A charging circuit and a power supply device

Abstract

The application provides a charging circuit and a power supply device; a first charging voltage is provided by a charging power supply to charge a wearable device; before charging, a detection module is used to detect a connection relationship between the charging power supply and the wearable device, and connection state information is output; the connection state information represents any one of positive connection, reverse connection and no connection; a switch control module adaptively controls the conduction and shutdown of first to fourth switch units according to the connection state information, so that the wearable device can be normally charged by the charging circuit through only one pair of contact points regardless of positive connection or reverse connection.

Description

Technical Field

[0001] This invention relates to the field of charging wearable devices, and more particularly to a charging circuit and power supply device. Background Technology

[0002] More and more wearable devices, such as smart rings and smartwatches, are now incorporating POGO pins as charging ports on their casings. To charge a wearable device, both the compatible charger and the device itself need a power POGO pin and a ground POGO pin, electrically coupled to each other. For aesthetic reasons, the two POGO pins on the device are often small and symmetrical. This makes it easy to accidentally connect the device to the compatible charger when charging is needed.

[0003] Please refer to Figure 1 Existing technology adds an extra POGO pin on both the charging and device sides. The first set of POGO pins (Pa), corresponding to the power terminal (VDD) on the device side and the charging power output terminal on the charging side, is positioned in the center. The second set of POGO pins (Pb) and the third set of POGO pins (Pc), corresponding to the ground terminal (GND) on the charging side and the ground terminal (GND) on the device side, respectively, are positioned on either side of the center. This ensures normal charging of the device regardless of whether the device and charging ends are connected in reverse. However, this method requires an extra set of POGO pins, which significantly increases the cost of the wearable device. Furthermore, the extra set of POGO pins occupies considerable physical space in the mechanical structure of the wearable device, affecting the overall design aesthetics. Summary of the Invention

[0004] This invention provides a charging circuit and power supply device to enable wearable devices to be charged normally regardless of whether they are connected in the correct or reverse direction.

[0005] According to a first aspect of the present invention, a charging circuit is provided for charging a wearable device, the wearable device having a first contact and a second contact, the first contact and the second contact being electrically connected to a device power supply terminal and a device ground terminal of the wearable device, respectively; the circuit includes:

[0006] A charging power supply, comprising a power output terminal and a power ground terminal, wherein the charging power supply is used to provide a first charging voltage;

[0007] A first switching unit is coupled between the power output terminal and the first power pin. The first switching unit is used to control the connection and isolation between the power output terminal and the first power pin.

[0008] The second switching unit is coupled between the power output terminal and the second power pin. The second switching unit is used to control the connection and isolation between the power output terminal and the second power pin.

[0009] A third switching unit is coupled between the power ground terminal and the first power pin. The third switching unit is used to control the connection and isolation between the power ground terminal and the first power pin.

[0010] A fourth switching unit is coupled between the power ground terminal and the second power pin. This fourth switching unit controls the connection and isolation between the power ground terminal and the second power pin. The first power pin and the second power pin are respectively used to electrically connect to the first contact or the second contact. When the first power pin is electrically connected to the first contact and the second power pin is electrically connected to the second contact, the wearable device is positively connected to the charging power supply. When the first power pin is electrically connected to the second contact and the second power pin is electrically connected to the first contact, the wearable device is reversely connected to the charging power supply. When neither the first power pin nor the second power pin is electrically connected to the first contact, the wearable device is not connected to the charging power supply.

[0011] The detection module is used to detect the connection status between the wearable device and the charging power supply, and output connection status information; the connection status information represents any one of positive connection, reverse connection, or no connection;

[0012] A switch control module is used to receive the status information and control the first switch unit, the second switch unit, the third switch unit, and the fourth switch unit to turn on and off according to the status information, so that the charging power supply can charge the wearable device regardless of whether the wearable device and the charging power supply are in a positive or negative connection state; wherein:

[0013] If the connection status information indicates that the connection is not established, the switch control module controls the first switch unit, the second switch unit, and the third switch unit to all turn off, and controls the fourth switch unit to turn on.

[0014] If the connection status information indicates a positive connection, the switch control module controls both the first switch unit and the fourth switch unit to be turned on, and controls both the second switch unit and the third switch unit to be turned off.

[0015] If the connection status information indicates a reverse connection, the switch control module controls both the second switch unit and the third switch unit to be turned on, and controls both the first switch unit and the fourth switch unit to be turned off.

