Detection circuit for short circuit detection of power supply output port and power supply device

Abstract

The application discloses a detection circuit used for short circuit detection of a power supply output port, comprising a short circuit detection circuit used for short circuit detection, a first port of the short circuit detection circuit is connected in series with a first auxiliary power supply circuit, a second port of the short circuit detection circuit is connected in parallel with the power supply output port, and a detection signal output by the short circuit detection circuit is input to a processor; the processor controls the power supply output port and the power supply to be in an isolated state in response to the power supply starting operation, and the detection current from the first auxiliary power supply circuit flows into the first end of the first port. Detection current flowing into the first end flows back to the first auxiliary power supply circuit through the second port, currently in the short circuit state, of the short circuit detection circuit and the second end in the first port of the short circuit detection circuit in sequence, so that the short circuit detection circuit outputs a first level signal used for representing existence of short circuit. According to the invention, short-circuit detection consumes less time, rapid residual voltage discharge can be realized, and damage to a power supply and internal components of a load is avoided.

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 of the existing power supply devices do not have an output short-circuit detection function before outputting the power supply. If the power supply output end does not perform short-circuit detection before powering on, the internal components of the power supply device will burn out. For example, the relay on the AC power output channel will burn out due to overcurrent, and even cause the load to heat up and burn out due to short circuit. Summary of the invention

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

[0004] A first aspect of the present invention provides a detection circuit for short-circuit detection of a power supply output port, the detection circuit comprising: 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.

[0005] As a possible implementation manner, the power 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; As a possible implementation manner, 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. As a possible implementation, the detection circuit further includes: a unidirectional current circuit for causing current to flow into the short-circuit detection circuit in a single direction, 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. As a possible implementation manner, 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 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 back to the first auxiliary power supply circuit 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; As a possible implementation manner, 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. As a possible implementation manner, the second residual voltage at both ends of the power supply output port is discharged through a second discharge loop formed by a second port of the short-circuit detection circuit and an internal circuit in the short-circuit detection circuit. The first residual voltage and the second residual voltage have opposite residual voltage polarities.

[0006] As a possible implementation manner, 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. 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.

[0007] As a possible implementation, 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 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.

[0008] As a possible implementation manner, the internal circuit in 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.

[0009] As a possible implementation manner, the clamping branch includes: a fifth switch, a third current-limiting resistor, and a voltage regulator 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.

[0010] As a possible implementation manner, the clamping branch further includes a third unidirectional conduction tube for preventing a reverse breakdown current from flowing into the voltage regulator tube, the third unidirectional conduction tube being in a conducting state when a 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; As a possible implementation, the coupling circuit includes: an optocoupler and a second auxiliary power supply for providing working power to the optocoupler. 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.

[0011] As a possible implementation manner, 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; As a possible implementation manner, 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 circuit 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; As a possible implementation manner, 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; As a possible implementation mode, when a short circuit occurs at a power supply output port, the detection current passes through a first unidirectional conduction tube, a first current limiting resistor, a fourth switch, a second port, a third switch, a fuse, and a second current limiting resistor from one end of the first auxiliary power supply to the other end of the first auxiliary power supply, wherein the second ports are in a short circuit state; As a possible implementation mode, 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-limiting tube and the parallel circuit formed by the primary side of the optocoupler connected in parallel with the voltage-limiting 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.

[0012] As a possible implementation, the power supply is a charging device for charging a vehicle-mounted charger. As a possible implementation manner, the first auxiliary power source is a power source generated by a flyback power supply circuit in the charging device. As a possible implementation manner, the first unidirectional conducting tube is a first diode, a cathode of the first diode is connected to a first current limiting resistor, and an anode of the first diode is connected to a positive electrode of a 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.

[0013] A second aspect of the present application provides a power supply device, which includes any of the detection circuits for short-circuit detection of a power supply output port.

[0014] A third aspect of the present application provides a charger, which includes any of the detection circuits for short-circuit detection of a power supply output port.

[0015] A fourth aspect of the present application provides a detection method for short circuit detection of a power supply output port, the method comprising: at a 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 output port of the first switch circuit. The detection signal output by the short-circuit detection circuit is input to the processor.

[0016] A detection circuit for short-circuit detection of a power supply output port provided in an embodiment of the present application controls the power supply and the power supply output port to be in an isolated state through a processor in response to a power supply startup operation, 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, thereby avoiding damage to circuit components caused by 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 end 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 for characterizing the presence of a short circuit; when 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 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 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 characterizing the absence of a short circuit, thereby greatly improving the efficiency of short-circuit detection and being unaffected by the voltage of the power supply provided by the power supply device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 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.

[0018] Figure 2 A schematic diagram of detecting the current path when a short circuit occurs at the power output port.

[0019] Figure 3 A schematic diagram of detecting the current path when there is no short circuit at the power output port.

