WO2020108509A1

WO2020108509A1 - Protection circuit, circuit and operation method therefor, and corresponding vehicle light and vehicle

Info

Publication number: WO2020108509A1
Application number: PCT/CN2019/121142
Authority: WO
Inventors: Tianxun GONG; Jintao LIANG; Sylvain Yvon; Peiliang YUAN; Shangye FANG; Zhenyu Zhang
Original assignee: Foshan Ichikoh Valeo Auto Lighting Systems Co., Ltd.
Priority date: 2018-11-27
Filing date: 2019-11-27
Publication date: 2020-06-04
Also published as: CN111224373A; CN111224373B; EP3888209A1; EP3888209A4

Abstract

A protection circuit(100) for ground short circuit protection, the circuit(100) comprising: a high conduction circuit(110) for controlling the supply of electric power for a functional circuit(1000), wherein the functional circuit(1000) has a boost function; and a charging subcircuit(120) for controlling, based on an input voltage of an input power source of the protection circuit(100) and an output voltage from the functional circuit(1000), the high conduction circuit(110) to be turned on or turned off; and an energy storage circuit(130) for storing electric power from the input power source so as to provide electric power for the functional circuit(1000).

Description

Protection circuit, circuit and operation method therefor, and corresponding vehicle light and vehicle

Technical Field

The present disclosure relates to the field of electronic devices, and in particular to a protection circuit, a circuit and a method, and a corresponding vehicle light and vehicle.

Background Art

In electronic circuits, there is always a risk of ground short-circuiting. When ground short-circuiting occurs, an extremely large short-circuit current may occur in a circuit, and consequently, a fault occurs in a line or a device. To solve this problem, a variety of circuits for ground short-circuiting protection are proposed in the prior art. In these circuits, the turn-on and turn-off of a switch are always controlled by detecting an output current and analyzing the detected current by software, so as to implement protection for a functional circuit such as a driving circuit.

Although such a circuit for ground short-circuiting protection can implement protection for a functional circuit, a feedback process is always relatively slow and has a relatively low reliability because of the need of detection, analysis, and control by means of software.

Therefore, there is a need to provide a protection circuit and a protection method that can carry out ground short-circuiting protection.

Summary of the Invention

The present disclosure is to provide a protection circuit for ground short-circuiting protection, wherein the circuit may comprise:

a high conduction circuit for controlling the supply of electric power for a functional circuit, wherein the functional circuit has a boost function; and

a charging subcircuit for controlling, based on an input voltage of an input power source of the protection circuit and an output voltage from the functional circuit, the high conduction circuit to be turned on or turned off; and

an energy storage circuit for storing electric power from the input power source so as to provide electric power for the functional circuit.

In one example, a first terminal of the charging subcircuit is connected to the input power source, and a second terminal thereof is connected to an output terminal of the functional circuit; and

a first terminal of the high conduction circuit is connected to the input power source, a second terminal thereof is connected to an input terminal of the functional circuit via the energy storage circuit, and a control terminal thereof is connected to an output terminal of the charging subcircuit,

wherein the high conduction circuit is configured to be turned on in response to the control terminal thereof being at a high voltage and to be turned off in response to the control terminal thereof being at a low voltage.

In another example, the high conduction circuit uses one or more NMOS transistors.

High conductivity of an NMOS transistor enables the turn-off or turn-on of the high conduction circuit to be controlled by using a voltage of the output terminal of the functional circuit as feedback.

In another example, the energy storage circuit comprises a first capacitor, one end of the first capacitor is connected to the input terminal of the functional circuit, and the other end thereof is grounded.

The energy storage circuit can store energy when the functional circuit is not started, and provides, in response to the starting of the functional circuit, the stored energy to the functional circuit to serve as an initial input.

In another example, when the high conduction circuit uses a plurality of NMOS transistors, the plurality of NMOS transistors comprise at least two NMOS transistors connected in a mirroring manner, wherein a source electrode of a first transistor of the two NMOS transistors connected in a mirroring manner is connected to a source electrode of a second transistor thereof, and a gate electrode of each of the first transistor and the second transistor is connected to the second terminal of the charging subcircuit as the control terminal of the high conduction circuit.

The NMOS transistors connected in a mirroring manner can ensure that the turn-on or turn-off of the high conduction circuit is controlled according to an output voltage of the charging subcircuit, and also ensure that a current does not flow in reverse from the energy storage circuit or the functional circuit, through parasitic diodes of the NMOS transistors connected in a mirroring manner, into the input power source.

In another example, when the high conduction circuit uses a plurality of NMOS transistors, a source electrode and a drain electrode of two adjacent NMOS transistors of the plurality of NMOS transistors are connected to each other.

In another example, when the high conduction circuit uses a single NMOS transistor, a gate electrode of the single NMOS transistor is connected to the second terminal of the charging subcircuit as a control terminal.

In another example, the charging subcircuit comprises a diode and a second capacitor,

wherein a positive electrode of the diode is connected to the input power source, and a negative electrode thereof is connected to the output terminal of the functional circuit; and

one end of the second capacitor is connected to the output terminal of the functional circuit, and the other end thereof is grounded.

In another example, the functional circuit is a DC-DC conversion circuit.

According to another aspect of the present disclosure, an operation method for a circuit is provided, the circuit being as described in any one of the examples above, wherein the operation method comprises the step of:

controlling, according to an output voltage of the functional circuit, the high conduction circuit to be turned on or turned off.

