WO2021120947A1

WO2021120947A1 - Processing circuit at power output end, electronic device, and ground impedance measurement method

Info

Publication number: WO2021120947A1
Application number: PCT/CN2020/129079
Authority: WO
Inventors: 陶红霞
Original assignee: 上海爻火微电子有限公司
Priority date: 2019-12-16
Filing date: 2020-11-16
Publication date: 2021-06-24
Also published as: CN111007321A

Abstract

A processing circuit at a power output end, an electronic device, and a ground impedance measurement method. The processing circuit comprises: a first voltage source (11), a first switch unit (12), a control unit (14), a second switch unit (18), a current adjustment unit (17), and a voltage measurement unit (15). The current adjustment unit (17) and the second switch unit (18) are connected in series between a second voltage source (16) and a power output end (13); the control unit (14) is separately connected to the current adjustment unit (17), the first switch unit (12), the second switch unit (18), and the voltage measurement unit (15); the voltage of the first voltage source (11) is greater than that of the second voltage source (16); and the voltage measurement unit (15) is connected to the power output end (13) by means of the second switch unit (18). The provided technical solution can provide a basis for avoiding potential safety hazards and dangers. In addition, because different ranges of ground impedance are related to the cause of ground impedance, the determination of the cause of ground impedance facilitates timely and accurate response.

Description

Power output terminal processing circuit, electronic equipment and ground impedance detection method

Technical field

The present invention relates to the field of power supply, in particular to a processing circuit, electronic equipment and a method for detecting impedance to ground at the output end of a power supply.

Background technique

Electronic equipment may include electrical equipment and power supply equipment, and the power supply equipment can be connected to the electrical equipment by means of pluggable cables or fixedly connected cables.

In the related art, it is difficult to know the size of the externally connected load before the power supply equipment supplies power. If the load is too low (such as a short circuit or a micro short circuit), it will easily lead to high temperature or even burning of the interface, causing an accident. If the connected object exists Sweat and other liquids, although the impedance is not low, if the voltage output is maintained for a long time, it will accelerate the metal corrosion of the power supply pin and the ground pin in the cable. Further, the corrosion will cause the contact impedance to increase and cause heat accumulation at the interface, which is serious. It will cause the interface to deform or burn out. The load can be regarded as the impedance to the ground of the power supply terminal.

It can be seen that, in the existing power supply equipment, potential safety hazards and dangers are easily caused by not knowing the impedance to the ground of the power supply terminal in advance.

Summary of the invention

The invention provides a processing circuit, an electronic device and a ground impedance detection method at the output end of a power supply, so as to solve the problem of potential safety hazards and dangers.

According to a first aspect of the present invention, there is provided a processing circuit for a power output terminal, which includes a first switch unit provided at a first voltage source and the power output terminal, and also includes a control unit, a second switch unit, and 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 the second voltage source and the power output; the control unit is respectively connected to the adjustable current source unit, In 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 output terminal of the power supply via the second switch unit for detecting the voltage range in which the voltage of the output terminal of the power supply is located;

The control unit is used for:

When the first switch unit is kept off, controlling the second switch unit to be turned on, so that the second voltage source, the adjustable current source unit, and the power output terminal are sequentially turned on;

Adjusting the current value of the current output by the second voltage source to the output terminal of the power supply by the adjustable current source unit;

According to the different current values determined by the adjustment and the detected voltage range, the ground impedance range of the output end of the power supply is determined, wherein the different ground impedance ranges are related to the cause of the ground impedance At least two different impedance ranges to ground are determined according to different current values determined by the adjustment of the adjustable current source unit.

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

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

If the ground impedance range matches the ground impedance when the electrical equipment is normally connected, the first switching unit is controlled to be turned on, the second switching unit is turned off, and the electrical equipment is connected to the ground. Handshake communication;

If the ground impedance range matches the ground impedance when the power supply output terminal or the power supply pin of the cable connected to the ground is short-circuited, the first switch unit is controlled to remain off, and the The first switch unit is prohibited from being turned on.

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

Impedance range at no-load, which matches the impedance to ground at the output terminal of the power supply at no-load;

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

The impedance range when the external object is connected, which matches the impedance to the ground when the external object is connected to the output terminal of the power supply and the ground;

The impedance range when the salt-containing liquid is connected, which matches the impedance to ground when the salt-containing liquid is connected between the output terminal of the power supply and the ground;

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

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;

The control unit is also 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 the lower limit value of each voltage range, and at least two different impedances to ground The range is determined according to different reference voltages adjusted and determined.

