Processing Circuit of Power Output Terminal, Electronic Device and Ground Impedance Detection Method

Abstract

The present invention provides a processing circuit for a power output terminal, an electronic device and a ground impedance detection method. The processing circuit includes a first voltage source, a first switch unit, a control unit, a second switch unit, an adjustable current source unit and a voltage detection unit. The adjustable current source unit and the second switch unit are connected in series between a second voltage source and the power output terminal. The control unit is respectively connected to the adjustable current source unit, the first switch unit, the second switch unit and the voltage detection unit. The voltage of the first voltage source is greater than the voltage of the second voltage source. The voltage detection unit is connected to the power output terminal through the second switch unit. The present invention can provide a basis for avoiding potential safety hazards and dangers. At the same time, since different ground impedance ranges are associated with the causes of ground impedance, the present invention can judge the causes of ground impedance, which is conducive to timely and accurate response.

Description

Technical Field

[0001] The present invention relates to the field of power supply, and particularly to a processing circuit for a power output terminal, an electronic device, and a method for detecting the impedance to ground. Background Art

[0002] In an electronic device, there may be an electrical device and a power supply device. The power supply device can be connected to the electrical device by means of a pluggable cable or a fixedly connected cable.

[0003] In the prior related art, before the power supply device supplies power externally, it is difficult to know the size of the externally connected load. If the load is too low (for example, a short circuit or a micro short circuit occurs), it is easy to cause the interface to be overheated or even burned, resulting in an accident. If there is a liquid such as sweat in the connected object, although its impedance is not low, if the voltage is output for a long time, it will accelerate the metal corrosion of the power pin and the ground pin in the cable. Further, the corrosion will cause the contact impedance to become larger, resulting in heat accumulation at the interface. In severe cases, it will cause the interface to deform or burn out. This load can be regarded as the impedance to ground of the power supply end.

[0004] It can be seen that in the existing power supply devices, it is easy to have potential safety hazards and dangers due to not knowing in advance the impedance to ground of the power supply end. Summary of the Invention

[0005] The present invention provides a processing circuit for a power output terminal, an electronic device, and a method for detecting the impedance to ground, so as to solve the problem of easy generation of potential safety hazards and dangers.

[0006] According to a first aspect of the present invention, there is provided a processing circuit for a power output terminal, including a first switching unit provided between a first voltage source and the power output terminal, and further including a control unit, a second switching unit, an adjustable current source unit, and a voltage detection unit; the adjustable current source unit and the second switching unit are connected in series between a second voltage source and the power output terminal; the control unit is respectively connected to the adjustable current source unit, the first switching unit, the second switching unit, and the voltage detection unit, and the voltage of the first voltage source is greater than the voltage of the second voltage source;

[0007] The voltage detection unit is connected to the power output terminal through the second switching unit, and is used for detecting the voltage range in which the voltage of the power output terminal is located;

[0008] The control unit is configured to:

[0009] When the first switching unit remains open, control the second switching unit to conduct, so that the second voltage source, the adjustable current source unit, and the power output terminal are conducted in sequence;

[0010] Adjust the current value of the current output from the second voltage source to the power output terminal through the adjustable current source unit;

[0011] Determine the ground impedance range of the power output terminal according to different current values determined by the adjustment and the detected voltage range, where different ground impedance ranges are associated with the causes of the ground impedance, and at least two different ground impedance ranges are determined according to different current values determined by the adjustment of the adjustable current source unit.

[0012] Optionally, the control unit is further configured to: when the first switch unit remains off, control the on / off of the first switch unit and the second switch unit according to the ground impedance range.

[0013] Optionally, when the control unit controls the on / off of the first switch unit according to the ground impedance range, it is specifically configured to implement at least one of the following:

[0014] If the ground impedance range matches the ground impedance when the electrical device is normally connected, control the first switch unit to conduct, the second switch unit to disconnect, and perform a handshake communication with the electrical device;

[0015] If the ground impedance range matches the ground impedance when the power output terminal or the power supply pin of the cable connected thereto is short-circuited to the ground, control the first switch unit to remain off and prohibit the first switch unit from being conducted.

[0016] Optionally, the ground impedance range of the power output terminal includes at least one of the following:

[0017] Impedance range when no load, which matches the ground impedance of the power output terminal when no load;

[0018] Impedance range when short-circuited, which matches the ground impedance when the power output terminal or the power supply pin of the cable connected thereto is short-circuited or slightly short-circuited to the ground;

[0019] Impedance range when an external object is connected, which matches the ground impedance when an external object is connected between the power output terminal and the ground;

[0020] Impedance range when a saline liquid is connected, which matches the ground impedance when a saline liquid is connected between the power output terminal and the ground;

[0021] Impedance range when there is leakage, which matches the ground impedance when leakage occurs at the power input terminal or the power supply pin of the cable connected thereto and the leakage current value is greater than the threshold;

[0022] Optionally, the voltage detection unit includes a comparator; one input terminal of the comparator is used to access a reference voltage, and the other input terminal is connected to the power supply output terminal;

[0023] The control unit is further configured to adjust the voltage value of the reference voltage, wherein the voltage value of the reference voltage is determined according to the upper limit value and / or the lower limit value of each voltage range, and at least two different ground impedance ranges are determined according to different adjusted reference voltages.

[0024] Optionally, when the control unit determines the ground impedance range where the ground impedance of the power supply output terminal is located according to the different currents determined by the adjustment and the detected voltage range, it is specifically configured to:

[0025] When the current value of the current is adjusted to the minimum target current value and the voltage value of the reference voltage is adjusted to the maximum target voltage value, if the voltage range where the voltage of the power supply output terminal is located is greater than the voltage range of the maximum target voltage, then: determine that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range at no load;

[0026] When the current value of the current is adjusted to the maximum target current value and the voltage value of the reference voltage is adjusted to the minimum target voltage value, if the voltage range where the voltage of the power supply output terminal is located is less than the voltage range of the minimum target voltage, then: determine that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range at short circuit.

