TWI777703B - Foreign object detection method and power side capable of detecting foreign object - Google Patents

Abstract

A foreign object detection method for detecting whether a foreign object exists on a function pin of a power supplier side or a power receiver side, wherein the power supplier side and the power receiver side are coupled in a pluggable configuration. The foreign object detection method includes: discharging a capacitor through the function pin, wherein the capacitor is electrically connected to the function pin; providing a detection current through the function pin to charge the capacitor; detecting a voltage variation of the function pin within a predetermined period; and comparing the voltage variation with a predetermined variation, so as to determine whether there is a foreign object on the function pin.

Description

Foreign object detection method and power supply terminal with foreign object detection function

The present invention relates to a foreign object detection method and a power supply terminal with a foreign object detection function, in particular to a foreign object detection method for determining whether there is a foreign object on a functional pin according to a voltage change on a functional pin, and a foreign object detection method with a foreign object The power terminal of the detection function.

Please refer to FIG. 1 , which shows a schematic circuit diagram of a power supply system of the prior art. In this prior art, the pin CC2 is discharged through the resistor Rd through the control switches SW2 and SW4, and then the pin CC2 is set to a floating state by the control switches SW2 and SW4, and the comparator COM2 outputs the voltage level of the pin CC2 and The comparison result Det_R of the level of the reference voltage Vref. When a foreign object such as moisture exists between the pin VBUS and the pin CC2 in the power terminal, the power supply voltage (such as the voltage 5V provided by the pin VBUS) will be supplied to the pin CC2 through the foreign object such as moisture, so the connection The voltage of pin CC2 will increase. Therefore, when the voltage of the pin CC2 is judged by the comparator COM2 to be higher than the reference voltage Vref, the system will determine that there is foreign matter such as moisture in the power supply terminal; however, this prior art must wait for the voltage of the pin CC2 to stabilize before It takes a lot of time to determine whether it is higher than the reference voltage Vref.

In view of this, the present invention provides a foreign object detection method capable of determining whether there is a foreign object on the functional pin according to the voltage change on the functional pin, and a power terminal with a foreign object detection function.

From one point of view, the present invention provides a foreign object detection method for detecting whether there is a foreign object on a functional pin of a power supply terminal or a power receiving terminal, and the power supply terminal and the power receiving terminal are pluggable. coupled to each other, the foreign object detection method includes: discharging a capacitor through the functional pin, wherein the capacitor is electrically connected to the functional pin; providing a sensing current to charge the capacitor via the functional pin; A voltage change of the functional pin is sensed during a preset period; and the voltage change is compared with a preset change to determine whether there is foreign matter on the functional pin.

From another viewpoint, the present invention also provides a power terminal with a foreign object detection function, the power terminal has the function of detecting whether there is a foreign object on one of the functional pins, and the power terminal is a power supply terminal or a power receiving terminal. terminal, wherein the power supply terminal and the power receiving terminal are coupled to each other in a pluggable manner, and the power supply terminal is used to supply power to the power receiving terminal, the power supply terminal includes: a discharge circuit, including a switch, the switch and the function The pin is electrically connected with a capacitor, the switch is used to discharge the capacitor through the functional pin, wherein the capacitor is electrically connected with the functional pin; a current source circuit, the current element circuit, the functional pin and the capacitor electrical connection, the current source circuit is used for providing a sensing current flowing through the functional pin to charge the capacitor; and a foreign object detection circuit is used for sensing a voltage change of the functional pin during a preset period , and compare the voltage change with a preset change to determine whether there is foreign matter on the functional pin.

In a preferred embodiment, the predetermined change is determined according to the capacitance value of the capacitor.

In a preferred embodiment, the power supply terminal or the power receiving terminal is a universal serial bus (USB), and the functional pins include a VBUS pin of the USB, a DP pin, a DM pin, one CC1 pin, one CC2 pin, one SBU1 pin or one SBU2 pin.