In one example, the step of controlling, according to the output voltage of the functional circuit, the high conduction circuit to be turned on or turned off further comprises:

in response to the output voltage being a high voltage, completely turning on the high conduction circuit; and

in response to the output voltage being a low voltage, turning off the high conduction circuit.

In another example, the operation method further comprises the following steps:

in response to the functional circuit being not started, the charging subcircuit controlling, based on an input voltage and a low output voltage of the functional circuit, the high conduction circuit to be partly turned on, so that the energy storage circuit stores power; and

in response to the functional circuit being started, the charging subcircuit enabling, based on the input voltage and a high output voltage of the functional circuit, the high conduction circuit to be completely turned on under the control of the charging subcircuit, so that power is supplied from the input power source to the functional circuit.

According to still another aspect of the present disclosure, a circuit having an output grounding protection function is provided, wherein the circuit comprises: the protection circuit as described previously; and a functional circuit, wherein the functional circuit has a boost function.

According to yet another aspect of the present disclosure, an operation method for a circuit is provided, wherein the circuit is as described previously, and the operation method comprises:

outputting a low voltage by the functional circuit to the protection circuit, so that the high conduction circuit in the protection circuit is turned off; or

outputting a high voltage by the functional circuit to the protection circuit, so that the high conduction circuit in the protection circuit is turned on.

According to another aspect of the present disclosure, a vehicle light is provided, wherein the vehicle light comprises the protection circuit as described in any one of the examples above, or the vehicle light comprises the circuit as described in any one of the examples above.

According to another aspect of the present disclosure, a vehicle is provided, wherein the vehicle uses the vehicle light as described in any one of the examples above.

According to the protection circuit, the circuit, the method, and the corresponding vehicle light and vehicle in the present disclosure, the turn-on and turn-off of the high conduction circuit can be controlled according to the voltage of the output terminal of the functional circuit, so that when ground short-circuiting occurs in the functional circuit, the input power source is cut off more quickly, thereby providing more secure protection. Furthermore, due to the existence of the energy storage circuit, according to the protection circuit, the circuit, the method, and the corresponding vehicle light and vehicle in the present disclosure, when the functional circuit is started, the functional circuit can further be stabilized more quickly.

Brief Description of the Drawings

In order to more completely understand the present disclosure and the advantages thereof, reference will now be made to the following descriptions in conjunction with the accompanying drawings, in which:

FIG. 1 shows a block diagram of a protection circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

FIGs. 2A to 2C show exemplary circuit diagrams of a protection circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

FIG. 3 shows a schematic circuit diagram of a circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

FIGs. 4A to 6B show diagrams of tests for the circuit shown in FIG. 3 according to the exemplary embodiment of the present invention.

FIG. 7 shows a flowchart of an operation method for operating a protection circuit carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

Detailed Description of Embodiments

The embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. Furthermore, in the following illustration, descriptions of well-known structures and techniques are omitted so as to avoid unnecessarily obscuring the concepts of the present disclosure.

The terms used herein are only intended to describe specific embodiments, and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the words “a” , “an” , and “the” , etc. used herein should also comprise the meaning of “a plurality of” and “a variety of” . Furthermore, the terms “comprise” , “contain” , etc. used herein indicate the existence of the features, steps, operations, and/or components, but do not exclude the existence or addition of one or more other features, steps, operations, or components.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the meaning commonly understood by those skilled in the art. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, but should not be interpreted in an ideal or too rigid manner.

Some block diagrams and/or flowcharts are shown in the accompanying drawings. It should be understood that some blocks or combinations thereof in the block diagrams and/or flowcharts may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, a dedicated-purpose computer, or other programmable data processing apparatuses, so that when executed by the processor, these instructions may create an apparatus for implementing the functions/operations illustrated in these block diagrams and/or flowcharts.

Therefore, the techniques of the present disclosure may be implemented in the form of hardware and/or software (including firmware, microcode, etc. ) . In addition, the techniques of the present disclosure may take the form of a computer program product on a computer readable medium storing instructions, and the computer program product may be used by an instruction execution system or used in combination with the instruction execution system. In the context of the present disclosure, the computer readable medium may be any medium that can contain, store, convey, propagate, or transmit instructions. For example, the computer readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. Specific examples of the computer readable medium comprise: a magnetic storage apparatus, such as a magnetic tape or a hard disk drive (HDD) ; an optical storage apparatus, such as a compact disk (CD-ROM) ; a memory, such as a random access memory (RAM) or a flash memory; and/or a wired/wireless communication link.

The embodiments of the present disclosure provide a protection circuit and a protection method for carrying out ground short-circuiting protection, which are able to quickly turn off an input power source when a functional circuit is short-circuited, and enable the functional circuit to be stabilized more quickly when the functional circuit is started.

It should be noted that the “connection” described in the present disclosure may be direct connection, that is to say, two terminals are directly connected by means of a line; the “connection” may also be any equivalent connection that does not affect the operation that the two terminals are to perform. For example, the two terminals are connected by means of one resistor, and as long as the connection does not affect the operation originally to be implemented between the two terminals, such a case should also be comprised in the word “connection” used in the present invention.

FIG. 1 shows a block diagram of a protection circuit 100 for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

The protection circuit 100 for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention may comprise: a high conduction circuit 110 for controlling the supply of electric power for a functional circuit 1000; a charging subcircuit 120 for controlling, based on an input voltage of the protection circuit 100 and an output voltage from the functional circuit 1000, the high conduction circuit 110 to be turned on or turned off; and an energy storage circuit 130 for storing electric power from the input power source so as to provide electric power for the functional circuit 1000.