[0027] Optionally, adjusting the determined voltage value of the reference voltage includes at least two target voltage values, where the maximum target voltage value is k times the minimum target voltage value, and k is greater than or equal to 10;

[0028] Adjusting the determined current value includes at least two target current values, where the maximum target current value is n times the minimum target current value, and n is greater than or equal to 1000.

[0029] Optionally, adjusting the determined current value includes at least two target current values,

[0030] When the control unit adjusts and determines the current value of the current output from the second voltage source to the power supply output terminal through the adjustable current source unit, it is specifically configured to:

[0031] Sequentially adjust the current value of the current from large to small to the at least two target current values, wherein the adjustment of the current value is implemented regularly.

[0032] According to a second aspect of the present invention, there is provided a method for detecting the impedance to ground of a power output terminal, which is applied to a control unit in a processing circuit of the power output terminal. The processing circuit includes a first switching unit provided between a first voltage source and the power output terminal, a second switching unit, and a second voltage source. The voltage of the first voltage source is greater than the voltage of the second voltage source. The method includes:

[0033] When the first switching unit remains open, control the second switching unit to conduct, so that the second voltage source and the power output terminal can be conducted;

[0034] Adjust the current value of the current output from the second voltage source to the power output terminal;

[0035] According to the different current values determined by the adjustment and the detected voltage range, determine the impedance range to ground of the power output terminal, wherein different impedance ranges to ground are associated with the causes of the impedance to ground, and at least two different impedance ranges to ground are determined according to the different current values determined by the adjustment.

[0036] According to a third aspect of the present invention, there is provided an electronic device, including the processing circuit of the power output terminal involved in the first aspect and its alternative solutions.

[0037] In the processing circuit of the power output terminal, the electronic device, and the method for detecting the impedance to ground provided by the present invention, when the first switching unit is controlled to be open (that is, when the power supply terminal does not supply power to the outside at the required higher voltage), the second voltage source with a smaller voltage can be used to supply power to the power supply terminal, and when supplying power, the voltage detection unit is used to detect the voltage of the power supply terminal. Furthermore, based on the detection result, the impedance to ground of the power supply terminal can be effectively detected. It can be seen that the present invention can detect the impedance to ground before the first voltage source supplies power to the outside, which is beneficial to preventing potential safety hazards and dangers caused by still supplying power when the impedance to ground is abnormal, and provides a basis for avoiding potential safety hazards and dangers.

[0038] At the same time, by adjusting the current output from the second voltage source to the power supply terminal, the present invention can facilitate accurately determining the impedance range to ground where the current impedance to ground is located within a relatively large impedance to ground span. Furthermore, since different impedance ranges to ground are associated with the causes of the impedance to ground, the present invention can also be understood as being able to judge the causes of the impedance to ground, which is beneficial to timely and accurately taking countermeasures. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0040] Figure 1 is a schematic diagram of the structure of the processing circuit at the power output terminal in an embodiment of the present invention Figure 1 ;

[0041] Figure 2 is a schematic diagram of the structure of the voltage detection unit, control unit and power output terminal in an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of the structure of the processing circuit at the power output terminal in an embodiment of the present invention Figure 2 。

[0043] Description of reference numerals:

[0044] 11 - First voltage source;

[0045] 12 - First switch unit;

[0046] 13 - Power output terminal;

[0047] 14 - Control unit;

[0048] 15 - Voltage detection unit;

[0049] 151 - Comparator;

[0050] 16 - Second voltage source;

[0051] 17 - Adjustable current source unit;

[0052] 18 - Second switch unit;

[0053] 100 - Power supply device;

[0054] 200 - Access circuit;

[0055] Isrc - Current source;

[0056] VIN - First voltage source;

[0057] VDD - Second voltage source;

[0058] VOUT - Power output terminal;

[0059] VCON - Power pin;

[0060] Switch - Analog switch;

[0061] FET - Field Effect Transistor;

[0062] Comp - Comparator;

[0063] Rload - Load Impedance;

[0064] Figure 4 is a schematic flow diagram of the ground impedance detection method in an embodiment of the present invention Figure 1 ;

[0065] Figure 5 is a schematic flow diagram of the ground impedance detection method in an embodiment of the present invention Figure 2 。 Detailed Embodiment

[0066] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0067] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above - mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0068] Next, the technical solutions of the present invention will be described in detail with specific embodiments. These specific embodiments can be combined with each other, and for the same or similar concepts or processes, they may not be repeated in some embodiments.

[0069] Figure 1 is a schematic diagram of the structure of the processing circuit at the power output end in an embodiment of the present invention Figure 1 。

[0070] The processing circuit involved in this embodiment can be an integrated chip or a functional module within an integrated chip. Any circuit that can meet the following description does not deviate from the description of this embodiment. This processing circuit can be understood as the circuit in the power supply device. At the same time, this embodiment does not exclude the situation where it is distributed in different devices.

[0071] Please refer to Figure 1 , the processing circuit at the power output terminal includes a first switch unit 12 provided between the first voltage source 11 and the power output terminal 13. It can be understood as the circuit form for the power supply terminal in the existing related technologies. In the specific implementation process, other devices can also be connected in series and / or in parallel. As long as it meets the above description, regardless of whether other devices are configured, it does not deviate from the description of this embodiment.

[0072] The power output terminal 13 herein can be understood as follows: If the processing circuit is applied to a power supply device, then this power output terminal 13 can be fixedly or detachably connected to one end of a cable or an electrical device (for example, it can also be understood as the power pin of the power supply device). The structure of this power output terminal 13 can vary according to different power supply methods. For example, it can be a USB Type C interface.

[0073] The first switch unit 12 herein can be any device that can achieve conduction and cutoff. For example, it can be a field effect transistor, which can also be characterized as FET, and it is the abbreviation of Field Effect Transistor.

