC / DC module, or the power module can be set independently. These will not be elaborated here, and can be determined according to the actual situation, all of which are within the protection scope of this application.

[0068] This application can be applied to the automotive field, that is, the power module can convert the 12V / 24V of the vehicle battery to 5V and output it to the LED module in the vehicle through the power supply protection circuit.

[0069] See Figure 2 The power supply protection circuit includes: a current detection module 10, a sampling resistor R1, a drive control module 30, and a switching unit 20.

[0070] This power supply protection circuit can be a purely hardware circuit.

[0071] One end of the input terminal of the current detection module 10 is connected to one end of the sampling resistor R1, and the connection point is connected to the output terminal of the power supply module.

[0072] In other words, the input terminal of the current detection module 10, the sampling resistor R1, and the output terminal of the power supply module are connected; the sampling resistor R1 receives the voltage output by the power supply module.

[0073] The other end of the input terminal of the current detection module 10 is connected to the other end of the sampling resistor R1, the first end of the drive control module 30, and the input terminal of the switching unit 20, respectively.

[0074] The current detection module 10 can detect the current of the sampling resistor R1. Specifically, the current of the sampling resistor R1 can be detected by a current sensor. In addition, since I=U / R, the resistance value of the sampling resistor R1 is determined, so voltage acquisition can also be used to detect the current of the sampling resistor R1.

[0075] The output terminal of the current detection module 10 is connected to the second terminal of the drive control module 30.

[0076] In other words, the drive control module 30 can receive the output signal of the current detection module 10 and then perform corresponding actions based on the output signal of the current detection module 10.

[0077] The output terminal of the drive control module 30 is connected to the control terminal of the switch unit 20.

[0078] Specifically, when the current detected by the current detection module 10 is greater than the threshold, the signal output by the current detection unit causes the drive control module 30 to control the switch unit 20 to turn off, thereby disconnecting the power module and the electrical equipment to avoid overvoltage and overcurrent damage to the power module and the electrical equipment.

[0079] The output terminal of the switching unit 20 is connected to the third terminal of the drive control module 30 and the positive terminal of the input terminal of the electrical equipment, respectively.

[0080] Current flows from the output of the power module, through the sampling resistor R1 and the switching unit 20, to the electrical equipment.

[0081] In other words, the working state of the switch unit 20 can affect the power supply status of the electrical equipment. Specifically, when the switch unit 20 is in the closed state, the power of the power module can be transmitted to the electrical equipment through the sampling resistor R1 and the switch unit 20. When the switch unit 20 is in the off state, the power supply is prohibited from being transmitted to the electrical equipment.

[0082] When a short grounding GND or overcurrent occurs, the drive control module 30 will receive the short grounding GND or overcurrent signal through its first terminal, and then control the switch unit 20 to be in the off state, thereby protecting the power module and electrical equipment.

[0083] When a short circuit or overvoltage occurs, the drive control module 30 will receive the short circuit or overvoltage signal through its third terminal, and then control the switch unit 20 to be in the off state, thereby protecting the power module and the electrical equipment.

[0084] In this embodiment, in the power supply protection circuit located between the power supply module and the electrical device, the output terminal of the power supply module is connected to the input terminal of the electrical device in sequence through a sampling resistor R1 and a switching unit 20; the current detection module 10 collects the electrical signal of the sampling resistor R1 and outputs the signal to the first terminal of the drive control module 30; the second terminal of the drive control module 30 is connected to the electrical device; the drive control module 30 controls the working state of the switching unit 20; and when an overcurrent or short-circuit grounding GND occurs on the power supply module side, or when a short circuit or overvoltage occurs on the electrical device side, the switch unit 20 is controlled to be in the off state, disconnecting the connection between the power supply module and the electrical device. That is, for problems such as incorrect plug-in insertion and overvoltage and overcurrent caused by the electrical device itself, the power supply protection circuit protects the power supply module and the electrical device without software intervention. The pure hardware circuit has a fast response speed. This circuit does not need to consider the range of input and output voltage and current. The protection threshold can be set by setting the resistance value, etc. The current detection method is simple and low cost.

