Charging cable with charging state indication

Abstract

The charging cable has a current sensor, a state of charge indicator, and logic circuitry to operate the indicator based on a detected current flowing to the chargeable device. If the sensor detects that the current is below a low threshold, the logic circuit operates the indicator to indicate that the cable is not connected to any chargeable device. If the sensor detects that the current is equal to or higher than a higher threshold, the logic circuit operates the indicator to provide a perceptible output indicating that the cable has been connected to the chargeable device and that the current is charging the battery. If the sensor detects that the current is equal to or higher than the low threshold but lower than the high threshold, the logic circuit operates the indicator to provide a perceptible output indicating that the cable has been connected to the chargeable device but does not charge the battery of the device, e.g., when the battery is fully or approximately fully charged.

Description

This application is a divisional application of the invention patent entitled "Charging Cable with Charging Status Indicator", filed on February 20, 2020, with application number 202080016576.0. Cross-reference of related applications

[0001] This application claims priority to U.S. Provisional Application No. 62 / 809,805, filed February 25, 2019, entitled “Charging Cable with Charging Status Indicator,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The disclosed subjects include examples of charging cables, rechargeable devices, and systems that combine cables and devices together, wherein the cables include status indicators and elements configured to detect and provide responsive indications of various cable-to-device coupling or charging states. background

[0003] Many types of electronic devices, such as portable or wearable devices, have integrated electronics that require a built-in power source in the form of a battery. From time to time, such devices are coupled to a power source to charge the battery. This method of charging electronic devices often uses a charging cable that connects to a suitable receiver on the electronic device. Rechargeable devices can provide users with indications of the battery charging status, including the progress of the charging process. Brief description of the attached diagram

[0004] The accompanying drawings illustrate one or more embodiments by way of example only and not by way of limitation. The same reference numerals in the drawings denote the same or similar elements.

[0005] Figure 1 It is a high-level block diagram of an example combination or system, including charging cables and rechargeable devices.

[0006] Figure 2 It is an isometric view of an example of a socket for a charging cable head and an example of a cable plug as a receiver (or part of a receiver) for a rechargeable device, for example, for rotatable coupling of a cable to a rechargeable device.

[0007] Figure 3 This is a function block diagram of an example of a rechargeable device powered by a downstream battery to be charged.

[0008] Figure 4 It is a graph showing example current consumption of a rechargeable device in several states and two current detection thresholds used to indicate various coupling or charging states.

[0009] Figure 5 It is similar to Figure 4The graph shows the current consumption of an example rechargeable device, and also shows the modulation of current in two or more parts of the current consumption curve.

[0010] Figure 6 This is a function block diagram of a charging cable example.

[0011] Figure 7 It can be used Figure 6 A logic diagram of a circuit example for a charging cable, controlling a perceptible visible output to indicate various connection and charging states.

[0012] Figure 8 , 9 Numbers 10, 11, 12, 13, and 14 are used in a similar manner. Figure 7 Example graphs showing how the sensed current changes over time with respect to two thresholds under several different system states sensed and indicated by the circuit.

[0013] Figure 15A , 15B And 15C describes the use of similar Figure 7 logic circuits, responses Figure 8 to 14 Several timing aspects of the current example of the status indication. Detailed description

[0014] In the following detailed description, many specific details are illustrated by way of examples to provide a thorough understanding of the relevant teachings. However, it will be apparent to those skilled in the art that these teachings can be implemented without these details.

[0015] The following examples are intended to be read in conjunction with the accompanying drawings, which are considered an integral part of the written description. In this description, related terms such as “right,” “left,” “down,” “up,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the direction as described at the time or as shown in the accompanying drawings under discussion. These related terms are for ease of description and do not require the instrument to be constructed or operated in a particular direction. Terms relating to connection, coupling, etc., such as “coupled,” “connected,” and “interconnected,” refer to a relationship in which the structures are directly or indirectly fixed or connected to each other by an intermediary structure, and where two structures form a removable or rigid connection or relationship, unless otherwise explicitly stated.

[0016] The various examples disclosed herein relate to cables for charging battery-powered electronic devices, systems for combining such cables with rechargeable devices, circuitry in the cables, and circuitry in the possible rechargeable devices to facilitate the detection and provision of perceptible indications of various connection and charging states.

[0017] It is useful to detect cable coupling to a rechargeable device and one or more charging states, and to indicate the detected states to the user of the charging cable and the rechargeable device. Some rechargeable devices already provide various types of such indications. However, in the examples described herein and shown in the accompanying drawings, the charging cable senses and provides indication of cable coupling to the rechargeable device and one or more charging states. In some of the following examples, the circuitry of such a charging cable provides the user with an indication of whether the cable is connected to the rechargeable device, and if so, whether the system is charging the rechargeable device's battery during a primary charging state. For example, when connected but not charging or charging at a slower rate (i.e., during a secondary charging state), the device's battery is typically near or fully charged.

[0018] Depending on the size and configuration of the rechargeable device cable head and receiver, the cable head may only have two prongs contacting the receiver's two corresponding contact pads. However, in the examples, the charging cable is able to detect whether a rechargeable device is connected to the cable and can detect at least two charging states based on sensing the current flowing through the prongs upon connection. This eliminates the need for additional prongs in the cable head or contact pads in the receiver for sensing connection or charging states. For efficiency and to provide a good user experience, these examples offer rapid detection of transitions to each charging state.

[0019] While other indicator technologies can be used to provide perceptible output to users, such as tactile output devices for visually impaired users, a typical example of an indicator is a low-power light-emitting diode (LED) that provides visible light output. The following examples of LED indicators are configured to subtly handle intermittent disconnections. These examples can also be configured for optimized size, cost, and efficiency.

[0020] These examples detect cable coupling and charging status from the cable side. Detection involves sensing current on the charging circuitry (e.g., only through the two pins of the cable head and the two contact pads of the receiver) and comparing the sensed current value to two current thresholds. One threshold is a low connection-state current threshold used to detect when a device is connected to the cable head. The other current threshold is set higher to detect when the device is charging. When disconnected, no current triggers even the low connection-state current threshold. A current equal to or higher than the charging state current threshold (and therefore higher than the lower connection-state threshold) indicates that the rechargeable device is consuming current to charge the battery. A current at least periodically equal to or higher than the connection-state current threshold but lower than the charging state current threshold indicates a connection that is not supplying charging current or is supplying a relatively low charging current, for example, when the device is at or near a fully charged battery.

[0021] Therefore, in some specific examples, the charging cable includes logic circuitry configured to compare a current level detected by a current sensor with first and second thresholds, and control a status indicator based on the comparison results over time to detect different system states. The first threshold is higher than the second threshold. When the current level detected by the current sensor is lower than the lower second threshold, the logic circuitry controls the status indicator to provide a first type of perceptible output indicating that the cable head is not electrically coupled to the receiver. When the current detected by the current sensor is equal to or higher than the higher first threshold, the logic circuitry controls the status indicator to provide a third type of perceptible output indicating that the cable head is electrically coupled to the receiver and the current is charging the battery of the rechargeable device during the primary charging state. When the current detected by the current sensor is lower than the first threshold but still equal to or higher than the second threshold, the logic circuitry also controls the status indicator to provide a third type of perceptible output indicating that the cable head is electrically coupled to the receiver but the current is charging the battery of the rechargeable device at a lower rate during the secondary charging state.

[0022] In some examples, the rechargeable device also pulse-modulates the current it consumes from the charging cable to facilitate certain aspects of coupling and state-of-charge detection. In these examples, the circuitry of the rechargeable device modulates the current pulses of the current consumed through the cable to trigger two current sensing thresholds under certain conditions. In some examples, the modulated current pulses have two different pulse amplitudes. For example, during the pre-charge / trickle charge state, a high current pulse amplitude periodically triggers a higher current threshold for state-of-charge detection. For example, during the lower portion of the constant voltage state or in the end-of-charge (EOC) state, a lower current pulse amplitude triggers a lower current threshold for connection detection but does not trigger the higher state-of-charge current threshold.

