System and method for adaptive USB charging

Abstract

Systems and methods for charging a rechargeable electronic device having a USB interface are provided. An example method includes comparing a charging voltage level of a charging device to a charging voltage range. The method may also include charging the battery with the charging current based on the charging voltage level being within the charging voltage range. The method may also include comparing the charging current to a charging current range, and increasing the charging current based on determining that the charging current is within the charging current range. The method may include again comparing the charging voltage level to the charging voltage range and comparing the charging current to the charging current range, and based on determining that the charging voltage level is within the charging voltage range and the charging current is within the charging current range, continuing to charge the rechargeable electronic device with the charging current.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 18 / 182,432, filed on March 13, 2023, and also claims priority to U.S. provisional application No. 63 / 486,529, filed on February 23, 2023, the entire contents of each of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to systems and methods for charging electronic devices. Background Art

[0004] Some power charging protocols (e.g., USB-C) require power negotiation between a power source (e.g., a battery charger) and a power receiver (e.g., a rechargeable electronic device) prior to charging. This power negotiation involves communication between the power source and the power receiver and can be used to establish charging parameters (e.g., charging current and charging voltage) that not only effectively charge the rechargeable battery but also remain within the operating parameters of both the power source and the power receiver. The negotiation between the power source and the power receiver may involve the power source sending a source capabilities message via the positive and negative data pins of the power source's USB plug, indicating the charging parameters the power source supports. The power receiver then evaluates the source capabilities message (which may include multiple charging parameters) and sends a power request message requesting the power source to charge the power receiver using the charging parameters specified in the power request message. The power source then evaluates the power request message and determines whether it can charge the power receiver using the specified charging parameters. The power source then sends an accept message to the power receiver and begins charging the power receiver using the charging parameters specified in the request message. If the power source cannot charge the power receiver using the specified parameters, it may send a reject message to the power receiver and not supply power to the power receiver.

[0005] However, some conventional power receivers (e.g., rechargeable electronic devices) utilize older charging protocols and lack the ability to negotiate with power sources to establish valid charging parameters. For example, some conventional rechargeable electronic devices rely on fixed hardware signals (e.g., resistors on the charging cable) to determine the upper limit of the charging power or charging current they can receive (e.g., receiver) or generate (e.g., source). Consequently, some charging cables may include hardware (e.g., resistors) that indicate low charging parameters (e.g., 500mA charging current) to establish compatibility with a wide range of low-power external power sources, including those that do not utilize USB Power Delivery (USB-PD) technology. Consequently, even when connected to a charging source capable of generating higher charging parameters, conventional rechargeable electronic devices may charge at lower charging parameters than they are capable of receiving. This can result in prolonged charging times and damage to the battery within the conventional rechargeable electronic device.

[0006] Furthermore, conventional rechargeable electronic devices may provide power to auxiliary circuits (e.g., LEDs or USB output ports) that consume more power from the conventional rechargeable electronic device's rechargeable battery than is allocated to the rechargeable battery by the power source's charging parameters. Consequently, when connected to a power source, the rechargeable battery of a conventional rechargeable electronic device may experience a net loss of battery charge. Therefore, there is a need in the art for a rechargeable electronic device that is not capable of conventional power negotiation and can be charged by a power source with improved, efficient charging parameters. Summary of the Invention

[0007] An example method for charging a rechargeable electronic device may include comparing a charging voltage level of a charging device with a charging voltage range of the electronic device. The method may also include, based on determining that the charging voltage level of the charging device is within the charging voltage range of the electronic device, charging a battery of the electronic device with a charging current. The method may also include comparing the charging current with a minimum current threshold of the electronic device. The method may also include increasing the charging current based on determining that the charging current is within the charging current range. The method may also include again comparing the charging voltage level of the charging device with the charging voltage range and comparing the charging current with the charging current range. Furthermore, the method may include continuing to charge the rechargeable electronic device with the charging current based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range.

[0008] The method may be performed without requiring power negotiation between the charging device and the rechargeable electronic device. The method may further include determining whether an auxiliary circuit of the electronic device is enabled or disabled based on determining that the charging current is equal to or below a minimum current threshold. The method may further include disabling the auxiliary circuit based on determining that the auxiliary circuit is enabled. The method may further include placing the electronic device in a low power mode or displaying an error indicator on the electronic device based on determining that the auxiliary circuit is disabled. The method may further include reducing the charging current based on determining that the charging voltage level of the charging device is not within a charging voltage range or the charging current is not within a charging current range, and again comparing the charging voltage level of the charging device with the charging voltage range and again comparing the charging current with the charging current range.