In the exemplary embodiment of the present disclosure, the functional circuit 1000 has a boost function. Preferably, the functional circuit 1000 has two states of being started and being not started, which may alternatively be referred to as a started state and an un-started state. When the functional circuit 1000 is not started, an output terminal thereof may output a low voltage, and when the functional circuit 1000 is started, the output terminal thereof may output a high voltage. More preferably, the functional circuit 1000 comprises, but is not limited to, a DC-DC circuit.

It should be noted that the “high voltage” or “low voltage” described in the present disclosure is not an absolute voltage but a relative voltage. For example, herein, a voltage with a voltage value greater than or equal to a voltage value which can enable the high conduction circuit to be completely turned on may be referred to as a high voltage, while a voltage which cannot enable the high conduction circuit to be in a completely turned-on state is referred to as a low voltage.

The high conduction circuit 110 is configured to be turned on or turned off under control according to output of the charging subcircuit 120, so that electric power from the input power source can be stored by the energy storage circuit 130 and can be provided to the functional circuit 1000.

Preferably, controlling the high conduction circuit 110 to be turned on or turned off means enabling the high conduction circuit 110 to be in any one of the following states: (1) a completely turned-on state; (2) a turned-off state; or (3) a partly turned-on state.

According to one preferred exemplary embodiment of the present invention, the high conduction circuit 110 may be implemented using one or more NMOS transistors.

According to one preferred exemplary embodiment of the present invention, the energy storage circuit 130 may be implemented using one capacitor component with at least one end being grounded.

In the exemplary embodiment of FIG. 1, a first input terminal of the charging subcircuit 120 is connected to the input power source of the protection circuit 100, and a second input terminal thereof is connected to the output terminal of the functional circuit 1000. A first terminal of the high conduction circuit 110 is connected to the input power source, a second terminal thereof is connected to an input terminal of the functional circuit 1000, and a control terminal thereof is connected to the output terminal of the charging subcircuit 120. The high conduction circuit is configured to be turned on in response to the control terminal thereof being at a high voltage and to be turned off in response to the control terminal thereof being at a low voltage. The energy storage circuit 130 is connected between the high conduction circuit 110 and the functional circuit 1000, and is used to store electric power when the high conduction circuit 110 is in the partly turned-on state, so as to provide an initial electric power input for the functional circuit 1000 in response to the starting of the functional circuit 1000. Such a structure can provide electric power for the functional circuit 1000 more quickly when the functional circuit 1000 is started. In one example, when the energy storage circuit 130 is implemented by a capacitor, one end of the capacitor is connected to a second terminal of the high conduction circuit 110 and the input terminal of the functional circuit 1000, and the other end thereof is grounded.

In the circuit structure shown in FIG. 1, when the functional circuit 1000 is in the un-started state, the charging subcircuit 120 is charged by the input power source, so that the high conduction circuit 110 is partly turned on, and then electric power is continuously accumulated at the energy storage circuit 130, so as provide an input for the functional circuit.

It should be noted that, according to the disclosure in this specification, those skilled in the art can understand that an output voltage of the charging subcircuit 120 in this case is mainly from the process of an input voltage of the input power source charging the charging subcircuit 120; moreover, because the voltage of the input power source is relatively low, and the output voltage of the charging subcircuit 120 in this case is insufficient to completely turn on the high conduction circuit, in this case, the high conduction circuit 110 is in the partly turned-on state.

When the functional circuit is set to be in the started state, the electric power stored on the energy storage circuit 130 can serve as an initial input of the functional circuit 1000. In this case, because the functional circuit 1000 has a boost function, the output voltage of the output terminal of the functional circuit 1000 may be greatly boosted, and a voltage value of the voltage may even exceed the input voltage of the protection circuit 100. In this case, the output voltage of the functional circuit 1000 will dominate the charging of the charging subcircuit 120. In this case, the output of the charging subcircuit 120 controls the high conduction circuit 110 to be completely turned on, and then enables the functional circuit 1000 to work normally.

In a normal working process of the functional circuit 1000, high voltages can be continuously output, and dominate the charging of the charging subcircuit 120, so that a voltage on the charging subcircuit 120 is sufficient to control the high conduction circuit 110 to maintain the turned-on state, so as to implement supply of power to the functional circuit 1000 by the input power source.

When ground short-circuiting occurs in the functional circuit 1000, the output voltage of the functional circuit drops to a low voltage and in this case, the output voltage of the charging subcircuit 120 accordingly drops, so that the high conduction circuit 110 is turned off, causing cutoff of the supply of power to the functional circuit 1000 by the input power source and implementing ground short-circuiting protection.

Compared with traditional circuits that implement ground short-circuiting protection by controlling the turn-off of a switch after detecting a current and analyzing the detected current via software, such a protection manner can implement quicker and more secure protection.

It can be seen from the above that the circuit shown in FIG. 1 can implement ground short-circuiting protection, being able to accumulate electric power at the energy storage circuit 130 by enabling the high conduction circuit 110 to be in the partly turned-on state during the un-started state of the functional circuit 1000, and perform ground short-circuiting protection according to the voltage of the output terminal of the functional circuit by enabling the high conduction circuit 110 to be in the completely turned-on state during the started state of the functional circuit 1000.

