A detection circuit and a power supply device for detecting a short circuit of a power supply output port

Abstract

The present application discloses a detection circuit for short - circuit detection of a power - supply output port, including: a short - circuit detection circuit for short - circuit detection, whose first port is connected in series with a first auxiliary power - supply circuit, whose second port is connected in parallel with the power - supply output port, and the detection signal output therefrom is input to a processor. The processor controls the power - supply output port to be in an isolated state from the power - supply in response to a power - supply startup operation. The detection current from the first auxiliary power - supply circuit flows into the first end in the first port. In the case of a short - circuit in the power - supply output port, the detection current flowing into the first end sequentially flows back to the first auxiliary power - supply circuit through the second port of the short - circuit detection circuit that is currently in a short - circuit state and the second end in the first port of the short - circuit detection circuit, so that the short - circuit detection circuit outputs a first - level signal for indicating the existence of a short - circuit. The short - circuit detection in the present application takes less time and can achieve rapid discharge of the residual voltage, avoiding damage to the power - supply and internal components of the load.

Description

Technical Field

[0001] The present invention relates to the field of short - circuit detection, and in particular, to a detection circuit for short - circuit detection of a power supply output port. Background Art

[0002] Most existing power supply devices do not have a short - circuit detection function at the output end before outputting the power supply. If the short - circuit detection is not performed at the power supply output end before power supply, it will cause the internal components of the power supply device to burn out. For example, the relay on the mains output channel will burn out due to over - current, and even the load will burn out due to short - circuit heating. Summary of the Invention

[0003] The present invention provides a detection circuit for short - circuit detection of a power supply output port to improve the safety of power supply output.

[0004] In a first aspect of the present invention, a detection circuit for short - circuit detection of a power supply output port is provided. The detection circuit includes:

[0005] A short - circuit detection circuit for short - circuit detection. The first port of the short - circuit detection circuit is connected in series with a first auxiliary power supply circuit for providing a detection current to the short - circuit detection circuit. The second port of the short - circuit detection circuit is connected in parallel with the power supply output port. The detection signal output by the short - circuit detection circuit is input to a processor.

[0006] Wherein,

[0007] The detection signal is generated in the following manner:

[0008] The processor controls the power supply output port to be in an isolated state from the power supply in response to a power - on start operation.

[0009] The detection current output by the first auxiliary power supply circuit flows through the first port of the short - circuit detection circuit.

[0010] And, in the case of a short - circuit at the power supply output port, the detection current flowing into the first end of the first port of the short - circuit detection circuit flows back to the first auxiliary power supply circuit through the second port of the short - circuit detection circuit that is currently in a short - circuit state and the second end of the first port of the short - circuit detection circuit in sequence, so that the short - circuit detection circuit outputs a first - level signal indicating the existence of a short - circuit.

[0011] In the case of no short - circuit at the power supply output port, the detection current flowing into the first end of the first port of the short - circuit detection circuit flows back to the first auxiliary power supply circuit through one end of the second port of the short - circuit detection circuit that is currently not in a short - circuit state and the second end of the first port of the short - circuit detection circuit in sequence, so that the short - circuit detection circuit outputs a second - level signal indicating the non - existence of a short - circuit.

[0012] As a possible implementation, between the power supply output port and the power supply, there is included:

[0013] A first switch circuit for turning on and off the power supply output to the power supply output port. Among them, the input port of the first switch circuit is connected in series with the power supply, and the output port of the first switch circuit is connected in series with the power supply output port;

[0014] As a possible implementation, the processor controls the first switch circuit to be in the off state in response to a power supply startup operation, controls the first switch circuit to be in the off state in response to a first level signal, and controls the first switch circuit to be in the on state in response to a second level signal.

[0015] As a possible implementation, the detection circuit further includes: a unidirectional current circuit for enabling current to flow into the short-circuit detection circuit in a single direction.

[0016] As a possible implementation, the output port of the first auxiliary power supply circuit is connected in series with the input port of the unidirectional current circuit, and the output port of the unidirectional current circuit is connected in series with the first port of the short-circuit detection circuit.

[0017] As a possible implementation, the detection current from the first auxiliary power supply circuit flows into the first end of the first port of the short-circuit detection circuit successively through one end of the input port of the unidirectional current circuit, the unidirectional current circuit, and one end of the output port of the unidirectional current circuit. The detection current flowing back from the second end of the first port of the short-circuit detection circuit to the first auxiliary power supply circuit flows back to the first auxiliary power supply circuit successively through the other end of the output port of the unidirectional current circuit, the unidirectional current circuit, and the other end of the input port of the unidirectional current circuit.

[0018] As a possible implementation, the first residual voltage across the power supply output port is discharged through a first discharge loop formed by the second port of the short-circuit detection circuit, the internal circuit between this second port and the first port of the short-circuit detection circuit, the output port of the unidirectional current circuit, and the internal circuit in the unidirectional circuit.

[0019] As a possible implementation, the second residual voltage across the power supply output port is discharged through a second discharge loop formed by the second port of the short-circuit detection circuit and the internal circuit in the short-circuit detection circuit.

[0020] Among them, the polarities of the residual voltages between the first residual voltage and the second residual voltage are opposite.

[0021] As a possible implementation, the unidirectional current circuit includes: a first unidirectional conductor, a first current-limiting resistor, a second current-limiting resistor, a fuse, and a second unidirectional conductor.

[0022] Among them,

[0023] One end of the first one-way conductor is connected in series with one end of the first current-limiting resistor, and the other end of the first one-way conductor is connected in series with one end of the first auxiliary power supply.

[0024] One end of the second current-limiting resistor is connected in series with one end of the fuse, and the other end of the second current-limiting resistor is connected in series with the other end of the first auxiliary power supply.

[0025] The second one-way conductor is connected in series between the connection point of one end of the first one-way conductor and one end of the first current-limiting resistor and the connection point of one end of the second current-limiting resistor and one end of the fuse.

[0026] The other end of the first current-limiting resistor and the other end of the fuse form the output port of the one-way current circuit, which is connected in series with the first port of the short-circuit detection circuit.