[0023] Based on current sensing, the logic of the charging cable in the following example drives the LED-type status indicator to turn off (stable off-light output condition) when no device is detected at the cable head and cable plug (disconnected, detected current below a low threshold). During the primary charging state, the LED flashes to indicate that the battery is charging when the current meets or exceeds the high threshold during any of the several possible valid charging states (e.g., the higher current portion of a pre-charge / trickle charge state, a constant current charge state, or a constant voltage charge state). Driving the LED provides a stable on-light output indicating that the cable is electrically coupled to the device, but the current is not charging the battery of the rechargeable device, or that the battery is being charged relatively slowly during a secondary charging state (device connected and, for example, the battery is fully charged or nearly fully charged).

[0024] Now refer in detail to the illustrations in the accompanying drawings and the examples discussed below. Figure 1An example of the overall assembly of the components forming system 10 is illustrated. As shown, system 10 includes a rechargeable device 11 and a charging cable 15.

[0025] The rechargeable device 11 includes device circuitry 17, as described below. Figure 3 As shown, the device includes a battery and a battery charger circuit coupled to the battery. The rechargeable device 11 also includes a receiver 18 for coupling to a cable head 33 of a charging cable 15. The exemplary receiver 18 allows for rotatable coupling and includes, for example, a cable plug 19 including coupled first and second charging contact pads to supply charging current / power to the battery charger circuit. An insulator electrically isolates the contact pads. Figure 2 In the example shown, as discussed in more detail later, the contact pads of plug 19 include a coupled power contact pad to supply current to the battery charger circuitry and a ground contact pad coupled to the ground of the rechargeable device 11, and may include an insulator electrically isolating the power contact pad and the ground contact pad. However, it will be apparent that the contacts or contact pads of the receiver need not strictly be power or ground; either pad can serve as an alternative function. For convenience only, further discussion of the non-limiting examples sometimes refers to a particular contact or pad as a power contact pad and another contact or pad as a ground contact pad. While this description depicts specific examples of the cable head 33 of the charging cable 15 and the cable plug 19 of the rechargeable device 11, it should be understood that this is merely an example, and the invention can utilize other types of connectors to interconnect the charging cable with the rechargeable device, such as conventional 2-wire connectors.

[0026] The charging cable 15 includes a connection to a power source. While other types of connectors and associated power sources can be used, the power connector in this example is a convex USB connector 21. Although not necessarily part of system 10, the accompanying drawings also show a compatible power source, which in the example using USB connector 21 would be a USB power supply 23. Examples of USB power supplies 23 include computers, wall adapters (such as AC chargers, sometimes referred to as "charging bricks"), or car chargers, where a concave USB port is configured to receive the convex USB connector 21 of the charging cable 15.

[0027] The charging cable 15 in the example includes an insulated wire harness 25, which includes a power bus 27 and a ground bus 29. Other wires or buses for other purposes may be included. In this example, the harness 25 connects cable circuit 31 to cable head 33. The connection between cable circuit 31 and the pins of USB connector 21 is not shown separately. However, the illustrated arrangement is a non-limiting example, and other arrangements of the cable elements may be used. In alternative configurations, other harnesses may be present between USB connector 21 and cable circuit 31, possibly with other wires (e.g., data bus wires). In another alternative configuration, cable circuit 31 may be connected to or integrated with cable head 33, where the power and ground buses are internal to circuit 31 or cable head 33.

[0028] In the rotatable coupling example, the cable head 33 has a recess 55 configured to receive insertion of the cable plug 19 when the cable head 33 is rotatably coupled to the receiver 18 of the rechargeable device 11. The cable head 33 has a pair of pins 57, 59 to contact a pad on the receiver 18, such as a pad on the cable plug 19. (See below for reference.) Figure 2 Cable plug 19 and cable head 33 will be discussed in more detail. An example of the cable circuit will be provided later. Figure 6 and Figure 7 discuss.

[0029] The example charging cable 15 also includes an output device or indicator designed to provide the user of system 10 with information about the detected connection or charging status. This example uses a light-emitting diode (LED) 34 as the indicator. Other light output elements or other types of indicators may be used in place of LED 34 or in any other way. The LED or other indicator is part of the charging cable 15. Figure 1 In the example, LED 34 is implemented as part of cable circuit 31, although the indicator may be located elsewhere on cable 15 (e.g., on cable head 33, with one or more additional wires between cable circuit 31 and cable head 33 to allow the logic of cable circuit 31 to operate LED 34). An example of connection and charging status indication by LED sensed by cable circuit 31 is described in more detail below.

[0030] Now for reference Figure 2 An example of rotatable coupling is shown where the cable plug 19 is a cylindrical terminal extending from the wall 41 of the housing of the rechargeable device, etc. While other shapes may be used, the fairly rounded cylindrical shape is particularly effective in allowing the cable head with a suitably shaped mating socket recess to rotate. An example of a cable head 33 is shown in the figure, which takes the form of a cylindrical socket 43 and is laterally connected to the end of the wire harness 25. For convenience, from... Figure 2The cable circuitry is omitted. In the example provided, the cable plug 19 is exposed on the outer surface of the rechargeable device housing, and there are no obstructions nearby that could affect or interfere with the rotation of the cable around the cable plug 19 when the plug 19 and the cable head 33 are coupled together for device charging.

[0031] Although not shown, cable plug 19 may be recessed as part of the receiver in the device, and other components of the cable (e.g.) Figure 1 The wiring harness 25 or circuit 31 can be axially connected to the end of the cable head socket 43 (e.g., to the top side in the illustrative direction), opposite the socket recess intended to receive the cable plug 19. In this arrangement, the charging receiver on the device will include a cylindrical recess slightly larger than the outer periphery of the cylindrical socket 43, and the cable plug 19 will be located approximately at the center of this recess. However, if the rechargeable device does not have a receiver with such a cylindrical recess, the external shape of the socket 43 does not need to be cylindrical and can have some other design or shape, for example, to facilitate a user gripping the cable head socket 43 to couple the socket 43 to or remove the socket 43 from the cable plug 19, or to allow the socket 43 to rotate about the axis of the cable plug 19.

[0032] In an embodiment where the cable plug 19 is configured to insert into the cylindrical recess 55 ( Figure 1 The cable plug 19 is formed in the socket 43 of the cable head 33. The cable plug 19 includes two charging contact pads of a suitable conductive material (e.g., metal) separated by an insulator (e.g., a suitable plastic). Various configurations of the contact pads and separators can be used. Figure 2 The example uses a terminal 45 made of plastic or other insulating material. The terminal 45 is typically cylindrical. Each contact pad 47 and 49 is formed of a conductive material such as metal. At least some surface areas of each contact pad 47, 49 are exposed to allow for possible electrical contact via one or more pins 57, 59. Figure 1 Pins 57 and 59 are located in socket 43 of example cable head 33. (For example...) Figure 2 As shown, contact pads 47 and 49 are positioned at different locations around the cylindrical side of the terminal 45 of the cable plug 19 to provide exposed contact surfaces. In the illustrated direction, the first (1) charging contact pad 47 is mounted on the left side of the cylindrical side of the terminal 45, and the second (2) charging contact pad 49 is mounted on the opposite (right) side of the cylindrical side of the terminal 45.

[0033] The metal forming the contact pads can be deposited on the cylindrical side surface of the terminal 45, in which case the contact pads 47, 49 can slightly bulge outward from or extend from the cylindrical side surface of the terminal 45. Alternatively, the metal forming the contact pads 47, 49 can be embedded in the material of the terminal 45 and have a certain thickness to form a smooth cylindrical side surface of the plug 19. In another alternative example, the metal forming one or both contact pads 47, 49 can be sufficiently embedded to form one or more small recesses in the cylindrical side surface of the plug 19. However, in any of these configurations, the surfaces of the contact pads 47, 49 are exposed for contact with the pins included in the cable head socket 43 (e.g., as shown in the image). Figure 1 Pins 57 and 59 in the middle are mechanical and electrical contacts.