Specific circuit structures of various subcircuits comprised in a protection circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention are described below in conjunction with FIGs. 2A to 2C. FIGs. 2A to 2C show exemplary circuit diagrams of a protection circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

In the exemplary embodiment shown in FIG. 2A, the high conduction circuit 110 may be implemented by a single NMOS transistor Q1, wherein a drain electrode (i.e. electrode D) of the transistor is connected to the input power source, a source electrode (i.e. electrode S) thereof is connected to the energy storage circuit 130, and a gate electrode (i.e. electrode G) thereof is connected to the output terminal (node A) of the charging subcircuit 120 as a control electrode. The energy storage circuit 130 may be implemented by a capacitor (referred to as first capacitor below) C1 having a relatively large capacitance value, wherein one end of the capacitor is connected to an input terminal of the functional circuit 1000, and the other end thereof is grounded. The charging subcircuit 120 may be implemented by a combination of a diode D1 and a second capacitor C2. A positive electrode of the diode D1 is connected to the input power source, and a negative electrode thereof is connected to an output terminal of the charging subcircuit; and one end of the second capacitor C2 is also connected to the output terminal of the charging subcircuit, and the other end thereof is grounded.

In this example, as shown in FIG. 2A, a parasitic diode (alternatively referred to as body diode) at both ends of the source and drain electrodes of the NMOS transistor Q1 is inversely connected in the protection circuit, that is to say, a negative electrode of the parasitic diode is connected to the input power source, and a positive electrode thereof is connected to an output terminal of the high conduction circuit 110. In this way, the NMOS transistor Q1 is not always in the turned-on state, that is to say, a forward current corresponding to the input power source will not be always provided to the energy storage circuit 130 or the functional circuit 1000 via the parasitic diode, so as to ensure that the turn-on or turn-off of the high conduction circuit 110 can be controlled by the output of the charging subcircuit 120, so that when ground short-circuiting occurs in the functional circuit 1000, the high conduction circuit 110 can be controlled to be turned off in a similar manner to that in the embodiment shown in FIG. 1 above so as to implement ground short-circuiting protection.

Furthermore, for the circuit shown in FIG. 2A, because a current may possibly flow in reverse from the energy storage circuit C1 or the output terminal of the functional circuit 1000, through the parasitic diode of the NMOS transistor Q1, into the input power source, a unidirectional element 140 such as a diode is further needed for the protection circuit to prevent reverse flow of the current.

In the circuit shown in FIG. 2A, when the functional circuit 1000 is in the un-started state, the input power source charges the second capacitor C2 via the transistor D1, so that a channel of the NMOS transistor Q1 is partly turned on, and then electric power is continuously accumulated at the first capacitor C1. When the functional circuit is set to the started state, the electric power stored on the first capacitor C1 serves as an initial input of the functional circuit 1000. Because the functional circuit 1000 has a boost function, the output voltage of the output terminal of the functional circuit 1000 may be greatly boosted, and a voltage value of the voltage may even exceed the input voltage of the protection circuit 100. In this case, a voltage of the second capacitor C2 is rapidly boosted to control the channel of the NMOS transistor Q1 to be completely turned on, so that a forward current flows to the functional circuit 1000 via the completely turned-on channel.

During a normal working process of the functional circuit 1000, high voltages can be continuously output, and dominate charging of the second capacitor C2, so that the NMOS transistor Q1 remains in the turned-on state, so as to implement the supply of power to the functional circuit 1000 by the input power source. When ground short-circuiting occurs in the functional circuit 1000, the output voltage of the functional circuit drops to a low voltage and in this case, the output voltage of the second capacitor C2 accordingly drops, thereby causing the NMOS transistor Q1 to be turned off, causing cutoff of the supply of power to the functional circuit 1000 by the input power source and thus implementing ground short-circuiting protection.

It should be noted that although FIG. 2A shows the case where the high conduction circuit 110 is implemented as a single NMOS transistor, the high conduction circuit 110 may further be implemented as a plurality of NMOS transistors, which is shown by the NMOS transistors Q1 and Q2 in the high conduction circuit 110 in FIGs. 2C and 2B.

FIGs. 2B and 2C respectively exemplarily show the case where the high conduction circuit 110 comprises a plurality of (for example, 2) NMOS transistors.

As shown in FIG. 2B, the high conduction circuit 110 comprises two NMOS transistors, that is, a first transistor Q1 and a second transistor Q2, with a source electrode and a drain electrode (i.e. electrode S and electrode D) connected to each other. In this example, gate electrodes (i.e. electrode G) of the first transistor Q1 and the second transistor Q2 may both be connected to an output terminal (node A) of the charging subcircuit 120 so as to serve as a control terminal of the high conduction circuit 110. Parasitic diodes (alternatively referred to as body diodes) of the first transistor Q1 and the second transistor Q2 are both inversely connected in the protection circuit.

A working principle of the protection circuit shown in FIG. 2B is similar to a working principle of the protection circuit shown in FIG. 2A, that is, when the functional circuit 1000 is not started, the input power source charges the second capacitor C2 via the transistor D1, so that the first transistor Q1 and the second transistor Q2 are both partly turned on, and then electric power is continuously accumulated at the first capacitor C1. When the functional circuit 1000 is set to the started state, the electric power stored on the first capacitor C1 serves as an initial input of the functional circuit 1000, so that the output voltage of the output terminal of the functional circuit 1000 is greatly boosted. In this case, the first transistor Q1 and the second transistor Q2 are completely turned on, and the functional circuit 1000 works normally, so that a forward current from the input power source flows to the functional circuit 1000 via channels of the first transistor Q1 and the second transistor Q2. Subsequently, the turn-off or turn-on of the first transistor Q1 and the second transistor Q2 is controlled according to the output voltage of the output terminal of the functional circuit 1000, so as to then implement ground short-circuiting protection.