[0016] Optionally, the detection module includes a first current source, a fifth switching unit, and a detection unit;

[0017] The first current source is coupled to the first power supply pin through the fifth switching unit; the first current source is used to output a first detection current under a preset voltage supply; wherein, the fifth switching unit is used to turn on or off under the control of the switching control module;

[0018] The detection unit is coupled to the first power pin and the switch control module respectively. The detection unit determines the connection relationship between the charging power supply and the wearable device by detecting the first voltage of the first power pin and outputs the connection status information. If the first voltage is equal to the preset voltage, the connection status information indicates that the device is not connected. If the first voltage is within a first threshold range, the connection status information indicates that the device is connected in the correct direction. If the first voltage is within a second threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining that the connection status information indicates that the device is connected in the correct direction or initially indicates that the device is connected in the reverse direction, the switch control module controls the fifth switch unit to turn off.

[0019] Optionally, the detection module further includes a sixth switching unit;

[0020] The sixth switch unit is coupled between the first current source and the second power supply pin; the sixth switch unit is used to turn on or off under the control of the switch control module; wherein, after the connection status information initially indicates a reverse connection, the switch control module controls the sixth switch unit to turn on.

[0021] Optionally, the detection unit is further configured to detect a second voltage at the second power supply pin when the connection status information initially indicates a reverse connection; if the second voltage is within the first threshold range, then the connection status information indicates a reverse connection.

[0022] Optionally, the detection module includes a first resistor, a fifth switching unit, and a detection unit;

[0023] The first resistor is coupled to the first power supply pin through the fifth switching unit; the first resistor is used to divide a preset voltage; wherein, the fifth switching unit is used to turn on or off under the control of the switching control module;

[0024] The detection unit is coupled to the first power pin and the switch control module respectively. The detection unit determines the connection relationship between the charging power supply and the wearable device by detecting the first voltage of the first power pin, and outputs the connection status information. If the first voltage is equal to the preset voltage, the connection status information indicates that the device is not connected. If the first voltage is within the third threshold range, the connection status information indicates that the device is connected in the correct direction. If the first voltage is within the fourth threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining that the connection status information indicates that the device is connected in the correct direction or initially connected in the reverse direction, the switch control module controls the fifth switch unit to turn off.

[0025] Optionally, the detection module further includes a sixth switching unit;

[0026] The sixth switch unit is coupled between the first resistor and the first power supply pin; the sixth switch unit is used to turn on or off under the control of the switch control module; wherein, after the connection status information initially indicates a reverse connection, the switch control module controls the sixth switch unit to turn on.

[0027] Optionally, the detection unit is further configured to detect a second voltage at the second power supply pin when the connection status information initially indicates a reverse connection; if the second voltage is within the range of the third threshold, then the connection status information indicates a reverse connection.

[0028] Optionally, the first to the sixth switching units are each composed of N parallel-connected MOS transistors; where N is a positive integer and N≥1.

[0029] Optionally, the switch control module is further configured to control the fifth switch unit to conduct when the connection status information indicates that the connection is not connected; the switch control module is further configured to control the sixth switch unit and the third switch unit to conduct when the connection status information initially indicates that the connection is reversed, and control the fifth switch unit, the first switch unit, the second switch unit, and the fourth switch unit to be turned off.

[0030] Optionally, both the first contact and the second contact are POGO pins.

[0031] Optionally, the charging power source is specifically a DC voltage source.

[0032] According to a second aspect of the present invention, a power supply device is provided, including the charging circuit described in the first aspect and alternative embodiments of the present invention.

[0033] The charging circuit provided by the present invention uses a detection module to determine the connection status between the charging circuit and the wearable device, and outputs corresponding connection status information to the switch control module according to the determination result. The switch control module controls the conduction and cutoff of the first switch unit to the fourth switch unit through the connection status information, so that the charging circuit can charge the wearable device normally through only the first power pin and the second power pin, regardless of whether the wearable device is connected in the correct or reverse direction. Attached Figure Description

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0035] Figure 1 Circuit diagram of existing charging circuits and corresponding wearable devices;

[0036] Figure 2 A module block of the charging circuit provided in the embodiments of the present invention. Figure 1 ;

[0037] Figure 3(a) is a structural diagram of the charging power supply and the wearable device connected in the positive direction according to an embodiment of the present invention;

[0038] Figure 3(b) is a structural diagram of the reverse connection of the charging power supply and the wearable device provided in an embodiment of the present invention;

[0039] Figure 4 A module block of the charging circuit provided in the embodiments of the present invention. Figure 2 ;

[0040] Figure 5 The third module block diagram of the charging circuit provided in the embodiment of the present invention;

[0041] Figure 6 A module block of the charging circuit provided in the embodiments of the present invention. Figure 4 ;

[0042] Figure 7 A module block of the charging circuit provided in the embodiments of the present invention. Figure 5 . Attached image description:

[0044] 10 - Rechargeable power supply;

[0045] 20 - First Switching Unit;

[0046] 30 - Second switching unit;