[0034] exist Figure 2 In the example, the insulating material of the terminal 45 provides structural support for the contact pads 47, 49 and forms a spacer between the contact pads to electrically insulate or isolate them from each other. The insulating material separates the metal or other metals of the contact pads on opposite sides of the plug structure (e.g., laterally across the vertical axis of the cylindrical terminal 45 in the illustrated direction). The exemplary plug structure has exposed portions on the cylindrical side of the insulating material of the terminal 45, which are located between adjacent ends of the exposed surfaces of the contact pads 47, 49. One of the exposed portions 51 on the cylindrical surface of the terminal 45 located between the ends of the contact pads 47, 49 is visible in the illustrated direction. A second similar portion is located on the opposite (back) surface of the cylindrical terminal 45 and is not visible in the figure.

[0035] Each exposed insulation region 51 can be relatively small to minimize the size of any potential dead zones. For example, region 51 can be just large enough to prevent current from flowing from one end of a contact pad to the adjacent end of another contact pad through that region. In another example, region 51 can be slightly wider than the width of the pins 55, 57 of the cable head 33 (or the width of the largest pin among pins 57, 59), such that the pins in the cable head cannot simultaneously contact both contact pads 47, 49.

[0036] Figure 3 This is a functional block diagram of an example of the components powering the battery of the rechargeable device 11, including device circuitry 17 and cable plug 19 (as a receiver or as part of a receiver). While other receivers and contact pads could be used, Figure 3 The cable plug 19 in the device example can be as described above relative to... Figure 2The proposed implementation includes two charging contact pads. In this example configuration, one contact pad is coupled to supply power to the battery charger circuit 63 at the VBUS port. The other contact pad is connected to the ground of the rechargeable device 11. The device circuit 17 includes a battery 61 and a battery charger circuit 63 coupled to the battery 61. For example, depending on the type and size of the battery 61, various known circuits can be used to implement the battery charging circuit 63. The positive terminal of the battery 61 is connected to the battery charger circuit 63, and the negative terminal of the battery 61 is connected to the ground of the rechargeable device 11.

[0037] For simplicity, device electronics (if any) that can consume power from battery 61 for general device functions (other than the charging function considered herein) are omitted. The charging cables and charging technologies discussed herein can be applied to any of a variety of portable or wearable devices that utilize rechargeable batteries to power specific electronic components or act as battery packs to charge other devices.

[0038] The device circuit 17 in the example also includes a coupled first switch 65 and a second switch 66 to draw current from the battery charger circuit 63. Controlling switches 65 and 66 in this example to selectively shunt additional current to ground causes the battery charger circuit 63 of a particular type to add two pulses of different amplitudes to the current flowing through the charging path formed by the cable plug 19 and the cable end 33. Any switching device configured to switch an appropriate amount of current can be used, such as any of a variety of switching transistors. The figure, for example, shows a field-effect transistor (FET) as switch 65 and a field-effect transistor (FET) as switch 66.

[0039] Various switches can be used to connect to the battery charger 63, and various intermediary or associated circuit elements may also be used. In this example, switch 65 is connected to the switch (SW) port of the battery charger circuit 63 via resistor R1 and inductor L1. Similarly, switch 66 is connected to the switch (SW) port of the battery charger circuit 63 via resistor R2 and inductor L1. A path is also provided from the connection point between inductor L1 and resistors R1, R2 to the system voltage port (VSYS) of the battery charger circuit 63. Each switch 65 or 66 in this example is connected in series from resistor R1 or R2 to the ground of the rechargeable device 11. Device circuit 17 also includes a device controller that provides a signal (PWM_pulse) to control switch 65 and a signal (PWM_trickle) to control switch 66. While discrete logic, field-programmable gate arrays, other programmable processors, etc., can be used, this example utilizes a programmable microcontroller (MCU) 67 as the controller of the rechargeable device 11.

[0040] Resistors R1 and R2 are chosen such that the pulse provided by closed switch 66 is higher than the pulse generated by closed switch 65. Furthermore, the resistor values ​​are chosen such that when the battery charger circuit 63 adds current to the pulses in different states, the addition of pulses will exceed different thresholds. For example, when cable 15 is coupled to the head of charging cable 15 via receiver, the peak value of the pulse added to the low current via the operation of switch 65 and resistor R1 will periodically meet or exceed the low current threshold I_detect used to detect the connection. In this example, when cable 15 is coupled to the head of charging cable 15 via receiver, the peak value of the pulse added to a current equal to or higher than the low current threshold but possibly not triggering the higher state-of-charge current threshold I_chg will cause the modulated current to periodically meet or exceed the higher state-of-charge current threshold I_chg. The threshold levels and pulse amplitudes (and therefore the values ​​of resistors R1 and R2) will be selected based on the charging requirements of the specific type of battery 61 used in the particular rechargeable device 11.

[0041] The two switches and associated resistor / inductor circuitry are given only as a non-limiting example; other circuit arrangements can also be used to pulse-modulate the current consumption, giving it two different amplitudes in different states of the charging current profile. For example, an alternative approach could use a single switch controlled by the MCU 67 and a variable impedance device connected in series with that switch, where the impedance is set to different impedance values ​​(to establish different pulse amplitudes) in different states of the charging current profile.

[0042] As previously described, device circuitry 17 also includes a device controller, such as MCU 67. An MCU is typically a system-on-a-chip (SoC) that includes a processor, memory, peripheral input / output (I / O) interfaces and ports, and possibly other circuit components. For example, a single SoC may integrate battery charger circuitry with the circuitry forming the MCU. For the purposes of this discussion, MCU 67 controls functions related to battery charging, although the MCU may perform other functions related to device 11 depending on the device type or application of the specific electronic device 11. However, it is clear that other controllers could be used to implement these functions. The functionality of MCU 67 is determined by executable program instructions or configuration data (e.g., firmware) stored in the MCU's memory.

[0043] In the example rechargeable device 11, the MCU 67, forming the device controller, responds to power from the cable plug 19 and is configured to operate switches 65, 66 to cause the charger circuit 63 to pulse-modulate the current through the cable plug 19, thereby providing a status indication to the circuit 31 of the charging cable 15 (see [link to relevant documentation]). Figure 1In this example implementation for supporting state detection, the MCU 67 controls the battery charger circuit 63, configures the device circuit 17 to regulate the current profile for charging the battery 61 at time intervals, and adds modulated current pulses to the current flowing through the cable plug 19 and the charging cable 15 during some portions or sub-intervals of the current consumption profile.

[0044] Figure 4 It is used for battery charging. Figure 1 and 3 A graph illustrating the example current consumption of the example rechargeable device 11 (showing no optional pulse modulation). The current at various stages of the graph is given only by way of example. Device 11 may be implemented with different currents or graphs at different stages, for example, to address the charging requirements of a specific type of battery 61 for a particular rechargeable device 11.

[0045] refer to Figure 4 For example, when device 11 is coupled to the charging path via cable plug 19, the regulated current achieves... Figure 4 The graph shows several states. In the initial portion of the example graph (e.g., during a sub-interval where a connection to cable 15 exists but the charge on battery 61 is above a certain percentage), battery charging circuit 63 consumes approximately 100 mA for pre-charging or trickle charging current. At a later time (the second portion of the graph), such as when certain conditions for MCU operation or battery charging are met, battery charging circuit 63 enters a primary charging state (e.g., consuming a constant charging current of approximately 500 mA for rapid full-power charging of battery 61). At a later time, such as when the battery reaches a specific threshold of charge percentage, battery charging circuit 63 enters a secondary charging state (e.g., consuming current to apply a constant voltage to battery 61). In this third portion of the graph, while the voltage remains constant, the current decreases until the battery is fully charged, and device 11 reaches the end-of-charge (EOC) portion of the graph, consuming minimal current. The current values ​​shown in the various portions of the graph are merely examples, and other values ​​will be applied, for example, when charging other types of batteries 61.