However, it should be noted that, for the circuit shown in FIG. 2B, also because a current may possibly flow in reverse from the energy storage circuit C1 or the output terminal of the functional circuit 1000, through the parasitic diodes of the first transistor Q1 and the second transistor Q2, into the input power source, a unidirectional element 140 such as a diode is also needed to prevent reverse flow of the current.

In addition, FIG. 2C exemplarily shows the other case where the high conduction circuit 110 comprises a plurality of (for example, 2) NMOS transistors. In the example shown in FIG. 2C, the high conduction circuit 110 may comprise a first transistor Q1’ and a second transistor Q2’ connected in a mirroring manner; the expression “connected in a mirroring manner” means that a source electrode (i.e. electrode S) of the first transistor Q1’ is connected to a source electrode (i.e. electrode S) of the second transistor Q2’, or a drain electrode (i.e. electrode D) of the first transistor Q1’ is connected to a drain electrode (i.e. electrode D) of the second transistor Q2’. In the example shown in FIG. 2C, the source electrodes of the first transistor Q1’ and the second transistor Q2’ are connected, and gate electrodes (i.e. G electrodes) of the two are connected to the output terminal of the charging subcircuit 120 as the control terminal of the high conduction circuit. Specifically, the gate electrodes of the first transistor Q1’ and the second transistor Q2’ may both be connected to the output terminal (node A) of the charging subcircuit 120 so as to serve as the control terminal of the high conduction circuit 110. Parasitic diodes comprised in the first transistor Q1’ and the second transistor Q2’ are also connected in a mirroring manner in the protection circuit, wherein the manner of connecting a parasitic diode of at least one transistor (in this example, a parasitic diode of the first transistor Q1’) can ensure that a forward current must flow to the functional circuit through a corresponding channel of the transistor.

That is to say, when the functional circuit is in the un-started state, under the action of charging by the input power source, a voltage of the second capacitor C2 enables the first transistor Q1’ and the second transistor Q2’ to be partly turned on. In this case, a carrier flows to the first capacitor C1 via the channel of the first transistor Q1’ and the parasitic diode of the second transistor Q2’, so that the first capacitor C1 stores electric power. When the functional circuit is in the started state, the first capacitor C1 supplies power to the functional circuit 1000 so that the output voltage is rapidly boosted, the first transistor Q1’ and the second transistor Q2’ are completely turned on, and a forward current flows to the functional circuit 1000 via channels of the first transistor Q1’ and the second transistor Q2’. Subsequently, the turn-off or turn-on of the first transistor Q1’ and the second transistor Q2’ is controlled according to the output voltage of the output terminal of the functional circuit 1000, so as to then implement ground short-circuiting protection.

It is worth noting that because the circuit shown in FIG. 2C uses a structure in which NMOS transistors are connected in a mirroring manner, to serve as the high conduction circuit 110, the circuit, compared with the circuit shown in FIG. 2B, additionally has an effect of preventing a current from flowing in reverse into the input power source. That is, the current can be prevented from flowing from the energy storage circuit C1, through the parasitic diodes of the first transistor Q1’ and the second transistor Q2’, to the power source, thereby protecting the input power source.

Furthermore, it is recognized that although FIG. 2C exemplarily shows the high conduction circuit 110 as a pair of NMOS transistors with source electrodes being connected, it is recognized by those skilled in the art that the manner of connecting a pair of NMOS transistors is not limited thereto, and the pair of NMOS transistors may alternatively be a pair of NMOS transistors with two drain electrodes being connected. Alternatively, in addition to a pair of NMOS transistors connected in a mirroring manner, at least one other transistor connected to the pair of transistors may further be comprised. In conclusion, it is further recognized by those skilled in the art that, according to the understanding of the present disclosure, the number of transistors of the high conduction circuit 110 is not limited to one shown in FIG. 2A or two shown in FIGs. 2B and 2C, and may actually comprise three, four, or even more transistors, provided that there is at least one NMOS transistor of the plurality of transistors that is inversely connected in the circuit (inversely connected in the circuit for a parasitic diode of the transistor) , so that the turn-on or turn-off of the high conduction circuit 110 can be controlled by means of the charging subcircuit 120.

FIG. 3 shows a schematic circuit diagram of a protection circuit for carrying out ground short-circuiting protection according to an exemplary embodiment of the present invention.

In the circuit shown in FIG. 3, a dashed box 1000 shows a circuit diagram of a functional circuit. In this embodiment, the functional circuit 1000 is implemented as an LED driving circuit for driving an LED string. As shown in the figure, the LED driving circuit may comprise a transistor Q4, inductors L1 and L2, a diode D4, capacitors C3 and C4, resistors R2 and R8, and a pulse width modulation (PWM) controller. In the circuit described above, the PWM controller performs pulse width modulation by sensing an LED current and sensing a peak current to implement desired DC-DC conversion. It should be noted that the functional circuit 1000 is not limited to the forms described above, and may be various circuits having a boost function well known to those skilled in the art.

As shown in FIG. 3, the charging subcircuit 120 comprises the diode D1 and the capacitor C2 to control the high conduction circuit 110, so that the high conduction circuit 110 is turned on or turned off.

In addition to comprising a pair of NMOS transistors Q1’ and Q2’ connected in a mirroring manner as shown in FIG. 2C, the high conduction circuit 110 may further comprise: a device for preventing an excessively large input voltage, such as a third transistor Q3, a diode D3, and a resistor R5; a device for preventing excessively large base electrode voltages of the first transistor Q1’ and the second transistor Q2’ , such as voltage stabilizing diodes D2 and D14; and a device for resistance matching and current protection, such as resistors R3, R7, and R1.