[0027] The first one-way conductor is in a conducting state when the detection current from the first auxiliary power supply flows into the one-way current circuit, and is in a cut-off state when discharging the first residual voltage in the first discharge circuit.

[0028] The second one-way conductor is in a cut-off state when the detection current from the first auxiliary power supply flows into the one-way current circuit, and is in a conducting state when discharging the first residual voltage in the first discharge circuit.

[0029] As a possible implementation, the short-circuit detection circuit includes: a second switch circuit for enabling the detection circuit to work when the switch in the first switch circuit is in the off state and disabling the detection circuit when the switch in the first switch circuit is in the off state, a clamping branch, and a detection signal generation circuit.

[0030] Among them,

[0031] The input port of the second switch circuit is connected in series with the output port of the one-way current circuit. A clamping branch is connected in series between the output ports of the second switch circuit. Among them, the input port of the second switch circuit is the first port of the short-circuit detection circuit, and the output port of the second switch circuit is the second port of the short-circuit detection circuit. This second port enables the clamping branch to have no clamping voltage when there is a short-circuit state at the power supply output port so that the detection signal generation circuit generates a first-level signal, and generates a clamping voltage when there is no short-circuit state at the power supply output port so that the detection signal generation circuit generates a second-level signal.

[0032] The input port of the detection signal generation circuit is connected in parallel with the clamping branch to generate a corresponding level signal based on the clamping voltage.

[0033] As a possible implementation, the internal circuit in the short-circuit detection circuit includes a clamping branch and a detection signal generation circuit.

[0034] The internal circuit in the one-way circuit includes: a branch formed by a first current-limiting resistor, a second one-way conductor, and a fuse.

[0035] The first switch circuit includes: a first switch connected in series between the first end of the power supply output and the first end of the second port, and a second switch connected in series between the second end of the power supply output and the second end of the second port.

[0036] The second switch circuit includes: a third switch with one end connected in series to the first end of the first port and the other end connected in series to the first end of the second port, and a fourth switch with one end connected in series to the second end of the first port and the other end connected in series to the second end of the second port.

[0037] As a possible implementation, the clamping branch includes: a fifth switch, a third current-limiting resistor, and a voltage regulator diode connected in series in sequence.

[0038] The detection signal generation circuit includes: a coupling circuit for coupling the voltage across the voltage regulator diode and generating a detection signal based on the coupled voltage.

[0039] As a possible implementation, the clamping branch further includes a third one-way conductor for preventing reverse breakdown current from flowing into the voltage regulator diode. The third one-way conductor is in a conducting state when the detection current from the first auxiliary power supply flows into the clamping circuit and is in a conducting state when the second residual voltage is discharged in the second discharge loop.

[0040] As a possible implementation, the coupling circuit includes: an optocoupler and a second auxiliary power supply for providing a working power supply to the optocoupler.

[0041] Among them,

[0042] The primary side of the optocoupler is connected in parallel with both ends of the voltage regulator diode through a fifth current-limiting resistor. The secondary side of the optocoupler is connected in series with both ends of the second auxiliary power supply through a fourth pull-up resistor. The level signal output by the secondary side of the optocoupler is output to the input / output terminal of the processor.

[0043] The second auxiliary power supply is isolated from the first auxiliary power supply.

[0044] As a possible implementation, when the processor controls the switch in the first switch circuit to be in the off state, it controls the second switch circuit and the fourth switch to be in the on state. When the processor controls the switch in the first switch circuit to be in the on state, it controls the second switch circuit and the fourth switch to be in the off state.

[0045] As a possible implementation, the first residual voltage is that the potential of the second end in the second port is greater than the potential of the first end in the second port, and the first discharge current in the first discharge circuit sequentially passes from the second end in the second port through the third switch, the fuse, the second unidirectional conduction tube, the first current-limiting resistor, the fourth switch, and reaches the first end in the second port;

[0046] As a possible implementation, the second residual voltage is that the potential of the first end in the second port is greater than the potential of the second end in the second port, and the second discharge current in the second discharge circuit sequentially passes from the first end in the second port through the fifth switch, the third current-limiting resistor, the parallel circuit formed by the zener diode and the primary side of the optocoupler connected in parallel with the zener diode through the fifth current-limiting resistor, and the third unidirectional conduction tube and reaches the second end in the second port;

[0047] As a possible implementation, when a short-circuit state exists at the power supply output port, the detection current sequentially passes from one end of the first auxiliary power supply through the first unidirectional conduction tube, the first current-limiting resistor, the fourth switch, the second port, the third switch, the fuse, and the second current-limiting resistor and reaches the other end of the first auxiliary power supply, where the second port is in a short-circuit state;

[0048] As a possible implementation, when a non-short-circuit state exists at the power supply output port, the detection current sequentially passes from one end of the first auxiliary power supply through the first unidirectional conduction tube, the first current-limiting resistor, the fourth switch, the fifth switch, the third current-limiting resistor, the parallel circuit formed by the zener diode and the primary side of the optocoupler connected in parallel with the zener diode through the fifth current-limiting resistor, the third unidirectional conduction tube, the third switch, the fuse, and the second current-limiting resistor and reaches the other end of the first auxiliary power supply.

[0049] As a possible implementation, the power supply is a charging device for charging an in-vehicle charger,

[0050] As a possible implementation, the first auxiliary power supply is the power generated by the flyback power supply circuit in the charging device,

[0051] As a possible implementation, the first unidirectional conduction tube is the first diode, the cathode of the first diode is connected to the first current-limiting resistor, and the anode of the first diode is connected to the positive electrode of the first auxiliary power supply;

[0052] The second unidirectional conduction tube is the second diode, the cathode of the second diode is connected to the cathode of the first diode, and the anode of the second diode is connected in series to the point where one end of the second current-limiting resistor and one end of the fuse are connected in series;

[0053] The fuse is a fuse element,

[0054] The third unidirectional conduction tube is a third diode, which is connected in series with a voltage stabilizing tube. The cathode of the third diode is connected in series with the second end of the second port, and the anode of the third diode is connected in series with the voltage stabilizing tube.