Optionally, when the control unit determines the impedance-to-ground impedance range of the output end of the power supply according to the different currents determined by the adjustment and the detected voltage range, it is specifically used for:

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 maximum The voltage range of the target voltage of, then: determine the impedance range to ground where the impedance to ground of the output terminal of the power supply is located as the impedance range at no-load;

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 minimum For the voltage range of the target voltage, it is determined that the ground impedance range of the output terminal of the power supply is located as the impedance range during short-circuit.

Optionally, adjusting the determined voltage value of the reference voltage includes at least two target voltage values, wherein the largest target voltage value is k times the smallest target voltage value, and k is greater than or equal to 10;

The current value determined by the adjustment includes at least two target current values, wherein the largest target current value is n times the smallest target current value, and n is greater than or equal to 1000.

Optionally, the current value determined by the adjustment includes at least two target current values,

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

The current value of the current is adjusted to the at least two target current values sequentially from large to small, wherein the adjustment of the current value is implemented periodically.

According to a second aspect of the present invention, there is provided a method for detecting impedance to ground at the output end of a power supply, which is applied to a control unit in a processing circuit at the output end of the power supply. The processing circuit includes The first switch unit, the second switch unit and the second voltage source, the voltage of the first voltage source is greater than the voltage of the second voltage source; the method includes:

When the first switch unit is kept off, controlling the second switch unit to be turned on, so that the second voltage source and the output terminal of the power supply can be turned on;

Adjusting the current value of the current output by the second voltage source to the output terminal of the power supply;

According to the different current values determined by the adjustment and the detected voltage range, the ground impedance range of the output end of the power supply is determined, wherein the different ground impedance ranges are related to the cause of the ground impedance At least two different impedance ranges to ground are determined according to different current values determined by adjustment.

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

In the processing circuit, electronic equipment and ground impedance detection method of the power output provided by the present invention, the voltage can be used when the first switch unit is controlled to be turned off (that is, when the power supply terminal is not supplying external power at a higher voltage required) The smaller second voltage source supplies power to the power supply terminal, and the voltage detection unit is used to detect the voltage at 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 the present invention can detect the impedance to ground before the first voltage source supplies power to the outside, thereby helping to prevent potential safety hazards and dangers caused by powering the outside when the impedance to ground is abnormal, and provide a basis for avoiding potential safety hazards and dangers.

At the same time, by adjusting the current output from the second voltage source to the power supply terminal of the power supply in the present invention, it is convenient to accurately determine the current impedance-to-ground impedance range within a larger impedance-to-ground span. Furthermore, due to different pairs of The ground impedance range is related to the cause of the ground impedance, and the present invention can also be understood as being able to judge the cause of the ground impedance, thereby facilitating timely and accurate response.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

FIG. 1 is a first structural diagram of a processing circuit at the output end of a power supply in an embodiment of the present invention;

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

Fig. 3 is a second structural diagram of a processing circuit at the output end of a power supply in an embodiment of the present invention.

Description of reference signs:

11-The first voltage source;

12-The first switch unit;

13- Power output terminal;

14-Control unit;

15-Voltage detection unit;

151-comparator;

16-Second voltage source;

17-Adjustable current source unit;

18- The second switch unit;

100-power supply equipment;

200- access circuit;

Isrc-current source;

VIN-first voltage source;

VDD-second voltage source;

VOUT- power output terminal;

VCON-power supply pin;

Switch-analog switch;

FET-field effect tube;

Comp-comparator;

Rload- load impedance;

Fig. 4 is a first schematic diagram of a flow chart of a method for detecting impedance to ground in an embodiment of the present invention;

FIG. 5 is a schematic diagram of the second flow of a method for detecting impedance to ground in an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below 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 work shall fall within the protection scope of the present invention.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used Describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those clearly listed. Those steps or units may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

The technical solutions of the present invention will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

FIG. 1 is a first structural diagram of a processing circuit at the output end of a power supply in an embodiment of the present invention.

The processing circuit involved in this embodiment may be an integrated chip or a functional module inside an integrated chip, and any circuit that can satisfy the following description does not depart from the description of this embodiment. The processing circuit can be understood as a circuit in the power supply device. At the same time, this embodiment does not exclude the situation that it is distributed in different devices.

Please refer to FIG. 1, the processing circuit of the power output terminal includes a first switch unit 12 provided at the first voltage source 11 and the power output terminal 13. It can be understood as a circuit form for the power supply terminal in the related art. In the specific implementation process, other devices can be connected in series and/or in parallel. As long as the above description is satisfied, regardless of whether other devices are configured, they will not deviate from this Description of the embodiment.