[0020] Figure 4 A schematic diagram of a detection current path with a unidirectional current circuit and a first discharge loop.

[0021] Figure 5 A schematic diagram of the second discharge circuit.

[0022] Figure 6 The figure is a schematic diagram of a detection circuit for short-circuit detection of a power supply output port of a charging device according to the present embodiment.

[0023] Figure 7 A schematic diagram of detecting a current path when a short circuit occurs at a power output port of this embodiment.

[0024] Figure 8 A schematic diagram of a detection current path when there is no short circuit at the power output port of this embodiment.

[0025] Fig. 9 It is a schematic diagram of the second residual voltage discharge current when there is no short circuit at the power output port of this embodiment.

[0026] Fig.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.

[0027] Fig.11 The figure is a flow chart of a detection method for short circuit detection of a power supply output port according to the present embodiment. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical means and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings.

[0029] See also Figure 1 As shown, Figure 1 This 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. The detection circuit includes: A first switch circuit for switching the power supply output to the power supply output port, 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, 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, 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. in, The detection signal is generated in the following manner: The processor controls the power output port to be isolated from the power supply in response to the power supply startup operation. A detection current from the first auxiliary power supply circuit flows into a first end of the first port of the short-circuit detection circuit, In the case of a short circuit at the power output port, the detection current 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 in sequence, so that the short circuit detection circuit outputs a first level signal for indicating the existence of a short circuit. Figure 2 As shown, Figure 2 A schematic diagram of detecting the current path when a short circuit occurs at the power supply output port. In the figure, the red arrow represents a type of detection current. It should be understood that the red arrow in the figure may also be reversed, and the present application does not impose any limitation on this.

[0030] In the case that there is no short circuit at the power supply output port, the detection current 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 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. Figure 3 As shown, Figure 3 A schematic diagram of detecting the current path when there is no short circuit at the power supply output port. In the figure, the red arrow represents a type of detection current. It should be understood that the red arrow in the figure can also be reversed, and the present application does not impose any restrictions on this.

[0031] It should be understood that the power supply can be an AC power supply or a DC power supply, and this application does not impose any limitation on this.

[0032] The detection circuit for short-circuit detection of the power supply output port provided in the embodiment of the present application controls the power supply output port and the power supply to be in an isolated state in response to the power supply startup operation, so that the power supply output port is short-circuited before the power supply outputs power to the power supply output port, and a corresponding detection signal is output according to the detected short-circuit situation, so that the short-circuit detection can be performed before the power supply provides power to the power supply output port, thereby avoiding the impact of the short circuit of the power supply output port on the power supply line and the load. Due to the use of a hardware circuit detection method, the detection time is short and the short-circuit detection efficiency is high.

[0033] As an example, The detection circuit further includes: 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, see Figure 4 As shown, Figure 4 It is a schematic diagram of a detection current path and a first discharge loop of a unidirectional current circuit. The blue path in the figure represents the first discharge loop, and the red arrow represents a type of detection current. It should be understood that the red arrow in the figure can also be reversed, and the present application does not impose any restrictions on this.

[0034] 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, see Figure 5 As shown, Figure 5 Schematic diagram of the second discharge circuit. The blue path in the figure represents the second discharge circuit.

[0035] The first residual voltage and the second residual voltage have opposite residual voltage polarities.

[0036] The present application uses the first discharge circuit and the second discharge circuit to facilitate the discharge of residual pressure at both ends of the power supply output port, thereby preventing devices in the load circuit from being damaged due to overvoltage or overcurrent.

[0037] 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 supply 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. To facilitate understanding of the embodiments of the present application, the following description is made using a charging device for charging a charger as an example. It should be understood that the embodiments of the present application are not limited to charging devices for charging chargers, but may also be applicable to other power supply devices.

[0038] In this embodiment, the charger has the ability to safely and automatically fully charge the power battery of the electric vehicle, including an on-board 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 based on the data provided by the battery management system (BMS), perform corresponding actions, and complete the charging process.

[0039] See also Figure 6 As shown, Figure 6 The schematic diagram of the detection circuit for detecting short circuit of the power supply output port of the charging device in this embodiment is shown in FIG. 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.

[0040] The detection circuit includes: a unidirectional current circuit and a short-circuit detection circuit.

[0041] The first switch circuit is located between the AC charging device and the charger, wherein 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 end L_IN of the power supply, i.e., the output of the AC charging device, and the first end L_OUT of the second port of the short-circuit detection circuit, and a second switch k2 connected in series between the second end N_IN of the power supply output and the second end 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 via the first switch k1 and the second switch k2.

[0042] The first auxiliary power supply VCCP is used to provide a detection current, and in this embodiment is a power supply generated by a flyback power supply circuit of the AC charging device, which is obtained by rectifying the AC power.