[0085] Optional, see Figure 3 The current detection module 10 includes a current monitoring chip 11 and a first voltage divider unit 12.

[0086] The two ends of the input terminal of the current monitoring chip 11 serve as the two ends of the input terminal of the current detection module 10.

[0087] Specifically, one end of the input terminal of the current monitoring chip 11 is connected to one end of the sampling resistor R1 and one end of the power supply module; the other end of the input terminal of the current monitoring chip 11 is connected to the other end of the sampling resistor R1, the first end of the drive control module 30 and the input terminal of the switching unit 20.

[0088] The output terminal of the current monitoring chip 11 is connected to the first terminal of the first voltage divider unit 12.

[0089] The current monitoring chip 11 can be an INA186-Q1, which amplifies the voltage difference by 25 times. If the sampling resistor R1 is 8mΩ, the output voltage of the power module is 5V, and the operating current of the electrical equipment is 5A, according to Ohm's law, the voltage drop across the sampling resistor R1 is 0.008Ω x 5A = 0.04V. After the current monitoring chip amplifies the voltage by 25 times, the output Vout = 0.04V x 25 = 1V.

[0090] The second terminal of the first voltage divider unit 12 is grounded to GND.

[0091] The output terminal of the first voltage divider unit 12 serves as the output terminal of the current detection module 10 and is connected to the second terminal of the drive control module 30.

[0092] Optional, see Figure 4The first voltage divider unit 12 includes: a first voltage divider resistor R6 and a second voltage divider resistor R7.

[0093] One end of the first voltage divider resistor R6 serves as the first end of the first voltage divider unit 12 and is connected to the output terminal of the current monitoring chip 11.

[0094] The other end of the first voltage divider resistor R6 is connected to one end of the second voltage divider resistor R7, and the connection point serves as the output terminal of the first voltage divider unit 12.

[0095] Specifically, the common terminal of the first voltage divider resistor R6 and the second voltage divider resistor R7 is connected to the second terminal of the drive control module 30.

[0096] The other end of the second voltage divider resistor R7 serves as the second end of the first voltage divider unit 12, that is, the other end of the second voltage divider resistor R7 is grounded to GND.

[0097] Optional, see Figure 5 The drive control module 30 includes: a drive unit 31, a freewheeling unit 32, and a second voltage divider unit 33.

[0098] The output terminal of the drive unit 31 serves as the output terminal of the drive control module 30 and is connected to the control terminal of the switch unit 20.

[0099] The control terminal of the drive unit 31 is connected to the output terminal of the freewheeling unit 32; specifically, the drive unit 31 combines the control signal of the freewheeling unit 32 and controls the switching unit 20 to turn on and off according to the control signal.

[0100] The positive input terminal of the drive unit 31 serves as the first terminal of the drive control module 30 and is connected to the other end of the sampling resistor R1, the other end of the input terminal of the current monitoring chip 11 in the current detection module 10, and the input terminal of the switch unit 20.

[0101] The first input terminal of the freewheeling unit 32 serves as the second terminal of the drive control module 30 and is connected to the output terminal of the current detection module 10. Specifically, the first input terminal of the freewheeling unit 32 is connected to the common terminal of the first voltage divider resistor R6 and the second voltage divider resistor R7 in the current detection module 10.

[0102] The second input terminal of the freewheeling unit 32 is connected to the output terminal of the second voltage divider unit 33.

[0103] The first end of the second voltage divider unit 33 serves as the third end of the drive control module 30, and is connected to the output end of the switch unit 20 and the input end of the electrical equipment, respectively.

[0104] The second voltage divider unit 33 transmits the voltage at the input terminal of the electrical equipment to the drive unit 31 through the freewheeling unit 32, thereby enabling the drive unit 31 to control the switching unit 20 on and off according to the situation on the side of the electrical equipment.

