Power supply negative surge interference protection circuit

Abstract

The application provides a power negative surge interference protection circuit, comprising: a forward voltage isolation unit electrically connected to an input channel; a primary protection unit electrically connected to the forward voltage isolation unit; a discharge switch unit electrically connected to the forward voltage isolation unit; a detection delay unit electrically connected to the discharge switch unit; an enabling unit electrically connected to the detection delay unit; a power supply unit electrically connected to the enabling unit and the discharge switch unit; an enabling maintenance circuit electrically connected to the enabling unit and the power supply unit; and an anti-reverse connection circuit electrically connected to the primary protection unit and the discharge switch unit. The circuit can realize multi-channel multiplexing and absorb a high energy level negative surge protection circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit, in particular to a power negative surge interference protection circuit. BACKGROUND

[0002] In the field of LED signal lamp control for vehicles, LDM (LED Drive module) as a general electronic component needs to be able to adapt to vehicle models of each host manufacturer. The manufacturing level of engines and generators of each host manufacturer is not the same, resulting in that the LDM connected to the power line of the whole vehicle needs to withstand current and voltage surge interference of various voltages and time lengths. At the same time, the surge waveforms generated by gasoline vehicles, diesel vehicles, hydrogen vehicles, EV vehicles and other types of vehicles are different. In extreme cases, there will be negative surge waveforms with voltage above 600V, time above 10ms and power reaching thousands of watts. General protection devices will lose protection ability when encountering such a large amount of energy, causing LDM damage or even burning.

[0003] In addition, for LDM with multiple input channels, each input channel needs to have negative surge protection capability, but if a set of protection circuits is provided for each channel, there are too many devices and the cost is too high. Therefore, we need a negative surge protection circuit that can be multiplexed in multiple channels and can absorb a high level of energy. SUMMARY

[0004] The purpose of the embodiment of the present application is to provide a power negative surge interference protection circuit to solve the technical problems in the prior art.

[0005] In a first aspect, the present application provides a power supply negative surge interference protection circuit, comprising: a forward voltage isolation unit electrically connected to an input channel, configured to be not conductive when the voltage of the input channel is positive, so as to electrically isolate the input channel from other elements; and electrically connected to the input channel when the voltage of the input channel is negative; a primary protection unit electrically connected to the forward voltage isolation unit, configured to maintain the surge voltage within a preset voltage range; a discharge switch unit electrically connected to the forward voltage isolation unit, configured to short circuit the positive and negative electrodes of the power supply when the surge voltage is greater than the preset voltage range, and release the surge energy to the input channel through the forward voltage isolation unit; a detection delay unit electrically connected to the discharge switch unit, configured to detect the negative voltage value and configure a delay filter to the discharge switch unit; an enabling unit electrically connected to the detection delay unit, configured to send an enabling signal to start a power supply unit after the detection delay unit completes detection; the power supply unit electrically connected to the enabling unit and the discharge switch unit, configured to receive the enabling signal of the enabling unit to supply power to the discharge switch unit and the enabling maintenance circuit; the enabling maintenance circuit electrically connected to the enabling unit and the power supply unit, configured to maintain the continuous operation of the protection circuit; and a reverse connection prevention circuit electrically connected to the primary protection unit and the discharge switch unit, configured to prevent reverse connection of the circuit.

[0006] In an optional embodiment, the forward voltage isolation unit comprises: a plurality of diodes, the cathodes of the diodes being electrically connected to the input channel; wherein the number of the input channels is consistent with the number of the diodes.

[0007] In an optional embodiment, the primary protection unit comprises: an instantaneous pulse absorption module configured to absorb pulses; and a voltage clamping module configured to limit the upper limit of the surge voltage according to a preset voltage off value.

[0008] In an optional embodiment, the primary protection unit comprises: a transient diode electrically connected to the forward voltage isolation unit.

[0009] In an optional embodiment, the discharge switch unit comprises: a first N-type transistor, the emitter of the first N-type transistor being electrically connected to the forward voltage isolation unit, and the collector of the first N-type transistor being grounded; and a resistor R1, one end of the resistor R1 being electrically connected to the base of the first N-type transistor, and the other end of the resistor R1 being electrically connected to the power supply unit.