[0055] In a second aspect of the present application, a power supply device is provided, which includes any one of the detection circuits for detecting a short circuit of a power supply output port.

[0056] In a third aspect of the present application, a charger is provided, which includes any one of the detection circuits for detecting a short circuit of a power supply output port.

[0057] In a fourth aspect of the present application, a detection method for detecting a short circuit of a power supply output port is provided. The method includes: on the processor side,

[0058] In response to a power supply start operation, controlling the power supply output port to be in an isolated state from the power supply, so that:

[0059] The detection current from the first auxiliary power supply circuit in the detection circuit for providing a detection current to the short circuit detection circuit flows into the first end of the first port of the short circuit detection circuit in the detection circuit.

[0060] In the case where there is a short circuit at the power supply output port, the detection current flowing into the first end sequentially flows back to the first auxiliary power supply circuit through the second port of the short circuit detection circuit that is currently in a short circuit state and the second end of the first port of the short circuit detection circuit, so that the short circuit detection circuit outputs a first level signal indicating the existence of a short circuit.

[0061] In the case where there is no short circuit at the power supply output port, the detection current flowing into the first end sequentially flows back to the first auxiliary power supply circuit through one end of the second port of the short circuit detection circuit that is currently not in a short circuit state and the second end of the first port of the short circuit detection circuit, so that the short circuit detection circuit outputs a second level signal indicating the non-existence of a short circuit.

[0062] Wherein,

[0063] The short circuit detection circuit is used for short circuit detection. The first port of the short circuit detection circuit is connected in series with the first auxiliary power supply circuit.

[0064] The second port of the short circuit detection circuit is connected in parallel with the output port of the first switch circuit.

[0065] The detection signal output by the short circuit detection circuit is input to the processor.

[0066] A detection circuit for short - circuit detection of a power - supply output port provided by an embodiment of the present application controls, by a processor in response to a power - supply startup operation, the power - supply to be isolated from the power - supply output port, so that the detection circuit performs short - circuit detection on the power - supply output port before the power - supply device outputs power to the load, avoiding damage to circuit components due to a short - circuit at the power - supply output port. When there is a short - circuit at the power - supply output port, the detection current flowing into the first terminal flows back to the first auxiliary power - supply circuit through the second port of the short - circuit detection circuit that is currently in a short - circuit state and the second terminal in the first port of the short - circuit detection circuit in sequence, so that the short - circuit detection circuit outputs a first - level signal indicating the existence of a short - circuit. When there is no short - circuit at the power - supply output port, the detection current flowing into the first terminal flows back to the first auxiliary power - supply circuit through one end of the second port of the short - circuit detection circuit that is currently in a non - short - circuit state and the second terminal in the first port of the short - circuit detection circuit in sequence, so that the short - circuit detection circuit outputs a second - level signal indicating the non - existence of a short - circuit, greatly improving the short - circuit detection efficiency and being not affected by the voltage of the power provided by the power - supply device. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 FIG. is a schematic diagram of a detection circuit for short - circuit detection of a power - supply output port according to an embodiment of the present application.

[0068] Figure 2 FIG. is a schematic diagram of a detection - current path in the case of a short - circuit at the power - supply output port.

[0069] Figure 3 FIG. is a schematic diagram of a detection - current path in the case of no short - circuit at the power - supply output port.

[0070] Figure 4 FIG. is a schematic diagram of a detection - current path having a unidirectional - current circuit and a first discharge loop.

[0071] Figure 5 FIG. is a schematic diagram of a second discharge loop.

[0072] Figure 6 FIG. is a schematic diagram of a detection circuit for short - circuit detection of a power - supply output port of a charging device according to this embodiment.

[0073] Figure 7 FIG. is a schematic diagram of a detection - current path when there is a short - circuit at the power - supply output port in this embodiment.

[0074] Figure 8 FIG. is a schematic diagram of a detection - current path when there is no short - circuit at the power - supply output port in this embodiment.

[0075] Figure 9 FIG. is a schematic diagram of a second residual - voltage discharge current when there is no short - circuit at the power - supply output port in this embodiment.

[0076] Figure 10 It is a schematic diagram of the first residual voltage discharge current when there is no short circuit at the power supply output port of this embodiment.

[0077] Figure 11 It is a schematic flowchart of a detection method for detecting a short circuit at the power supply output port of this embodiment. Specific implementation manners

[0078] In order to make the objectives, technical means, and advantages of this application clearer, the following further describes this application in detail with reference to the accompanying drawings.

[0079] See Figure 1 as shown in Figure 1 It is a schematic diagram of a detection circuit for detecting a short circuit at the power supply output port of an embodiment of this application. The detection circuit includes:

[0080] A first switch circuit for turning on and off the power supply output to the power supply output port. Among them, the input port of the first switch circuit is connected in series with the power supply, and the output port of the first switch circuit is connected in series with the power supply output port.

[0081] A short - circuit detection circuit for short - circuit detection. The first port of the short - circuit detection circuit is connected in series with a first auxiliary power supply circuit for providing a detection current to the short - circuit detection circuit.

[0082] The second port of the short - circuit detection circuit is connected in parallel with the power supply output port.

[0083] The detection signal output by the short - circuit detection circuit is input to the processor.

[0084] Among them,

[0085] The detection signal is generated in the following manner:

[0086] The processor responds to the power - on start operation and controls the power supply output port to be in an isolated state from the power supply.

[0087] The detection current from the first auxiliary power supply circuit flows into the first end in the first port of the short - circuit detection circuit.

[0088] In the case where there is a short circuit at the power supply output port, the detection current sequentially flows back to the first auxiliary power supply circuit through the second port of the short - circuit detection circuit that is currently in a short - circuit state and the second end in the first port of the short - circuit detection circuit, so that the short - circuit detection circuit outputs a first - level signal indicating the existence of a short circuit. See Figure 2 as shown in Figure 2A schematic diagram for detecting a current path when there is a short circuit at the power supply output port. In the figure, the red arrow represents one kind of detection current. It should be understood that the red arrow in the figure can also be in the reverse direction, and the present application does not limit this.