[0074] The first voltage source herein can be understood as any device or set of devices that can provide direct current for the power supply of an electrical device. For example, it can be an AC - DC or DC - DC power supply device or a combination of devices in the power supply device.

[0075] In this embodiment, the processing circuit at the power output terminal may further include a control unit 14, a second switch unit 18, an adjustable current source unit 17, and a voltage detection unit 15.

[0076] The adjustable current source unit 17 and the second switch unit 18 are connected in series between the second voltage source 16 and the power output terminal 13. Further, when the first switch unit 18 is conducting, the power supply of the second voltage source 16 can be delivered to the power output terminal 13, and the adjustable current source unit 17 can adjust the current during delivery. Through the above second voltage source 16, adjustable current source unit 17, and second switch unit 18, a basis for the ground impedance detection circuit can be generated.

[0077] The adjustable current source unit 17 therein can be any device or set of devices that can adjust the current generated based on the supplied voltage. In one example, the adjustable current source unit 17 can include a current source connected in series between the second voltage source and the power output terminal. In another example, the adjustable current source unit 17 can also be implemented using a pull-up resistor with controllable on / off, for example, it can include a resistor component, which can include multiple parallel resistor branches. Among them, different resistor branches can generate the same impedance or different impedances. By selecting the conducting resistor branches (including the case of simultaneously conducting multiple branches and the case of separately conducting a single branch), the adjustment of the current can also be achieved. In other examples, the resistor can also be replaced with other devices. In addition, this embodiment does not exclude other circuit units that can achieve current adjustment.

[0078] The second switch unit 18 therein can be any device that can achieve conduction and cutoff, for example, it can be an analog switch, which can be cutoff when the first switch unit 12 conducts for power supply. Furthermore, it can avoid the damage to the adjustable current source unit 17 caused by the power supply at the power output terminal 13 during normal power supply, that is: the second switch unit 18 can isolate the damage to the adjustable current source unit 17 caused by the possible high voltage at the power output terminal 13. It can be seen that in the specific implementation process, the second switch unit 18 can be an analog switch that can isolate high voltage.

[0079] The control unit 14 is respectively connected to the adjustable current source unit 17, the voltage detection unit 15, the first switch unit 12, and the second switch unit 18. The voltage of the first voltage source 11 is greater than the voltage of the second voltage source 16; the voltage of the second voltage source can be the low-voltage operating voltage of the circuit, for example, it can be 3.3V, and the voltage of the first voltage source can be the normal power supply voltage, for example, it can be 5V. The second voltage source 16 can be obtained by stepping down the first voltage source 11, or it can be a separately provided voltage source. For example, its voltage can be provided by other devices outside the first voltage source 11.

[0080] The voltage detection unit 15 is connected to the power output terminal 13 through the second switch unit 18, and it can be understood as any circuit unit used to detect the voltage range of the voltage at the power output terminal. This voltage range can refer to the voltage range greater than a certain target voltage value or the voltage range less than a certain target voltage value.

[0081] Among them, by disconnecting the second switch unit 18, it can also avoid the damage to the voltage detection unit 15 caused by the power supply at the power output terminal 13 during normal power supply, that is: the second switch unit 18 can isolate the damage to the voltage detection unit 15 caused by the possible high voltage at the power output terminal 13.

[0082] The control unit 14 involved in this embodiment can be any circuit unit that can realize the corresponding control function. It can be a single integrated chip or a functional unit inside a chip. It can realize the corresponding functions described in this embodiment by building a circuit, or by executing a program. This embodiment does not exclude the combination of circuits and programs. At the same time, the control unit 14 can be integrated with the control part of the power supply device (such as an information processing circuit), or the control unit 14 and the control part can be separate circuits.

[0083] Figure 2 It is a schematic diagram of the structure of a voltage detection unit, a control unit and a power output terminal in one embodiment of the present invention.

[0084] In one implementation, please refer to Figure 2 The voltage detection unit 15 includes a comparator 151; one input end of the comparator 151 is used to access the reference voltage, and the other input end is connected to the power output end 13, for example, it can be connected to the power output end 13 via the second switch unit 18. At the same time, the means of accessing other devices is not excluded.

[0085] During the specific implementation process, the voltage value of the reference voltage may be adjustable, for example, it may be controlled by the control unit 14, and further, the control unit 14 is further used to adjust the voltage value of the reference voltage, wherein the voltage value of the reference voltage is determined according to the upper limit value and / or lower limit value of each voltage range, and at least two different impedance ranges to ground are determined according to the different reference voltages determined by the adjustment.

[0086] In other implementations, the voltage detection unit 15 may also be implemented using a voltage analog-to-digital converter ADC.

[0087] In this embodiment, the control unit 14 is used to:

[0088] When the first switch unit 12 remains disconnected, the second switch unit 18 is controlled to be turned on, so that the second voltage source 16, the adjustable current source unit 17 and the power output terminal 13 are turned on in sequence;

[0089] adjusting the current value of the current outputted from the second voltage source 16 to the power output terminal 13 by the adjustable current source unit 17;

[0090] According to the different current values ​​determined by adjustment and the detected voltage range, the impedance range to ground of the power output terminal 13 is determined.

[0091] The impedance range to ground can be understood as any specified impedance range under the impedance span required for detection.

[0092] In the ground impedance, the formed situation can be, for example, a low impedance where the corresponding power supply pin is shorted to the ground (for example, the power supply pin and the ground pin of the external charging cable head are directly shorted or are close to being shorted intermittently), or, for another example, an impedance of about several hundred to several thousand ohms appears between the corresponding power supply pin and the ground pin due to saline water, sweat, etc., and it can also be, for example, an insertion impedance ranging from tens of thousands to hundreds of thousands of ohms when an electrical device (such as a mobile phone) is connected (at this time, the power output is in the power channel off state). It can be seen that the ground impedance has a large span. In this embodiment, by determining the ground impedance range within the span, it is convenient to implement corresponding countermeasures based on the measured impedance range. Therefore, in this embodiment, different ground impedance ranges are associated with the causes of the ground impedance, and at least two different ground impedance ranges are determined according to different current values adjusted by the adjustable current source unit. It can also be understood that at least two different ground impedance ranges are determined under different current values adjusted by the adjustable current source unit.