In a preferred embodiment, the step of sensing a voltage change of the functional pin during a preset period includes: sensing an initial voltage of the functional pin at an initial time point of the preset period, wherein The starting time point is after the step of discharging the capacitor through the function pin and before the step of providing the sensing current to charge the capacitor through the function pin; at a preset time point of the preset period , sensing a period voltage of the function pin; and sensing an end voltage of the function pin at an end time point of the preset period, wherein the end time point is after the preset time point.

In a preferred embodiment, the voltage change includes a first voltage change and a second voltage change; wherein the first voltage change is the difference between the end voltage and the initial voltage, and the second voltage change is the The difference between the end voltage and the period voltage.

In a preferred embodiment, the step of sensing a voltage change of the functional pin during a preset period further includes: sensing the end voltage of the functional pin at the end point of the preset period After the step of , discharge the capacitor through the function pin.

In a preferred embodiment, the step of comparing the voltage change with a predetermined change to determine whether there is foreign matter on the functional pin includes: comparing the first voltage change with a first predetermined change of the predetermined change. set a change; when the first voltage change is not greater than the first predetermined change, compare the second voltage change with a second predetermined change of the predetermined change; and when the second voltage change is not greater than the second predetermined change If the setting is changed, it is determined that there is a foreign body on the function pin.

In a preferred embodiment, the period from the start time point to the end time point is no more than 100 milliseconds.

In a preferred embodiment, the switch includes a high voltage metal oxide semiconductor (MOS) device or a low voltage MOS device.

In a preferred embodiment, the foreign object detection circuit includes an analog-to-digital converter or a comparator.

The advantage of the present invention is that the present invention does not need to wait for the voltage on the functional pins to reach a stable state, so the present invention can detect whether foreign objects exist on the functional pins within a predetermined time.

The following describes in detail with specific embodiments, when it is easier to understand the purpose, technical content, characteristics and effects of the present invention.

20: Power terminal with foreign object detection function

30: Foreign object detection method

201: function pin

202: Discharge circuit

203: Current source circuit

204: Foreign object detection circuit

301~304, 3031~3034, 3041~3043: Steps

Cfp: Capacitance

COM2: Comparator

Det_R: Compare results

Id: sense current

Rd, Rp: resistance

Rfod: resistance value of foreign matter

SW2, SW4: switch

t0: starting time point

t1: preset time point

t2: end time

VBUS, CC2: pin

Vfp: Voltage

Vfp_t0: initial voltage

Vfp_t1: Period voltage

Vfp_t2: end voltage

Vref: reference voltage

△Vfp1: The first voltage change

△Vfp2: The second voltage change

△Vth1: The first preset change

△Vth2: Second preset change

FIG. 1 is a schematic circuit diagram showing a power supply system of the prior art.

FIG. 2 is a block diagram illustrating a power terminal with a foreign object detection function according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a signal waveform of a power terminal with a foreign object detection function according to an embodiment of the present invention.

FIG. 4 is a graph showing a first voltage change of a functional pin of a power terminal with a foreign object detection function corresponding to a capacitance value according to an embodiment of the present invention.

FIG. 5 is a graph showing the second voltage change of the functional pin of the power terminal with the foreign object detection function corresponding to the capacitance value according to an embodiment of the present invention.

6-9 are flow charts showing steps of a foreign object detection method according to an embodiment of the present invention.

The drawings in the present invention are schematic, mainly intended to represent the coupling relationship between the circuits and the relationship between the signal waveforms, and the circuits, signal waveforms and frequencies are not drawn to scale.

FIG. 2 is a block diagram illustrating a power terminal with a foreign object detection function according to an embodiment of the present invention. Referring to FIG. 2 , the power terminal 20 with the foreign object detection function of the present invention has the function of detecting whether there is a foreign object on one of the functional pins 201 . In one embodiment, the power terminal 20 with the foreign object detection function is, for example, a power supply terminal or a power receiving terminal. The power supply terminal and the power receiving terminal are coupled to each other in a pluggable manner, and the power supply terminal is used for supplying power to the power receiving terminal. In one embodiment, the power supply terminal or the power receiving terminal is, for example, a universal serial bus (USB).