[0089] When there is no short circuit at the power supply output port, the detection current sequentially flows through one end of the second port of the short circuit detection circuit that is currently in a non - short - circuit state, the second end of the first port of the short circuit detection circuit, and then flows back to the first auxiliary power supply circuit, so that the short circuit detection circuit outputs a second - level signal for indicating the absence of a short circuit. See Figure 3 as shown Figure 3 A schematic diagram for detecting a current path when there is no short circuit at the power supply output port. In the figure, the red arrow represents one kind of detection current. It should be understood that the red arrow in the figure can also be in the reverse direction, and the present application does not limit this.

[0090] It should be understood that the power supply can be an AC power supply or a DC power supply, and the present application does not limit this.

[0091] The detection circuit for short - circuit detection of the power supply output port provided by the embodiments of the present application controls the power supply output port to be in an isolated state in response to a power - on start operation, so as to perform short - circuit detection on the power supply output port before the power supply outputs power to the power supply output port, and outputs a corresponding detection signal according to the detected short - circuit situation, enabling short - circuit detection to be performed before the power supply provides power to the power supply output port, avoiding the impact of a short - circuit at the power supply output port on the power supply line and the load. Since a hardware - circuit detection method is adopted, the detection time is short and the short - circuit detection efficiency is high.

[0092] As an example,

[0093] The detection circuit further includes: a unidirectional current circuit for enabling current to flow into the short - circuit detection circuit in a single direction.

[0094] The output port of the first auxiliary power supply circuit is connected in series with the input port of the unidirectional current circuit, and the output port of the unidirectional current circuit is connected in series with the first port of the short - circuit detection circuit.

[0095] The detection current from the first auxiliary power supply circuit sequentially flows through one end of the input port of the unidirectional current circuit, the unidirectional current circuit, and one end of the output port of the unidirectional current circuit and then flows into the first end of the first port of the short - circuit detection circuit. The detection current flowing back to the first auxiliary power supply circuit from the second end of the first port of the short - circuit detection circuit sequentially flows through the other end of the output port of the unidirectional current circuit, the unidirectional current circuit, and the other end of the input port of the unidirectional current circuit and then flows back to the first auxiliary power supply circuit.

[0096] The first residual voltage across the power supply output port is discharged through a first discharge loop formed by the second port of the short - circuit detection circuit, the internal circuit between this second port and the first port of the short - circuit detection circuit, the output port of the unidirectional current circuit, and the internal circuit in the unidirectional circuit. Refer to Figure 4 as shown in Figure 4 FIG. Figure 4 is a schematic diagram of a detection current path with a unidirectional current circuit and the first discharge loop. In the figure, the blue path represents the first discharge loop, and the red arrow represents one kind of detection current. It should be understood that the red arrow in the figure can also be in the reverse direction, and this application does not limit this.

[0097] The second residual voltage across the power supply output port is discharged through a second discharge loop formed by the second port of the short - circuit detection circuit and the internal circuit in the short - circuit detection circuit. Refer to Figure 5 as shown in Figure 5 FIG. Figure 5 is a schematic diagram of the second discharge loop. In the figure, the blue path represents the second discharge loop.

[0098] Among them, the polarities of the residual voltages between the first residual voltage and the second residual voltage are opposite.

[0099] This application is beneficial to the discharge of the residual voltage across the power supply output port through the first discharge loop and the second discharge loop, and avoids damage to the devices in the load circuit due to over - voltage or over - current.

[0100] Between the power supply output port and the power supply, there are included:

[0101] A first switch circuit for turning on and off the power supply output to the power supply output port. Among them, the input port of the first switch circuit is connected in series with the power supply, and the output port of the first switch circuit is connected in series with the power supply output port;

[0102] The processor controls the first switch circuit to be in the off state in response to a power - on start operation, controls the first switch circuit to be in the off state in response to a first level signal, and controls the first switch circuit to be in the on state in response to a second level signal. To facilitate the understanding of the embodiments of this application, the following takes a charging device for a charger as an example for illustration. It should be understood that the embodiments of this application are not limited to the charging device for a charger, and are also applicable to other power supply devices.

[0103] In this embodiment, the charger has the ability to safely and automatically charge the power battery of an electric vehicle, including an on - vehicle charger fixedly installed in the electric vehicle and a non - load - bearing charger independent of the electric vehicle; the charger can dynamically adjust the charging current or voltage parameters according to the data provided by the battery management system (BMS), perform corresponding actions, and complete the charging process.

[0104] Refer to Figure 6 as shown inFigure 6 This is a schematic diagram of a detection circuit for short - circuit detection of the power supply output port of a charging device. The charging device can be an AC charging device or a DC charging device. In this embodiment, an AC charging device is taken as an example.

[0105] The detection circuit includes: a unidirectional current circuit and a short - circuit detection circuit.

[0106] The first switch circuit is located between the AC charging device and the charger. Here, the charger is equivalent to the load of the AC charging device. As an example, the first switch circuit includes: a first switch k1 connected in series between the first terminal L_IN of the power supply output (i.e., the output of the AC charging device) and the first terminal L_OUT of the second port of the short - circuit detection circuit, and a second switch k2 connected in series between the second terminal N_IN of the power supply output and the second terminal N_OUT of the second port of the short - circuit detection circuit. When the first switch circuit is turned on, the power supply from the AC charging device is output to the charger load through the first switch k1 and the second switch k2.

[0107] The first auxiliary power supply VCCP is used to provide a detection current. In this embodiment, it is the power supply generated by the flyback power supply circuit of the AC charging device, which is obtained by rectifying the alternating current.

[0108] The input port of the unidirectional current circuit is connected in series with the output port of the first auxiliary power supply VCCP, and the output port of the unidirectional current circuit is connected in series with the first port of the short - circuit detection circuit. As an example, the unidirectional current circuit includes: a first unidirectional conductor, a first current - limiting resistor R1, a second current - limiting resistor R2, a fuse F1, and a second unidirectional conductor. Among them,

[0109] One end of the first unidirectional conductor is connected in series with one end of the first current - limiting resistor R1, and the other end of the first unidirectional conductor is connected in series with one end of the first auxiliary power supply VCCP.