[0105] The negative terminal of the input of the drive unit 31 and the second terminal of the second voltage divider unit 33 are both grounded to GND.

[0106] Optional, see Figure 6 The drive unit 31 includes: a pull-up resistor R3, a fourth resistor R4, a third switch Q3, a fourth switch Q4, and a pull-down resistor R8.

[0107] The first terminal of the third switch Q3 is connected to one terminal of the fourth resistor R4.

[0108] The control terminal of the third switch Q3 is connected to one end of the pull-up resistor R3 and the first end of the fourth switch Q4.

[0109] The control terminal of the fourth switch Q4 is connected to one end of the pull-down resistor R8. The connection point serves as the control terminal of the drive unit 31 and is connected to the output terminal of the freewheeling unit 32.

[0110] The second terminal of the third switch Q3, the second terminal of the fourth switch Q4, and the other terminal of the pull-down resistor R8 are grounded to GND.

[0111] The second terminal of the third switch Q3, the second terminal of the fourth switch Q4, and the other terminal of the pull-down resistor R8 are connected, and the connection point serves as the negative terminal of the input of the drive unit 31 and ground GND.

[0112] The other end of the fourth resistor R4 serves as the output terminal of the drive unit 31 and is connected to the control terminal of the switch unit 20.

[0113] The function of the fourth resistor R4 is to limit the current flowing through the collector and emitter of the third switch Q3.

[0114] The other end of the pull-up resistor R3 serves as the input terminal of the drive unit 31 and is connected to the common terminal of the switch unit 20 and the sampling resistor R1.

[0115] The third switch Q3 and the fourth switch Q4 can be transistors.

[0116] Optional, see Figure 6 The freewheeling unit 32 includes: a first diode D1 and a second diode D2.

[0117] The anode of the first diode D1 serves as the first input terminal of the freewheeling unit 32 and is connected to the output terminal of the current detection module 10. Specifically, the anode of the first diode D1 is connected to the output terminal of the first voltage divider unit 12 in the current detection module 10. More specifically, the anode of the first diode D1 is connected to the common terminal of the first voltage divider resistor R6 and the second voltage divider resistor R7 in the first voltage divider unit 12.

[0118] The anode of the second diode D2 serves as the second input terminal of the freewheeling unit 32 and is connected to the output terminal of the second voltage divider unit 33. Specifically, the anode of the second diode D2 is connected to the common terminal of the third voltage divider resistor R9 and the fourth voltage divider resistor R10 in the second voltage divider unit 33.

[0119] The cathodes of the first diode D1 and the second diode D2 are connected, and the connection point serves as the output terminal of the freewheeling unit 32 and is connected to the control terminal of the driving unit 31.

[0120] Specifically, the connection point between the cathode of the first diode D1 and the cathode of the second diode D2 is connected to the control terminal of the fourth switch Q4 in the drive unit 31.

[0121] The first diode D1 and the second diode D2 can be Schottky diodes.

[0122] Optional, see Figure 6 The second voltage divider unit 33 includes a third voltage divider resistor R9 and a fourth voltage divider resistor R10.

[0123] One end of the third voltage divider resistor R9 serves as the first end of the second voltage divider unit 33, and is connected to the output end of the switch unit 20 and the input end of the electrical equipment, respectively.

[0124] The other end of the third voltage divider resistor R9 is connected to one end of the fourth voltage divider resistor R10. The connection point serves as the output terminal of the second voltage divider unit 33 and is connected to the second input terminal of the freewheeling unit 32.

[0125] Specifically, the common terminal of the third voltage divider resistor R9 and the fourth voltage divider resistor R10 is connected to the anode of the second diode D2 in the freewheeling unit 32.

[0126] The other end of the fourth voltage divider resistor R10 serves as the second end of the second voltage divider unit 33.

[0127] Specifically, the other end of the fourth voltage divider resistor R10 is grounded to GND.