The power output terminal 13 can be understood as: if the processing circuit is applied to a power supply device, the power supply terminal 13 can be an end that is fixedly or detachably connected to a cable or a power device (for example, it can also be understood as a power supply device). The power supply pin), the structure of the power output terminal 13 may vary according to different power supply modes, for example, it may be a USB Type C interface.

The first switch unit 12 may be any device that can be turned on and off, for example, it may be a field effect transistor, which may also be characterized as a FET, which is an abbreviation of Field Effect Transistor.

The first voltage source can be understood as any device or a collection of devices that can provide direct current for the power supply of electric equipment, for example, it may be an AC-DC or DC-DC power supply device or a combination of devices in the power supply equipment.

In this embodiment, the processing circuit of 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.

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 turned on, the second voltage source The power supply of 16 can be delivered to the power output terminal 13, where 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 circuit basis for detecting impedance to ground can be generated.

The adjustable current source unit 17 may be any device or a collection of devices that can adjust the current generated by it based on the supplied voltage. In an example, the adjustable current source unit 17 may include a second voltage in series. The current source between the power source and the output terminal of the power supply; in another example, the adjustable current source unit 17 can also be implemented by using a pull-up resistor with controllable on-off. For example, it may include a resistance component, which may include multiple Parallel resistance branches, where different resistance branches can produce the same impedance or different impedances. By selecting the resistance branches that are turned on (including the case where multiple branches are turned on at the same time, it also includes the case where multiple branches are turned on at the same time). When a single branch is turned on), the current can also be adjusted. In other examples, the resistor can also be replaced with other devices. In addition, this embodiment does not exclude other circuit units that can implement current adjustment.

The second switch unit 18 can be any device that can be turned on and off, for example, it can be an analog switch, which can be turned off when the first switch unit 12 is turned on for power supply, thereby avoiding the power supply during normal power supply. The power supply of the output terminal 13 causes damage to the adjustable current source unit 17, that is, the second switch unit 18 can isolate the adjustable current source unit 17 from damage caused by the high voltage that may appear at the power output terminal 13. It can be seen that in the specific implementation process, the second switch unit 18 may be an analog switch capable of isolating high voltage.

The control unit 14 is respectively connected to the adjustable current source unit 17 and the voltage detection unit 15, as well as the first switch unit 12 and the second switch unit 18. The voltage of the first voltage source 11 is greater than that of the second switch unit. The voltage of the voltage source 16; the voltage of the second voltage source may be the low-voltage working voltage of the circuit, for example, 3.3V, and the voltage of the first voltage source may be the voltage of the normal power supply, for example, 5V. The second voltage source 16 may be obtained after the first voltage source 11 is stepped down, or may be a separately provided voltage source. For example, the voltage of the second voltage source 16 may be provided by a device other than the first voltage source 11.

The voltage detection unit 15 is connected to the power output terminal 13 via the second switch unit 18, which can be understood as any circuit unit for detecting the voltage range of the power output terminal. The voltage range can refer to a voltage range greater than a certain target voltage value, or can be a voltage range smaller than a certain target voltage value.

Wherein, by disconnecting the second switch unit 18, the voltage detection unit 15 can be prevented from being damaged by the power supply of the power output terminal 13 during normal power supply. That is, the second switch unit 18 can isolate the high voltage that may occur at the power output terminal 13 The voltage detection unit 15 is damaged.

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 certain chip. It can be built by circuit construction. To realize the corresponding functions described in this embodiment, the corresponding functions described in this embodiment can also be realized by program execution, and this embodiment does not exclude the realization of a combination of circuits and programs. At the same time, the control unit 14 may be a control part (such as an information processing circuit) of the power supply device integrated together, or the control unit 14 and the control part may be separate circuits.

2 is a schematic diagram of the structure of a voltage detection unit, a control unit and a power output terminal in an embodiment of the present invention.

In one of the embodiments, please refer to FIG. 2. The voltage detection unit 15 includes a comparator 151; one input terminal of the comparator 151 is used to connect to a reference voltage, and the other input terminal is connected to the power output terminal. 13, for example, can be connected to the power output terminal 13 via the second switch unit 18. At the same time, it does not rule out the means of separately connecting other devices.

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

In other embodiments, the voltage detection unit 15 may also be implemented by a voltage analog-to-digital converter ADC.

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

When the first switch unit 12 is kept off, the second switch unit 18 is controlled to be turned on, so that the second voltage source 11, the adjustable current source unit 17 and the power output terminal 13 are sequentially turned on. Turn on

Adjusting the current value of the current output from the second voltage source 16 to the power output terminal 13 by the adjustable current source unit 17;

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

The impedance range to ground can be understood as any specified impedance range under the impedance span to be detected.