[0110] One end of the second current - limiting resistor R2 is connected in series with one end of the fuse, and the other end of the second current - limiting resistor R2 is connected in series with the other end of the first auxiliary power supply VCCP. The other end of the first unidirectional conductor and the other end of the second current - limiting resistor R2 form the input port of the unidirectional current circuit.

[0111] The second unidirectional conductor is connected in series between the connection point where one end of the first unidirectional conductor is connected in series with one end of the first current - limiting resistor R1 and the connection point where one end of the second current - limiting resistor R2 is connected in series with one end of the fuse.

[0112] The other end of the first current - limiting resistor R1 and the other end of the fuse form the output port of the unidirectional current circuit, which is connected in series with the first port of the short - circuit detection circuit.

[0113] The first unidirectional conductor is in a conducting state when the detection current from the first auxiliary power supply VCCP flows into the unidirectional current circuit, and is in a cut-off state when discharging the first residual voltage in the first discharge circuit.

[0114] The second unidirectional conductor is in a cut-off state when the detection current from the first auxiliary power supply VCCP flows into the unidirectional current circuit, and is in a conducting state when discharging the first residual voltage in the first discharge circuit.

[0115] In this embodiment, the first unidirectional conductor is the first diode D1, the second unidirectional conductor is the second diode D2. The anode of the first diode D1 is connected to the positive pole of the first auxiliary power supply VCCP, the cathode of the first diode D1 is connected to one end of the first current-limiting resistor R1, the cathode of the second diode D2 is connected to the cathode of the first diode D1, and the anode of the second diode D2 is connected to the connection point where one end of the second current-limiting resistor R2 and one end of the fuse are connected in series.

[0116] As an example, the short-circuit detection circuit includes: a second switch circuit for making the detection circuit work when the switch in the first switch circuit is in the off state and making the detection circuit not work when the switch in the first switch circuit is in the off state, a clamping branch, and a detection signal generation circuit.

[0117] The input port of the second switch circuit is the first port of the short-circuit detection circuit, the output port of the second switch circuit is the second port of the short-circuit detection circuit. A clamping branch is connected in series between the second ports. The second port makes the clamping branch have no clamping voltage when there is a short-circuit state at the power supply output port so that the detection signal generation circuit generates a first-level signal. That is to say, when there is a short-circuit state at the power supply output port, the detection current is bypassed and does not flow through the clamping branch. When there is no short-circuit state at the power supply output port, a clamping voltage is generated so that the detection signal generation circuit generates a second-level signal. That is to say, when there is no short-circuit state at the power supply output port, the detection current flows through the clamping branch.

[0118] As an example, the second switch circuit includes: a third switch k3 with one end serially connected to the first end of the first port and the other end serially connected to the first end of the second port, and a fourth switch k4 with one end serially connected to the second end of the first port and the other end serially connected to the second end of the second port.

[0119] As an example, the clamping branch includes: a fifth switch k5, a third current-limiting resistor R3, and a voltage-regulator diode TVS1 connected in series in sequence. Among them, the fifth switch k5 is used to control the on-off of the clamping branch and the second port of the short-circuit detection circuit. The clamping branch further includes a third unidirectional conduction tube for preventing reverse breakdown current from flowing into the voltage-regulator diode. The third unidirectional conduction tube is in a conducting state when the detection current from the first auxiliary power supply VCCP flows into the clamping circuit and is in a conducting state when discharging the second residual voltage in the second discharge loop.

[0120] In this embodiment, the third unidirectional conduction tube is a third diode D3. The third diode D3 is connected in series with the voltage-regulator diode TVS1. The cathode of the third diode D3 is connected in series with the second end of the second port, and the anode of the third diode D3 is connected in series with the voltage-regulator diode TVS1.

[0121] The input port of the detection signal generation circuit is connected in parallel with the clamping branch to generate a corresponding level signal based on the clamping voltage. As an example, the detection signal generation circuit includes: a coupling circuit for coupling the voltage across the voltage-regulator diode and generating a detection signal according to the coupled voltage.

[0122] As an example, the coupling circuit includes: an optocoupler OP1 and a second auxiliary power supply VCC for providing a working power supply to the optocoupler. The primary side of the optocoupler OP1 is connected in parallel with both ends of the voltage-regulator diode TVS1 through a fifth current-limiting resistor R5. The secondary side of the optocoupler OP1 is connected in series across both ends of the second auxiliary power supply VCC. To make the output voltage across both ends of the secondary side of the optocoupler OP1 reach the set voltage threshold, a fourth pull-up resistor R4 is also connected in series in the series branch where the secondary side of the optocoupler OP1 is located. The voltage output across both ends of the secondary side of the optocoupler OP1 is input as a detection signal to the input / output I / O terminal of the MCU. To suppress noise, a filter capacitor C2 is also connected in parallel across both ends of the secondary side of the optocoupler OP1.

[0123] To suppress the voltage fluctuation of the output voltage of the second auxiliary power supply VCC, filter capacitor C1 is connected across both ends of the second DC auxiliary power supply VCC. Moreover, the second auxiliary power supply VCC and the first auxiliary power supply VCCP are isolated from each other, that is to say, the grounding terminal of the second auxiliary power supply and the grounding terminal of the first auxiliary power supply VCCP are not common ground. The second auxiliary power supply VCC and the first auxiliary power supply VCCP are both DC power supplies.

[0124] In this embodiment, switches k1~k5 can be relays.

[0125] The following combines Figure 6 to illustrate the working process of this embodiment.

[0126] In response to a charging start operation, the MCU controls the first switch K1 and the second switch K2 to be in the off state, and controls the third switch K3, the fourth switch K4, and the fifth switch K5 to be in the on state to perform a short-circuit detection on both ends of the connected load before charging.

[0127] When there is a short circuit between the two ends L_OUT and N_OUT of the power supply output port, the impedance between the power supply output ports is very low, generally 0Ω, as Figure 7 shown by the red line segment in the figure. The detection current flows from the positive pole of the first auxiliary power supply VCCP through D1, R1, K4, K3, fuse F1, and R2 to the negative pole of the first auxiliary power supply VCCP in sequence. Since there is a short circuit at the power supply output port, the detection current does not flow through the clamping branch, and no detection current flows through the secondary side of the optocoupler OP1. The detection signal is at a high level, and this signal is detected by the MCU circuit, and it can be determined that there is a short-circuit state. In response to this detection signal, the MCU controls the first switch K1 and the second switch K2 to be in the off state and can output a short-circuit prompt.