[0010] In an optional embodiment, the detection delay unit comprises: a voltage stabilizing diode, the cathode of the voltage stabilizing diode being electrically connected to the power supply unit, and the anode of the voltage stabilizing diode being electrically connected to a filter circuit; and the filter circuit comprises: a resistor R3, one end of the resistor R3 being electrically connected to the voltage stabilizing diode, and the other end of the resistor R3 being electrically connected to the enabling unit.

[0011] In an optional embodiment, the enable unit comprises a second N-type transistor, a base of the second N-type transistor is electrically connected to the detection delay unit, an emitter of the second N-type transistor is electrically connected to the forward voltage isolation unit, and a collector of the second N-type transistor is electrically connected to the power supply unit.

[0012] In an optional embodiment, the power supply unit comprises a first P-type transistor, an emitter of the first P-type transistor is electrically connected to the detection delay unit, a base of the first P-type transistor is electrically connected to the enable unit, and a collector of the first P-type transistor is electrically connected to the discharge switch unit.

[0013] In an optional embodiment, the enable maintaining circuit comprises a resistor R4, which is electrically connected to the collector of the first P-type transistor.

[0014] In an optional embodiment, the reverse connection prevention circuit comprises a transient diode, which is electrically connected to the forward voltage isolation unit; and a voltage stabilizing diode, a negative electrode of the voltage stabilizing diode is electrically connected to the power supply unit, and a positive electrode of the voltage stabilizing diode is electrically connected to the filter circuit.

[0015] Generally, when a vehicle is running normally, negative interference occurs due to abnormality of an engine and a generator. The energy of the interference is random, and the size of the energy is mainly embodied in the internal resistance of the interference source and the time of interference loading. For small energy interference, TVS, capacitor and other devices can be used for absorption. However, for large energy interference, the capacity range of TVS, capacitor and other transient protection devices is exceeded, thereby causing the entire module to be damaged. Therefore, for large energy surge interference, the most effective method is to guide the energy of the surge back to the interference source, that is, to short the positive and negative power supply lines.

[0016] In addition, since there is a requirement for reverse connection prevention in a vehicle, the circuit needs to be able to distinguish whether a reverse connection situation or surge interference occurs. For a vehicle, generally, the output voltage of the generator is below 16V, so the protection circuit generally needs to leave some margin at-16V, for example, -20V cannot be started, to prevent reverse connection failure. At the same time, the monitoring circuit also needs to add some delay filter to ensure that no false triggering occurs.

[0017] When the voltage is normally input, the protection circuit and the input circuit need to be electrically isolated, so that the protection circuit will not affect the normal work of the module even if an abnormality occurs. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0019] Figure 1 A functional schematic diagram of a power negative surge interference protection circuit provided by the embodiments of the present application;

[0020] Figure 2 A circuit diagram of a power negative surge interference protection circuit provided by the embodiments of the present application.

[0021] Icon: 1-protective circuit; 10-positive voltage isolation unit; 20-primary protection unit; 21-transient diode; 30-drainage switch unit; 31-first N-type triode; 40-detection delay unit; 41-stabilized diode; 42-filter circuit; 50-enable unit; 51-second N-type triode; 60-power supply unit; 61-first P-type triode; 70-enable maintenance circuit; 80-anti-reverse connection circuit. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application.

[0023] As Figure 1 shown, it is a functional schematic diagram of a power negative surge interference protection circuit 1 provided by the embodiments of the present application, including: a positive voltage isolation unit 10, a primary protection unit 20, a drainage switch unit 30, a detection delay unit 40, an enable unit 50, a power supply unit 60, an enable maintenance circuit 70 and an anti-reverse connection circuit 80.

[0024] Among them, the positive voltage isolation unit 10 is electrically connected to the input channel IN, used for not conducting when the voltage of the input channel IN is positive, making the input channel IN and other elements electrically isolated; when the voltage of the input channel IN is negative, it is electrically connected with the input channel IN.