[0128] Under normal circumstances, the fourth switch Q4 operates in the off state with the help of the pull-down resistor R8, and the third switch Q3 operates in the on state with the help of the pull-up resistor R3. The NPN transistor is turned on when VBE>0, the field-effect transistor in the switching unit 20 is turned on, and the PMOS transistor is turned on when VGS<0, so the power module can supply power to the equipment normally.

[0129] When a short grounding GND or overcurrent occurs, the voltage division of the first voltage divider resistor R6 and the second voltage divider resistor R7 will cause the first diode D1 to conduct, which in turn will cause the fourth switch Q4 to conduct and the third switch Q3 to turn off. The switches in the switching unit 20 will then turn off, disconnecting the power module and the electrical equipment, thus protecting the power module and the electrical equipment.

[0130] When a short circuit or overvoltage occurs, the voltage division of the third voltage divider resistor R9 and the fourth voltage divider resistor R10 will cause the second diode D2 to conduct, which in turn will cause the fourth switch Q4 to conduct, while the third switch Q3 will be cut off. The switch in the switching unit 20 will be cut off, disconnecting the power module from the electrical equipment and protecting the power module and the electrical equipment.

[0131] Optional, see Figure 6 The switching unit 20 includes: a first switching transistor Q1, a second switching transistor Q2, and a second resistor R2.

[0132] The first terminal of the first switching transistor Q1 serves as the input terminal of the switching unit 20 and is connected to one terminal of the sampling resistor R1, one terminal of the current detection module 10, and the first terminal of the drive control module 30, respectively.

[0133] Specifically, the first terminal of the first switch Q1 is connected to one end of the sampling resistor R1, one end of the input terminal of the current monitoring chip 11 in the current detection module 10, and one end of the pull-up resistor R3 in the drive control module 30.

[0134] The second terminal of the first switch Q1 is connected to the second terminal of the second switch Q2 and the first terminal of the second resistor R2.

[0135] The first terminal of the second switching transistor Q2 serves as the output terminal of the switching unit 20, and is connected to the third terminal of the drive control module 30 and the input terminal of the electrical equipment, respectively.

[0136] Specifically, the first terminal of the second switch Q2 is connected to the first terminal of the second voltage divider unit 33 in the drive control module 30 and the input terminal of the electrical device. More specifically, the first terminal of the second switch Q2 is connected to one terminal of the third voltage divider resistor R9 in the second voltage divider unit 33 and the input terminal of the electrical device.

[0137] The control terminal of the first switch Q1 is connected to the control terminal of the second switch Q2 and the other end of the second resistor R2, respectively. The connection point serves as the control terminal of the switch unit 20 and is connected to the output terminal of the drive control module 30.

[0138] Specifically, the control terminals of the first switch Q1, the second switch Q2, and the other end of the second resistor R2 are all connected to the output terminal of the drive unit 31 in the drive control module 30; more specifically, the control terminals of the first switch Q1, the second switch Q2, and the other end of the second resistor R2 are all connected to one end of the fourth resistor R4 in the drive unit 31.

[0139] The function of the second resistor R2 is to stably turn off the first switch Q1 and the second switch Q2 when the third switch Q3 is turned off.

[0140] The first switch Q1 and the second switch Q2 can be field-effect transistors, such as PMOS transistors. Of course, other switches are also possible, but they will not be described in detail here. They can be selected according to the actual situation and are all within the scope of protection of this application.