[0047] 40 - Third Switching Unit;

[0048] 50 - Fourth Switching Unit;

[0049] 60 - Detection module;

[0050] 61-Detection unit;

[0051] 62 - Fifth Switching Unit;

[0052] 63 - Sixth Switching Unit;

[0053] 70 - Switch control module;

[0054] P1 - First power supply pin;

[0055] P2 - Second power supply pin;

[0056] P3 - First contact point;

[0057] P4 - Second contact;

[0058] VDD - Device power supply terminal;

[0059] VBUS - First charging voltage;

[0060] VOUT1 - First voltage;

[0061] VOUT2 - Second voltage;

[0062] GND1 - Equipment ground;

[0063] GND - Power ground;

[0064] V1 - Preset voltage;

[0065] I1 - First current source;

[0066] R1 - First resistor. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0068] Before describing the embodiments of the present invention, the design concept of the present invention will be briefly explained:

[0069] Currently, an increasing number of wearable devices, such as smart rings and smartwatches, are incorporating POGO pins on their casings as charging ports. These POGO pins correspond to the power and ground terminals of the wearable device, respectively. Wearable devices also include smart glasses, wireless Bluetooth headsets, etc., and are not limited to these examples. To charge the wearable device using a compatible charging accessory, the charging accessory also needs corresponding POGO pins that electrically connect one-to-one with the POGO pins on the wearable device. However, because the POGO pins on the wearable device are symmetrical for aesthetic purposes, they can easily be reversed with the POGO pins on the charging accessory.

[0070] In view of this, to enable wearable devices to be charged via the charging accessory regardless of whether they are connected in the correct orientation, this invention designs a switching network in the charging circuit inside the charging accessory. This switching network represents the connection relationship between the charging power supply inside the charging circuit and the POGO pin on the charging accessory. It detects the voltage at the POGO pin at the power supply terminal of the charging accessory to determine the connection relationship between the wearable device and the charging power supply 10. Based on this connection relationship, it changes the connection relationship between the charging power supply 10 in the charging circuit and the POGO pin on the charging accessory, thus enabling the wearable device to be charged via the charging accessory regardless of whether it is connected in the correct orientation. Furthermore, the solution of this invention does not require an additional POGO pin.

[0071] In the following embodiments of the present invention, the wearable device is equivalent to a load circuit and an ESD circuit connected in parallel. This is because the wearable device can be regarded as a load in a certain sense, and an ESD circuit is usually provided on it to protect the wearable device.

[0072] Please refer to Figure 2 Figures 3(a) and 3(b) illustrate an embodiment of the present invention that provides a charging circuit for charging a wearable device. The wearable device is provided with a first contact P3 and a second contact P4, which are electrically connected to the device power terminal VDD and the device ground terminal GND1 of the wearable device, respectively. The circuit includes:

[0073] The charging power supply 10 includes a power output terminal and a power ground terminal GND, and the charging power supply 10 is used to provide a first charging voltage VBUS.

[0074] The first switching unit 20 is coupled between the power output terminal and the first power pin P1. The first switching unit 20 is used to control the connection and isolation between the power output terminal and the first power pin P1.

[0075] The second switching unit 30 is coupled between the power output terminal and the second power pin P2. The second switching unit 30 is used to control the connection and isolation between the power output terminal and the second power pin P2.

[0076] The third switching unit 40 is coupled between the power ground terminal GND and the first power pin P1. The third switching unit 40 is used to control the connection and isolation between the power ground terminal GND and the first power pin P1.

[0077] A fourth switching unit 50 is coupled between the power ground terminal GND and the second power pin P2. The fourth switching unit 50 is used to control the connection and isolation between the power ground terminal GND and the second power pin P2. The first power pin P1 and the second power pin P2 are respectively used to electrically connect to the first contact P3 or the second contact P4. When the first power pin P1 is electrically connected to the first contact P3 and the second power pin P2 is electrically connected to the second contact P4, the wearable device is positively connected to the charging power supply 10, as shown in Figure 3(a). When the first power pin P1 is electrically connected to the second contact P4 and the second power pin P2 is electrically connected to the first contact P3, the wearable device is reversely connected to the charging power supply 10, as shown in Figure 3(b). When the first power pin P1 is not electrically connected to the first contact P3 and the second power pin P2 is not electrically connected to the second contact P4, the wearable device is not connected to the charging power supply 10.