[0025] It is the protection for negative surge interference, and when the module works normally, the voltage is positive input, so the positive isolation is needed, so that the protection circuit 1 does not affect the normal work of other circuits. When multiple inputs need to share a protection circuit 1, this function module needs to establish a shared relationship between multiple input channels IN and the protection circuit 1. At the same time, mutual interference is prevented in the sharing process.

[0026] The primary protection unit 20 is electrically connected to the forward voltage isolation unit 10, and is used to maintain the surge voltage within a preset voltage range.

[0027] Because the establishment speed of the surge voltage is very fast, and the high-power discharge protection circuit 1 has a certain delay, before the discharge circuit starts, a circuit capable of fast response is needed for primary protection.

[0028] The discharge switch unit 30 is electrically connected to the forward voltage isolation unit 10, and is used to short-circuit the positive and negative poles of the power supply when the surge voltage is greater than the preset voltage range, and release the surge energy to the input channel IN through the forward voltage isolation unit 10.

[0029] For high-energy level surges, a discharge switch with a low on-voltage is needed to short-circuit the positive and negative power supply lines and return the surge energy directly to the noise source.

[0030] The detection delay unit 40 is electrically connected to the discharge switch unit 30, and is used to detect the negative voltage value and configure a delay filter for the discharge switch unit 30.

[0031] The discharge switch is used to short-circuit the positive and negative lines of the power supply, and if it is mis-triggered, it will cause the module anti-reverse connection function to be abnormal, so a detection delay is needed. Generally, the power supply provided by the automobile body is 9-16V, in order to prevent the module from losing the anti-reverse connection function, the detection threshold needs to be lower than -16V (absolute value greater than 16V), so as not to accidentally enable the discharge circuit when the power supply is reversed, causing the reverse connection function to fail.

[0032] The enable unit 50 is electrically connected to the detection delay unit 40, and is used to send an enable signal to start the power supply unit 60 after the detection delay unit 40 completes detection. When the detection is completed, an enable signal is sent to start the power supply of the protection circuit 1.

[0033] The power supply unit 60 is electrically connected to the enable unit 50 and the discharge switch unit 30, and is used to receive the enable signal of the enable unit 50 to supply power to the discharge switch unit 30 and the enable maintenance circuit 70. It supplies power to the discharge switch and also supplies power to the enable maintenance circuit 70.

[0034] The enable maintenance circuit 70 is electrically connected to the enable unit 50 and the power supply unit 60, and is used to maintain the continuous operation of the protection circuit 1. Because the detection threshold of the discharge circuit is lower than -16V (absolute value greater than 16V), during the absorption process, when the absolute value of the surge voltage is lower than the detection voltage absolute value, the protection circuit 1 will be turned off. At this time, the surge interference still has a strong energy, so an enable maintenance circuit 70 is needed to ensure that the discharge switch continues to work before the absolute value of the surge voltage approaches 0V.

[0035] The reverse connection protection circuit 80 is electrically connected to the primary protection unit 20 and the discharge switch unit 30, and is used for reverse connection protection. Since a negative surge circuit, like a reverse power connection, will generate a negative voltage, this circuit is required to ensure that the module passes both the reverse connection test and the negative surge test. (Generally, the reverse connection protection requirement is that for voltages with an absolute value below 16V, the circuit should not conduct when the input is reversed.)

[0036] like Figure 2 As shown, this is a circuit diagram of a power supply negative surge interference protection circuit 1 provided in an embodiment of this application. As shown, the positive voltage isolation unit 10 includes a plurality of diodes D, the negative terminals of which are electrically connected to the input channel IN. The number of input channels IN is the same as the number of diodes.

[0037] In an optional implementation, the primary protection unit 20 includes: an instantaneous pulse absorption module for absorbing pulses; and a voltage clamping module for limiting the surge voltage limit according to a preset voltage disconnection value.

[0038] In an optional implementation, the primary protection unit 20 includes a transient diode 21 electrically connected to the forward voltage isolation unit 10.