[0009] Another example method for charging a rechargeable electronic device having a USB interface includes comparing a charging voltage level of the charging device with a charging voltage range of the rechargeable electronic device. The method may also include charging a battery of the rechargeable electronic device with a charging current based on determining that the charging voltage level of the charging device is within the charging voltage range of the rechargeable electronic device. The method may also include comparing the charging current with a minimum current threshold of the rechargeable electronic device. Based on determining that the charging current is greater than the minimum current threshold, the charging current may be increased. The method may also include again comparing the charging voltage level of the charging device with the charging voltage range and comparing the charging current with the charging current range. Based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, the method may include increasing the charging current.

[0010] The method may further include, based on determining that the charging voltage level of the charging device is not within the charging voltage range or the charging current is not within the charging current range, reducing the charging current to a previous charging current level and continuing to charge the electronic device at the previous charging current level. The method may further include, after starting to charge the battery of the rechargeable electronic device with the charging current, reserving a predetermined time before comparing the charging current with the charging current range of the rechargeable electronic device. The predetermined time is based on a stabilization time of the charging device or a stabilization time of the rechargeable electronic device.

[0011] An example electronic device with a USB interface can be configured to attach to and detach from a charging device. The electronic device may include a rechargeable battery configured to receive and charge a charging current. The electronic device may also include a current sensor coupled to the rechargeable battery, the current sensor configured to measure the charging current. The electronic device may also include a voltage sensor configured to measure the charging voltage level of the charging device when the charging device is attached to the electronic device. The electronic device may also include a controller coupled to the voltage sensor and the current sensor.

[0012] The controller may be configured to compare the charging voltage level with a charging voltage range for the electronic device. The controller may be further configured to charge the battery with the charging current based on a determination that the charging voltage level is within the charging voltage range. The controller may be further configured to measure the charging current. Based on a determination that the charging current is above a minimum charging current threshold, the controller may be further configured to increase the charging current. The controller may be further configured to again compare the charging voltage level of the charging device with the voltage range and again compare the charging current with the charging current range. Based on a determination that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, the controller may be further configured to continue charging the rechargeable electronic device with the charging current.

[0013] The charging device may not be configured to perform power negotiation between the charging device and the chargeable electronic device. The controller may be further configured to determine whether an auxiliary circuit of the electronic device is enabled or disabled based on determining that the charging current is equal to or below a minimum current threshold. The controller may be further configured to disable the auxiliary circuit based on determining that the auxiliary circuit is enabled. The controller may be further configured to place the electronic device in a low-power mode or display an error indicator on the electronic device based on determining that the auxiliary circuit is disabled.

[0014] The controller can be further configured to, based on determining that the charging voltage level of the charging device is not within the charging voltage range or the charging current is not within the charging current range, reduce the charging current, and again compare the charging voltage level of the charging device with the charging voltage range and again compare the charging current with the charging current range. The controller can be further configured to, after starting to charge the battery of the electronic device with the charging current, reserve a predetermined time before comparing the charging current with the charging current range of the electronic device, wherein the predetermined time is based on a stabilization time of the charging device or a stabilization time of the electronic device. The rechargeable electronic device can also include a DC-DC converter coupled to the controller. The DC-DC converter can be configured to generate the charging current. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following detailed description will be better understood when read in conjunction with the accompanying drawings. For ease of illustration, certain embodiments of the present disclosure are shown in the accompanying drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of systems and devices consistent with the present invention and, together with the description, serve to explain advantages and principles consistent with the present invention.

[0016] Figure 1 A rechargeable electronic device is depicted in accordance with some embodiments.

[0017] Figure 2 A charging system according to some embodiments is depicted.

[0018] Figure 3 Depicted is a circuit diagram of a rechargeable electronic device according to some embodiments.

[0019] Figure 4 A flow chart is depicted of a method of charging an electronic device in accordance with some embodiments.

[0020] Figure 5 A flow chart is depicted of a method of charging an electronic device in accordance with some embodiments.

[0021] Figure 6 A method of charging an electronic device according to some embodiments is described.

[0022] Figure 7 A method of charging an electronic device according to some embodiments is described.

[0023] Figure 8 Depicted is another example circuit diagram of a rechargeable electronic device in accordance with some embodiments.