[0078] The detection module 60 is used to detect the connection status between the wearable device and the charging power supply 10, and output connection status information; the connection status information represents any one of positive connection, reverse connection, or no connection;

[0079] A switch control module 70 is used to receive the status information and control the on / off states of the first switch unit 20, the second switch unit 30, the third switch unit 40, and the fourth switch unit 50 based on the status information, so that the charging power supply 10 can charge the wearable device regardless of whether the wearable device and the charging power supply 10 are in a positive or negative connection state; wherein:

[0080] If the connection status information indicates that the connection is not established, the switch control module 70 controls the first switch unit 20, the second switch unit 30 and the third switch unit 40 to be turned off, and controls the fourth switch unit 50 to be turned on.

[0081] If the connection status information indicates a positive connection, the switch control module 70 controls both the first switch unit 20 and the fourth switch unit 50 to be turned on, and controls both the second switch unit 30 and the third switch unit 40 to be turned off.

[0082] If the connection status information indicates a reverse connection, the switch control module 70 controls both the second switch unit 30 and the third switch unit 40 to be turned on, and controls both the first switch unit 20 and the fourth switch unit 50 to be turned off.

[0083] Specifically, the first power pin P1 and the second power pin P2 are metal elastic contacts; the first contact P3 and the second contact P4 are specifically metal rigid contacts. The first power pin P1 can make electrical contact with the second contact P4 or the first contact P3, and the second power pin P2 can make electrical contact with the first contact P3 or the second contact P4.

[0084] By employing the above-described technical solution, this invention enables the charging circuit to charge the wearable device without increasing the number of contacts, regardless of whether the connection between the circuit and the wearable device is positive or negative. The specific principle is as follows:

[0085] As shown in Figure 3(a), when the connection status information indicates a positive connection, both the first switch unit 20 and the fourth switch unit 50 are turned on, while both the second switch unit 30 and the third switch unit 40 are turned off. The first charging voltage VBUS output by the charging power supply 10 flows through the first power pin P1 via the first switch unit 20. Since the first power pin P1 is electrically connected to the first contact P3 and the second power pin P2 is electrically connected to the second contact P4, the first charging voltage VBUS flows into the wearable device from the first contact P3, then flows back to the second power pin P2 from the second contact P4, and finally flows into the power ground terminal GND from the second power pin P2, forming a complete power supply circuit to charge the wearable device.

[0086] As shown in Figure 3(b), when the connection status information indicates a reverse connection, both the first switch unit 20 and the fourth switch unit 50 are turned off, while both the second switch unit 30 and the third switch unit 40 are turned on. The first charging voltage VBUS output by the charging power supply 10 flows through the second power pin P2 via the second switch unit 30. Because the first power pin P1 and the second contact P4 are electrically connected at this time, and the second power pin P2 and the first contact P3 are electrically connected, the first charging voltage VBUS flows into the wearable device from the first contact P3, then flows back to the first power pin P1 from the second contact P4, and finally flows into the power ground terminal GND from the first power pin P1, forming a complete power supply circuit to charge the wearable device.

[0087] The following describes in detail different implementations of the detection module 60 in embodiments of the present invention.

[0088] Please refer to Figure 4 In one specific implementation, the detection module 60 includes a first current source I1, a fifth switching unit 62, and a detection unit 61;

[0089] The first current source I1 is coupled to the first power supply pin P1 through the fifth switching unit 62. The first current source I1 is used to output a first detection current under the power supply of a preset voltage V1. The fifth switching unit 62 is used to turn on or off under the control of the switching control module 70. Specifically, the first current source I1 is a constant current source that can continuously output a constant current when the load changes over a large range. The voltage value of the preset voltage V1 is preset, for example, it is set to about 3.3V in this invention. Of course, the voltage value of the preset voltage V1 can also be adjusted according to the actual situation, which is not limited here. Since the first detection current output by the first current source I1 is used for detection function, the current value of the first detection current output by the first current source I1 under the drive of the preset voltage V1 will be very small, for example, the first detection current in this invention is about 1.5μA. Of course, the current value of the first detection current will change with the preset voltage V1, which is not limited here. Specifically, the preset voltage V1 is output by the first charging voltage VBUS through the LDO circuit. Of course, the first charging voltage VBUS can also be obtained by converting it through a DC-DC converter, or the first charging voltage VBUS can be directly output without passing through the LDO circuit; there are no limitations here. However, considering cost issues, a DC-DC converter is usually not used.

[0090] The detection unit 61 is coupled to the first power pin P1 and the switch control module 70 respectively. The detection unit 61 determines the connection relationship between the charging power supply 10 and the wearable device by detecting the first voltage VOUT1 of the first power pin P1, and outputs the connection status information. If the first voltage VOUT1 is equal to or approximately equal to the preset voltage V1, the connection status information indicates that the device is not connected. If the first voltage VOUT1 is within a first threshold range, the connection status information indicates that the device is connected in the correct direction, and the switch control module 70 controls the fifth switch unit 62 to turn off. If the first voltage VOUT1 is within a second threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining whether the connection status information indicates that the device is connected in the correct direction or initially connected in the reverse direction, the switch control module 70 controls the fifth switch unit 62 to turn off.