[0046] Figure 4 A circuit 31 for the charging cable 15 used for state current response detection is also shown. Figure 1Examples of two current thresholds used. A first current detection threshold (I_chg) is used for primary charging state detection. A second current detection threshold (I_detect) relates to connection state detection. The first current threshold I_chg is higher than the second current threshold I_detect. Detecting a current value below the threshold I_detect indicates that the charging cable 15 is not connected to the rechargeable device 11. Any current equal to or higher than the second current threshold I_detect (including currents equal to or higher than the higher first current detection threshold I_chg) indicates that the charging cable 15 is connected to the rechargeable device 11. Therefore, a current value equal to or higher than the second lower threshold I_detect indicates that the charging cable 15 is connected to the rechargeable device 11, and a current value equal to or higher than the first higher threshold I_chg indicates that the battery charging circuit 63 consumes current to charge the battery 61 during the primary charging state. A current value equal to or higher than the threshold I_detect but lower than the threshold I_chg indicates that the charging cable 15 is connected to the rechargeable device 11, but the battery charging circuit 63 does not consume current to charge the battery 61 (see [link to relevant documentation]). Figure 3 (or the battery charging circuit is in a secondary charging state.)

[0047] As described above, when the battery is fully charged (e.g., fully charged or nearly fully charged), in the illustrated EOC state, a current needs to be sensed to indicate to cable circuit 31 that the rechargeable device 11 is still electrically connected to the charging cable 15. Various techniques can be used to assist this detection. For example, the rechargeable device can be configured to consume a low current sufficient to trigger the I_detect threshold. Any current can work if a current sensor with a sufficiently low threshold is used. For example, the idle system current consumption of the rechargeable device 11 may itself be sufficient to trigger the I_detect threshold depending on the type, configuration, or application of the rechargeable device. Similarly, a current needs to be sensed as an indication to cable circuit 31 that the rechargeable device 11 is charging its battery 61 in all charging states of the curve, and various techniques can be used to assist this detection. For example, the I-chg charging state current detection threshold can be set above the connection state current threshold I_detect but below... Figure 4 The example current consumption curve shows the precharge / trickle current (e.g., less than 100 mA).

[0048] To reduce power consumption in low-current states, the example rechargeable device 11 consumes the lowest possible idle system current for the device circuitry. Instead of setting the connection-state current threshold I_detect low to detect such idle-state currents, which could lead to erroneous connection detections due to static electricity or noise, the cable circuit 31 utilizes... Figure 4 and 5The connection state current threshold Idetect is shown as slightly higher. In such a system example, cable circuit 31 utilizes an I-chg charging state current detection threshold that is slightly higher than the pre-charge / trickle current to provide a larger distinction between thresholds and avoid noise in the idle state unintentionally triggering the I-chg charging state current detection threshold. Instead of relying solely on normal current consumption to trigger the relevant threshold in all states of the current consumption curve, as shown... Figure 4 and 5 Example implementation of thresholding by adding pulse modulation to current consumption ( Figure 5 )middle.

[0049] The non-limiting examples show a current detection threshold (I_detect) of approximately 60 mA for connection detection and an example showing a current detection threshold (I_chg) of approximately 300 mA for charging detection. These thresholds are suitable for a specific type or technology of battery 61 and a related type of battery charging circuit 63. Other thresholds can be selected for use with other battery types and corresponding charger circuits.

[0050] Regarding Figure 4 The example graphs shown indicate that in the pre-charge or trickle charge, constant current, and mostly constant voltage states, the current consumed through the charging path at the cable head and cable plug exceeds the I_detect threshold. As the battery approaches full charge in the later stages of the constant voltage state, the current consumed through the charging path at the cable head and receiver drops below the I_detect value used for connection detection. Furthermore, the current consumption in the End-of-Charge (EOC) state is lower than the I_detect value used for connection detection. Therefore, in the low-current portions of the constant voltage and EOC states, the current is too low to trigger connection detection. Moreover, even when the battery charger circuit 63 is consuming charging current, the current in the pre-charge or trickle charge state and a portion of the constant voltage state drops below the I_chg threshold used for charging detection. To address the situation where the actual current consumed by these rechargeable devices 11 does not trigger the appropriate threshold, Figure 3 Example device circuit 11 introduces periodic pulse modulation via the periodic operation of switches 65 and 66. An example of this modulation is... Figure 5 As shown in the image.

[0051] Generally, if the current consumed by the rechargeable device 11 may drop below the I_detect threshold used by the cable circuit 31, the addition of periodic pulses will cause the peak value of the modulated current to reach or exceed the I_detect threshold. Similarly, if the current consumed by the rechargeable device in at least one charging state may reach or exceed the I_detect threshold used by the cable circuit 31, but not the I_chg threshold used by the cable circuit 31, the addition of periodic pulses will cause the peak value of the modulated current to reach or exceed the I_chg threshold.

[0052] Figure 5 It is similar to Figure 4 The graph shows an example of the current consumption of a rechargeable device, but also illustrates an example of this pulse modulation of the current. As shown above relative to... Figure 3 Specifically, MCU 67 operates switch 65 to pulse-modulate the current through cable connector 19, adding a pulse of one amplitude, while operating switch 66 pulse-modulates the current through cable connector 19, adding a pulse of another amplitude. Although the relationship between the two amplitudes can vary, for example for different applicable thresholds or for different currents at different stages of the applicable current consumption curve, the pulse amplitude provided by the operation of switch 66 (the first pulse amplitude) is higher than the pulse amplitude provided by the operation of switch 65 (the second pulse amplitude). The resulting pulses of two amplitudes increase the current consumed by device 11, triggering the connection detection and charging detection thresholds used by cable circuit 31 where appropriate.

[0053] Reference Figure 3 and 5 When switch 65 is in its open state, battery charger circuit 63 consumes current, such as... Figure 4 As shown. Whenever switch 65 is periodically closed, current flows through switch 65 to ground, causing battery charger circuit 63 to consume an additional amount of current through the charging path formed by cable plug 19 and cable end 33 to add a second pulse (determined by the resistance of R1). Switching back and forth between the open and closed states of switch 65 generates a first pulse, and causes battery charger circuit 63 to superimpose a corresponding pulse onto the current through the charging path formed by cable plug 19 and cable end 33. Similarly, whenever switch 66 is periodically closed, current flows through switch 66 to ground, causing battery charger circuit 63 to consume an additional amount of current through the charging path formed by cable plug 19 and cable end 33 to add a first higher amplitude pulse (determined by the resistance of R2). Switching back and forth between the open and closed states of switch 66 generates a second pulse, and causes battery charger circuit 63 to superimpose a corresponding pulse onto the current through the charging path formed by cable plug 19 and cable end 33.

[0054] The amplitude of the modulation pulse generated by the operation of switch 65 depends on the value of resistor R1. R1 is chosen to provide a low-amplitude current pulse to add to the current, which will be higher than the threshold I-detect in the low-current state, for example, sufficient to... Figure 5 The detection is performed under low current connection conditions during the End of Charge (EOC) state.

[0055] The amplitude of the modulation pulse generated by the operation of switch 66 depends on the value of resistor R2. R2 is chosen to provide a slightly higher amplitude current pulse to be added to the current in at least one charging current state, which is above the connection detection threshold I_detect but may be below the charging state detection threshold I_chg (in the absence of a pulse). For example, in a pre-charge or trickle charge state, the added pulse provides sufficient amplitude for detection such as... Figure 5 The amplitude of the periodic current during battery charging is shown.

[0056] The lower amplitude pulses generated by the periodic closing of switch 65 are added to the current consumption during the lower part of the constant voltage portion of the current consumption curve in the example and during the EOC state. The peak values ​​of those lower amplitude pulses modulating the current rise to equal or higher than the I_detect threshold. Based on the appropriate timing of cable circuit 31, cable 15 is able to sense the peak values ​​of current pulses that periodically exceed the I_detect threshold to maintain an indication of the connection between cable head 33 and cable plug 19, for example, indicating the availability of the charging path if the MCU or battery charger circuitry determines an increase in charging current. For the user, LEDs, etc., provide an output that typically notifies the user that the battery is fully charged.

[0057] This figure represents an example where, during the pre-charge or trickle charge portion of the graph, higher-amplitude pulses generated by the periodic closing of switch 66 are added to the current consumption. The peak values ​​of those higher-amplitude pulses modulating the current rise to equal or higher than the I_chg threshold. Based on the appropriate timing of cable circuit 31, cable 15 is able to sense the peak values ​​of current pulses that periodically exceed the I_chg threshold to maintain charging indication during the pre-charge or trickle charge portion of the graph.