[0093] In one implementation, the ground impedance range of the power output terminal includes at least one of the following:

[0094] The impedance range when no load is present, which matches the ground impedance of the power output terminal when the first switch unit is kept disconnected and there is no load; it can be understood that on the premise that the power supply is disconnected (i.e., when the first switch is off), it is the input impedance range shown by a normal electrical device, which matches the ground impedance when the electrical device is normally connected to the power output terminal (at this time, the first switch is off) and the ground; for example, it can be greater than 3 M ohms (i.e., 3000 K ohms);

[0095] The impedance range during normal power supply, which matches the ground impedance when an electrical device is normally connected to the power output terminal and the ground; for example, it can be 30 K to 3000 K ohms;

[0096] The impedance range during short - circuit, which matches the ground impedance when the power supply pin of the power output terminal or the cable connected thereto is short - circuited or slightly short - circuited to the ground; for example, it can be 0 to 300 ohms;

[0097] The impedance range when an external object is connected, which matches the ground impedance when an external object is connected to the power output terminal and the ground; for example, it can be in the range of 30 K to 3000 K ohms;

[0098] The impedance range when a saline - containing liquid is connected, which matches the ground impedance when a saline - containing liquid is connected between the power output terminal and the ground; for example, it can be 300 to 3 K ohms; the saline - containing liquid can be, for example, some materials with relatively low impedance such as saline water and sweat;

[0099] The impedance range during leakage, which matches the impedance to ground when leakage occurs between the power input terminal or the power pins of the cable it is connected to, and the leakage current value is greater than the threshold value; it can be, for example, a situation where there is a certain degree of interface blockage and short circuit, or interface moisture, or general quality resulting in leakage, and a relatively large leakage current electronic load is connected. Specifically, it can be from 3K to 30K ohms.

[0100] Among them, the impedance range when no load, the impedance range during normal power supply, the impedance range during leakage, the impedance range when salt-containing liquid is connected, and the impedance range during short circuit can be distributed in descending order; the impedance range when foreign objects are connected can be less than the impedance range when no load, and greater than the impedance range during leakage.

[0101] When determining the impedance range to ground, it can be determined according to the interval range of the voltage measured after adjusting the current once, or it can also be determined according to the value range of the voltage obtained each time after adjusting the current multiple times.

[0102] Since the span of the impedance to ground is relatively large, for example, it needs to span a range of 0 to 3M ohms, the current value of the current and the voltage value of the reference voltage involved above can be correspondingly selected to match the span.

[0103] In one implementation, adjusting the voltage value of the determined reference voltage includes at least two target voltage values, where the largest target voltage value is k times the smallest target voltage value, and k is greater than or equal to 10. Adjusting the determined current value includes at least two target current values, where the largest target current value is n times the smallest target current value, and n is greater than or equal to 1000. Based on the values of n and k exemplified here, while ensuring the detection of the impedance range, it is convenient to more efficiently complete all the impedance ranges to ground listed above.

[0104] In addition, the number of target current values and target voltage values can both change arbitrarily according to requirements, and the gap between their maximum and minimum values can also change arbitrarily according to requirements. For example, k may not be limited to the range greater than or equal to 10, and n may not be limited to the range greater than or equal to 1000. They are all changes in numerical value or quantity. No matter how they change, they will not deviate from the solution of this embodiment.

[0105] Based on the configured target current value and target voltage value, since the impedance to ground is the largest when no load, for the convenience of testing, it can be adjusted to the smallest current and the largest reference voltage for testing. When short circuit or micro short circuit occurs, the impedance to ground is the smallest. For the convenience of testing, it can be adjusted to the largest current and the smallest reference voltage for testing. Thus:

[0106] When the control unit determines the ground impedance range of the power supply output terminal according to the different currents determined by the adjustment and the detected voltage range, it is specifically used for:

[0107] When the current value of the current is adjusted to the minimum target current value and the voltage value of the reference voltage is adjusted to the maximum target voltage value, if the voltage range of the power supply output terminal is greater than the voltage range of the maximum target voltage, then: determine that the ground impedance range of the power supply output terminal is the impedance range at no load;

[0108] When the current value of the current is adjusted to the maximum target current value and the voltage value of the reference voltage is adjusted to the minimum target voltage value, if the voltage range of the power supply output terminal is less than the voltage range of the minimum target voltage, then: determine that the ground impedance range of the power supply output terminal is the impedance range at short circuit.

[0109] In the above solution, when the first switch unit is controlled to be disconnected (that is, when the power supply terminal does not supply power to the outside at the required higher voltage), the power supply terminal can be powered by the second voltage source with a smaller voltage, and the voltage of the power supply terminal can be detected by the voltage detection unit during the power supply. Furthermore, the ground impedance of the power supply terminal can be effectively detected based on the detection result. Furthermore, in this embodiment, the ground impedance can be detected before the first voltage source supplies power to the outside, which is beneficial to preventing potential safety hazards and dangers caused by still supplying power when the ground impedance is abnormal, and providing a basis for avoiding potential safety hazards and dangers.

[0110] At the same time, by adjusting the current output from the second voltage source to the power supply terminal in this embodiment, it is convenient to accurately determine the ground impedance range where the current ground impedance is located within a relatively large ground impedance span. Furthermore, since different ground impedance ranges are associated with the causes of the ground impedance, this embodiment can also be understood as being able to judge the causes of the ground impedance, which is beneficial to timely and accurately responding.