[0091] By employing the technical solution of the detection module described above, this embodiment of the invention can determine the connection relationship between the charging power supply 10 and the wearable device using only a small current without damaging the wearable device.

[0092] Specifically: If the wearable device and the charging power supply 10 are not connected, the first power pin P1 and the second power pin P2 are in a high-impedance state. At this time, the first voltage VOUT1 detected by the detection unit 61 is equal to or approximately equal to the preset voltage V1.

[0093] If the wearable device and the charging power supply 10 are in the positive connection state, the first power pin P1 is electrically connected to the first contact P3, and the second power pin P2 is electrically connected to the second contact P4. Then the first detection current flows into the first contact P3 through the first power pin P1, then into the wearable device through the first contact P3, and finally flows back to the second power pin P2 from the second contact P4. As described above, the wearable device can be equivalent to a parallel connection of an ESD circuit and a load circuit. The positive and negative terminals of the ESD circuit correspond to the second contact P4 and the first contact P3, respectively. Therefore, the first detection current will flow through the load circuit, and the first voltage VOUT1 generated at the first power pin P1 will be within the first threshold range. The first threshold range and the magnitude of the first detection current are related to the equivalent resistance of the load circuit. For example, in a smartwatch, the equivalent resistance of the load circuit is about 1 megaΩ, so the first threshold range is about 1.5V. Of course, the equivalent resistance of the load circuit will vary depending on the wearable device, which will cause the first threshold range to change. This is not limited here.

[0094] If the wearable device and the charging power supply 10 are in reverse connection, the first power pin P1 and the second contact P4 are electrically connected, and the second power pin P2 and the first contact P3 are electrically connected. Then, the first detection current flows through the first power pin P1 into the second contact P4, then through the first contact P3 into the wearable device, and finally flows back from the first contact P3 to the second power pin P2. At this time, because the first detection current flows into the wearable device from the second contact P4, it is known that the first detection current will flow through the ESD circuit. Therefore, the first voltage VOUT1 generated at the power pin will be within the second threshold range; the second threshold range is approximately 0.7V, corresponding to the forward voltage drop of the ESD circuit.

[0095] Please refer to Figure 5In one specific implementation, the detection module 60 further includes a sixth switching unit 63, which is coupled between the first current source I1 and the second power supply pin P2. The sixth switching unit 63 is used to turn on or off under the control of the switch control module 70. The beneficial effects of the above technical means are: it can ensure the accuracy of reverse connection when the connection status information initially indicates reverse connection; for example, a short circuit may occur inside the device, thus requiring secondary confirmation.

[0096] The specific process is as follows: The switch control module 70 controls the sixth switch unit 63 and the third switch unit 40 to be turned on, and controls the fifth switch unit 62, the first switch unit 20, the second switch unit 30, and the fourth switch unit 50 to be turned off. At this time, the first detection current should flow into the first contact P3 through the second power pin P2, then into the wearable device through the first contact P3, and finally flow back to the first power pin P1 from the second contact P4. As can be seen from the above, the first detection current will pass through the load circuit. Therefore, if the second voltage VOUT2 detected by the detection unit 61 at the second power pin P2 is within the first threshold range, then the connection status information officially indicates a reverse connection.

[0097] Please refer to Figure 6 In another specific implementation, the detection module 60 includes a first resistor R1, a fifth switch unit 62, and a detection unit 61;

[0098] The first resistor R1 is coupled to the first power supply pin P1 through the fifth switching unit 62; the first resistor R1 is used to divide a preset voltage V1; wherein, the fifth switching unit 62 is used to turn on or off under the control of the switch control module 70; specifically, in this embodiment of the invention, the resistance value of the first resistor R1 is 1 megaohm. Of course, the resistance value of the first resistor R1 can be adjusted according to the actual situation, and is not limited here. Specifically, the preset voltage V1 is the first charging voltage VBUS output through the LDO circuit. Of course, it can also be the first charging voltage VBUS converted by a DC-DC converter or the first charging voltage VBUS directly output without going through the LDO circuit, and is not limited here. However, considering cost issues, a DC-DC converter is usually not used.

[0099] The detection unit 61 is coupled to the first power pin P1 and the switch control module 70 respectively. The detection unit 61 determines the connection relationship between the charging power supply 10 and the wearable device by detecting the first voltage VOUT1 of the first power pin P1, and outputs the connection status information. If the first voltage VOUT1 is equal to or approximately equal to the preset voltage V1, the connection status information indicates that the device is not connected. If the first voltage VOUT1 is within the third threshold range, the connection status information indicates that the device is connected in the correct direction. If the first voltage VOUT1 is within the fourth threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining that the connection status information indicates that the device is connected in the correct direction or initially connected in the reverse direction, the switch control module 70 controls the fifth switch unit 62 to turn off.