[0128] When there is no short circuit between the two ends L_OUT and N_OUT of the power supply output port, the impedance between the power supply output ports is not 0Ω, and the impedance generally ranges from 1kΩ to 10MΩ, as Figure 8 shown by the red line segment in the figure. The detection current flows from the positive pole of the first auxiliary power supply VCCP through D1, R1, K4, K5, R3, the zener diode TVS1 and its parallel resistor R5 and the primary side of OP1, D3, K3, F1, and R2 to the negative pole of the first auxiliary power supply VCCP in sequence. Since there is a shunt flow of the detection current through the primary side of OP1, there is current flowing through the secondary side of OP1, and the detection signal is pulled down to a low level. This signal is detected by the MCU circuit, and it is determined that there is no short-circuit state. In response to this detection signal, the MCU controls the third switch K3, the fourth switch K4, and the fifth switch K5 to be in the on state, and controls the switches K1 and K2 to be off to perform residual voltage discharge.

[0129] When there is no short-circuit state at the two ends L_OUT and N_OUT of the power supply output port, there may be a capacitor residual voltage due to the charger load. If the capacitor residual voltage between the two ends L_OUT and N_OUT of the power supply output port is the second residual voltage, that is, the potential of the L_OUT end is greater than the potential of the N_OUT end, as Figure 9 shown by the blue line segment in the figure, the second residual voltage quickly discharges from L_OUT through K5, R3, the zener diode TVS1 and its parallel resistor R5 and the primary side of OP1, and D3 to N_OUT to form a second loop, and the formed discharge current is the second discharge current. Generally, R3 uses a PPTC resistor, and the resistance value of R3 is much smaller than that of R5. TVS1 is a zener diode to clamp the voltage on the series circuit of R5 and OP1 to avoid overcurrent damage to the primary side of OP1.

[0130] If the residual voltage of the capacitor between the two ends L_OUT and N_OUT of the power supply output port is the first residual voltage, that is, the potential of the N_OUT end is greater than the potential of the L_OUT end, as Figure 10 shown by the blue line segment in Figure 10 , the first residual voltage rapidly discharges through the first loop formed by N_OUT, k3, F1, D2, R1, k4, and L_OUT in sequence, and the formed discharge current is the first discharge current. Generally, R1 uses a PPTC resistor, and the resistance value of R1 is much smaller than that of R2. In addition, components R2, C1, D1, and D2 form a parallel circuit. Due to the large resistance value of R2, almost all of the first discharge current of the first residual voltage passes through the diode D2, and the discharge current of the capacitor C1 is greatly restricted, reducing the voltage fluctuation of VCCP.

[0131] After the short-circuit detection is completed and the residual voltage is discharged, for example, when the MCU reaches the set duration threshold, the MCU controls the switches k1 and k2 to close and controls k4, k5, and k3 to open, so that the AC charging device provides power to the load.

[0132] In this embodiment, the MCU can use the microprocessor in the charging device. It should be understood that it can also be an independent microprocessor. The short-circuit detection in this embodiment takes less time. Generally, the detection time can be shortened to within 30 ms. Compared with the relevant short-circuit detection technology that takes about 0.5 s to 10 s, the efficiency of short-circuit detection is greatly improved, and the short-circuit state of the power supply output port can be quickly detected, avoiding the burning of the AC charging device and avoiding greater damage to the charger load, improving the reliability of the charging device; because the auxiliary power supply is independently provided, it is suitable for charging devices with a wide voltage AC input voltage, the parameter design is simple, and it is not affected by the value of the AC input voltage; when there is residual voltage at the power supply output port, it can be quickly discharged through the discharge circuit, avoiding damage to the internal circuit of the load due to overvoltage or overcurrent; when short-circuit detection is not performed or the first switch circuit is disconnected, the DC auxiliary power supply and the power supply output port are default separated and isolated through the second switch circuit, ensuring that there is no voltage at the power supply output port and there is no electric shock risk at the power supply output port.

[0133] See Figure 11 shown in Figure 11 is a schematic flowchart of a detection method for short-circuit detection of a power supply output port in this embodiment. The method includes: on the processor side,

[0134] Step 101, in response to a power supply start operation, control the first switch circuit for turning on and off the power supply output to the power supply output port to be in an off state, and control the detection circuit to generate a detection current, so that:

[0135] The detection current from the first auxiliary power supply circuit flows into the first end of the first port of the short-circuit detection circuit,

[0136] In the case of a short circuit at the power supply output port, the detection current flowing into the first terminal flows back to the first auxiliary power supply circuit through the second terminal in the first port of the short-circuit detection circuit and the second port of the short-circuit detection circuit that is currently in a short-circuit state, so that the short-circuit detection circuit outputs a first level signal indicating the existence of a short circuit.

[0137] In the case of no short circuit at the power supply output port, the detection current flowing into the first terminal flows back to the first auxiliary power supply circuit through one end in the second port of the short-circuit detection circuit that is currently not in a short-circuit state and the second terminal in the first port of the short-circuit detection circuit, so that the short-circuit detection circuit outputs a second level signal indicating the non-existence of a short circuit.

[0138] As an example, controlling the detection circuit to generate a detection current includes: controlling the fifth switch for clamping the branch and the second port to be in a conducting state, and controlling the second switch circuit for making the detection circuit work when the switch in the first switch circuit is in an off state and making the detection circuit not work when the switch in the first switch circuit is in an off state to be in a conducting state. That is to say, in the case where the detection circuit includes a unidirectional current circuit, the second switch circuit is used for the connection and disconnection between the short-circuit detection circuit and the unidirectional current circuit; in the case where the detection circuit does not include a unidirectional current circuit, the second switch circuit is used for the connection and disconnection between the short-circuit detection circuit and the first auxiliary power supply.