[0111] It should also be noted that in some technologies, the command to turn on or off the power output terminal can also come from the judgment of other signal lines (for example, when the CC line of the USB Type C interface is pulled low by a 5.1K ohm pull-down resistor to the ground (GND), it indicates that a standard USB Type C device load is connected) or the response to changes in the environmental state (such as controlling the disconnection of the first switching unit such as an FET when the interface temperature is too high), or from the visual judgment of the operator (such as pressing a corresponding button after judgment). It can be seen that in these technologies, no matter which method is used, it is always difficult to know the actual situation of the impedance to the ground before turning on the main power channel, and the solution involved in this embodiment can be judged when the main power channel is closed. As mentioned before, compared with these existing technologies, this embodiment can help prevent safety hazards and dangers caused by still supplying power externally when the impedance to the ground is abnormal, provide a basis for avoiding safety hazards and dangers, and be able to judge the cause of the impedance to the ground, so as to facilitate timely and accurate response.

[0112] In one implementation, the control unit 14 is further configured to: when the first switching unit remains disconnected, control the on / off of the first switching unit and the second switching unit according to the impedance range to the ground.

[0113] In addition to controlling the on / off, at least one of the following processes can be implemented: reporting an alarm signal; reporting the value of the impedance to the ground or its impedance range to the ground, adjusting the reference voltage, adjusting the current delivered by the second voltage source to the power output terminal, implementing handshake communication, etc.

[0114] During the specific implementation process, when the control unit 14 controls the on / off of the first switching unit according to the impedance range to the ground, it can specifically be used to implement at least one of the following:

[0115] If the impedance range to the ground matches the impedance to the ground when the electrical device is normally connected, control the first switching unit to conduct, the second switching unit to disconnect, and implement handshake communication with the electrical device;

[0116] If the impedance range to the ground matches the impedance to the ground when the power output terminal or the power supply pin of the cable connected thereto is short-circuited to the ground, control the first switching unit to remain off and prohibit the first switching unit from being conducted.

[0117] When the control unit 14 adjusts and determines the current value of the current output from the second voltage source to the power output terminal through the adjustable current source unit, it is specifically used for:

[0118] The current value of the current is adjusted to the at least two target current values in descending order. Herein, the adjustment of the current value is implemented regularly. Further, after each adjustment, the upper limit value or the lower limit value corresponding to one or more ground impedance ranges can be determined. In other alternative embodiments, the means of adjusting in ascending order is not excluded either.

[0119] Figure 3 is a schematic diagram of the structure of the processing circuit at the power output end in an embodiment of the present invention Figure 2 。

[0120] In Figure 3 , the adjustable current source unit 17 can adopt the current source Isrc, and the current value of the current generated by it can also be characterized by Isrc. The first switch unit 12 can adopt the field effect transistor FET, the second switch unit 18 can adopt the analog switch Switch, and the voltage detection unit 15 can adopt the comparator Comp. At the same time, the first voltage source 11 and its voltage can also be characterized by VIN, the second voltage source 16 and its voltage can be characterized by VDD, the power output end and its voltage can be characterized by VOUT, and the power supply pin of the cable or the electrical device on the power consumption side can be characterized by VCON. At the same time, the load impedance Rload therein can be regarded as the ground impedance, and its resistance value can also be characterized by Rload. The left box can be regarded as a part of the circuit in the power supply device, and the right box can include, for example, a cable and various objects that can form an impedance connected to the cable. The object can be, for example, a circuit object (such as an electrical device, a metal wire of the cable, etc.), a non-circuit object (such as an external object, sweat, etc.) or a combination of at least one of them.

[0121] The following takes Figure 3 shown as an example to illustrate the specific implementation manner of this embodiment.

[0122] Among them, the number of target voltage values of the reference voltage of the comparator Comp can be two, which can be respectively characterized as Ref1 and Ref2, and the reference voltage Ref1 or Ref2 can select different voltage values according to actual needs.

[0123] In Figure 3 shown in the example, the reference voltage is connected to the inverting terminal of the comparator Comp, the output pin of the current source Isrc is connected to the power output end VOUT through the analog switch Switch, and the output pin of the current source Isrc is also connected to the non-inverting terminal of the comparator Comp. In other examples, the reference voltage can also be connected to the non-inverting terminal of the comparator Comp, and the output pin of the current source Isrc is connected to the inverting terminal of the comparator Comp. The low-voltage operating voltage of the circuit used by the second voltage source VDD can be set to 3.3V, for example. The second voltage source VDD can be generated by the first voltage source VIN or provided by an external source (such as other circuits in the device).

[0124] Figure 3 In the illustrated example, pins such as the EN pin, SDA pin, SCL pin, and INT pin of the control unit 14 can be used for the control unit to interact with the main body of the affiliated power supply device. Among them, the SDA pin, SCL pin, and INT pin can be understood as the pins of the I 2 C function module in the control unit 14. In other examples, the EN pin, SDA pin, SCL pin, and INT pin can also be replaced by several GPIO pins (which can also be understood as general-purpose input / output ports).

[0125] To facilitate the description of its operation process, it can be assumed that the current source Isrc can be configured as 1uA, 10uA, 100uA, and 1mA and can output regularly (for example, spending 1 millisecond every 1 second) to detect and judge the load impedance Rload until the main power supply channel from the first voltage source VIN to the power output terminal VOUT is controlled to conduct based on the detection result.

[0126] Furthermore, it can be assumed that Ref 1 is 0.3V and Ref2 is 3.0V. At the same time, ke regards the power output terminal VOUT of the power supply and the power pin VCON of the cable as the same power pin (in fact, after connecting the output of the power supply device and the electrical device through a standard cable, the power output terminal VOUT and the power pin VCON of the cable are basically equal) to elaborate on the implementation process of the processing circuit.