[0100] By employing the technical solution of the detection module described above, this embodiment of the invention can determine the connection relationship between the charging power supply 10 and the wearable device without damaging the wearable device by simply using a resistor to divide the preset voltage V1.

[0101] Specifically: If the wearable device and the charging power supply 10 are not connected, the first power pin P1 and the second power pin P2 are in a high-impedance state. At this time, the first voltage VOUT1 detected by the detection unit 61 is equal to or approximately equal to the first preset voltage V1.

[0102] If the wearable device and the charging power supply 10 are in a positive connection state, the first power pin P1 is electrically connected to the first contact P3, and the second power pin P2 is electrically connected to the second contact P4. The load circuit inside the wearable device and the first resistor R1 divide the preset voltage V1. Therefore, the first voltage VOUT1 generated at the first power pin P1 will be within the third threshold range. For example, if the preset voltage V1 is 3.3V, and the equivalent resistance of the first resistor R1 and the load circuit inside the smartwatch is one megaohm, then the first voltage VOUT1 at the first power pin P1 will be 1.65V. Of course, this is just a specific example and is not a limitation. Because the voltage value of the preset voltage V1 and the resistance value of the first resistor R1 are preset, while the equivalent resistance of the load circuit inside the wearable device will change with different wearable devices, the third threshold range will also change accordingly, and is not limited here.

[0103] If the wearable device and the charging power supply 10 are in reverse connection, the first power pin P1 and the second contact P4 are electrically connected, and the second power pin P2 and the first contact P3 are electrically connected. Then the ESD circuit inside the wearable device will clamp the first voltage VOUT1 at the first power pin P1 to stabilize it within the fourth threshold range, which is about 0.7V, corresponding to the forward conduction voltage drop of the ESD circuit.

[0104] Please refer to Figure 7 In one specific implementation, the detection module 60 further includes a sixth switch unit 63, which is coupled between the first resistor R1 and the first power supply pin P1. The sixth switch unit 63 is used to turn on or off under the control of the switch control module 70. The beneficial effects of the above technical means are: it can ensure the accuracy of reverse connection when the connection status information initially indicates reverse connection; for example, a short circuit may occur inside the device, thus requiring secondary confirmation.

[0105] The specific process is as follows: the switch control module 70 controls the sixth switch unit 63 and the third switch unit 40 to be turned on, and controls the fifth switch unit 62, the first switch unit 20, the second switch unit 30, and the fourth switch unit 50 to be turned off. As can be seen from the above, at this time, the first resistor R1 and the equivalent resistance of the load circuit within the wearable device should divide the preset voltage V1. Therefore, if the second voltage VOUT2 detected by the detection unit 61 at the second power pin P2 is within the third threshold range, then the connection status information formally indicates a reverse connection.

[0106] In a preferred embodiment, the first switching unit 20 to the sixth switching unit 63 are each composed of N MOSFETs connected in parallel; where N is a positive integer and N≥1. The beneficial effect here is to reduce the on-resistance of the switching units and decrease power loss.

[0107] The detection unit 61 of this embodiment will be described in detail below.

[0108] In one specific implementation, the detection unit 61 is configured as a window comparator. The window comparator is composed of a first comparator and a second comparator connected together. The output terminals of the first comparator and the second comparator are coupled together. The non-inverting input terminal of the first comparator and the inverting input terminal of the second comparator are simultaneously connected to either the first voltage VOUT1 or the second voltage VOUT2. The inverting input terminal of the first comparator is connected to a first reference voltage, and the non-inverting input terminal of the second comparator is connected to the second reference voltage. The window comparator is used to compare the first reference voltage and the second reference voltage with the first voltage VOUT1 or the second voltage VOUT2 respectively, and output the connection status information according to the comparison result. For example, the first reference voltage is set to 3V, the second reference voltage is set to 1V, and the preset voltage V1 is 3.3V. If the first comparator outputs a high level and the window comparator outputs a high level overall, it indicates that the wearable device and the charging power supply 10 are not connected, because at this time the first voltage VOUT1 is equal to the preset voltage V1, i.e., 3.3V. If the window comparator outputs a low level, it indicates that the wearable device and the charging power supply 10 are connected correctly. Because the first voltage VOUT1 is within 1V to 3V at this time, which meets the preset range for positive connection; if the window comparator outputs a high level and the second comparator outputs a high level, it initially indicates that the wearable device and the charging power supply 10 are reversed. Because when reversed, the first voltage VOUT1 is around 0.7V. However, the possibility of short circuit in the prior art cannot be ruled out, so the sixth switch unit 63 and the third switch unit 40 are both turned on, and the fifth switch unit 62 and the fourth switch unit 50 are both turned off; wherein, before formally determining whether the wearable device and the charging power supply 10 are reversed, the first switch unit 20 and the second switch unit 30 are both turned off. Then, the second voltage VOUT2 at the second power supply pin P2 is simultaneously input to the non-inverting input of the first comparator and the inverting input of the second comparator. If the window comparator outputs a low level, it formally indicates that the wearable device and the charging power supply 10 are reversed. Of course, the above is only one specific embodiment, because the first reference voltage and the second reference voltage will change with the preset voltage V1 and the second threshold range or the fourth threshold range, and the specific data is not limited here. In addition, to improve the accuracy of the judgment, the specific first voltage VOUT1 or second voltage VOUT2 can also be obtained through an analog-to-digital converter, which will not be elaborated here.