[0043] 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, wherein: 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. 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 an input port of a unidirectional current circuit. 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 R1 and the point where one end of the second current limiting resistor R2 is connected in series with one end of the fuse. The other end of the first current limiting resistor R1 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 VCCP 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 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 the first discharge loop discharges the first residual voltage.

[0044] In this embodiment, the first unidirectional conductor is a first diode D1, and the second unidirectional conductor is a second diode D2. The anode of the first diode D1 is connected to the positive electrode 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 point where one end of the second current limiting resistor R2 and one end of the fuse are connected in series.

[0045] 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 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. 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. A clamping branch is connected in series between the second ports. The second port makes the clamping branch have no clamping voltage when a short-circuit state exists at the power supply output port so that the detection signal generating circuit generates a first level signal. That is, when a short-circuit state exists at the power supply output port, the detection current is bypassed and does not flow through the clamping branch. When the short-circuit state does not exist at the power supply output port, a clamping voltage is generated so that the detection signal generating circuit generates a second level signal. That is, when the short-circuit state does not exist at the power supply output port, the detection current flows through the clamping branch.

[0046] As an example, the second switching circuit includes: a third switch k3 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 k4 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.

[0047] As an example, the clamping branch includes: a fifth switch k5, a third current limiting resistor R3, and a voltage regulator TVS1 connected in series in sequence, wherein the fifth switch k5 is used to control the on-off of the second port of the clamping branch and the short-circuit detection circuit, and the clamping branch also includes a third unidirectional conduction tube for preventing reverse breakdown current from flowing into the voltage regulator tube, and the third unidirectional conduction tube makes the detection current from the first auxiliary power supply VCCP flow into the clamping circuit when it is in the on state, and is in the on state when the second discharge circuit discharges the second residual voltage.

[0048] In this embodiment, the third unidirectional conducting tube is a third diode D3, which is connected in series with the voltage regulator tube 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 tube TVS1.

[0049] 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. As an example, the detection signal generating circuit includes: a coupling circuit for coupling the voltage across the voltage regulator tube and generating a detection signal according to the coupled voltage.

[0050] 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 the two ends of the voltage regulator tube TVS1 through the fifth current limiting resistor R5, and the secondary side of the optocoupler OP1 is connected in series with the two ends of the second auxiliary power supply VCC. In order to make the output voltage at the two 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, and the output voltage at the two ends of the secondary side of the optocoupler OP1 is input as a detection signal to the input and output I / O terminal of the MCU. In order to suppress noise, a filter capacitor C2 is also connected in parallel at both ends of the secondary side of the optocoupler OP1.

[0051] In order to suppress the fluctuation of the output voltage of the second auxiliary power supply VCC, filter capacitors C1 are connected to both ends of the second DC auxiliary power supply VCC, and the second auxiliary power supply VCC is isolated from the first auxiliary power supply VCCP, that is, the ground terminal of the second auxiliary power supply is not grounded with the ground terminal of the first auxiliary power supply VCCP. Both the second auxiliary power supply VCC and the first auxiliary power supply VCCP are DC power supplies.

[0052] In this embodiment, the switches k1 - k5 may be relays.

[0053] The following combination Figure 6 The working process of this embodiment is described.

[0054] In response to the charging start operation, the MCU controls the first switch k1 and the second switch k2 to be in an open state, and controls the third switch k3, the fourth switch k4, and the fifth switch k5 to be in a closed state, so as to perform a short circuit detection on both ends of the connected load before charging.

[0055] When the two ends of the power supply output port L_OUT and N_OUT are short-circuited, the impedance between the power supply output ports is very low, generally 0Ω, such as Figure 7 As shown in the red line, the detection current flows from the positive electrode of the first auxiliary power supply VCCP through D1, R1, k4, k3, insurance F1, and R2 to the negative electrode of the first auxiliary power supply VCCP. Due to the 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 high level, and the signal is detected by the MCU circuit, which can determine the state of the short circuit. In response to the detection signal, the MCU controls the first switch k1 and the second switch k2 to be in the disconnected state, and can output a short circuit prompt.

[0056] When there is no short circuit at both ends of the power supply output port, L_OUT and N_OUT, the impedance between the power supply output ports is not 0Ω, and the impedance generally ranges from 1kΩ to 10MΩ. Figure 8 As shown in the red line, the detection current reaches the negative electrode of the first auxiliary power supply VCCP from the positive electrode of the first auxiliary power supply VCCP through D1, R1, k4, k5, R3, the voltage regulator TVS1 and its parallel R5 and the primary side of OP1, D3, k3, F1, R2. Since the detection current flows through the primary side of OP1, the current flows through the secondary side of OP1, and the detection signal is pulled down to a low level. The signal is detected by the MCU circuit and it is determined that there is no short circuit. In response to the detection signal, the MCU controls the third switch k3, the fourth switch k4, and the fifth switch k5 to be in a closed state, and controls switches k1 and k2 to be opened to discharge the residual pressure.