[0139] Step 102, in response to the first level signal, control the first switch circuit to be in an off state, and control the second switch circuit and the fifth switch to be in a conducting state until the second level signal is detected.

[0140] Step 103, in response to the second level signal, start timing, and control the first switch circuit to be in an off state, and control the second switch circuit and the fifth switch to be in a conducting state until the timing duration reaches a set duration threshold to discharge the residual voltage, and then control the first switch circuit to be in a conducting state, and control the second switch circuit and the fifth switch to be in an off state to isolate the detection circuit from the power supply device, the power supply output port or the load.

[0141] The above-mentioned processor may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or a microprocessor.

[0142] For the device / network-side device / storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, please refer to the partial description of the method embodiments.

[0143] In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0144] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A detection circuit for short circuit detection of a power supply output port, characterized in that: The detection circuit includes: A short circuit detection circuit for short circuit detection, wherein a first port of the short circuit detection circuit is connected in series with a first auxiliary power supply circuit for providing a detection current to the short circuit detection circuit, a second port of the short circuit detection circuit is connected in parallel with a power supply output port, and a detection signal output by the short circuit detection circuit is input to a processor, in, The detection signal is generated in the following manner: The processor controls the power output port to be in an isolated state from the power supply in response to the power supply startup operation. The detection current output by the first auxiliary power supply circuit flows through the first port of the short-circuit detection circuit. Furthermore, in the case where a short circuit exists at the power supply output port, the detection current flowing into the first end of the first port of the short-circuit detection circuit sequentially flows back to the first auxiliary power supply circuit through the second port of the short-circuit detection circuit currently in a short-circuit state and the second end of the first port of the short-circuit detection circuit, so that the short-circuit detection circuit outputs a first level signal for indicating the existence of a short circuit. When there is no short circuit at the power supply output port, the detection current flowing into the first end of the first port of the short-circuit detection circuit flows back to the first auxiliary power supply circuit in sequence through one end of the second port of the short-circuit detection circuit which is currently in a non-short circuit state and the second end of the first port of the short-circuit detection circuit, so that the short-circuit detection circuit outputs a second level signal for characterizing the absence of a short circuit.

2. The detection circuit according to claim 1, characterized in that: The power supply output port and the power supply include: A first switch circuit for switching the power supply output to the power supply output port on and off, wherein the input port of the first switch circuit is connected in series with the power supply, and the output port of the first switch circuit is connected in series with the power supply output port; The processor controls the first switch circuit to be in an off state in response to a power-on startup operation, controls the first switch circuit to be in an off state in response to a first level signal, and controls the first switch circuit to be in an on state in response to a second level signal. The detection circuit further comprises: a unidirectional current circuit for causing current to flow into the short-circuit detection circuit in a single direction, The output port of the first auxiliary power supply circuit is connected in series with the input port of the unidirectional current circuit, and the output port of the unidirectional current circuit is connected in series with the first port of the short-circuit detection circuit. The detection current from the first auxiliary power supply circuit flows into the first end of the first port of the short-circuit detection circuit sequentially through one end of the unidirectional current circuit input port, the unidirectional current circuit, and one end of the unidirectional current circuit output port, and the detection current from the second end of the first port of the short-circuit detection circuit flows back to the first auxiliary power supply circuit sequentially through the other end of the unidirectional current circuit output port, the unidirectional current circuit, and the other end of the unidirectional current circuit input port to flow back to the first auxiliary power supply circuit; The first residual voltage at both ends of the power supply output port is discharged through a first discharge loop formed by the second port of the short-circuit detection circuit, the internal circuit between the second port and the first port of the short-circuit detection circuit, the output port of the unidirectional current circuit and the internal circuit in the unidirectional circuit. The second residual voltage at both ends of the power supply output port is discharged through a second discharge loop formed by the second port of the short-circuit detection circuit and the internal circuit of the short-circuit detection circuit. The first residual voltage and the second residual voltage have opposite residual voltage polarities.

3. The detection circuit according to claim 2, characterized in that: The unidirectional current circuit comprises: a first unidirectional conductor, a first current limiting resistor, a second current limiting resistor, a fuse, and a second unidirectional conductor. in, One end of the first unidirectional conductor is connected in series with one end of the first current limiting resistor, and the other end of the first unidirectional conductor is connected in series with one end of the first auxiliary power supply. One end of the second current limiting resistor is connected in series with one end of the fuse, and the other end of the second current limiting resistor is connected in series with the other end of the first auxiliary power supply. The second unidirectional conductor is connected in series between the point where one end of the first unidirectional conductor is connected in series with one end of the first current limiting resistor and the point where one end of the second current limiting resistor is connected in series with one end of the fuse. The other end of the first current limiting resistor and the other end of the fuse form an output port of a unidirectional current circuit which is connected in series with the first port of the short-circuit detection circuit; The first unidirectional conductor is in a conducting state when the detection current from the first auxiliary power supply flows into the unidirectional current circuit, and is in a cut-off state when the first discharge circuit discharges the first residual voltage. The second unidirectional conductor is configured to be in a cut-off state when the detection current from the first auxiliary power supply flows into the unidirectional current circuit, and to be in a conducting state when the first discharge circuit discharges the first residual voltage.

4. The detection circuit according to claim 3, characterized in that: The short circuit detection circuit comprises: a second switch circuit for making the detection circuit work when the switch in the first switch circuit is in an off state and making the detection circuit not work when the switch in the first switch circuit is in an off state, as well as a clamping branch and a detection signal generating circuit, in, The input port of the second switch circuit is connected in series with the output port of the unidirectional current circuit, and a clamping branch is connected in series between the output ports of the second switch circuit, wherein the input port of the second switch circuit is the first port of the short-circuit detection circuit, and the output port of the second switch circuit is the second port of the short-circuit detection circuit, and the second port makes the clamping branch have no clamping voltage when the power supply output port is in a short-circuit state so that the detection signal generating circuit generates a first level signal, and generates a clamping voltage when the power supply output port is not in a short-circuit state so that the detection signal generating circuit generates a second level signal, The input port of the detection signal generating circuit is connected in parallel with the clamping branch to generate a corresponding level signal based on the clamping voltage.