[0109] The following is a brief introduction to the switch control module 70 of an embodiment of the present invention.

[0110] In one specific implementation, the switch control module 70 is a logic circuit and a state machine. The state machine receives the connection status information and a setting information, and outputs a control signal. The logic circuit controls the conduction and disconnection of the first switch unit 20 to the sixth switch unit 63 according to the control signal. Specifically, the first switch unit 20 to the sixth switch unit 63 are all turned off before the charging circuit is powered on. After the charging circuit is powered on, the state machine outputs a first control signal according to the setting information. The logic circuit controls the fourth switch unit 50 and the fifth switch unit 62 to be turned on according to the first control signal, while the other switch units are not turned on. When the state machine receives the connection status information indicating no connection, it outputs a second control signal. The logic circuit controls all switch units to remain unchanged according to the second control signal. When the state machine receives the connection status information indicating a positive connection, it outputs a third control signal. The logic circuit controls the fifth switch unit 62 to be turned off, the first switch unit 20 to be turned on, and the other switch units to remain unchanged according to the third control signal. When the state machine receives the connection status information and initially indicates a reverse connection, it outputs a fourth control signal. Based on this fourth control signal, the logic circuit controls the sixth switch unit 63 and the third switch unit 40 to be turned on, while the fourth switch unit 50 and the fifth switch unit 62 are turned off, and the other switch units remain unchanged. When the state machine receives the connection status information and formally indicates a reverse connection, it outputs a fifth control signal. Based on this fifth control signal, the logic circuit controls the second switch unit 30 to be turned on, the sixth switch unit 63 to be turned off, and the other switch units remain unchanged. The specific structure of the logic circuit is a conventional technique in this field and will not be described in detail here.

[0111] In one specific implementation, the charging power supply 10 is a DC voltage source.

[0112] In one specific implementation, the other circuits in the charging circuit, except for the charging power supply 10, can be integrated by a single chip to achieve a more comprehensive and convenient detection of positive and negative connections.

[0113] The beneficial effects of the charging circuit provided in this embodiment of the invention are as follows:

[0114] (1) Because POGO feet are exposed to complex application environments for extended periods, such as frequent corrosion from sweat, POGO feet are generally of high quality and very expensive. The charging circuit provided by this invention enables reversible charging of wearable devices using only two sets of POGO feet, thereby saving production costs.

[0115] This invention also provides a power supply device, including the charging circuit.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A charging circuit for charging a wearable device, wherein the wearable device is provided with a first contact and a second contact, the first contact and the second contact being electrically connected to the device power supply terminal and the device ground terminal of the wearable device, respectively; characterized in that, The circuit includes: A charging power supply, comprising a power output terminal and a power ground terminal, wherein the charging power supply is used to provide a first charging voltage; A first switching unit is coupled between the power output terminal and the first power pin. The first switching unit is used to control the connection and isolation between the power output terminal and the first power pin. The second switching unit is coupled between the power output terminal and the second power pin. The second switching unit is used to control the connection and isolation between the power output terminal and the second power pin. A third switching unit is coupled between the power ground terminal and the first power pin. The third switching unit is used to control the connection and isolation between the power ground terminal and the first power pin. A fourth switching unit is coupled between the power ground terminal and the second power pin. This fourth switching unit controls the connection and isolation between the power ground terminal and the second power pin. The first power pin and the second power pin are respectively used to electrically connect to the first contact or the second contact. When the first power pin is electrically connected to the first contact and the second power pin is electrically connected to the second contact, the wearable device is positively connected to the charging power supply. When the first power pin is electrically connected to the second contact and the second power pin is electrically connected to the first contact, the wearable device is reversely connected to the charging power supply. When neither the first power pin nor the second power pin is electrically connected to the first contact, the wearable device is not connected to the charging power supply. The detection module is used to detect the connection status between the wearable device and the charging power supply, and output connection status information; the connection status information represents any one of positive connection, reverse connection, or no connection; A switch control module is used to receive the status information and control the first switch unit, the second switch unit, the third switch unit, and the fourth switch unit to turn on and off according to the status information, so that the charging power supply can charge the wearable device regardless of whether the wearable device and the charging power supply are in a positive or negative connection state; wherein: If the connection status information indicates that the connection is not established, the switch control module controls the first switch unit, the second switch unit, and the third switch unit to all turn off, and controls the fourth switch unit to turn on. If the connection status information indicates a positive connection, the switch control module controls both the first switch unit and the fourth switch unit to be turned on, and controls both the second switch unit and the third switch unit to be turned off. If the connection status information indicates a reverse connection, the switch control module controls both the second switch unit and the third switch unit to be turned on, and controls both the first switch unit and the fourth switch unit to be turned off.