In the impedance to ground, the situation can be, for example, the low impedance where the corresponding power pin is short-circuited to the ground (for example, the power pin of the external charging cable is directly shorted or disconnected for a short time. Connected), and for example, an impedance of about several hundred to several thousand ohms appears between the corresponding power pin and the ground pin due to salt water or sweat. It can also be used for example when an electrical device (such as a mobile phone) is connected (the power output is at this time). The power channel is off state) and the insertion impedance is tens of thousands to hundreds of thousands of ohms. It can be seen that the impedance span to the ground is relatively large, and this embodiment determines the impedance range to the ground within the span to facilitate the corresponding response 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 determined by the adjustment of the adjustable current source unit, It can also be understood that at least two different impedance ranges to ground are determined under different current values determined by the adjustment of the adjustable current source unit.

In one of the implementation manners, the impedance range of the power output terminal to ground includes at least one of the following:

The impedance range at no-load, which matches the impedance to ground at the output of the power supply when the first switch unit is kept off; it can be understood as the premise that the power is off (that is, the first switch is off) When the power is turned on), the input impedance range of the normal electric equipment is matched with the impedance to the ground when the electric equipment is normally connected to the power output terminal (the first switch is off at this time) and the ground; for example, it may be greater than 3M ohm (ie 3000K ohm);

The impedance range during normal power supply, which matches the impedance to ground when the electrical equipment is normally connected to the output terminal of the power supply and the ground; for example, it may be 30K to 3000K ohms;

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

The impedance range when the external object is connected, which matches the impedance to the ground when the external object is connected to the output terminal of the power supply and the ground; it can be, for example, 30K to 3000K ohm;

The impedance range when the salt-containing liquid is connected is matched with the impedance to the ground when the salt-containing liquid is connected between the output terminal of the power supply and the ground; it can be, for example, 300 to 3K ohms; the salt-containing liquid can be, for example, Some materials with low impedance such as salt water and sweat;

The impedance range during leakage, which matches the impedance to ground when the power input terminal or the power supply pin of the cable connected to it leaks, and the leakage current value is greater than the threshold; it can be, for example, a certain degree of interface blockage In the case of a short circuit or a wet interface or normal quality, which results in leakage, and an electronic load with a relatively large leakage current is connected, the specific value can be 3K to 30K ohms.

Wherein, the impedance range at no load, the impedance range at normal power supply, the impedance range at leakage, the impedance range at the time of access of the salt-containing liquid, and the impedance range at the time of short circuit may be distributed in order from large to small The impedance range when the foreign object is connected may be smaller than the impedance range at no-load and larger than the impedance range at leakage.

When determining the impedance range to ground, it can be determined according to the range of the voltage measured after a single adjustment of the current, or it can be determined according to the value range of the voltage obtained after multiple adjustments of the current.

Since the impedance to ground has a relatively large span, such as a range of 0 to 3M ohms, the current value of the current involved and the voltage value of the reference voltage can be selected correspondingly to match the span.

In one of the embodiments, adjusting the determined voltage value of the reference voltage includes at least two target voltage values, wherein the largest target voltage value is k times the smallest target voltage value, and k is greater than or equal to 10. The current value determined by the adjustment includes at least two target current values, wherein 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 complete all the above-listed impedance ranges more efficiently.

In addition, the target current value and the number of target voltage values can be arbitrarily changed according to demand, and the gap between the maximum value and the minimum value can also be changed arbitrarily according to demand. For example, k may not be limited to a range greater than or equal to 10. N may not be limited to a range greater than or equal to 1000, and they are all changes in value or quantity, and no matter how they change, they will not deviate from the solution of this embodiment.

Based on the configured target current value and target voltage value, since the impedance to ground is the largest when there is no load, in order to facilitate the test, it can be adjusted to the minimum current and the maximum reference voltage for testing. The impedance to ground is the smallest when a short circuit or a micro short circuit occurs. In order to facilitate the test, it can be adjusted to the maximum current and minimum reference voltage for testing, and then:

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

In the above scheme, when the first switch unit is controlled to be turned off (that is, when the power supply terminal is not supplying external power with the required higher voltage), the second voltage source with a lower voltage can be used to supply power to the power supply terminal, and When power is supplied, the voltage detection unit is used to detect the voltage of the power supply terminal of the power supply, and further, the ground impedance of the power supply terminal of the power supply can be effectively detected based on the detection result. Furthermore, this embodiment can detect the impedance to ground before the first voltage source supplies power to the outside, which is beneficial to prevent potential safety hazards and dangers caused by powering the outside when the impedance to ground is abnormal, and provides a basis for avoiding potential safety hazards and dangers. .