[0141] The following is an example Figure 6 Taking the power supply protection circuit shown as an example, the protection process of the power supply protection circuit will be explained:

[0142] Among them, the fourth switch Q4 is an NPN transistor, and it operates in the off state; the third switch Q3 is also an NPN transistor, and it operates in the on state; the on-state voltage of the third switch Q3 and the fourth switch Q4 is VBE=0.6V; the first switch Q1 and the second switch Q2 are both PMOS transistors; the on-state voltage of the first diode D1 is VD1=0.24V, the sampling resistor R1=0.008Ω, and the current monitoring chip 11 is I. NA186-Q1, pull-up resistor R3=10KΩ, pull-down resistor R8=100KΩ, first voltage divider resistor R6=2.2KΩ, second voltage divider resistor R7=10KΩ, third voltage divider resistor R9=10KΩ, fourth voltage divider resistor R10=1.8KΩ, second resistor R2=10KΩ, fourth resistor R4=10KΩ; the power supply module is a DC / DC module, and the LED module of the electrical equipment has a first diode D1 and a second diode D2 that are Schottky diodes.

[0143] (1) Under normal circuit conditions: Because the third switch Q3 is turned on, the gate of the first switch Q1 is 0V. The first switch Q1 is turned on. After the first switch Q1 is turned on, the source of the second switch Q2 is VS2=VS1=5V. The second switch Q2 is turned on. The gate of the second switch Q2 and the gate of the first switch Q1 are both grounded to GND and are 0V because the third switch Q3 is turned on. Therefore, VGS<0 is turned on. The output of the DC / DC module is provided to the LED module through the first switch Q1 and the second switch Q2.

[0144] Turning on the first switch Q1 involves two processes. First, the first switch Q1 has a body diode, so the source voltage of the first switch Q1 VS1 = 5V - 0.7V = 4.3V, VGS < 0, and the first switch Q1 is turned on. At this time, VS1 = 5V.

[0145] (2) In the case of overcurrent in the circuit: Assuming the maximum current under normal operating conditions is 5A, and the current current in the circuit is 5.5A, the output voltage Vout of INA186-Q1 is 0.008Ω × 5.5A × 25 = 1.1V. The anode voltage of the first diode D1 is obtained by dividing the voltage by the first voltage divider resistor R6 and the second voltage divider resistor R7: 1.1V × 10KΩ / (2.2KΩ + 10 The voltage drop across the first diode D1 is 0.9V, and after passing through the first diode D1, the voltage drop is VD1 = 0.24V. The base voltage of the fourth switch Q4 is 0.9V - 0.24V = 0.66V. Since the base voltage of the fourth switch Q4 is greater than its forward voltage VBE = 0.6V, the fourth switch Q4 is turned on. The base voltage of the third switch Q3 is pulled down to 0V, and the fourth switch Q4 is turned off. The first switch Q1 and the second switch Q2 are also turned off, disconnecting the electrical equipment from the power module.

[0146] When the current is within the normal operating range of 5A, the output voltage Vout of INA186-Q1 is 0.008Ω×5A×25=1V. The anode voltage of the first diode D1 is 1V×10KΩ / (2.2KΩ+10KΩ)=0.82V. 0.82V is less than the sum of the conduction voltages of the first diode D1 and the fourth switch Q4, which is 0.84V: 0.24V+0.6V=0.84V. Therefore, the fourth switch Q4 is turned off, as in normal conditions.

[0147] (3) In case of overvoltage in the circuit: Assume that the maximum voltage under normal operating conditions is 5V and the current voltage of the circuit is 6V. The anode voltage of the second diode D2 is 6V×1.8KΩ / (1.8KΩ+10KΩ)=0.91V. 0.91V is greater than the sum of the conduction voltage of the second diode D2 and the fourth switch Q4, which is 0.84V. The fourth switch Q4 is turned on, the base of the third switch Q3 is pulled low, the third switch Q3 is turned off, the first switch Q1 and the third switch Q3 are turned off, and the electrical equipment and power module are disconnected.

[0148] When the voltage is within the normal operating range of 5V, the anode voltage of the second diode D2 is 5V × 1.8KΩ / (1.8KΩ + 10KΩ) = 0.76V. Since 0.76V is less than the sum of the conduction voltage of the second diode D2 and the fourth switch Q4 (0.84V), the fourth switch Q4 is turned off, as in normal conditions.