As shown in FIG. 2 , the power supply terminal 20 with the foreign object detection function of the present invention includes a discharge circuit 202 , a current source circuit 203 and a foreign object detection circuit 204 . In one embodiment, the discharge circuit 202 includes a switch, and the aforementioned switch is coupled to a ground potential. In one embodiment, the aforementioned switch is, for example, but not limited to, a high-voltage metal oxide semiconductor (MOS) device or a low-voltage MOS device. For example, the discharge circuit 202 is electrically connected to the functional pin 201 and the capacitor Cfp in an on-off relationship, and the capacitor Cfp is electrically connected to the functional pin 201 . The discharge circuit 202 is, for example, a switch for discharging the capacitor Cfp through the function pin 201 .

The current source circuit 203 is electrically connected to the functional pin 201 and the capacitor Cfp, and the current source circuit 203 is used for providing a sensing current Id to flow through the functional pin 201 to charge the capacitor Cfp. In one embodiment, the current source circuit 203 is, for example, but not limited to, a low dropout voltage regulator. The foreign object detection circuit 204 is coupled to the functional pin 201 for sensing the change of the voltage Vfp of the functional pin 201 during a preset period, and compares the voltage change with the preset change to determine whether there is a foreign object on the functional pin 201 live exist. In one embodiment, the foreign object detection circuit 204 is, for example, but not limited to, an analog-to-digital converter (ADC) or a comparator.

In one embodiment, the predetermined change is determined according to the capacitance value of the capacitor Cfp. In one embodiment, the functional pins 201 include VBUS pins, DP pins, DM pins, CC1 pins, CC2 pins, SBU1 pins or SBU2 pins of USB.

FIG. 3 is a schematic diagram showing a signal waveform of a power terminal with a foreign object detection function according to an embodiment of the present invention. Please refer to FIG. 2 and FIG. 3 at the same time, the foreign object detection circuit 204 senses the change of the voltage Vfp of the function pin 201 during the preset period by the following steps: First, at the starting time point t0 of the preset period, the sensing function The initial voltage Vfp_t0 of the pin 201, wherein the starting time point t0 is after the step of discharging the capacitor Cfp through the functional pin 201 and before the step of providing the sensing current Id to charge the capacitor Cfp through the functional pin 201. Then, at the preset time point t1 of the preset period, the period voltage Vfp_t1 of the sensing function pin 201 is sensed. Next, at the end time point t2 of the predetermined period, the end voltage Vfp_t2 of the sensing function pin 201 is sensed, wherein the end time point t2 is after the predetermined time point t1 .

As shown in FIG. 3 and FIG. 2 , the step of sensing the voltage change of the functional pin 201 by the foreign object detection circuit 204 during the preset period further includes: at the end point t2 of the preset period, sensing the end voltage of the functional pin 201 After the step of Vfp_t2 , the capacitor Cfp is discharged through the function pin 201 . In one embodiment, the period from the start time point t0 to the end time point t2 is, for example, not more than 100 milliseconds (millisecond).

，其中Rfod代表異物的電阻值，t2代表結束時點，Id代表感測電流。於一實施例中，圖5所示之第二電壓變化△Vfp2與電容Cfp的關係方程式係為

，其中Rfod代表異物的電阻值，t1代表預設時點，t2代表結束時點。 In one embodiment, the voltage change includes a first voltage change ΔVfp1 and a second voltage change ΔVfp2 . The first voltage change ΔVfp1 is the difference between the end voltage Vfp_t2 and the initial voltage Vfp_t0 , and the second voltage change ΔVfp2 is the difference between the end voltage Vfp_t2 and the period voltage Vfp_t1 . FIG. 4 is a graph showing the first voltage change ΔVfp1 of the functional pin 201 of the power terminal 20 with foreign object detection function corresponding to the capacitance Cfp according to an embodiment of the present invention. 5 is a graph showing the second voltage change ΔVfp2 of the functional pin 201 of the power terminal 20 with foreign object detection function corresponding to the capacitance Cfp according to an embodiment of the present invention. In one embodiment, the relational equation between the first voltage change ΔVfp1 and the capacitance Cfp shown in FIG. 4 is ΔVfp1 = Id * Rfod (1-

, where Rfod represents the resistance value of the foreign object, t2 represents the end point, and Id represents the sensing current. In one embodiment, the relationship equation between the second voltage change ΔVfp2 and the capacitance Cfp shown in FIG. 5 is:

, where Rfod represents the resistance value of the foreign object, t1 represents the preset time point, and t2 represents the end time point.