[0024] Figure 9 Depicted is yet another example circuit diagram of a rechargeable electronic device in accordance with some embodiments. DETAILED DESCRIPTION

[0025] The following detailed description is provided to help the reader fully understand the methods, devices, and / or systems described herein. Therefore, various changes, modifications, and equivalents of the systems, devices, and / or methods described herein will be suggested to those skilled in the art. Furthermore, descriptions of well-known functions and structures may be omitted for clarity and brevity.

[0026] It will be understood that the phraseology and terminology employed herein are for descriptive purposes and should not be regarded as limiting. For example, the use of singular terms such as "a" is not intended to limit the quantity of the items. Furthermore, the use of relative terms such as, but not limited to, "top," "bottom," "left," "right," "upper," "lower," "downward," "upward," and "side" in the description is for clarity and is not intended to limit the scope of the invention or the appended claims. Furthermore, it will be understood that any one feature may be used alone or in combination with other features. Other systems, methods, features, and advantages of the present invention will be or will become apparent to one skilled in the art upon inspection of the detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the appended claims.

[0027] Conventional rechargeable electronic devices can determine the specified charging power or charging current they can receive from a charging device based on fixed hardware signals (such as from a resistor on a charging cable). However, conventional charging cables may indicate charging parameters that are lower than the charging parameters that the conventional rechargeable electronic device can actually receive in order to establish compatibility with a variety of charging devices, including low-power external power supplies and charging devices that do not use USB Power Delivery (USB-PD) technology. As a result, conventional rechargeable electronic devices may charge at charging parameters lower than the charging parameters they are capable of receiving. This can result in lower efficiency and longer charging times.

[0028] Furthermore, the charging power supplied to these conventional rechargeable electronic devices may not be sufficient to overcome the power drawn from the rechargeable battery of the conventional rechargeable electronic device. For example, the charging power may not be sufficient to overcome the power from the rechargeable battery supplied to auxiliary circuits within the conventional rechargeable electronic device (such as an LED or USB output circuit). As a result, conventional charging systems and methods may cause the conventional rechargeable electronic device to indicate that it is charging when the rechargeable battery is actually experiencing a net loss of charge. The systems and methods disclosed herein can safely and efficiently increase the charging current received by a rechargeable electronic device from a charging device without requiring conventional power negotiation between the rechargeable electronic device and the charging device, thereby shortening charging time and improving charging efficiency.

[0029] Figure 1 A rechargeable electronic device is depicted according to some embodiments. Figure 1 In the example of FIG. 1 , the rechargeable electronic device 100 is a jump-start device that can be used to jump-start a battery of, for example, a motor vehicle. The rechargeable electronic device 100 can include a USB charging port 101 (e.g., a USB receptacle). For example, the USB charging port 101 can include a USB-C or USB input port for charging an internal rechargeable battery. The rechargeable electronic device 100 can be connected to a charging device (not shown) at the USB charging port 101, as described below with reference to FIG. Figure 2 As further described, the rechargeable electronic device 100 may include auxiliary circuitry that may consume power from the internal rechargeable battery during charging and during standard operation (eg, jump-starting a depleted or discharged battery).

[0030] For example, the auxiliary circuitry may include a USB output port 106 for supplying charge from the rechargeable battery to other portable devices such as smartphones, tablet computers, and portable speakers. Additional auxiliary circuitry may include an output indicator 107 that indicates power is being supplied to the USB output port; a power-on indicator 109 that indicates the rechargeable electronic device is receiving power; an LED fuel gauge indicator 102; and a reverse indicator 108 that indicates the rechargeable battery is connected to an external battery with reverse polarity. The rechargeable electronic device 100 may include a power-on switch 105 and a flash control switch 104 for activating one or more flash LEDs. A positive battery cable (not shown) and a negative battery cable (not shown) may be attached to the rechargeable electronic device 100 at the output port 103. A battery clamp (not shown) may be attached to each of the positive and negative battery clamps. For example, the battery clamp may be attached to a car battery.

[0031] Figure 2 A charging system according to some embodiments is depicted. The charging system may include a charging device 201. For example, the charging device 201 may be a USB wall charger. The charging device 201 may receive power from a power source 202. Figure 2 In the example embodiment depicted in FIG, power source 202 is an alternating current (AC) power source. For example, charging device 201 can be connected to power source 202 via a power outlet (e.g., a wall outlet). In some example embodiments, charging device 201 can generate power independently (e.g., from an internal battery). Charging device 201 can include a charging cable 203 that can connect to and disconnect from rechargeable electronic device 100. For example, charging cable 203 can include a USB or USB-C plug for attaching to USB charging port 101 of rechargeable electronic device 100.