[0149] In this embodiment, the power supply protection circuit does not need to consider the input and output voltage and current ranges. It can set the overvoltage and overcurrent protection threshold ranges for device selection, and facilitate the setting of monitoring current and voltage thresholds.

[0150] Optionally, it may also include: an ADC acquisition module connected to the output terminal of the current detection module 10, and / or a control module connected to the control terminal of the drive control module 30.

[0151] Specifically, an ADC acquisition module sampling interface can be reserved at the output end of the current monitoring chip 11 in the current detection module 10. This ADC acquisition module sampling interface can then be connected to the ADC acquisition module to enable software monitoring of the current output.

[0152] An I / O interface is reserved at the base of the third switch Q3 in the drive control module 30. This I / O interface is connected to the control module through the fifth resistor R5.

[0153] like Figure 7 As shown, both the control module and the ADC acquisition module can be connected to the onboard controller. By combining the ADC acquisition module and the control module, the switching on and off of the third switch Q3 is controlled based on the current detection module's readings. This enables software-controlled switching of the power supply protection circuit, protecting the power supply module and the electrical equipment. The electrical equipment can be an LED module.

[0154] In this embodiment, a pure hardware circuit is used to achieve shutdown, which has a fast response speed after a problem occurs. A software interface can be reserved to combine the ADC acquisition module and the control module to realize monitoring and control.

[0155] Another embodiment of this application provides an LED system, including: a power module, an LED module, and a power supply protection circuit.

[0156] For details on the specific structure and working principle of the power supply protection circuit, please refer to the power supply protection circuit provided in the above embodiments. It will not be described in detail here, and all of them are within the protection scope of this application.

[0157] The power supply protection circuit is located between the power module and the LED module.

[0158] Specifically, the power supply protection circuit's power supply terminal is connected to the output terminal of the power module; the device terminal of the power supply protection circuit is connected to the power interface of the LED module.

[0159] The power supply protection circuit can be integrated with the power module as a power supply device; of course, the power supply protection circuit can also be integrated with the LED module as an electrical device; the power supply protection circuit can also be used independently. No specific limitation is made here, depending on the actual situation, and all of these are within the protection scope of this application.

[0160] The LED module can be connected to the power module via the power supply protection circuit in the form of a plug-in, or other forms, which will not be elaborated here. It depends on the actual situation and is within the protection scope of this application.

[0161] The power module can be a DC / DC module, which may include at least one DC / DC chip; the power module can be integrated on the motherboard, for example, the power module is an onboard DC / DC module, or the power module can be set independently. These will not be elaborated here, and can be determined according to the actual situation, all of which are within the protection scope of this application.

[0162] This application can be applied to the automotive field, that is, the power module can convert the 12V / 24V of the vehicle battery to 5V and output it to the LED module in the vehicle through the power supply protection circuit.

[0163] In this embodiment, the power supply to the LED module is automatically shut off by the hardware circuit of the power supply protection circuit to prevent overvoltage or overcurrent from damaging the power module or the LED module.

[0164] The features described in the various embodiments of this specification can be substituted for or combined with each other. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0165] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0166] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power supply protection circuit, characterized in that, The power supply protection circuit is located between the power supply module and the electrical equipment, and the power supply protection circuit includes: a current detection module, a sampling resistor, a drive control module, and a switching unit; One end of the input terminal of the current detection module is connected to one end of the sampling resistor, and the connection point is connected to the output terminal of the power supply module. The other end of the input terminal of the current detection module is connected to the other end of the sampling resistor, the first end of the drive control module, and the input terminal of the switching unit, respectively. The output terminal of the current detection module is connected to the second terminal of the drive control module; The output terminal of the drive control module is connected to the control terminal of the switch unit; The output terminal of the switching unit is connected to the third terminal of the drive control module and the positive terminal of the input terminal of the electrical equipment, respectively.