Please refer to FIG. 3 , FIG. 4 and FIG. 5 at the same time, the foreign object detection circuit 204 compares the voltage change with the preset change in the following steps to determine whether there is foreign object on the functional pin 201 : First, compare the first voltage change Δ Vfp1 and the first preset change ΔVth1 of the preset change. Next, when the first voltage change ΔVfp1 is not greater than the first predetermined change ΔVth1 , the second voltage change ΔVfp2 is compared with the second predetermined change ΔVth2 of the predetermined change. Then, when the second voltage change ΔVfp2 is not greater than the second predetermined change ΔVth2, it is determined that there is a foreign body on the functional pin 201 .

6-9 are flow charts showing steps of a foreign object detection method according to an embodiment of the present invention. As shown in FIG. 6 , the foreign object detection method 30 of the present invention includes, in step 301 , discharging the capacitor through the functional pin, wherein the capacitor is electrically connected to the functional pin. Then, in step 302, a sensing current is provided to charge the capacitor through the function pin. Then, in step 303, the voltage change of the function pin is sensed during a preset period. Next, in step 304, the voltage change is compared with the preset change to determine whether there is foreign matter on the functional pin.

As shown in FIG. 7 , in one embodiment, step 303 includes steps 3031 , 3032 and 3033 . In step 3031, the initial voltage of the function pin is sensed at the start time point of the preset period, wherein the start time point is after the step of discharging the capacitor through the function pin, and the sensing voltage is provided. Before the step of charging the capacitor by flowing through the functional pin. Then, in step 3032, the period voltage of the function pin is sensed at a preset time point of the preset period. Next, in step 3033, at the end time point of the preset period, the end voltage of the sensing function pin is sensed, wherein the end time point is after the preset time point.

As shown in FIG. 8 , in one embodiment, step 303 may further include step 3034 . In step 3034, at the end of the preset period, after the step of sensing the end voltage of the functional pin, the capacitor is discharged through the functional pin. As shown in FIG. 9 , in one embodiment, step 304 includes steps 3041 , 3042 and 3043 . In step 3041, the first voltage variation is compared with the first predetermined variation of the predetermined variation. Next, in step 3042, when the first voltage change is not greater than the first predetermined change, the second voltage change is compared with the second predetermined change of the predetermined change. Then, in step 3043, when the second voltage change is not greater than the second predetermined change, it is determined that there is a foreign object on the functional pin.

As described above, the present invention provides a power terminal with a foreign object detection function and a foreign object detection method. The present invention detects the voltage change, not the stable voltage on the function pins. Since the present invention does not need to wait for the voltage on the functional pin to reach a stable state, the present invention can detect whether there is foreign matter on the functional pin within a predetermined time.

The present invention has been described above with respect to the preferred embodiments, but the above-mentioned descriptions are only intended to make it easy for those skilled in the art to understand the content of the present invention, and are not intended to limit the scope of rights of the present invention. The described embodiments are not limited to be used alone, but can also be used in combination. For example, two or more embodiments can be used in combination, and some components in one embodiment can also be used to replace those in another embodiment. corresponding components. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. Depending on the signal itself, it also includes, when necessary, voltage-to-current conversion, current-to-voltage conversion, and/or scaling of the signal Conversion, etc., and then process or operate according to the converted signal to generate an output result. It can be seen from this that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which are not listed and described here. Accordingly, the scope of the present invention should cover the above and all other equivalent changes.