[0058] Figure 6 This is a function block diagram of an example charging cable 15 with current sensing and a status indicator for status detection. Connection to a USB power supply (see [link]). Figure 1 ) including such Figure 6The power bus 27 shown in the VBUS diagram is for USB-compatible connectors. Wiring to the USB-type power supply also includes a ground bus 29. The cable circuit 31 in this example includes protection circuitry 71 providing one or both of overvoltage protection (OVP) and overcurrent protection (OCP). Power from protection circuitry 71 flows to power pin 57 via current sensor 73. Ground bus 29 is connected to ground pin 59.

[0059] Cable circuit 31 includes LED 75, which, in this non-limiting example, acts as a status indicator. LED 75 is connected to a power supply on the protection side of OVP / OCP circuit 71. LED 75 is connected to a ground bus via one or more switches controlled by logic circuit 77. This example shows two switches, 79 and 81. Of course, other arrangements of LEDs, switches, and their connections to power and ground can also be used. In this example, logic circuit 77 provides a pulse signal (LED_PWM) to periodically open and close switch 79, producing a perceptible blinking light output from LED 75 for status indication when device 11 is consuming sufficient current to actively charge battery 61. Logic circuit 77 provides a steady-state signal (LED_SOLID) to close switch 81, producing a perceptible steady-on light output from LED 75 for indicating a device connected but not charging state, such as when battery 61 is fully charged or nearly fully charged at EOC in a minor charging state. The logic circuit 77 provides a steady-state signal to the two switches 79 and 81 to turn on the two switches 79 and 81, thereby keeping the LED off (stable and not emitting light) as a sensing indication that no connection is detected between the cable 15 and the rechargeable device.

[0060] exist Figure 6In the example, switches 79 and 80 are connected in parallel from LED 75 to ground at point 29. The LED light output is off only when both switches are open. If one or both of switches 79 and 80 are closed, the light is emitted. For example, to provide a blinking LED output from LED 75, logic circuitry 77 periodically opens and closes switch 79 while simultaneously opening switch 81. If switch 81 remains closed, LED 75 will provide a continuous light output. While switch 81 remains closed, switch 79 can be open, or switch 79 can still be periodically opened and closed. Switches 79, 81, and LED 75 are configured such that the closed switch 81 effectively overrides the operation of switch 79. For example, LED 75 may have a maximum current limit when switch 81 is closed, in which case, when switch 79 is periodically closed, even if some of the maximum current through LED 75 flows through the closed switch 79, no current is consumed. Even though there is some additional current each time switch 79 is closed, the components 75, 79, and 81 are configured such that any increase in the light output of LED 75 is low enough that this additional periodic light output would appear imperceptible to a typical user. Therefore, even though switch 79 operates periodically, the light output of LED 75 remains stable when switch 81 is closed.

[0061] Figure 7 An example of a discrete logic circuit arrangement for implementing current response logic circuit 77 is illustrated. As previously stated, current sensing for state detection can be implemented without pulse modulation. However, in Figure 7 In the example logic, this logic implements timing associated with the detection of pulse-modulated current.

[0062] The function of logic circuit 77 can be implemented in other ways, such as using an MCU or other programmable processor. Furthermore, Figure 7 Example logic circuit 77 is configured to sense and indicate similarly Figure 5 The example curves shown represent various states. The battery charging circuit and MCU can be configured to generate different current consumption curves, for example, for different types of batteries. In this case, the logic circuit 77 of the charging cable 15 can be appropriately modified to sense the state of different current consumption curves.

[0063] Reference Figure 6 and 7 The illustrated example of the switching logic circuit 77 includes two comparators 85 and 87. The voltage Isense from the current sensor 73... Figure 6The Isense voltage is proportional to the instantaneously sensed current, and is coupled to the input of each of comparators 85 and 87. Comparator 85 determines whether the Isense voltage reaches or exceeds a reference voltage I_det that is proportional to the lower current threshold I_detect used for connection state detection. When the voltage Isense, representing the sensed current, is equal to or higher than (greater than or equal to) the reference voltage I_det, comparator 85 provides a relatively high output voltage (e.g., 1). If Isense is lower than the I_det reference, comparator 85 outputs a low voltage (e.g., 0). Comparator 87 determines whether the Isense voltage reaches or exceeds a reference voltage I_chg that is proportional to the higher current threshold I_chg used for charging state detection. When the voltage Isense, representing the sensed current, is equal to or higher than (greater than or equal to) the reference voltage I_chg, comparator 87 provides a relatively high output voltage (e.g., 1). If Isense is lower than the I_chg reference, comparator 87 outputs a low voltage (e.g., 0). Comparators 85 and 89 have sufficient responsiveness to respond to the peak and trough values ​​of two pulses of different amplitudes that modulate current consumption under different states, such as... Figure 5 The example is shown in the image.

[0064] For example, if cable 15 is connected to rechargeable device 11, comparator 85 will provide a stable high output voltage throughout the pre-charge / trickle charge state, throughout the constant current state, and during the higher current portion of the constant voltage state. Comparator 85 will provide a periodic pulsed high-low output during the lower current portion of the constant voltage state and the end-of-charge (EOC) state in response to pulse modulation of the current by device 11. When device 11 is not connected to cable 15, comparator 85 will provide a low output when there is no current (or no pulse) to trigger the low I_detect threshold.

[0065] In this example, comparator 89 will provide a high output voltage during the higher current portion of both the constant current and constant voltage states. Comparator 89 will provide a periodic pulsed high-low output during the pre-charge / trickle-down state in response to pulse modulation of the current by device 11. When there is no current (or no pulse) to trigger the higher I_chg threshold, comparator 89 will provide a low output. The low output will include the low current portion during the constant voltage and end-of-charge (EOC) states, as well as at any time when device 11 is not connected to cable 15.

[0066] Example state sensing and indication logic 77 includes coupled delay circuitry 89 to receive the output of comparator 85. Circuitry 89 implements a delay time interval t_DET relative to each falling edge of the comparator 85 output (e.g., in response to each transition when the value Isense representing the sensed current drops below the I_det threshold).

[0067] The example state sensing and indication logic 77 also includes a pulse width modulation (PWM) type drive circuit 91 for outputting a periodic signal, in this case, the LED_PWM signal for periodically closing and opening the switch 79, and periodically causing the light to flash as the LED 75 turns on and off. The PWM drive circuit 91 receives an output from the delay circuit 89 to activate / deactivate the pulse signal output of the drive circuit 91, thereby activating / deactivating the flashing output of the LED 75.

[0068] The example state sensing and indication logic 77 also includes an inverter 92 coupled to one input of an AND gate 93. The output of comparator 87 is connected to inverter 92, such that an inverted comparator signal is applied to one input of AND gate 93. AND gate 93 receives the output from delay circuit 89 at its other input.

[0069] The example state sensing and indication logic 77 also includes another delay circuit 95, implementing a delay time interval t_CHG. The output of AND gate 93 reaches the input of delay circuit 95, and the output of delay circuit 95 reaches latch 97. Latch 97 responds to the signal from delay circuit 95, switching between high and low output states and holding these states respectively. The output of latch 97 is the LED_SOLID signal that operates switch 81. When the latch output is high, the signal closes switch 81, and LED 75 is turned on, presenting a stable on state, as long as latch 97 maintains a high output. When the latch output is low, the signal opens switch 81, and LED 75 is turned off, presenting a stable off state, as long as latch 97 maintains a low output.

[0070] Further discussion will also refer to Figure 6 and 7 as well as Figure 8 to 14 Various timing diagrams are provided. First, a general discussion of the logic is given, but the processing of current consumption curves including current-modulated pulses is not yet covered. The aspect of the delay interval relative to different amplitude modulation pulse parameters will be explained later.