At the same time, in this embodiment, by adjusting the current output from the second voltage source to the power supply terminal of the power supply, it is convenient to accurately determine the current impedance-to-ground impedance range within a larger impedance-to-ground span. Furthermore, due to different The ground impedance range is related to the cause of the ground impedance, and this embodiment can also be understood to be able to judge the cause of the ground impedance, thereby facilitating timely and accurate response.

It should also be pointed out that in some technologies, the command to turn on or turn off the power output can also come from the judgment of other signal lines (for example, the CC line of the USB Type C interface is pulled down by a 5.1K ohm pull-down resistor to ground (GND). The standard USB Type C device load is connected) or the response to changes in environmental conditions (such as the control to turn off the first switch unit of the FET after the interface temperature is too high), or the visual judgment of the operator (such as judgment) Then press a corresponding button), it can be seen that in these technologies, no matter what method it is, it is always difficult to learn the actual situation of the impedance to ground before the main power supply channel is turned on, and the scheme involved in this embodiment can be used in the main power supply. Judge when the channel is closed. As mentioned above, compared with the prior art, this embodiment can help prevent potential safety hazards and dangers caused by external power supply when the impedance to ground is abnormal, and provide a basis for avoiding potential safety hazards and dangers. In order to be able to judge the cause of the impedance to the ground, it is conducive to timely and accurate response.

In one of the embodiments, the control unit 14 is further configured to: when the first switch unit is kept off, control the first switch unit and the second switch unit according to the impedance range to ground The on-off.

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

During specific implementation, when the control unit 14 controls the on-off of the first switch unit according to the impedance range to ground, it can be specifically used to implement at least one of the following:

If the impedance range to ground matches the impedance to ground when the power supply output terminal or the power supply pin of the cable connected to the ground is short-circuited, the first switch unit is controlled to remain off, and the The first switch unit is prohibited from being turned on.

When the control unit 14 adjusts and determines the current value of the current output by the second voltage source to the output terminal of the power supply through the adjustable current source unit, it is specifically configured to:

The current value of the current is adjusted to the at least two target current values in sequence from large to small, wherein the adjustment of the current value is implemented periodically, and furthermore, one or more pairs can be determined after each adjustment. The upper limit or lower limit of the ground impedance range. In other alternative embodiments, the means of sequential adjustment from childhood is not excluded.

In FIG. 3, the adjustable current source unit 17 can be a current source Isrc, and the current value of the current it generates can also be characterized by Isrc. The first switch unit 12 can be a FET, and the second switch unit 18 can be For analog switch Switch, the voltage detection unit 15 can use a comparator Comp. At the same time, VIN can be used to characterize the first voltage source 11 and its voltage, VDD can be used to characterize the second voltage source 16 and its voltage, and VOUT can be used to characterize the power output and its voltage. For voltage, use VCON to characterize the power supply pin of the cable or power-consuming device. At the same time, the load impedance Rload can be regarded as the impedance to ground, and its resistance can also be characterized by Rload. The box on the left can be regarded as part of the circuit in the power supply equipment, and the box on the right can for example include cables and various impedance-forming objects connected to the cables. This object can be, for example, circuit objects (such as electricity Equipment, metal wires of cables, etc.), non-circuit objects (for example, foreign objects, sweat, etc.), or a combination of at least one of them.

The following takes the example shown in FIG. 3 as an example to illustrate the specific implementation of this embodiment.

Among them, the number of target voltage values of the reference voltage of the comparator Comp can be two, which can be represented as Ref1 and Ref2, respectively, and the reference voltage Ref1 or Ref2 can be selected according to actual needs.

In the example shown in Figure 3, 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 supply output terminal VOUT via the analog switch Switch, and the output pin of the current source Isrc is also the same as 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, for example, 3.3V, and the second voltage source VDD can be generated by the first voltage source VIN or provided by an external device (for example, other circuits in the device).

In the example shown in Fig. 3, the EN pin of the control unit 14 as well as the SDA pin, SCL pin, and INT pin can be used for the control unit to interact with the main body of the power supply device to which it belongs. The SDA pin, SCL pin, and INT pin can be used to interact with the main body of the power supply device. The pin can be understood as the pin of the I2C function module in the control unit 14. In other examples, the EN pin, SDA pin, SCL pin, and INT pin can also use several GPIO pins (also can be understood as general-purpose input and output ports). ) Replace.