2. The charging circuit according to claim 1, characterized in that, The detection module includes a first current source, a fifth switching unit, and a detection unit; The first current source is coupled to the first power supply pin through the fifth switching unit; the first current source is used to output a first detection current under a preset voltage supply; wherein, the fifth switching unit is used to turn on or off under the control of the switching control module; The detection unit is coupled to the first power pin and the switch control module respectively. The detection unit determines the connection relationship between the charging power supply and the wearable device by detecting the first voltage of the first power pin and outputs the connection status information. If the first voltage is equal to the preset voltage, the connection status information indicates that the device is not connected. If the first voltage is within a first threshold range, the connection status information indicates that the device is connected in the correct direction. If the first voltage is within a second threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining that the connection status information indicates that the device is connected in the correct direction or initially indicates that the device is connected in the reverse direction, the switch control module controls the fifth switch unit to turn off.

3. The charging circuit according to claim 2, characterized in that, The detection module also includes a sixth switching unit; The sixth switch unit is coupled between the first current source and the second power supply pin; the sixth switch unit is used to turn on or off under the control of the switch control module; wherein, after the connection status information initially indicates a reverse connection, the switch control module controls the sixth switch unit to turn on.

4. The charging circuit according to claim 3, characterized in that, The detection unit is also used to detect a second voltage at the second power supply pin when the connection status information initially indicates a reverse connection; if the second voltage is within the first threshold range, then the connection status information indicates a reverse connection.

5. The charging circuit according to claim 1, characterized in that, The detection module includes a first resistor, a fifth switching unit, and a detection unit; The first resistor is coupled to the first power supply pin through the fifth switching unit; the first resistor is used to divide a preset voltage; wherein, the fifth switching unit is used to turn on or off under the control of the switching control module; The detection unit is coupled to the first power pin and the switch control module respectively. The detection unit determines the connection relationship between the charging power supply and the wearable device by detecting the first voltage of the first power pin and outputs the connection status information. If the first voltage is equal to the preset voltage, the connection status information indicates that the device is not connected. If the first voltage is within the third threshold range, the connection status information indicates that the device is connected in the correct direction. If the first voltage is within the fourth threshold range, the connection status information initially indicates that the device is connected in the reverse direction. After determining that the connection status information indicates that the device is connected in the correct direction or initially connected in the reverse direction, the switch control module controls the fifth switch unit to turn off.

6. The charging circuit according to claim 5, characterized in that, The detection module also includes a sixth switching unit; The sixth switch unit is coupled between the first resistor and the first power supply pin; the sixth switch unit is used to turn on or off under the control of the switch control module; wherein, after the connection status information initially indicates a reverse connection, the switch control module controls the sixth switch unit to turn on.

7. The charging circuit according to claim 6, characterized in that, The detection unit is also used to detect a second voltage at the second power supply pin when the connection status information initially indicates a reverse connection; if the second voltage is within the range of the third threshold, then the connection status information indicates a reverse connection.

8. The charging circuit according to claim 7, characterized in that, Each of the first to the sixth switching units consists of N parallel-connected MOS transistors; where N is a positive integer and N≥1.

9. The charging circuit according to claim 8, characterized in that, The switch control module is also used to control the fifth switch unit to be turned on when the connection status information indicates that the connection is not connected; the switch control module is also used to control the sixth switch unit and the third switch unit to be turned on when the connection status information initially indicates that the connection is reversed, and to control the fifth switch unit, the first switch unit, the second switch unit, and the fourth switch unit to be turned off.

10. The charging circuit according to claim 9, characterized in that, Both the first contact and the second contact are POGO pins.

11. The charging circuit according to claim 1, characterized in that, The charging power source is specifically a DC voltage source.

12. A power supply device, characterized in that, Includes the charging circuit according to any one of claims 1 to 11.

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