[0071] Generally, when the voltage Isense, representing the sensed current, is lower than the reference voltage I_det for a considerable period of time, such as Figure 8 As shown (disconnected, LED off), comparator 85 outputs a low voltage (e.g., 0). In response, delay circuit 89 outputs a low voltage (e.g., 0). Driver 91 remains off, and there is no signal on the LED_PWM line to operate switch 79. Switch 79 remains on. In this state, the voltage Isense, representing the sensed current, also remains below the reference voltage I_chg for a considerable period of time, such as... Figure 8As shown, comparator 87 outputs a low voltage (e.g., 0). Although inverter 92 will provide a high (e.g., 1) value at one input of AND gate 93, AND gate 93 outputs a low voltage (e.g., 0) due to the low (0) input from delay circuit 89. In response to the low (0) output from AND gate 93, delay circuit 95 outputs a low voltage (e.g., 0), and latch 97 outputs a low voltage (e.g., 0) on the LED_SOLID wire leading to switch 81. Switch 81 remains open. In this state where both switches are open, no current flows through LED 75, and there is no light output (stable off), which serves as a sensing indication that no rechargeable device 11 is connected to charging cable 15.

[0072] When the voltage Isense, representing the sensed current, is equal to or greater than (greater than or equal to) the reference voltage I_det, comparator 85 outputs a higher voltage (e.g., 1). In response, delay circuit 89 outputs a higher voltage (e.g., 1) to activate pulse LED driver 91. Driver 91 outputs pulses on the LED_PWM wire to periodically open and close switch 79. Assuming switch 81 is open at this time, pulse current will flow through LED 75 when switch 79 opens and closes, causing LED 75 to provide at least a pulsed or "breathing" light output indicating that the rechargeable device 11 is connected to charging cable 15. However, in this example, logic 77 is configured to apply an I_chg threshold to achieve a pulsed output from LED 75 that further indicates that the connected rechargeable device 11 is charging the battery 61 of device 11.

[0073] When a rechargeable device 11 is connected to the charging cable 15 and the voltage Isense representing the sensed current is equal to or greater than (greater than or equal to) the I_chg reference voltage, the logic shown in the diagram ( Figure 7 Keep switch 81 open (see) Figure 9 The current will stably exceed two thresholds, such as... Figure 9 As shown (charging, LED flashing), for example, in Figure 4 and 5 The curve shown represents the constant current portion of the graph. Figure 9In the described state, the flashing light generated by driver 91, switch 79, and LED 75 indicates that the connected device 11 is consuming current to charge the battery. For the illustrated logic circuit, when the voltage Isense, representing the sensed current, is equal to or greater than (greater than or equal to) the charging state reference voltage I_chg, comparator 87 outputs a higher voltage (e.g., 1), and inverter 92 is converted to a low voltage (0) at the input of AND gate 93. Although the other input of AND gate 93 is high (1) due to the lower I_det threshold triggered by voltage Isense, AND gate 93 outputs a low voltage (0) due to the low (0) input from inverter 92. In response to the low (0) output from AND gate 93, delay circuit 95 outputs a low voltage (e.g., 0), and latch 97 outputs a low voltage (e.g., 0) on the LED_SOLID wire leading to switch 81. Switch 81 remains open. In this state, where the current is equal to or higher than the higher I_chg threshold used for charging status detection, logic 77 keeps switch 81 open, indicating that the flashing light of LED 75 indicates that the device is charging.

[0074] As mentioned above, Figure 9 This indicates a situation where the current is continuously above a higher I_chg threshold, such as during the constant current phase of the current consumption curve. The pre-charge / trickle current phase of the current consumption curve presents different scenarios, which are handled by the addition and detection of modulation pulses in example device circuit 17 and cable circuit 31. Figure 10 This is an example of pulse-modulated current and threshold in the pre-charge state. Device 11 is connected to cable 15, and device 11 consumes some current to charge battery 61. As will be discussed later, Figure 11 This shows the results for the low current portion of the constant voltage section and the EOC portion of the current consumption curve (…). Figure 5 Similar pulse timing to the added lower amplitude pulse.

[0075] Generally, the time interval during which the modulated pulse is high is called t_high, and the time interval during which the modulated pulse is low is called t_low. Although these time lengths can vary between pulses of different amplitudes, the attached diagram (e.g.) Figure 10 and 11 The diagram shows an example where t_high and t_low are essentially the same for the corresponding high and low levels for both types of pulses.

[0076] Now it's specifically switched to pre-charging mode. Figure 10 (Pre-charge, LED blinking) shows the pulse timing of the higher amplitude pulse added during the pre-charge portion of the current consumption curve. Figure 5 Rechargeable device circuit 17 ( Figure 4The switch 66 is configured to generate a sufficient amount of modulation pulses so that the current in the pre-charge state periodically rises above the charging state threshold I_chg. Furthermore, except when the current sensor 73 detects the peak amplitude of the current modulation pulse, the current remains above the connection state threshold I_det, but below the charging state threshold.

[0077] The purpose of the pre-charge state is to provide a flashing LED output as an indication of connection and charging, as mentioned earlier. Figure 9 The states discussed are very similar. For this purpose, the PWM driver 91 will periodically turn the drive switch 79 on and off, thereby pulsed the current flowing through the LED 75. As in Figure 9 As discussed earlier, the voltage Isense indicating the sensed current is equal to or higher than the reference voltage I_det. Therefore, comparator 85 outputs a higher voltage (e.g., 1), and delay circuit 89 outputs a higher voltage (e.g., 1) to activate the blinking LED driver 91 and periodically open and close switch 79. Meanwhile, in this state, switch 81 will remain open (so that the pulse is not overridden by the operation of switch 79).

[0078] As described above, when the current is higher than the threshold I_det, the outputs of comparator 85 and delay circuit 89 are high, and AND gate 93 receives a high input from delay circuit 89. Whenever the voltage Isense representing the sensed current is equal to or higher than the reference voltage I_chg, comparator 87 outputs a higher voltage (e.g., 1), and inverter 92 is switched to a low voltage (0) at the input of AND gate 93. Figure 10 In the described state, comparator 87 outputs a higher voltage (e.g., 1) in response to each peak of a current modulation pulse that causes the sensed current to satisfy or exceed the I_chg threshold. Otherwise, comparator 89 outputs a lower voltage (e.g., 0). Therefore, the output of the comparator is substantially corresponding to... Figure 10 The current pulse timing is a series of pulses, and inverter 92 provides the inverted output of the pulse train from comparator 89 to one input of AND gate 93. When the input from delay circuit 89 is continuously high, the output of AND gate 93 tracks the input received from inverter 92, i.e., the inverted output of comparator 89, thus tracking... Figure 10 The inversion of the modulated current pulse.

[0079] The inverter 92 and AND gate 93 are arranged as shown in the figure. The output of AND gate 93 goes high almost simultaneously with the current pulse (and thus the output of comparator 87) going low; the output of AND gate 93 goes low almost simultaneously with the current pulse (and thus the output of comparator 87) going high. The pulse triggers the charging state threshold I_chg only periodically. In the logic path to the LED_SOLID wire leading to the control switch 81, delay circuit 95 implements a delay t_CHG, which can be adjusted to match the parameters of higher amplitude current-modulated pulses. The delay interval t_CHG prevents state changes during the interval between pulses exceeding the I_chg threshold (less than or equal to the duration of t_CHG), and thus keeps the output of latch 87 low and switch 81 open during the pre-charge phase of the current consumption curve.

[0080] The delay circuit 95 is configured such that when the output of AND gate 93 has a high value (e.g., 1 when both inputs of AND gate 93 are 1s), the output of circuit 95 is generally high (e.g., representing 1). The delay circuit 95 is also configured such that when the output of AND gate 93 has a low value (e.g., 0 when at least one of the inputs of AND gate 93 is 0), the output of circuit 95 is generally low (e.g., representing 0). The output of delay circuit 95 is intended to be low in the charging state. For the pre-charge state, the delay circuit 95 is configured such that the output of circuit 95 changes from low to high in response to the rising edge of the output of gate 93 (corresponding to the falling edge of the current pulse), but only after the delay interval t_CHG with the transition of the AND gate 93 signal output has elapsed. However, if the input of circuit 95 goes low again before the delay interval t_CHG has elapsed (corresponding to the rising edge of the subsequent current pulse), the circuit 95 resets the count of the delay interval. Thus, if another current pulse is present, represented by the low output of the AND gate, the delay circuit 95 keeps the latch 97 set to output a low signal to keep the switch 81 open, thereby not covering the blinking of the LED output from the PWM driver 91 and the switch 79.