20: Power terminal with foreign object detection function

201: function pin

202: Discharge circuit

203: Current source circuit

204: Foreign object detection circuit

Cfp: Capacitance

Id: sense current

Rfod: resistance value of foreign matter

Vfp: Voltage

Claims (22)

A foreign object detection method is used to detect whether there is a foreign object on a functional pin of a power supply terminal or a power receiving terminal, the power supply terminal and the power receiving terminal are coupled to each other in a pluggable manner, and the foreign object detection method comprises: : discharge a capacitor via the functional pin, wherein the capacitor is electrically connected to the functional pin; provide a sensing current to charge the capacitor via the functional pin; in a first period of time within a preset period sensing a first voltage change of the functional pin within the first period; sensing a second voltage change of the functional pin within the second period during a second period within the predetermined period; and The first voltage change is compared with a first predetermined change threshold, and the second voltage change is compared with a second predetermined change threshold to determine whether there is foreign matter on the functional pin. The foreign object detection method according to claim 1, wherein the first preset change threshold and the second preset change threshold are determined according to the capacitance value of the capacitor and the resistance value used to determine whether there is foreign object. The foreign object detection method according to claim 1, wherein the power supply terminal or the power receiving terminal is a universal serial bus (USB), and the functional pins include a VBUS pin of the USB, a DP pin, one DM pin, one CC1 pin, one CC2 pin, one SBU1 pin or one SBU2 pin. The foreign object detection method as claimed in claim 1, wherein the step of sensing the first voltage change and the second voltage change of the functional pin comprises: Sensing an initial voltage of the functional pin at a start time point of the predetermined period, wherein the start time point is after the step of discharging the capacitor through the function pin, and after the sensing current is supplied through the function pin before the step of charging the capacitor with the function pin; at a preset time point of the preset period, sensing a period voltage of the function pin; and at an end point of the preset period, sensing the function connection An end voltage of a pin, wherein the end time is after the preset time; wherein from the start time to the end time is the first period, and from the preset time to the end time is the second period; wherein The first voltage changes to be the difference between the end voltage and the initial voltage, and the second voltage changes to the difference between the end voltage and the period voltage. The foreign object detection method according to claim 4, wherein the step of sensing the first voltage change and the second voltage change of the functional pin further comprises: at the end point of the preset period, sensing the After the step of ending the voltage of the functional pin, the capacitor is discharged through the functional pin. The foreign object detection method according to claim 1 or 4, wherein the step of determining whether there is a foreign object on the functional pin comprises: when the first voltage change is not greater than the first preset change threshold, and the second voltage When the change is not greater than the second preset change threshold, it is determined that there is a foreign body on the functional pin. The foreign object detection method according to claim 6, wherein when the first voltage change is greater than the first predetermined change threshold or the second voltage change is greater than the second predetermined change threshold, it is determined that there is no Foreign bodies exist. The foreign object detection method according to claim 6, wherein the first preset change threshold and the second preset change threshold are determined according to a capacitance value of the capacitor and a resistance value used to determine whether foreign objects exist, wherein the When the resistance value is equal to a preset short-circuit threshold, when the current of the capacitor is When the capacitance value is smaller than a corresponding first capacitance value, the first voltage change is greater than the first preset change threshold, and when the capacitance value of the capacitor is greater than the first capacitance value, the first voltage change is smaller than the first voltage change A preset change threshold, when the capacitance value of the capacitor is smaller than a corresponding second capacitance value, the second voltage change is smaller than the second preset change threshold value, and when the capacitance value of the capacitor is greater than the second capacitance value , the second voltage change is greater than the second preset change threshold. The foreign object detection method according to claim 8, wherein the first capacitance value is equal to the second capacitance value. The foreign object detection method according to claim 4, wherein the period from the start time point to the end time point is no more than 100 milliseconds (millisecond). A power supply terminal with foreign object detection function, the power supply terminal has the function of detecting whether there is a foreign object on one of the functional pins, and the power supply terminal is a power supply terminal or a power receiving terminal, wherein the power supply terminal and the power receiving terminal are connected by a They are coupled to each other in a pluggable manner, and the power supply terminal is used to supply power to the power receiving terminal. The power supply terminal includes: a discharge