[0032] Figure 3 Depicts a circuit diagram of a rechargeable electronic device according to some embodiments. Figure 2 When making reference, you can better understand Figure 3The rechargeable electronic device 100 may include a USB charging port 101, a DC-DC converter 301, a rechargeable battery 302, and a current sensor 303. For example, the DC-DC converter 301 may be an ISL9238 CIRTZ-T unit from Renesas Electronics. The USB charging port 101, the DC-DC converter 301, the rechargeable battery 302, and the current sensor 303 may be connected in series with each other. The rechargeable electronic device 100 may also include one or more auxiliary circuits 309 coupled to the battery 302. The rechargeable electronic device 100 may also include an amplifier 304 coupled to the current sensor 303 and a voltage sensor 306 coupled to the USB charging port 101. The rechargeable electronic device 100 may also include a controller 305 coupled to the amplifier 304 and the voltage sensor 306. The controller 305 may generate a control signal 315 based on the amplifier 304 and the voltage sensor 306.

[0033] The rechargeable electronic device 100 may receive a charging plug (eg, a USB or USB-C plug) from the charging device 201 at the USB charging port 101. The rechargeable electronic device 100 may detect the bus voltage node V BUS The charging voltage of the charging device 201 at 312. For example, the electronic device can detect the charging voltage through the connection between the corresponding pins of the USB charging port 101 and the charging plug of the charging device 201. Charging devices using later USB protocols can provide data connection points at additional corresponding pins of the USB charging port 101 and the charging plug of the connected device, which can be used for power negotiation between the charging device and the rechargeable electronic device. However, some rechargeable electronic devices utilize other USB protocols that the rechargeable electronic device cannot negotiate power with the charging device. The rechargeable electronic device 100 can use the available connection and charging voltage to improve the charging parameters of the attached charging device, even though it cannot negotiate or communicate with the charging device through the USB data pins.

[0034] The voltage sensor 306 may be coupled to the bus voltage node V BUS 312, and can be used to detect the charging voltage of the charging device 201. For example, the voltage sensor 306 can be a voltage divider. The voltage divider can include a first resistor 307 and a second resistor 308. As described above, the voltage sensor 306 can be coupled to the controller 305. For example, the controller 305 can be a microcontroller. When the charging device 201 is connected to the rechargeable electronic device 201 via the charging plug, the voltage sensor can detect the bus voltage node V BUS The controller 305 may receive the input voltage signal 313 based on the charge voltage level.

[0035] Based on the input voltage signal 313, the controller 305 can determine whether the charging voltage level is within the charging voltage range of the rechargeable electronic device 100. The charging voltage range may be an acceptable voltage range within which the rechargeable electronic device 100 can safely and efficiently charge the rechargeable battery 302. For example, for a USB or USB-C charging plug, a typical charging voltage level may be approximately 5.0V. The charging voltage range may be a range within a predetermined voltage range of the typical charging voltage level (e.g., 5.0V ± 1V or 4.0V-6.0V).

[0036] If the charge voltage level is not within the charge voltage range, the controller 305 may generate a control signal 315 indicating that the charge voltage level is not within the charge voltage range. Based on this control signal 315, the rechargeable electronic device 100 may enter a low-power mode and may display an error indicator (e.g., an error message or an error light). If the charge voltage level is within the charge voltage range, the controller 305 may generate a control signal 315 indicating that the charge voltage level is within the charge voltage range. Based on this control signal 315, the rechargeable electronic device 100 may enable the DC-DC converter 301, and the DC-DC converter 301 may generate a charging current to charge the rechargeable battery 302.

[0037] In an example where the charging voltage level is within the charging voltage range, the rechargeable electronic device 100 may reserve a predetermined time (e.g., one second) for the charging current to stabilize. This may be necessary, for example, to avoid measuring transient currents within the rechargeable electronic device 100. After a predetermined time has passed since the charging current was generated, the current sensor 303 may measure the charging current. For example, the charging current may be measured by measuring the voltage generated by the charging current passing through the current sensor 303. Figure 3 In the example embodiment depicted in FIG, the current sensor 303 includes a sensing resistor R SENSE The amplifier 304 can be coupled to a first side of the current sensor 303 and a second side of the current sensor 303. For example, the amplifier can be coupled to a first side of the current sensor 303 and a second side of the current sensor 303 by measuring the current of the current sensor 303 (eg, the sensing resistor R SENSE ) determines the charging current. Based on the charging current, amplifier 304 can generate a current level signal 314. Current level signal 314 can represent the charging current, but can be in the form of a current signal or a voltage signal.