[0081] The following discussion focuses on the pulse-related timing aspects implemented by the practical example logic circuit 77 in the EOC state. In the connected state, there is insufficient current for active battery charging, and the current detected by the current sensor is below a higher first threshold, but still equal to or higher than a lower second threshold. Before discussing the implementation of pulse modulation, consider an example (not shown) where the idle current of the device in the EOC state is higher than the low connected state detection threshold I_det (e.g., as if in...). Figure 4 The EOC current is relatively high, or in Figure 4The threshold I_detect is sufficiently low. In this state, device 11 is connected to charging cable 15, but charging circuit 63 of device 11 does not charge battery 61. Therefore, the voltage Isense, representing the sensed current, is lower than the reference voltage I_chg for a considerable period of time, and comparator 87 outputs a low voltage (e.g., 0). Inverter 92 will provide a high (e.g., 1) value at one input of AND gate 93. When the voltage Isense, representing the sensed current, is equal to or higher than (greater than or equal to) the reference voltage I_det, comparator 85 outputs a higher voltage (e.g., 1). In response, delay circuit 89 outputs the higher voltage (e.g., 1) to the other input of AND gate 93. With high (1) values ​​at both inputs, AND gate 93 outputs a high (1) value. The output of delay circuit 95 goes high (1), activating latch 97 to output a voltage on LED_Solid wire to close switch 81. When the EOC state persists, the latch output remains high, switch 81 remains closed, and current flows steadily through LED 75 to indicate that the connected device 11 is connected, but not charging or charging at a relatively low rate during a secondary charging state, such as when the battery is in a fully charged (EOC) state. Although switch 79 is open and closed in this state, the continuous closure of switch 81 effectively overrides the pulses via switch 79, making the visible indication appear as if it is steadily open.

[0082] An example of the state when charging is completed in the system using the example circuit. Figure 11 (LED illuminates when charging is complete) This indicates that the battery charger has reached the End-of-Charge (EOC) low-current state (see also...). Figure 5 The pulses of current during charging include current modulation pulses from the rechargeable device 11. Again, the time interval when the modulation pulse is high is called t_high, and the time interval when the modulation pulse is low is called t_low. Rechargeable device circuit 17 ( Figure 4 The circuit is configured to operate switch 65 to generate a modulation pulse. In this state, the low-amplitude modulation pulse does not trigger the charging state current threshold I_chg. However, the low-amplitude modulation pulse is strong enough that the current periodically rises above the I_det threshold. Therefore, the peak value of the Isense output voltage exceeds the I_det reference voltage used by comparator 85. Figure 7 This causes a periodic high output of the comparator to the input of the delay circuit 89, which in turn activates the PWM driver 91 to pulse current to the LED 75 via the switch 79. The delay interval t_DET keeps the output of the delay circuit 89 high as long as any period between pulses has a duration less than t_DET, and thus provides a stable higher voltage to the input of the AND gate 93 (1).

[0083] like Figure 11As shown, in this state, the I_sense voltage, representing the sensed modulation current, does not exceed the higher I_chg threshold, indicating that device 11 is not charging the battery through cable 15. Comparator 87 outputs a low voltage (0), which the inverter converts to a higher voltage (1) input to AND gate 93. AND gate 93, delay circuit 95, and latch 97 ( Figure 7 Close switch 81 ( Figure 6 This allows a constant current to flow through LED 75. The constant current provided by closing switch 81 effectively overrides the pulsed current flowing through switch 79. Therefore, the LED provides a stable on-light output, indicating that it is connected but not charging, such as when battery 61 is fully charged or nearly fully charged.

[0084] As described above, the output of comparator 85 is fed into delay circuit 89. Delay circuit 89 is configured to generally have a high value (e.g., representing 1) when the output of comparator 85 has a high value (e.g., 1 when the sensed current value Isense reaches or exceeds the I_det threshold). Delay circuit 89 is also configured to change its output from high to low in response to a falling edge of the output signal of comparator 85, but only after the delay interval t_DET following the falling edge of the signal output from comparator 85 has elapsed. However, if the input of circuit 89 goes high again before the delay interval t_DET has elapsed, circuit 89 resets the count of the delay interval.

[0085] More specifically, the delay circuit 89 detects the falling edge of the comparator 85 output at the end of a pulse, but waits before switching to a low output. When a subsequent pulse peak above the I_det threshold is detected via sensor 73 and comparator 85, the output of comparator 85 goes high again, and the delay circuit 89 stops its time counting for the delay interval t_DET. Thus, the output of the delay circuit 89 remains high as long as a pulse with a valley or minimum value is received, with the duration t_low of each valley or minimum pulse being less than the delay interval t_DET.

[0086] For example, after a period of disconnection (longer than t_DET), the delay circuit 89 outputs a high value as long as the output of comparator 85 remains high, such as during the pre-charge / trickle-charge portion of the current consumption curve, the high constant-current portion of the current consumption curve, and some constant-voltage portions of the current consumption curve. The delay circuit 89 can detect the falling edge of the comparator output signal in response to the disconnection of the rechargeable device 11 from the cable 15. And in this case, the output of the delay circuit 89 then goes low when the delay interval t_DET after the falling edge of the comparator 85 output expires (indicating the sensed disconnection), and the output of the delay circuit 89 remains low as long as no device 11 is connected to the cable 15, as indicated by the 0 output of comparator 85. However, the delay circuit 89 is configured such that the delay interval of t_DET exceeds the duration t_low of each valley of the modulation pulse, at least for pulses of lower amplitude. When the current consumed by device 11 drops below the I_det threshold, for example during the low-current portion of the constant voltage state and end-of-charge (EOC) state, comparator 85 pulses periodically between low and high values ​​due to pulse modulation of the current. Comparator 85 will output a high value in response to each peak of a current pulse equal to or exceeding the I_det threshold, and will output a low value in response to each valley below the threshold. However, the delay interval t_DET of circuit 89 allows circuit 89 to maintain its high output state as long as a single consecutive current pulse is received, and comparator 85 provides corresponding low-high transitions separated by low outputs with a duration t_low less than t_DET.

[0087] Figure 12 (Pre-charge, LED flashing, reset), 13 (charging, LED flashing, reset), and 14 (charging complete, LED on, reset) show the functions that can be used with... Figure 9 to 11 The reset and recovery functions are achieved by combining current response detection and status indication. Figure 12 This involves resetting during the pre-charge phase of the current consumption curve (and...). Figure 10 compared to), Figure 13 This relates to resetting the LED during the charging phase when it flickers due to continuous high current (e.g., during the constant current phase, with...). Figure 9 compared to). Figure 14 This involves resetting the device while it remains connected during the EOC phase (with...). Figure 11 (Compared to). Figure 14 In the timing diagram, the worst case is that the reset occurs exactly before the pulse appears (i.e., after t_LOW). Figure 15A to 15C A summary of the situation regarding... Figure 9 to 14 The various states shown, relative to the pulse timing conditions, are comprised of... Figure 7The example shows a time interval implemented by a delay element in an example logic circuit. Aspects of the reset and restore functions should be readily understood from the accompanying drawings.

[0088] It should be understood that, except for the specific meanings set forth herein, the terms and expressions used herein have the general meanings consistent with their respective fields of study. For example, terms such as first and second relational terms may be used merely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between these entities or actions. The terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article of manufacture, or apparatus that includes or comprises a list of elements or steps includes not only those elements or steps but may also include other elements or steps not expressly listed or inherent to such process, method, article of manufacture, or apparatus. An element preceded by “a” or “an” does not, without further limitation, exclude the presence of additional identical elements in the process, method, article of manufacture, or apparatus that includes that element.

[0089] Unless otherwise stated, any and all measurements, values, ratings, locations, sizes, dimensions, and other specifications set forth in this specification (including the appended claims) are approximate and imprecise. Such quantities are intended to have a reasonable range consistent with the functions they relate to and with the conventions in the art to which they pertain. For example, unless expressly stated otherwise, parameter values, etc., may differ from the specified quantities by ±10%, whether limited by terms of degree (e.g., approximate, substantially, or about).