[0127] During the process of the power supply device waiting for the electronic device to be connected, the field-effect transistor FET serving as the first switching unit is controlled to be in the off state, that is, the main power supply channel from the first voltage source VIN to the power output terminal VOUT is cut off. At this time, the analog switch Switch serving as the second switching unit is in the on state, and the current controlled by the current source Isrc can be configured as a target current value of 1uA, and the reference voltage is connected to the inverting terminal of the comparator and configured as Ref2 = 3.0V;

[0128] When the power output terminal VOUT is not connected to a cable, or when the power output terminal VOUT is connected to a cable, but the power pin VCON in the male head of the cable is not connected to any electronic device and is in a normal no-load state, at this time, the load impedance Rload seen from the power output terminal VOUT will be much greater than 3 megohms. After passing through the 1uA current source, the voltage at the power output terminal VOUT, that is, Isrc*Rload, will be greater than 3V (approximately equal to the voltage value of the second voltage source VDD, that is, Isrc*Rload≈VDD). Furthermore, at this time, the output of the comparator Comp is at a high level.

[0129] When the control unit 14 detects that the output of the comparator Comp is at a low level at this time, the reference voltage can be adjusted from Ref2 to Ref1 = 0.3V. If the output of the comparator Comp becomes high again at this time, it is known that the impedance of the load impedance Rload is between 300K and 3000K ohms. On the contrary, if the output of the comparator remains low at this time, the current value of the current source Isrc can be adjusted to the target current value of 10uA. At the same time, the reference voltage continues to be maintained at Ref 1 = 0.3V.

[0130] If the output of the comparator Comp is at a high level at this time, it is known that the load impedance Rload is between 30K and 300K ohms at this time. If the load impedance Rload is in the range of 30K to 3000K ohms, it is very likely that the electrical equipment that needs electricity has been connected at this time. The impedance of 30K to 3000K ohms is the load impedance reflected by them under the injection of a 1uA or 10uA current source. At this time, the main power supply channel from the first voltage source VIN to the power output terminal VOUT can be turned on to supply power to the electrical equipment. At the same time, the range information of the load impedance Rload (that is, the impedance range to the ground) can also be provided to the relevant information processing circuit of the power supply equipment, so that the information processing circuit of the power supply equipment can further judge the type of the load that generates the load impedance Rload.

[0131] However, even if the load impedance Rload is not a real electrical load at this time, but some debris with an impedance of 30K to 3000K ohms has bridged the power output terminal Vout and GND or the power supply pin VCON and GND of the cable, it will not cause damage due to turning on the power supply channel from the first voltage source VIN to the power output terminal VOUT (only a small leakage current of one or two microamps to one or two hundred microamps will be caused to the system). After correct judgment, it can be processed in time.

[0132] Based on a principle similar to the above process, by adjusting the current controlled by the current source Isrc to 100uA, a load impedance Rload of 3K to 30K can be judged. By adjusting the current controlled by the current source Isrc to 1mA, a load impedance Rload of 300 to 3K ohms, and a load impedance Rload less than 300 ohms can be judged (at this time, the reference voltage is Ref1 = 0.3V, and the output of the comparator Comp is at a low level).

[0133] After obtaining the load impedance Rload range obtained by the cooperation of the current source and the comparator, corresponding operations can be performed.

[0134] For example, when the load impedance Rload is less than 300 ohms, it usually indicates that there is a short circuit or micro short circuit between the power output terminal VOUT and GND of the power supply, or between the power supply pin VCON of the cable and GND. At this time, the main power supply channel from the first voltage source VIN to the power output terminal VOUT cannot be turned on, otherwise it may lead to high temperature or fire incidents. In the specific implementation process, the control unit can alarm the main body of the power supply device (such as its information processing circuit) through the interrupt pin INT or GPIO and feedback the resistance range or value of the load impedance Rload; the impedance range to the ground at this time can be understood as the impedance range during the short circuit involved in the previous text;

[0135] For another example, when the load impedance Rload is in the range of 300 to 3K ohms, it usually indicates that some materials with low impedance such as sweat and salt water, the power output terminal VOUT or the power supply pin of the cable, and GND form a path. At this time, it can also alarm and feedback the resistance range or value of the load condition Rload; the impedance range to the ground at this time can be understood as the impedance range when the saline liquid is connected involved in the previous text;

[0136] For yet another example, when the load impedance Rload is in the range of 3K to 30K, it may be that there is a certain degree of interface blockage short circuit, interface moisture, or an electronic load with general quality and relatively large leakage current is connected. At this time, the main power supply channel from the first voltage source VIN to the power output terminal VOUT can be turned on, and at the same time, the resistance range or its value of the load impedance Rload is fed back to the information processing circuit of the power supply device for judgment. The impedance range to the ground at this time can be understood as the impedance range during the leakage involved in the previous text;

[0137] For still another example, if the load impedance Rload is a voltage source with a certain voltage and output capacity when it is connected, the information processing circuit of the power supply device can perform more operations to judge and handle this situation.

[0138] In short, if you want to expand the span of the connected load impedance Rload, you can further configure the target current value of the current source and the target voltage value of the reference voltage to achieve it.

[0139] This embodiment also provides an electronic device (i.e., the power supply circuit involved in the previous text), including the processing circuit of the power output terminal involved in the above optional solutions.

[0140] The electronic device therein can be understood as any device capable of outputting direct current externally, such as a wall plug charger, a vehicle charger, a mobile power supply, a travel charger, a charging pile, etc. At the same time, non-specialized power supply and charging electronic devices are not excluded, such as computers, household appliances, industrial appliances, etc.