In this embodiment, the energy storage circuit 130 is implemented by the first capacitor C1, and is configured to perform charging in the case where the high conduction circuit 110 is partly turned on and to supply power to the functional circuit 1000 in response to the enabling of the functional circuit 1000.

A working principle of the protection circuit shown in FIG. 3 will be described in detail below.

When the LED driving circuit is not enabled, the LED driving circuit outputs a low voltage which is insufficient to drive the LED string, that is to say, a load exhibits a high impedance. In this case, the input voltage charges the capacitor C2 via the diode D1, so that the first transistor Q1’ and the second transistor Q2’ in the high conduction circuit 110 are partly turned on. Because the first transistor Q1’ and the second transistor Q2’ are partly turned on, the input voltage from the input power source charges the first capacitor C1, so that electric power is stored at the first capacitor C1.

When the LED driving circuit is enabled, the electric power stored at the first capacitor C1 is transferred to the capacitors C3 and C4 in the LED driving circuit. Therefore, the output voltage of the LED driving circuit will be sharply boosted, so that a voltage of the node A is also sharply boosted, and then the first transistor Q1’ and the second transistor Q2’ are completely turned on.

Afterwards, the LED driving circuit enters a normal working mode, an output terminal thereof will output a high voltage, and the first transistor Q1’ and the second transistor Q2’ remain completely turned on under the action of the high voltage of the output terminal of the LED driving circuit. If ground short-circuiting occurs during working of the LED driving circuit (the output terminal outputs a low voltage) , voltages of the gate electrodes of the first transistor Q1’ and the second transistor Q2’ will be pulled down due to the low voltage of the output terminal, causing the first transistor Q1’ and the second transistor Q2’ to be turned off. Finally, the functional circuit is disconnected from the input power source. In addition, it should be noted that if ground short-circuiting occurs as soon as the functional circuit is started, the gate electrodes of the first transistor Q1’ and the second transistor Q2’ will be maintained at a low voltage, and consequently, the LED driving circuit cannot be started. In this way, the protection circuit capable of carrying out ground short-circuiting protection is implemented, and because the turn-on or turn-off of the high conduction circuit is controlled using a voltage, compared with traditional circuits that implement ground short-circuiting protection by controlling the turn-off of a switch after detecting a current and analysing the detected current via software, quicker and more secure protection can be implemented.

FIGs. 4A to 6B show diagrams of tests for the protection circuit for carrying out ground short-circuiting protection shown in FIG. 3 according to the exemplary embodiment of the present invention.

Specifically, FIG. 4A shows a pulse diagram of an input current of the LED driving circuit in a normal working state. FIG. 4B shows curves of an input voltage of the protection circuit and an output voltage of the LED driving circuit in the normal working state, wherein the dashed line indicates the input voltage of the protection circuit, and the solid line indicates the output voltage of the LED driving circuit. As shown in FIGs. 4A and 4B, before about the 10th ms (T1 time period) , the functional circuit is not started, and because the high conduction circuit 110 is in the partly turned-on state, electric power from the input power source is stored at the first capacitor C1. In this case, the input current of the LED driving circuit is 0 A (see the T1 time period in FIG. 4A) , the output voltage of the LED driving circuit is relatively low, and a load exhibits a high impedance. In this phase, the output voltage is slowly boosted (see the T1 time period of the solid line in FIG. 4B) . When the PWM controller is started at a certain moment (for example, a time point of 10 ms) , the electric power stored at the first capacitor (for example, C1 in FIG. 3) quickly supplies power to the LED driving circuit, so that the output voltage is rapidly boosted. Because the high conduction circuit 110 is completely turned on in this case, the input power source supplies power normally to the LED driving circuit, the output voltage of the LED driving circuit reaches a stable 30 V, and then a change from an input voltage of about 13 V to an output voltage of about 30 V is implemented, and in this case, the corresponding input current is 3.5 A and the LED driving circuit enters the normal working mode (T2 time period) .

FIG. 5A shows a diagram of an input current of a driver in a state where ground short-circuiting occurs when the LED driving circuit is enabled. FIG. 5B shows curves of an input voltage of the protection circuit and an output voltage of the LED driving circuit in the state where ground short-circuiting occurs when the LED driving circuit is enabled, wherein the dashed line indicates the input voltage of the protection circuit, and the solid line indicates the output voltage of the LED driving circuit. When ground short-circuiting occurs in the LED driving circuit, the output voltage of the LED driving circuit is extremely low and in this case, the voltages of the gate electrodes of the first transistor Q1’ and the second transistor Q2’ in the high conduction circuit 110 will always be low voltages, and therefore, the high conduction circuit cannot be completely turned on.

Therefore, even if a control apparatus of the system erroneously turns on the PWM controller, because the high conduction circuit is always turned off, a sudden boost of the output voltage or the input current will not occur. Referring to FIGs. 5A and 5B, the input current of the LED driving circuit will always be maintained at 0 A (see FIG. 5A) , and the output voltage thereof will always be maintained at 0 V (see the solid line in FIG. 5B) .