[0090] Although an overview of the subject matter of the invention has been illustrated with reference to specific examples, various modifications and alterations may be made to these examples without departing from the broader scope of the examples disclosed herein. These examples of the subject matter of the invention may be referred to herein individually or collectively by the term "invention," for convenience only, and are not intended to voluntarily limit the scope of this application to any single disclosure or inventive concept, even if there are actually more than one disclosure.

[0091] The examples herein are described in sufficient detail to enable those skilled in the art to implement the disclosed teachings. Other examples may be used and derived from the examples herein, allowing for structural and reasonable substitutions and changes without departing from the scope of this disclosure. Therefore, the detailed description should not be construed as limiting, and the scope of the various examples is defined only by the appended claims and the full scope of their equivalents.

Claims

1. A system comprising: Rechargeable devices, including: Battery charger circuit; and The receiver includes a contact pad coupled to the battery charger circuitry and the ground of the rechargeable device; the charging cable includes: Power bus and ground bus; The cable head has a power pin and a ground pin respectively coupled to the power bus and the ground bus, and is configured to engage the contact pad when the cable head is coupled to the receiver of the rechargeable device; A current sensor, coupled to at least one of the buses, to detect the current through the pins of the cable head; Status indicators are used to provide user-perceived output; and A logic circuit, coupled to operate the status indicator, is configured to compare the current detected by the current sensor with a threshold, and in response to the result of the comparison, control the status indicator to provide a perceptible output, and maintain the perceptible output when the current sensor periodically detects a peak of a modulated current pulse at or above the threshold.

2. The system as claimed in claim 1, wherein: The receiver of the rechargeable device includes a cable plug; The contact pad is located on the cable plug; The cable head includes a socket with a recess configured to receive the cable plug to rotatably couple the socket of the cable head to the cable head of the receiver of the rechargeable device; as well as When the cable plug is received in the recess of the socket of the cable head, the power pin and the ground pin protrude into the recess of the socket of the cable head to contact the contact pad of the cable plug, respectively.

3. The system of claim 1, wherein the rechargeable device further comprises: At least one coupled switch to draw current from the battery charger circuit; as well as A device controller, in response to power received from the cable via the contact pad of the receiver, is configured to operate the at least one switch to pulse-modulate the current through the contact pad of the receiver with a pulse amplitude sufficient to periodically reach or exceed the threshold when the current is below a threshold and equal to or above another threshold.

4. The system of claim 3, wherein the logic circuitry of the cable is further configured to implement timing logic relative to the length of the current pulse detected by the current sensor to: When the current sensor periodically detects that the peak value of the modulated current pulse is equal to or higher than the threshold, the status indicator is activated to maintain the perceptible output.

5. The system of claim 4, wherein the device controller is further configured to control the battery charger circuit to implement a charging current curve, including: The pre-charge trickle current during the first part of the charging current curve is below the threshold and equal to or higher than another threshold. The constant current during the second part of the charging current curve is equal to or higher than another threshold. During the third part of the charging current curve, the voltage is constant, during which the current drops from the constant current to a minimum due to the increase in charge stored on the battery; as well as During the fourth part of the charging current curve when the battery has reached a fully charged state, the minimum current is maintained.

6. The system of claim 5, wherein the device controller is further configured to operate the at least one switch coupled to the battery charger circuit to: During the pre-charge trickle current in the first portion of the charging current curve, the current through the contact pad is pulse-modulated with the pulse amplitude.

7. The system of claim 1, wherein the logic circuitry of the cable is further configured as an operation indicator to: A stable shutdown output is provided as the sensed output, indicating that the cable head is not electrically coupled to the receiver.

8. The system of claim 1, wherein the logic circuitry of the cable is further configured as an operation indicator to: A pulse output is provided as the sensed output, indicating that the cable head is electrically coupled to the receiver and that the current is charging the battery of the rechargeable device.

9. The system of claim 1, wherein the logic circuitry of the cable is further configured as an operation indicator to: Provide a stable open output as the sensed output, indicating that the cable head is electrically coupled to the receiver but the current is not charging the battery of the rechargeable device.

10. A charging cable, comprising: Power bus and ground bus; A cable head having a power pin and a ground pin respectively coupled to the power bus and the ground bus and configured to engage the contact pads of the receiver of the rechargeable device when the cable head is coupled to the receiver of the rechargeable device; A current sensor, coupled to at least one of the power bus and the ground bus, to detect the current through the pin; Status indicators are used to provide user-perceptible output; as well as A logic circuit, coupled to operate the status indicator, is configured to compare the current detected by the current sensor with a threshold, and in response to the result of the comparison, control the status indicator to provide a perceptible output, and maintain the perceptible output when the current sensor periodically detects a peak of a modulated current pulse at or above the threshold.

11. The charging cable as claimed in claim 10, wherein: The cable head includes a socket with a recess configured to receive a cable plug of the receiver carrying the contact pad, so as to rotatably couple the socket of the cable head to the cable plug of the receiver of the rechargeable device; as well as When the cable plug is received in the recess of the socket of the cable head, the power pin and the ground pin protrude into the recess of the socket of the cable head to contact the contact pad of the cable plug, respectively.

12. The charging cable of claim 10, wherein the logic circuitry of the cable is further configured to implement timing logic relative to the pulse length of the modulated current detected by the current sensor to: When the current sensor periodically detects that the peak value of the modulated current pulse is equal to or higher than the threshold, the status indicator is activated to maintain the perceptible output.

13. The charging cable of claim 10, wherein the logic circuitry is further configured to operate the indicator to: A stable shutdown output is provided as the sensed output, indicating that the cable head is not electrically coupled to the receiver.

14. The charging cable of claim 10, wherein the logic circuitry is further configured to operate the indicator to: A pulse output is provided as the sensed output, indicating that the cable head is electrically coupled to the receiver and that the current is charging the battery of the rechargeable device.

15. The charging cable of claim 10, wherein the logic circuitry of the cable is further configured as an operation indicator to: Provide a stable open output as the sensed output, indicating that the cable head is electrically coupled to the receiver but the current is not charging the battery of the rechargeable device.

16. A rechargeable device, comprising: Battery; A battery charger circuit coupled to the battery; The receiver includes a contact pad coupled to the battery charger circuitry and the ground of the rechargeable device; At least one switch is coupled to draw current from the battery charger circuit; as well as The device controller, in response to power from the contact pad of the receiver, is configured to control the battery charger circuit to implement a charging current profile and operate the at least one switch to pulse-modulate the current through the contact pad of the receiver with a high pulse amplitude that periodically reaches or exceeds the charging state threshold when the current defined by the charging current profile is equal to or higher than a cable connection state threshold but lower than a charging state threshold.

17. The rechargeable device of claim 16, wherein the device controller, in response to power from the contact pad of the receiver, is further configured to operate the at least one switch to periodically modulate the current through the receiver contact pad with a low pulse amplitude pulse that satisfies or exceeds the connection state threshold but does not exceed the charging state threshold when the current defined by the charging current profile is below the cable connection state threshold, wherein the low pulse amplitude is less than the high pulse amplitude.

18. The rechargeable device of claim 17, wherein the device controller is further configured to control the battery charger circuit to implement the charging current profile, thereby comprising: The pre-charge trickle current during the first part of the charging current curve is equal to or higher than the cable connection state threshold and lower than the charging state threshold. During the second part of the charging current curve, the constant current is equal to or higher than the state-of-charge threshold. During the third part of the charging current curve, the voltage is constant, during which the current drops from the constant current to a minimum due to the increase in charge stored on the battery; as well as During the fourth part of the charging current curve when the battery has reached a fully charged state, the minimum current is maintained.

19. The rechargeable device of claim 18, wherein the device controller is further configured to operate the at least one switch coupled to the battery charger circuit to: During the pre-charge trickle current period in the first part of the charging current curve, the current through the contact pad of the receiver is pulse-modulated with a high pulse amplitude.

20. The rechargeable device of claim 18, wherein the device controller is further configured to operate the at least one switch coupled to the battery charger circuit to: During the low-current portion of the third part of the charging current curve, the current passing through the contact pads of the receiver is pulsed with a low pulse amplitude.

Images