In order to facilitate the description of its operation process, it can be assumed that the current source Isrc can be configured to 1uA, 10uA, 100uA and 1mA and can periodically (for example, spend 1 millisecond every 1 second) output to detect and judge the load impedance Rload until the first The main power supply channel from the voltage source VIN to the power output terminal VOUT is controlled to be turned on based on the detection result.

Further, it can be assumed that Ref 1 is 0.3V and Ref 2 is 3.0V. At the same time, ke regards the power output terminal VOUT and the power pin VCON of the cable as the same power pin (in fact, the power supply device After the output and the electrical equipment are connected, the power output terminal VOUT and the power supply pin VCON of the cable are basically the same) to illustrate the implementation process of the processing circuit.

While the power supply device is waiting for the access of the electronic device, the field effect transistor FET 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. , The analog switch Switch as the second switch unit is in the on state, the current under the control of the current source Isrc can be configured to a target current value of 1uA, and the reference voltage is connected to the inverting terminal of the comparator and configured to Ref 2=3.0V;

When the power output terminal VOUT is not connected to the cable, or the power output terminal VOUT is connected to the cable, but the power pin VCON in the male connector of the cable is not connected to any electronic equipment and is in a normal no-load state, the power output terminal The load impedance Rload seen at VOUT will be much greater than 3 megohms. After a 1uA current source, the voltage at the output terminal VOUT of the power supply is Isrc*Rload and will be greater than 3V (approximately equal to the voltage value of the second voltage source VDD, That is, Isrc*Rload≈VDD), and further, the output of the comparator Comp is high at this time.

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

If the output of the comparator Comp is high 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 likely that electricity is needed at this time. The electrical equipment has been connected. The impedance of 30K to 3000K ohm is the load impedance reflected by the injection of 1uA or 10uA current source. At this time, the main power supply channel from the first voltage source VIN to the power supply output terminal VOUT can be opened to provide At the same time, it can also provide the relevant information processing circuit of the power supply equipment with the range information of the load impedance Rload at this time (ie the impedance range to the ground), so that the information processing circuit of the power supply equipment can further determine the load that generates the load impedance Rload type.

However, at this time, even if the load impedance Rload is not a real electrical load, but some kind of debris with an impedance of 30K to 3000K ohms overlaps the power output terminal Vout and GND or the power supply pin VCON and GND of the cable, it will not Damage is caused by opening the power supply channel from the first voltage source VIN to the power output terminal VOUT (but it will cause the system to have a small leakage current of one or two microamps to one or two hundred microamps). After correct judgment, deal with it in time That's it.

Based on the principle similar to the above process, the load impedance Rload from 3K to 30K can be judged by adjusting the current under the control of the current source Isrc to 100uA, and 300 to 3K ohms can be judged by adjusting the current under the control of the current source Isrc to 1mA. The load impedance Rload of, and the load impedance Rload of less than 300 ohms (at this time, the reference voltage is Ref 1 = 0.3V, and the output of the comparator Comp is low).

After the load impedance Rload range obtained by the cooperation of the current source and the comparator, the corresponding operation can be done.

For example: if the load impedance Rload is less than 300 ohms, it usually means that the power supply output terminal VOUT and GND or the power supply pin VCON and GND of the cable is short-circuited or slightly short-circuited. At this time, the first voltage source VIN cannot be turned on to the power output. The main power supply channel of the terminal VOUT, otherwise it may cause a high temperature or a fire event. During the specific implementation process, the control unit can give the main part of the power supply equipment (such as its information processing circuit) an alarm and feedback the load impedance Rload through the interrupt pin INT or GPIO. Resistance range or resistance value; the impedance range to ground at this time can be understood as the impedance range during short circuit mentioned above;

Another example: if the load impedance Rload is in the range of 300 to 3K ohms, it usually means that some materials with low impedance such as sweat and salt water, the power output terminal VOUT or the power pin of the cable, and GND form a path. The Rload resistance range or resistance value that can alarm and feedback the load status; the impedance range to the ground at this time can be understood as the impedance range when the salt-containing liquid is connected in the previous article;

Another example: if the load impedance Rload is in the range of 3K to 30K, it may be a certain degree of interface blockage and short circuit, or the interface is wet or the electronic load of general quality and relatively large leakage current is connected. At this time, the first voltage source can be turned on The main power supply channel from VIN to the output terminal VOUT of the power supply. At the same time, the resistance range of the load impedance Rload or its resistance 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 leakage involved in the previous article. Time impedance range;

For another example, if the load impedance Rload is connected to a voltage source with a certain voltage and output capacity, the information processing circuit of the power supply device can do more operations to judge and deal with this situation.