[0141] In summary, in the processing circuit of the power output terminal and the electronic device provided in this embodiment, when the first switching unit is controlled to be disconnected (that is, when the power supply terminal does not supply power to the outside at the required higher voltage), the second voltage source with a smaller voltage can be used to supply power to the power supply terminal, and the voltage detection unit can be used to detect the voltage of the power supply terminal during power supply. Furthermore, the ground impedance of the power supply terminal can be effectively detected based on the detection result. It can be seen that this embodiment can detect the ground impedance before the first voltage source supplies power to the outside, which helps to prevent potential safety hazards and dangers caused by still supplying power to the outside when the ground impedance is abnormal, and provides a basis for avoiding potential safety hazards and dangers.

[0142] At the same time, by adjusting the current output from the second voltage source to the power supply terminal in this embodiment, it is convenient to accurately determine the ground impedance range where the current ground impedance is located within a relatively large ground impedance span. Furthermore, since different ground impedance ranges are associated with the causes of ground impedance, the present invention can also be understood as being able to judge the causes of ground impedance, which helps to respond in a timely and accurate manner.

[0143] Figure 4 is a schematic flowchart of the ground impedance detection method in an embodiment of the present invention Figure 1 ; Figure 5 is a schematic flowchart of the ground impedance detection method in an embodiment of the present invention Figure 2 。

[0144] Please refer to Figure 4 and Figure 5 for the ground impedance detection method of the power output terminal, which is applied to the control unit in the processing circuit of the power output terminal. The processing circuit can be understood as Figures 1 to 3 the processing circuit involved in the embodiment shown. The method includes:

[0145] S21: When the first switching unit remains disconnected, control the second switching unit to conduct, so that the second voltage source and the power output terminal can be conducted;

[0146] S22: Adjust the current value of the current output from the second voltage source to the power output terminal;

[0147] S23: Determine the ground impedance range where the ground impedance of the power output terminal is located according to the different current values determined by the adjustment and the detected voltage range, where different ground impedance ranges are associated with the causes of ground impedance.

[0148] Optionally, after step S23, it may further include:

[0149] S24: When the first switch unit remains off, control the on / off states of the first switch unit and the second switch unit according to the range of the impedance to the ground.

[0150] Step S24 may specifically include at least one of the following:

[0151] If the range of the impedance to the ground matches the impedance to the ground when the electrical device is normally connected, control the first switch unit to turn on, the second switch unit to turn off, and perform a handshake communication with the electrical device;

[0152] If the range of the impedance to the ground matches the impedance to the ground when the power output terminal or the power supply pin of the cable connected thereto is short-circuited to the ground, control the first switch unit to remain off and prevent the first switch unit from being turned on.

[0153] Optionally, the range of the impedance to the ground of the power output terminal includes at least one of the following:

[0154] The impedance range when no load is connected, which matches the impedance to the ground when the power output terminal is without load;

[0155] The impedance range during normal power supply, which matches the impedance to the ground when the electrical device is normally connected to the power output terminal and the ground;

[0156] The impedance range during short circuit, which matches the impedance to the ground when the power output terminal or the power supply pin of the cable connected thereto is short-circuited or slightly short-circuited to the ground;

[0157] The impedance range when an external object is connected, which matches the impedance to the ground when an external object is connected to the power output terminal and the ground;

[0158] The impedance range when a saline liquid is connected, which matches the impedance to the ground when a saline liquid is connected between the power output terminal and the ground;

[0159] The impedance range during leakage, which matches the impedance to the ground when leakage occurs at the power input terminal or the power supply pin of the cable connected thereto and the leakage current value is greater than the threshold;

[0160] Among them, the impedance range when no load is connected, the impedance range during normal power supply, the impedance range during leakage, the impedance range when a saline liquid is connected, and the impedance range during short circuit are distributed in descending order;

[0161] The impedance range when an external object is connected is less than the impedance range when no load is connected and greater than the impedance range during leakage.

[0162] Optionally, the voltage detection unit includes a comparator; one input terminal of the comparator is used to connect to a reference voltage, and the other input terminal is connected to the power output terminal;

[0163] The described method further includes:

[0164] Adjusting the voltage value of the reference voltage, wherein the voltage value of the reference voltage is determined according to the upper limit value and / or the lower limit value of each voltage range.

[0165] Optionally, step S23 specifically includes:

[0166] When the current value of the current is adjusted to the minimum target current value and the voltage value of the reference voltage is adjusted to the maximum target voltage value, if the voltage range where the voltage at the power supply output terminal is located is greater than the voltage range of the maximum target voltage, then: determining that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range at no load;

[0167] When the current value of the current is adjusted to the maximum target current value and the voltage value of the reference voltage is adjusted to the minimum target voltage value, if the voltage range where the voltage at the power supply output terminal is located is less than the voltage range of the minimum target voltage, then: determining that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range at short circuit.

[0168] Optionally, adjusting the voltage value of the determined reference voltage includes at least two target voltage values, where the maximum target voltage value is k times the minimum target voltage value, and k is greater than or equal to 10.

[0169] Optionally, adjusting the determined current value includes at least two target current values, where the maximum target current value is n times the minimum target current value, and n is greater than or equal to 1000;

[0170] Step S23 specifically includes:

[0171] Sequentially adjusting the current value of the current from large to small to the at least two target current values, where the adjustment of the current value is implemented regularly.

[0172] In summary, in the method for detecting the ground impedance of the power supply output terminal provided in this embodiment, when the first switch unit is controlled to be disconnected (that is, when the power supply terminal does not supply power to the outside at the required higher voltage), the second voltage source with a smaller voltage can be used to supply power to the power supply terminal, and when supplying power, the voltage detection unit is used to detect the voltage of the power supply terminal. Furthermore, the ground impedance of the power supply terminal can be effectively detected based on the detection result. It can be seen that this embodiment can detect the ground impedance before the first voltage source supplies power to the outside, which is beneficial to preventing potential safety hazards and dangers caused by still supplying power when the ground impedance is abnormal, and provides a basis for avoiding potential safety hazards and dangers.