2. The power supply protection circuit according to claim 1, characterized in that, The current detection module includes: a current monitoring chip and a first voltage divider unit; The two ends of the current monitoring chip serve as the two ends of the current detection module, respectively. The output terminal of the current monitoring chip is connected to the first terminal of the first voltage divider unit; The second terminal of the first voltage divider unit is grounded; The output terminal of the first voltage divider unit serves as the output terminal of the current detection module.

3. The power supply protection circuit according to claim 2, characterized in that, The first voltage divider unit includes: a first voltage divider resistor and a second voltage divider resistor; One end of the first voltage divider resistor serves as the first end of the first voltage divider unit; The other end of the first voltage divider resistor is connected to one end of the second voltage divider resistor, and the connection point serves as the output terminal of the first voltage divider unit. The other end of the second voltage divider resistor serves as the second end of the first voltage divider unit.

4. The power supply protection circuit according to claim 1, characterized in that, The switching unit includes: a first switching transistor, a second switching transistor, and a second resistor; The first terminal of the first switching transistor serves as the input terminal of the switching unit; The second terminal of the first switching transistor is connected to the second terminal of the second switching transistor and the first terminal of the second resistor, respectively. The first terminal of the second switching transistor serves as the output terminal of the switching unit; The control terminal of the first switching transistor is connected to the control terminal of the second switching transistor and the other end of the second resistor, and the connection point serves as the control terminal of the switching unit.

5. The power supply protection circuit according to claim 1, characterized in that, The drive control module includes: a drive unit, a freewheeling unit, and a second voltage divider unit; The output terminal of the drive unit serves as the output terminal of the drive control module. The control terminal of the drive unit is connected to the output terminal of the freewheeling unit; The positive input terminal of the drive unit serves as the first terminal of the drive control module. The first input terminal of the freewheeling unit serves as the second terminal of the drive control module; The second input terminal of the freewheeling unit is connected to the output terminal of the second voltage divider unit; The first terminal of the second voltage divider unit serves as the third terminal of the drive control module; The negative terminal of the input of the driving unit and the second terminal of the second voltage divider unit are both grounded.

6. The power supply protection circuit according to claim 5, characterized in that, The driving unit includes: a pull-up resistor, a fourth resistor, a third switch, a fourth switch, and a pull-down resistor; The first terminal of the third switch is connected to one terminal of the fourth resistor; The control terminal of the third switch is connected to one end of the pull-up resistor and the first end of the fourth switch, respectively. The control terminal of the fourth switch is connected to one end of the pull-down resistor, and the connection point serves as the control terminal of the drive unit. The second terminal of the third switch, the second terminal of the fourth switch, and the other terminal of the pull-down resistor are grounded; The other end of the fourth resistor serves as the output terminal of the driving unit. The other end of the pull-up resistor is connected to the common terminal of the switching unit and the sampling resistor.

7. The power supply protection circuit according to claim 5, characterized in that, The freewheeling unit includes: a first diode and a second diode; The anode of the first diode serves as the first input terminal of the freewheeling unit; The anode of the second diode serves as the second input terminal of the freewheeling unit; The cathodes of the first diode and the second diode are connected, and the connection point serves as the output terminal of the freewheeling unit.

8. The power supply protection circuit according to claim 5, characterized in that, The second voltage divider unit includes: a third voltage divider resistor and a fourth voltage divider resistor; One end of the third voltage divider resistor serves as the first end of the second voltage divider unit; The other end of the third voltage divider resistor is connected to one end of the fourth voltage divider resistor, and the connection point serves as the output terminal of the second voltage divider unit. The other end of the fourth voltage divider resistor serves as the second end of the second voltage divider unit.

9. The power supply protection circuit according to claim 1, characterized in that, Also includes: An ADC acquisition module connected to the output terminal of the current detection module, and / or a control module connected to the control terminal of the drive control module.

10. An LED system, characterized in that, include: Power module, LED module and power supply protection circuit as described in any one of claims 1-9; The power supply protection circuit is located between the power supply module and the LED module.

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