In short, if you want to expand the span of the 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 this.

This embodiment also provides an electronic device (that is, the power supply circuit involved in the foregoing), which includes the processing circuit of the power output terminal involved in the above optional solutions.

The electronic device can be understood as any device that can output direct current to the outside, such as a wall plug-in charger, a car charger, a mobile power supply, a travel charger, a charging pile, and so on. At the same time, electronic equipment that is not dedicated to power supply and charging, such as computers, household appliances, industrial appliances, etc., is not excluded.

In summary, in the processing circuit and electronic equipment of the power output terminal provided in this embodiment, when the first switch unit is controlled to be turned off (that is, when the power supply terminal is not powered externally with the required higher voltage), the use voltage is smaller. The second voltage source supplies power to the power supply terminal, and the voltage detection unit is 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 impedance to ground before the first voltage source supplies power to the outside, which is beneficial to prevent potential safety hazards and dangers caused by powering externally when the impedance to ground is abnormal, and provides a basis for avoiding potential safety hazards and dangers. .

At the same time, in this embodiment, by adjusting the current output from the second voltage source to the power supply end of the power supply, it is convenient to accurately determine the current impedance-to-ground impedance range within a larger impedance-to-ground span. Furthermore, due to different The ground impedance range is related to the cause of the ground impedance, and the present invention can also be understood as being able to judge the cause of the ground impedance, thereby facilitating timely and accurate response.

Fig. 4 is a first schematic diagram of a method for detecting impedance to ground in an embodiment of the present invention; Fig. 5 is a schematic diagram second of a method for detecting impedance to ground in an embodiment of the present invention.

Please refer to Figures 4 and 5, the method for detecting impedance to ground at the output of the power supply is applied to the control unit in the processing circuit at the output of the power supply. The processing circuit can be understood as the processing circuit involved in the embodiments shown in Figures 1 to 3 . The method includes:

S21: When the first switch unit is kept off, control the second switch unit to be turned on, so that the second voltage source and the output terminal of the power supply can be turned on;

S22: Adjust the current value of the current output by the second voltage source to the output terminal of the power supply;

S23: According to the different current values determined by the adjustment and the detected voltage range, determine the ground impedance range where the ground impedance of the power supply output end is located, where the different ground impedance ranges and the reasons for the ground impedance Associated.

Optionally, after step S23, it may further include:

S24: When the first switch unit is kept off, control the on-off of the first switch unit and the second switch unit according to the impedance range to the ground.

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

The impedance range during normal power supply, which matches the impedance to ground when the electrical equipment is normally connected to the output terminal of the power supply and the ground;

Wherein, the impedance range at no-load, the impedance range at normal power supply, the impedance range at leakage, the impedance range at the time of access of the salt-containing liquid, and the impedance range at the time of short circuit are distributed in descending order;

The impedance range when the foreign object is connected is smaller than the impedance range when there is no load, and is larger than the impedance range when the leakage occurs.

The method also includes:

The voltage value of the reference voltage is adjusted, 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.

Optionally, step S23 specifically includes:

Optionally, adjusting the determined voltage value of the reference voltage includes at least two target voltage values, where the largest target voltage value is k times the smallest target voltage value, where k is greater than or equal to 10.

Optionally, the current value determined by the adjustment includes at least two target current values, where the largest target current value is n times the smallest target current value, where n is greater than or equal to 1000;

Step S23 specifically includes:

In summary, in the method for detecting the impedance to the ground at the output terminal of the power supply provided in this embodiment, when the first switch unit is controlled to be turned off (that is, when the power supply terminal is not powered externally with the required higher voltage), the use of a lower voltage The second voltage source supplies power to the power supply terminal, and the voltage detection unit is 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 impedance to ground before the first voltage source supplies power to the outside, which is beneficial to prevent potential safety hazards and dangers caused by powering externally when the impedance to ground is abnormal, and provides a basis for avoiding potential safety hazards and dangers. .

A person of ordinary skill in the art can understand that all or part of the steps in the foregoing method embodiments can be implemented by a program instructing relevant hardware. The aforementioned program can be stored in a computer readable storage medium. When the program is executed, it executes the steps including the foregoing method embodiments; and the foregoing storage medium includes: ROM, RAM, magnetic disk, or optical disk and other media that can store program codes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not 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: The technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention. range.