circuit, including a switch, the switch is electrically connected with the functional pin and a capacitor, and the switch is used for to discharge the capacitor through the functional pin, wherein the capacitor is electrically connected to the functional pin; a current source circuit, the current source circuit is electrically connected to the functional pin and the capacitor, and the current source circuit is used to provide A sensing current flows through the functional pin to charge the capacitor; and a foreign object detection circuit is used to sense one of the functional pins in a first period of time within a predetermined period of time A first voltage change, sensing a second voltage change of the functional pin within the second time period during a second period within the predetermined period, and comparing the first voltage change with a first predetermined change threshold , and compare the second voltage change with a second preset change threshold to determine whether there is foreign matter on the functional pin. The power supply terminal with a foreign object detection function as claimed in claim 11, wherein the first preset change threshold and the second preset change threshold are determined according to a capacitance value of the capacitor and a resistance value used to determine whether there is a foreign object. Decide. The power supply terminal with foreign object detection function according to claim 11, wherein the power supply terminal or the power receiving terminal is a universal serial bus (USB), and the function pin includes a VBUS of the USB pin, a DP pin, a DM pin, a CC1 pin, a CC2 pin, an SBU1 pin or an SBU2 pin. The power terminal with foreign object detection function as claimed in claim 11, wherein the foreign object detection circuit senses the first voltage change and the second voltage change of the functional pin by the following steps: in the preset An initial voltage of the functional pin is sensed at a starting time point of the period, wherein the starting time point is after the step of discharging the capacitor through the functional pin, and after the sensing current is supplied through the functional pin Before the step of charging the capacitor; at a preset time point of the preset period, sensing a period voltage of the function pin; and at an end time point of the preset period, sensing the end of one of the function pins voltage, wherein the end time point is after the preset time point; wherein from the start time point to the end time point is the first period, and from the preset time point to the end time point is the second period; wherein the first voltage The change is the difference between the end voltage and the initial voltage, and the second voltage is changed to the difference between the end voltage and the period voltage. The power supply terminal with a foreign object detection function as claimed in claim 14, wherein the step of the foreign object detection circuit sensing the first voltage change and the second voltage change of the functional pin further comprises: At the end point of the preset period, after the step of sensing the end voltage of the function pin, the capacitor is discharged through the function pin. The power supply terminal with foreign object detection function as claimed in claim 11 or 14, wherein the foreign object detection circuit determines whether there is a foreign object on the functional pin by the following steps: when the first voltage change is not greater than the first voltage change When there is a preset change threshold, and the second voltage change is not greater than the second preset change threshold, it is determined that there is a foreign object on the functional pin. The power terminal with foreign object detection function as claimed in claim 16, wherein the function is determined when the first voltage change is greater than the first predetermined change threshold or the second voltage change is greater than the second predetermined change threshold There are no foreign objects on the pins. The power supply terminal with foreign object detection function as claimed in claim 16, wherein the first preset change threshold and the second preset change threshold are determined according to the capacitance value of the capacitor and the resistance value used to determine whether there is a foreign object. determine, wherein when the resistance value is equal to a preset short circuit threshold, when the capacitance value of the capacitor is less than a corresponding first capacitance value, the first voltage change is greater than the first preset change threshold, when the capacitor When the capacitance value of the capacitor is greater than the first capacitance value, the first voltage change is less than the first preset change threshold, and when the capacitance value of the capacitor is less than a corresponding second capacitance value, the second voltage change is less than the The second preset change threshold value, when the capacitance value of the capacitor is greater than the second capacitance value, the second voltage change is greater than the second preset change threshold value. The power terminal with a foreign object detection function as claimed in claim 18, wherein the first capacitance value is equal to the second capacitance value. The power terminal with foreign object detection function as described in claim 14, wherein the period from the start time point to the end time point is no more than 100 milliseconds (millisecond). The power supply terminal with foreign object detection function as claimed in claim 11, wherein the switch comprises a high voltage metal oxide semiconductor (MOS) device or a low voltage MOS device. The power terminal with a foreign object detection function as claimed in claim 11, wherein the foreign object detection circuit comprises an analog-to-digital converter or a comparator.

Images