[0173] Meanwhile, in this embodiment, by adjusting the current output from the second voltage source to the power supply terminal, it is convenient to accurately determine the ground impedance range where the current ground impedance is located within a relatively large ground impedance span. Furthermore, since different ground impedance ranges are associated with the causes of the ground impedance, the present invention can also be understood as being able to judge the cause of the ground impedance, which is beneficial for timely and accurate response.

[0174] Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments; and the aforementioned storage medium includes various media that can store program codes, such as ROM, RAM, magnetic disks, or optical discs.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A processing circuit for a power output terminal, including a first switching unit disposed between a first voltage source and the power output terminal, characterized in that, It further includes a control unit, a second switch unit, an adjustable current source unit and a voltage detection unit; the adjustable current source unit and the second switch unit are connected in series between a second voltage source and the power output terminal; the control unit is respectively connected to the adjustable current source unit, the first switch unit, the second switch unit and the voltage detection unit; the voltage of the first voltage source is greater than the voltage of the second voltage source; The voltage detection unit is connected to the power output terminal through the second switch unit and is used to detect the voltage range in which the voltage at the power output terminal is located; The control unit is used for: When the first switch unit remains off, controlling the second switch unit to conduct, so that the second voltage source, the adjustable current source unit and the power output terminal are conducted in sequence; Adjusting the current value of the current output from the second voltage source to the power output terminal through the adjustable current source unit; According to the different current values determined by the adjustment and the detected voltage range, determining the ground impedance range in which the ground impedance of the power output terminal is located, where different ground impedance ranges are associated with the causes of the ground impedance; 2. The processing circuit according to claim 1, wherein The control unit is further used for: when the first switch unit remains off, controlling the on / off of the first switch unit and the second switch unit according to the ground impedance range; 3. The processing circuit according to claim 2, characterized in that, When the control unit controls the on / off of the first switch unit according to the ground impedance range, it is specifically used to implement at least one of the following: If the ground impedance range matches the ground impedance when the electrical device is normally connected, controlling the first switch unit to conduct, the second switch unit to disconnect, and performing a handshake communication with the electrical device; If the ground impedance range matches the ground impedance when the power output terminal or the power supply pin of the cable connected thereto is shorted to the ground, controlling the first switch unit to remain off and preventing the first switch unit from being conducted; 4. The processing circuit according to claim 1, wherein The ground impedance range of the power output terminal includes at least one of the following: The impedance range when no load is connected, which matches the ground impedance of the power output terminal when no load is connected and the first switch unit remains off; The impedance range when short-circuited, which matches the ground impedance when the power output terminal or the power supply pin of the cable connected thereto is shorted or slightly shorted to the ground; The impedance range when an external object is connected, which matches the ground impedance when an external object is connected between the power output terminal and the ground; The impedance range when a saline liquid is connected, which matches the ground impedance when a saline liquid is connected between the power output terminal and the ground; The impedance range when there is leakage, which matches the ground impedance when leakage occurs at the power input terminal or the power supply pin of the cable connected thereto and the leakage current value is greater than the threshold; 5. The processing circuit according to any one of claims 1 to 4, characterized in that The voltage detection unit includes a comparator; one input terminal of the comparator is used to access a reference voltage, and the other input terminal is connected to the power output terminal through the second switch unit; The control unit is further configured to adjust the voltage value of the reference voltage, wherein the voltage value of the reference voltage is determined according to the upper limit value and / or the lower limit value of each voltage range, and at least two different ground impedance ranges are determined according to different reference voltages determined by the adjustment.

6. The processing circuit according to claim 5, characterized in that, When the control unit determines the ground impedance range where the ground impedance of the power supply output terminal is located according to the different currents determined by the adjustment and the detected voltage range, it is specifically configured to: When the current value of the current is adjusted to the minimum target current value, and the voltage value of the reference voltage is adjusted to the maximum target voltage value, if the voltage range where the voltage of the power supply output terminal is located is greater than the voltage range of the maximum target voltage, then: determine that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range when no load is applied; When the current value of the current is adjusted to the maximum target current value, and the voltage value of the reference voltage is adjusted to the minimum target voltage value, if the voltage range where the voltage of the power supply output terminal is located is less than the voltage range of the minimum target voltage, then: determine that the ground impedance range where the ground impedance of the power supply output terminal is located is the impedance range when short - circuited.

7. The processing circuit according to claim 5, characterized in that Adjusting the voltage value of the determined reference voltage includes at least two target voltage values, wherein the maximum target voltage value is k times the minimum target voltage value, and k is greater than or equal to 10; Adjusting the determined current value includes at least two target current values, wherein the maximum target current value is n times the minimum target current value, and n is greater than or equal to 1000.

8. The processing circuit according to any one of claims 1 to 4, characterized in that Adjusting the determined current value includes at least two target current values; When the control unit adjusts and determines the current value of the current output from the second voltage source to the power supply output terminal through the adjustable current source unit, it is specifically configured to: Sequentially adjust the current value of the current from large to small to the at least two target current values, wherein the adjustment of the current value is implemented regularly.

9. A method for detecting the impedance to ground of a power output terminal, which is applied to a control unit in a processing circuit of the power output terminal, is characterized in that, The processing circuit includes a first switch unit provided between the first voltage source and the power supply output terminal, a second switch unit and a second voltage source. The voltage of the first voltage source is greater than the voltage of the second voltage source. The voltage detection unit is connected to the power supply output terminal through the second switch unit and is used to detect the voltage range where the voltage of the power supply output terminal is located; The method includes: When the first switch unit remains open, control the second switch unit to conduct, so that the second voltage source and the power supply output terminal can be conducted; Adjust the current value of the current output from the second voltage source to the power supply output terminal; Determine the ground impedance range where the ground impedance of the power supply output terminal is located according to the different current values determined by the adjustment and the detected voltage range, wherein different ground impedance ranges are associated with the causes of the ground impedance.

10. An electronic device, comprising the processing circuit of the power supply output terminal according to any one of claims 1 to 8.

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