[0039] In an optional embodiment, the discharge switch unit 30 includes: a first N-type transistor 31, the emitter of which is electrically connected to the forward voltage isolation unit 10, and the collector of which is grounded; and a resistor R1, one end of which is electrically connected to the base of the first N-type transistor 31, and the other end of which is electrically connected to the power supply unit 60.

[0040] In an optional embodiment, the detection delay unit 40 includes: a Zener diode 41, the negative terminal of which is electrically connected to the power supply unit 60, and the positive terminal of which is electrically connected to the filter circuit 42; the filter circuit 42 includes: a resistor R3, one end of which is electrically connected to the Zener diode 41, and the other end of which is electrically connected to the enable unit 50.

[0041] In an optional embodiment, the enabling unit 50 includes: a second N-type transistor 51, the base of which is electrically connected to the detection delay unit 40, the emitter of which is electrically connected to the forward voltage isolation unit 10, and the collector of which is electrically connected to the power supply unit 60.

[0042] In an optional embodiment, the power supply unit 60 includes: a first P-type transistor 61, the emitter of the first P-type transistor 61 being electrically connected to the detection delay unit 40, the base of the first P-type transistor 61 being electrically connected to the enable unit 50, and the collector of the first P-type transistor 61 being electrically connected to the discharge switch unit 30.

[0043] In an optional embodiment, the enablement maintaining circuit 70 comprises a resistor R4 electrically connected to the collector of the first P-type transistor 61.

[0044] In an optional embodiment, the reverse connection prevention circuit 80 comprises a transient diode 21 electrically connected to the forward voltage isolation unit 10, and a voltage stabilizing diode 41, the negative pole of which is electrically connected to the power supply unit 60, and the positive pole of which is electrically connected to the filter circuit 42.

[0045] Generally, when a vehicle is running normally, negative interference occurs due to abnormality of the engine and the generator. The energy of the interference is random, and the size of the energy is mainly embodied in the internal resistance of the interference source and the time of interference loading. For small energy interference, TVS, capacitor and other devices can be used to absorb. However, for large energy interference, it will exceed the bearing capacity range of TVS, capacitor and other transient protection devices, thereby causing the entire module to be damaged. Therefore, for large energy surge interference, the most effective method is to guide the energy of the surge back to the source of the interference, that is, to short the positive and negative power lines.

[0046] In addition, since there is a requirement for reverse connection prevention in a vehicle, the circuit needs to be able to distinguish whether a reverse connection situation or a surge interference has occurred. For a vehicle, the output voltage of the generator is generally below 16V, so the protection circuit 1 needs to leave some margin at -16V, for example, -20V cannot be started, to prevent reverse connection failure. At the same time, the monitoring circuit also needs to add some delay filtering to ensure that false triggering does not occur.

[0047] When the voltage is normally input, the protection circuit 1 and the input circuit need to be electrically isolated, so that the protection circuit 1 will not affect the normal work of the module even if an abnormality occurs.

[0048] When the power supply is normally powered, only the multiplexing and mutual interference prevention part is started to prevent mutual interference between channels.

[0049] When the power supply appears negative surge, the instantaneous pulse absorption circuit and the voltage clamping circuit quickly respond and work, absorb the peak voltage, and maintain the voltage at an absolute value of 20V or more (the rated maximum input of a general module is generally 16V, and a certain margin is required to prevent protection mis-triggering and reverse connection failure, and the actual bearing capacity of the back-end circuit is adjusted). At this time, the detection circuit starts to work, and after a period of detection, it is ensured that the interference is a long-time surge interference (for short-time surge interference, it can be protected by the instantaneous pulse absorption and voltage clamping circuit, but long-time surge interference has too much energy and exceeds the protection capability range, so the bleeder switch needs to be used for protection), the protection circuit 1 enables the protection power supply circuit to open the bleeder switch, and at the same time enables the circuit to maintain to ensure that the negative surge energy is fully released before the bleeder switch is closed. When the voltage returns to normal, the loop power supply becomes a positive voltage, the protection circuit 1 is isolated and stops working, and the module enters the normal working mode.

[0050] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some communication interface, and can be electrical, mechanical or other forms.

[0051] In addition, the units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, some or all of the units can be selected to achieve the purpose of the embodiments.