FIG. 6A shows a diagram of an input current of the LED driving circuit in the state where ground short-circuiting occurs in a normal working process of the LED driving circuit. FIG. 6B shows curves of an input voltage of the protection circuit and an output voltage of the LED driving circuit in the state where ground short-circuiting occurs in the normal working process of the LED driving circuit, wherein the dashed line indicates the input voltage of the protection circuit, and the solid line indicates the output voltage of the LED driving circuit. The LED driving circuit is started at a moment of about 10 ms, and the process of the starting is as described in conjunction with FIGs. 4A and 4B. At a moment of about 30 ms, ground short-circuiting occurs in the LED driving circuit. In this case, the output voltage of the LED driving circuit rapidly drops to 0 V (as shown in FIG. 6B) , thereby causing the high conduction circuit 110 to be turned off, that is to say, the input power source is disconnected from the LED driving circuit. The input current of the LED driving circuit also accordingly drops from a normal working current to 0 A (as shown in FIG. 6A) .

It may be seen that, according to the exemplary embodiments of the present invention, a protection circuit for carrying out ground short-circuiting protection is implemented from the perspective of hardware; this can turn off an input power source more quickly and more securely when a functional circuit is short-circuited, and can make the functional circuit stable more quickly when the functional circuit is started.

FIG. 7 shows a flowchart of an operation method 700 for operating the circuit shown in FIG. 1 according to an exemplary embodiment of the present invention.

FIG. 7 shows the operation method 700 for operating the circuit shown in FIG. 1.The operation method 700 will be described below in conjunction with the specific circuit structure shown in FIG. 1. Specifically, the operation method 700 may comprise: controlling, according to an output voltage of the functional circuit 1000, the high conduction circuit 110 to be turned on or turned off (operation S715) . For example, the step of controlling, according to the output voltage of the functional circuit 1000, the high conduction circuit 110 to be turned on or turned off may further comprise: in response to the output voltage of the functional circuit 1000 being a high voltage, completely turning on the high conduction circuit 110; and in response to the output voltage of the functional circuit 1000 being a low voltage, turning off the high conduction circuit 110.

Additionally, the operation method 700 may further additionally comprise: when the functional circuit 1000 is not started, charging the charging subcircuit 120 based on an input voltage of an input power source and a low output voltage of the functional circuit 1000 (in this case, the input voltage of the input power source dominates) , so as to control the high conduction circuit 110 to be partly turned on, and thus the energy storage circuit 130 stores electric power (operation S705) . That is to say, in this case, the charging subcircuit 120 is charged from the input power source, so that the output voltage of the charging subcircuit 120 reaches a higher voltage with respect to the low voltage. The higher voltage is theoretically less than the defined high voltage and is therefore insufficient to completely turn on NMOS transistors in the high conduction circuit 110 that are inversely connected, but can partly turn on the NMOS transistors. That is to say, in this case, the high conduction circuit 110 is partly turned on under the control of the charging subcircuit 120, so that the input power source charges the energy storage circuit 130. When the functional circuit 1000 is started, the charging subcircuit 120 enables, based on the input voltage and a high output voltage of the functional circuit 1000, the high conduction circuit 110 to be completely turned on under the control of the charging subcircuit 120, so as to further enable the functional circuit 1000 to work normally (operation S710) . More specifically, because the energy storage circuit 130 has accumulated electric power before the functional circuit 1000 is started, when the functional circuit 1000 is started under the control of software, for example, the energy storage circuit 130 supplies power to the functional circuit 1000 to perform a boost operation. Therefore, the output voltage of the output terminal of the functional circuit 1000 is sharply boosted, and the charging subcircuit 120 is charged via a second input terminal of the charging subcircuit 120, so that the output voltage of the charging subcircuit 120 is boosted and then the high conduction circuit 110 is completely turned on. In this case, because the high conduction circuit 110 is completely turned on, the input power source directly supplies power to the functional circuit 1000 via the high conduction circuit. The functional circuit 1000 enters a stable running phase.

Afterwards, the process of controlling, according to the output voltage of the functional circuit 1000, the high conduction circuit 110 to be turned on or turned off may be carried out, that is to say, when the output terminal of the functional circuit 1000 is maintained at a high voltage, the high conduction circuit 110 is continuously turned on, and when the output terminal of the functional circuit 1000 is pulled down (ground short-circuiting occurs) , the high conduction circuit 110 is turned off so as to implement ground short-circuiting protection. Compared with traditional methods that implement ground short-circuiting protection by controlling the turn-off of a switch after detecting a current and analysing the detected current via software, such a method can implement quicker and more secure protection.

Furthermore, according to an exemplary embodiment of the present disclosure, a circuit having an output grounding protection function is further provided, wherein the circuit comprises: the protection circuit as described above; and a functional circuit, wherein the functional circuit has a boost function. The circuit can turn off an input power source more quickly and more securely when the functional circuit is short-circuited, and can make the functional circuit stable more quickly when the functional circuit is started.

According to another exemplary embodiment of the present disclosure, an operation method for a circuit is further provided, wherein the circuit is the circuit as described above, and the operation method comprises: outputting a low voltage by the functional circuit to the protection circuit, so that the high conduction circuit in the protection circuit is turned off; or outputting a high voltage by the functional circuit to the protection circuit, so that the high conduction circuit in the protection circuit is turned on. Such an operation method can ensure quicker and more secure turn-off of an input power source when the functional circuit is short-circuited, and can make the functional circuit stable more quickly when the functional circuit is started.

According to another exemplary embodiment of the present disclosure, a vehicle light is further provided, wherein the vehicle light comprises the protection circuit as described in any one of the examples above, or the vehicle light comprises the circuit as described in any one of the examples above.

According to another exemplary embodiment of the present disclosure, a vehicle is further provided, wherein the vehicle uses the vehicle light as described in any one of the examples above.