Claims

A processing circuit for a power output terminal includes a first switch unit arranged at a first voltage source and the power output terminal, and is characterized in that it also 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 the second voltage source and the power output; the control unit is respectively connected to the adjustable current source unit and 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 output terminal of the power supply via the second switch unit for detecting the voltage range in which the voltage of the output terminal of the power supply is located;

The control unit is used for:

When the first switch unit is kept off, controlling the second switch unit to be turned on, so that the second voltage source, the adjustable current source unit, and the power output terminal are sequentially turned on;

Adjusting the current value of the current output by the second voltage source to the output terminal of the power supply by the adjustable current source unit;

According to the different current values determined by the adjustment and the detected voltage range, the ground impedance range of the output end of the power supply is determined, wherein the different ground impedance ranges are related to the cause of the ground impedance At least two different impedance ranges to ground are determined according to different current values determined by the adjustment of the adjustable current source unit.
The processing circuit according to claim 1, wherein the control unit is further configured to: when the first switch unit is kept off, control the first switch unit to connect to the ground according to the impedance range to ground. The on-off of the second switch unit.
The processing circuit according to claim 2, wherein the control unit is specifically configured to implement at least one of the following when controlling the on-off of the first switch unit according to the impedance range to ground:

If the ground impedance range matches the ground impedance when the electrical equipment is normally connected, the first switching unit is controlled to be turned on, the second switching unit is turned off, and the electrical equipment is connected to the ground. Handshake communication;

If the ground impedance range matches the ground impedance when the power supply output terminal or the power supply pin of the cable connected to the ground is short-circuited, the first switch unit is controlled to remain off, and the The first switch unit is prohibited from being turned on.
The processing circuit according to claim 1, wherein the impedance range of the power output terminal to ground includes at least one of the following:

The impedance range at no-load, which matches the impedance to ground when the output terminal of the power supply is no-load when the first switch unit is kept off;

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

The impedance range when the external object is connected, which matches the impedance to the ground when the external object is connected to the output terminal of the power supply and the ground;

The impedance range when the salt-containing liquid is connected, which matches the impedance to ground when the salt-containing liquid is connected between the output terminal of the power supply and the ground;

The impedance range during leakage is matched with the impedance to ground when the power input terminal or the power supply pin of the cable connected to the power supply has leakage, and the leakage current value is greater than the threshold value.
The processing circuit according to any one of claims 1 to 4, wherein the voltage detection unit comprises a comparator; one input terminal of the comparator is used to connect to the reference voltage, and the other input terminal is connected to the reference voltage. The power output terminal;

The control unit is also 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 the lower limit value of each voltage range, and at least two different impedances to ground The range is determined according to different reference voltages adjusted and determined.
The processing circuit according to claim 5, wherein the control unit determines the impedance range to the ground of the power output terminal according to the different currents determined by the adjustment and the detected voltage range. , Specifically used for:

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 maximum The voltage range of the target voltage of, then: determine the impedance range to ground where the impedance to ground of the output terminal of the power supply is located as the impedance range at no-load;

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 minimum For the voltage range of the target voltage, it is determined that the ground impedance range of the output terminal of the power supply is located as the impedance range during short-circuit.
The processing circuit according to claim 5, wherein adjusting the voltage value of the determined reference voltage includes at least two target voltage values, wherein the largest target voltage value is k times the smallest target voltage value, and where k Greater than or equal to 10;

The current value determined by the adjustment includes at least two target current values, wherein the largest target current value is n times the smallest target current value, and n is greater than or equal to 1000.
The processing circuit according to any one of claims 1 to 4, wherein the current value determined by adjusting includes at least two target current values;

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

The current value of the current is adjusted to the at least two target current values sequentially from large to small, wherein the adjustment of the current value is implemented periodically.
A method for detecting impedance to ground at the output end of a power supply is applied to a control unit in a processing circuit at the output end of the power supply, wherein the processing circuit includes a first switch unit arranged at a first voltage source and the output end of the power supply, and The second switch unit and the second voltage source, the voltage of the first voltage source is greater than the voltage of the second voltage source; the method includes:

When the first switch unit is kept off, controlling the second switch unit to be turned on, so that the second voltage source and the output terminal of the power supply can be turned on;

Adjusting the current value of the current output by the second voltage source to the output terminal of the power supply;

According to the different current values determined by the adjustment and the detected voltage range, the ground impedance range of the output end of the power supply is determined, wherein the different ground impedance ranges are related to the cause of the ground impedance At least two different impedance ranges to ground are determined according to different current values determined by adjustment.
An electronic device comprising the processing circuit of the power output terminal according to any one of claims 1 to 8.