[0057] When the two ends L_OUT and N_OUT of the power supply output port are not short-circuited, there may be residual voltage of the capacitor due to the charger load. If the residual voltage of the capacitor 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, such as Fig. 9 As shown by the blue line in the figure, the second residual voltage is discharged quickly from L_OUT through k5, R3, voltage regulator TVS1 and the primary side of R5 and OP1 in parallel, D3 to N_OUT to form the second loop, and the discharge current formed is the second discharge current. Generally, R3 uses a PPTC resistor, and the resistance of R3 is much smaller than R5. TVS1 is a voltage regulator to clamp the voltage on the series circuit of R5 and OP1 to prevent overcurrent damage to the primary side of OP1.

[0058] 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, such as Fig.10 As shown by the blue line in , the first residual voltage is discharged quickly from N_OUT through the first loop formed by k3, F1, D2, R1, k4, and L_OUT in sequence, and the resulting discharge current is the first discharge current. Generally, R1 uses a PPTC resistor, and the resistance of R1 is much smaller than that of R2. In addition, components R2, C1, D1 and D2 form a parallel circuit. Since the resistance of R2 is relatively large, the first discharge current of the first residual voltage almost all passes through the diode D2, and the discharge current of the capacitor C1 is greatly limited, reducing the VCCP voltage fluctuation.

[0059] When the short circuit detection is completed and the residual pressure is released, for example, the MCU reaches the set time threshold, the MCU controls switches k1 and k2 to close, and controls switches k4, k5, and k3 to open, so that the AC charging device provides power to the load.

[0060] In this embodiment, the MCU can use the microprocessor in the charging device, and it should be understood that it can also be an independent microprocessor. In this embodiment, short-circuit detection takes less time, and the general detection time can be shortened to less than 30ms. Compared with the relevant short-circuit detection technology, which takes about 0.5S~10S, the efficiency of short-circuit detection is greatly improved, and the short-circuit state detection of the power supply output port can be quickly realized to avoid burning of the AC charging device and avoid causing greater damage to the charger load, thereby improving the reliability of the charging device; because the auxiliary power supply is provided independently, it can be suitable for charging devices with wide voltage AC input voltage, and the parameter design is simple and is not affected by the AC input voltage value; when there is residual pressure at the power supply output port, it can be discharged quickly through the discharge circuit to avoid 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 separated and isolated by default through the second switch circuit, ensuring that there is no voltage at the power supply output port and there is no risk of electric shock at the power supply output port.

[0061] See also Fig.11 As shown, Fig.11 FIG. 1 is a flow chart of a detection method for detecting a short circuit of a power supply output port according to an embodiment of the present invention. The method comprises: on the processor side, Step 101, in response to a power supply startup operation, controlling a first switch circuit for switching the power supply output to the power supply output port to be in an off state, and controlling a detection circuit to generate a detection current, so that: A detection current from the first auxiliary power supply circuit flows into a first end of the first port of the short-circuit 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. When 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 through one end of the second port of the short-circuit detection circuit which is currently in a non-short-circuited 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 characterizing the absence of a short circuit.

[0062] As an example, controlling the detection circuit to generate a detection current includes: controlling the fifth switch used to connect and disconnect the clamp branch and the second port to be in an on state, and controlling the second switch circuit used to make the detection circuit work when the switch in the first switch circuit is in an off state and to make the detection circuit not work when the switch in the first switch circuit is in an off state to be in an on state, that is, in a case where the detection circuit includes a unidirectional current circuit, the second switch circuit is used to connect and disconnect the short-circuit detection circuit and the unidirectional current circuit, and in a case where the detection circuit does not include a unidirectional current circuit, the second switch circuit is used to connect and disconnect the short-circuit detection circuit and the first auxiliary power supply.

[0063] Step 102, in response to the first level signal, controlling the first switch circuit to be in an off state, and controlling the second switch circuit and the fifth switch to be in an on state, until a second level signal is detected, Step 103, in response to the second level signal, start timing, control the first switch circuit to be in the off state, control the second switch circuit and the fifth switch to be in the on state, until the timing duration reaches the set duration threshold to discharge the residual pressure, and control the first switch circuit to be in the on state, control the second switch circuit and the fifth switch to be in the off state, so as to isolate the detection circuit from the power supply device, the power supply output port or the load.

[0064] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can 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.

[0065] As for the apparatus / network-side device / storage medium embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0066] In this article, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in 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 short-circuit detection 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 of 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 output port of the first switch circuit. The detection signal output by the short-circuit detection circuit is input to the processor.

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