It should be noted that although the implementations of the method according to the exemplary embodiments of the present disclosure are separately described above in separate forms, the features described in the various implementations described above may be combined in a single implementation in any manner without departing from the idea of the present disclosure, and the features described in a single implementation may also be implemented separately in a plurality of implementations.

Although the present disclosure has been shown and described with reference to the specific exemplary embodiments of the present disclosure, it should be understood by those skilled in the art that a variety of changes in form and detail may be made to the present disclosure without departing from the spirit and scope of the present disclosure that are defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the embodiments described above, but should be determined by both the appended claims and the equivalents of the appended claims.

Claims

Protection circuit (100) for ground short-circuiting protection, the protection circuit (100) comprising:

a high conduction circuit (110) for controlling the supply of electric power for a functional circuit (1000) , wherein the functional circuit (1000) has a boost function; and

a charging subcircuit (120) for controlling, based on an input voltage of an input power source of the protection circuit (100) and an output voltage from the functional circuit (1000) , the high conduction circuit (110) to be turned on or turned off; and

an energy storage circuit (130) for storing electric power from the input power source so as to provide electric power for the functional circuit (1000) .
Protection circuit according to Claim 1, wherein

a first terminal of the charging subcircuit (120) is connected to the input power source, and a second terminal thereof is connected to an output terminal of the functional circuit (1000) ; and

a first terminal of the high conduction circuit (110) is connected to the input power source, a second terminal thereof is connected to an input terminal of the functional circuit (1000) via the energy storage circuit, and a control terminal thereof is connected to an output terminal of the charging subcircuit (120) ,

wherein the high conduction circuit (110) is configured to be turned on in response to the control terminal thereof being at a high voltage and to be turned off in response to the control terminal thereof being at a low voltage.
Protection circuit according to Claim 2, wherein the high conduction circuit (110) uses one or more NMOS transistors.
Protection circuit according to Claim 3, wherein the energy storage circuit (130) comprises a first capacitor (C1) , one end of the first capacitor (C1) is connected to the input terminal of the functional circuit (1000) , and the other end thereof is grounded.
Protection circuit according to Claim 3, wherein when the high conduction circuit (110) uses a plurality of NMOS transistors, the plurality of NMOS transistors comprise at least two NMOS transistors (Q1’, Q2’) connected in a mirroring manner,

wherein a source electrode of a first transistor (Q1’) of the two NMOS transistors (Q1’, Q2’) connected in a mirroring manner is connected to a source electrode of a second transistor (Q2’) thereof, and a gate electrode of each of the first transistor (Q1’) and the second transistor (Q2’) is connected to the second terminal of the charging subcircuit (120) as the control terminal of the high conduction circuit (110) .
Protection circuit according to Claim 3, wherein when the high conduction circuit (110) uses a plurality of NMOS transistors, a source electrode and a drain electrode of two adjacent NMOS transistors (Q1, Q2) of the plurality of NMOS transistors are connected to each other.
Protection circuit according to Claim 3, wherein when the high conduction circuit (110) uses a single NMOS transistor (Q1) , a gate electrode of the single NMOS transistor (Q1) is connected to the second terminal of the charging subcircuit (120) as a control terminal.
Protection circuit according to Claim 2, wherein the charging subcircuit (120) comprises a diode (D1) and a second capacitor (C2) ,

wherein a positive electrode of the diode (D1) is connected to the input power source, and a negative electrode thereof is connected to the output terminal of the functional circuit (1000) ; and

one end of the second capacitor (C2) is connected to the output terminal of the functional circuit (1000) , and the other end thereof is grounded.
Protection circuit according to Claim 1, wherein the functional circuit (1000) is a DC-DC conversion circuit.
Operation method for a circuit, the circuit being as described in any one of Claims 1 to 9, wherein the operation method comprises the step of:

controlling, according to an output voltage of the functional circuit (1000) , the high conduction circuit (110) to be turned on or turned off.
Operation method according to Claim 10, wherein the step of controlling, according to the output voltage of the functional circuit (1000) , the high conduction circuit (110) to be turned on or turned off further comprises:

in response to the output voltage being a high voltage, completely turning on the high conduction circuit (110) ; and

in response to the output voltage being a low voltage, turning off the high conduction circuit (110) .
Operation method according to Claim 10, wherein the operation method further comprises the following steps:

in response to the functional circuit (1000) being not started, the charging subcircuit (120) controlling, based on an input voltage and a low output voltage of the functional circuit (1000) , the high conduction circuit (110) to be partly turned on, so that the energy storage circuit (130) stores power; and

in response to the functional circuit (1000) being started, the charging subcircuit (120) enabling, based on the input voltage and a high output voltage of the functional circuit (1000) , the high conduction circuit (110) to be completely turned on under the control of the charging subcircuit (120) , so that power is supplied from the input power source to the functional circuit (1000) .
Circuit having an output grounding protection function, comprising: the protection circuit of any one of Claims 1 to 9; and a functional circuit (1000) , wherein the functional circuit (1000) has a boost function.
Operation method for a circuit, wherein the circuit is as described in Claim 13, and the operation method comprises:

outputting a low voltage by the functional circuit (1000) to the protection circuit, so that the high conduction circuit (110) in the protection circuit is turned off; or

outputting a high voltage by the functional circuit (1000) to the protection circuit, so that the high conduction circuit (110) in the protection circuit is turned on.
Vehicle light, comprising the circuit of Claim 13.
Vehicle, which uses the vehicle light of Claim 15.