[0052] Furthermore, the functional modules in each of the embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0053] It should be noted that, if the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product in essence or in the form of a part or the technical solutions of the present application that make contributions to the prior art. The computer software product is stored in a storage medium, includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the method of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0054] In this article, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations.

[0055] The above is only an embodiment of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A power supply negative surge disturbance protection circuit, characterized by, The application relates to a protection circuit for a power supply, which comprises the following units: a forward voltage isolation unit electrically connected to an input channel, used for not conducting when the voltage of the input channel is positive, so as to electrically isolate the input channel from other elements; being electrically connected to the input channel when the voltage of the input channel is negative; a primary protection unit electrically connected to the forward voltage isolation unit, used for maintaining a surge voltage in a preset voltage range; a discharge switch unit electrically connected to the forward voltage isolation unit, used for short-circuiting the positive and negative poles of the power supply when the surge voltage is greater than the preset voltage range, and releasing the surge energy to the interference source of the input channel through the forward voltage isolation unit; a detection delay unit electrically connected to the discharge switch unit, used for detecting a negative voltage value and configuring a delay filter for the discharge switch unit; an enabling unit electrically connected to the detection delay unit, used for sending an enabling signal and starting a power supply unit after the detection delay unit is detected; the power supply unit electrically connected to the enabling unit and the discharge switch unit, used for receiving the enabling signal of the enabling unit and supplying power for the discharge switch unit and an enabling maintenance circuit; the enabling maintenance circuit electrically connected to the enabling unit and the power supply unit, used for maintaining the continuous work of the protection circuit; an anti-reverse connection circuit electrically connected to the primary protection unit and the discharge switch unit, used for circuit anti-reverse connection; wherein the input channel has a plurality of forward voltage isolation units, which comprise: a plurality of diodes, the negative poles of the diodes being electrically connected to the input channels; wherein the number of the input channels is consistent with the number of the diodes; the enabling unit comprises: a second N-type transistor, the base of the second N-type transistor being electrically connected to the detection delay unit, the emitter of the second N-type transistor being electrically connected to the forward voltage isolation unit, and the collector of the second N-type transistor being electrically connected to the power supply unit; the power supply unit comprises: a first P-type transistor, the emitter of the first P-type transistor being electrically connected to the detection delay unit, the base of the first P-type transistor being electrically connected to the enabling unit, and the collector of the first P-type transistor being electrically connected to the discharge switch unit.

2. The protection circuit of claim 1, wherein the primary protection unit comprises: a transient pulse absorption module, used for absorbing a pulse; a voltage clamping module, used for limiting the upper limit of the surge voltage according to a preset voltage off value.

3. The protection circuit of claim 1, wherein the primary protection unit comprises: a transient diode electrically connected to the forward voltage isolation unit.

4. The protection circuit of claim 1, wherein the discharge switch unit comprises: a first N-type transistor, the emitter of the first N-type transistor being electrically connected to the forward voltage isolation unit, and the collector of the first N-type transistor being grounded; a resistor R1, one end of the resistor R1 being electrically connected to the base of the first N-type transistor, and the other end of the resistor R1 being electrically connected to the power supply unit.

5. The protection circuit of claim 1, wherein the detection delay unit comprises: a voltage stabilizing diode, the negative pole of the voltage stabilizing diode being electrically connected to the power supply unit, and the positive pole of the voltage stabilizing diode being electrically connected to a filter circuit. The filter circuit comprises a resistor R3, one end of the resistor R3 is electrically connected to the voltage stabilizing diode, and the other end of the resistor R3 is electrically connected to the enabling unit.

6. The protection circuit of claim 1, wherein The enabling maintaining circuit comprises: A resistor R4 is electrically connected to the collector of the first P-type transistor.

7. The protection circuit of claim 1, wherein The reverse connection prevention circuit comprises: A transient diode is electrically connected to the forward voltage isolation unit. A voltage stabilizing diode, the negative electrode of the voltage stabilizing diode is electrically connected to the power supply unit, and the positive electrode of the voltage stabilizing diode is electrically connected to the filter circuit.

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