5. The detection circuit according to claim 4, characterized in that: The internal circuit of the short-circuit detection circuit includes a clamping branch and a detection signal generating circuit. The internal circuit of the unidirectional circuit includes: a branch formed by a first current limiting resistor, a second unidirectional conductor, and a fuse. The first switch circuit includes: a first switch connected in series between a first end of a power supply output and a first end of the second port, and a second switch connected in series between a second end of the power supply output and a second end of the second port. The second switch circuit includes: a third switch having one end connected in series with the first end of the first port and the other end connected in series with the first end of the second port; and a fourth switch having one end connected in series with the second end of the first port and the other end connected in series with the second end of the second port.

6. The detection circuit according to claim 5, characterized in that: The clamping branch includes: a fifth switch, a third current-limiting resistor, and a voltage-stabilizing tube connected in series in sequence; The detection signal generating circuit comprises: a coupling circuit for coupling the voltage across the voltage regulator tube and generating a detection signal according to the coupled voltage.

7. The detection circuit according to claim 6, characterized in that: The clamping branch further includes a third unidirectional conduction tube for preventing reverse breakdown current from flowing into the voltage regulator tube, the third unidirectional conduction tube being in a conducting state when the detection current from the first auxiliary power supply flows into the clamping circuit, and being in a conducting state when the second discharge circuit discharges the second residual voltage; The coupling circuit comprises: an optical coupler and a second auxiliary power supply for providing working power to the optical coupler. in, The primary side of the optocoupler is connected in parallel with the two ends of the voltage regulator tube through the fifth current limiting resistor, the secondary side of the optocoupler is connected in series with the two ends of the second auxiliary power supply through the fourth pull-up resistor, and the level signal output by the secondary side of the optocoupler is output to the input and output ends of the processor. The second auxiliary power supply is isolated from the first auxiliary power supply.

8. The detection circuit according to claim 7, characterized in that: The processor controls the switch in the first switch circuit to be in an off state while controlling the second switch circuit and the fourth switch to be in an on state, and controls the switch in the first switch circuit to be in an on state while controlling the second switch circuit and the fourth switch to be in an off state; The first residual voltage is that the potential of the second end of the second port is greater than the potential of the first end of the second port, and the first discharge current in the first discharge loop is from the second end of the second port through the third switch, the fuse, the second unidirectional guide tube, the first current limiting resistor, the fourth switch, and reaches the first end of the second port; The second residual voltage is that the potential of the first end of the second port is greater than the potential of the second end of the second port, and the second discharge current in the second discharge loop reaches the second end of the second port from the first end of the second port through the fifth switch, the third current limiting resistor, the parallel circuit formed by the voltage regulator and the primary side of the optocoupler connected in parallel with the voltage regulator through the fifth current limiting resistor, and the third unidirectional conduction tube in sequence; When the power supply output port is in a short-circuit state, the detection current passes through the first unidirectional guide tube, the first current-limiting resistor, the fourth switch, the second port, the third switch, the fuse, and the second current-limiting resistor from one end of the first auxiliary power supply to the other end of the first auxiliary power supply in sequence, wherein the second ports are in a short-circuit state; When the power supply output port is in a non-short-circuit state, the detection current flows from one end of the first auxiliary power supply through the first unidirectional conduction tube, the first current limiting resistor, the fourth switch, the fifth switch, the third current limiting resistor, the voltage-stabilizing tube and the parallel circuit formed by the primary side of the optocoupler connected in parallel with the voltage-stabilizing tube through the fifth current limiting resistor, the third unidirectional conduction tube, the third switch, the fuse, and the second current limiting resistor to reach the other end of the first auxiliary power supply.

9. The detection circuit according to claim 8, characterized in that: The power supply is a charging device for charging the vehicle-mounted charger. The first auxiliary power source is a power source generated by a flyback power supply circuit in the charging device. The first unidirectional conducting tube is a first diode, the cathode of the first diode is connected to the first current limiting resistor, and the anode of the first diode is connected to the positive electrode of the first auxiliary power supply; The second unidirectional conducting tube is a second diode, the cathode of the second diode is connected to the cathode of the first diode, and the anode of the second diode is connected in series with the point where one end of the second current limiting resistor and one end of the fuse are connected in series; The fuse is a safety element. The third unidirectional conducting tube is a third diode, which is connected in series with the voltage regulator tube, the cathode of the third diode is connected in series with the second end of the second port, and the anode of the third diode is connected in series with the voltage regulator tube.

10. A power supply device, characterized in that: The power supply device comprises a detection circuit for detecting short circuit of a power supply output port as claimed in any one of claims 1 to 9.

11. A charger, characterized in that: The charger comprises a detection circuit for detecting a short circuit at a power supply output port as claimed in any one of claims 1 to 9.

12. A detection method for short circuit detection of a power supply output port, characterized in that: The method comprises: at the processor side, In response to the power supply startup operation, the power supply output port is controlled to be in an isolated state from the power supply source, so that: A detection current from a first auxiliary power supply circuit in the detection circuit for providing a detection current to the short-circuit detection circuit flows into a first end of a first port of the short-circuit detection circuit in the detection circuit, In the case where a short circuit exists at the power supply output port, the detection current flowing into the first end flows back to the first auxiliary power supply circuit via the second port of the short circuit detection circuit which is currently in a short circuit state and the second end of the first port of the short circuit detection circuit in sequence, so that the short circuit detection circuit outputs a first level signal for indicating the existence of a short circuit. In the case that there is no short circuit at the power supply output port, the detection current flowing into the first end flows back to the first auxiliary power supply circuit via one end of the second port of the short circuit detection circuit which is currently in a non-short circuit state and the second end of the first port of the short circuit detection circuit in sequence, so that the short circuit detection circuit outputs a second level signal for indicating that there is no short circuit; in, The short circuit detection circuit is used for short circuit detection. The first port of the short circuit detection circuit is connected in series with the first auxiliary power supply circuit. The second port of the short-circuit detection circuit is connected in parallel with the power supply output port. The detection signal output by the short-circuit detection circuit is input to the processor.

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