[0038] Based on the current level signal 314, the controller 305 may compare the charging current to a minimum threshold current level. For example, the minimum threshold current level may be the minimum current level required to safely and efficiently charge the rechargeable battery 302. If the charging current is greater than the minimum threshold current level, the controller 305 may generate a control signal 315 indicating that the charging current is greater than the minimum threshold current level. The DC-DC converter 301 may receive the control signal 315 and increase the charging current. For example, the DC-DC converter 301 may increase the charging current by a predetermined amount.

[0039] If the charging current is not greater than the minimum threshold current level, the controller 305 may generate a control signal 315 indicating that the charging current is not greater than the minimum threshold current level. Based on the control signal 315, the rechargeable electronic device 100 may determine whether the auxiliary circuit 309 is active (e.g., enabled). For example, the auxiliary circuit may include a flash circuit 310 or a USB output circuit 311. If no auxiliary circuit is active, the rechargeable electronic device 100 may enter a low-power mode and display an error indicator. If one or more auxiliary circuits 309 are active, the rechargeable electronic device 100 may shut down (e.g., disable) the auxiliary circuit 309.

[0040] If the charging current has been increased based on a determination that the charging current is greater than a minimum threshold current level, the controller 305 may allow for a predetermined time (e.g., one second) for the charging system (including the charging voltage and charging current) to stabilize. As described above, allowing for a predetermined time for the charging voltage and charging current to stabilize may be necessary or desirable to avoid measuring transient currents or voltages that are not representative of the rechargeable electronic device 100. After the predetermined time has elapsed, the controller 305 may measure the charging current based on the current level signal 314 and may measure the charging voltage based on the input voltage signal 313.

[0041] Based on the current level signal 314 and the input voltage signal 313, the controller 305 can then determine whether the charging current is within a charging current range and whether the charging voltage level is within a charging voltage range. For example, the charging current range can be between a minimum threshold current level and an upper current limit, which represents the maximum current at which the rechargeable battery can be safely and efficiently charged. The upper current limit can additionally or alternatively represent the maximum output current level of the DC-DC converter 301. If the charging voltage level is within the charging voltage range and the charging current is within the charging current range, the rechargeable electronic device 100 can apply a flag (e.g., an indicator) indicating that the charging current has been modified. For example, the flag can be applied via a variable within the software of the controller 305. After applying the flag, the rechargeable electronic device 100 can continue charging the rechargeable battery 302 with the existing charging current until the charging cycle is complete (e.g., the rechargeable battery 302 is fully charged or the charging device 201 is disconnected from the rechargeable electronic device 100).

[0042] If the charging voltage level is not within the charging voltage range or the charging current is not within the charging current range, the controller 305 may generate a control signal 315 indicating that one or both of the charging voltage level and the charging current are not within their respective ranges. Based on this control signal 315, the DC-DC converter may reduce the charging current by a predetermined amount (e.g., 0.1 amps). The controller 305 may then allow a predetermined time for the charging current and charging voltage level to stabilize. After the predetermined time has passed since reducing the charging current and the charging current has stabilized, the controller 305 may again determine whether the charging current is within the charging current range and whether the charging voltage level is within the charging voltage range based on the current level signal 314 and the input voltage signal 313.

[0043] If the charging voltage level or the charging current is not within its respective range, the controller 305 may generate a control signal indicating that one or both of the charging voltage level and the charging current are not within their respective ranges, and the DC-DC converter may accordingly reduce the charging current by a predetermined amount. This process may be repeated sequentially until the charging current is within the charging current range and the charging voltage level is within the charging voltage range. When both the charging current and the charging voltage level are within their acceptable tolerances, a flag may be added, and the rechargeable electronic device 100 may continue to charge the rechargeable battery 302 until the charging cycle is complete.

[0044] In some example embodiments, after determining that the charging voltage level is within the charging voltage range and the charging current is within the charging current range, no flag may be applied. Instead, the controller 305 may generate a control signal 315 indicating that the charging voltage level and the charging current are within their respective ranges. Based on the control signal 315, the DC-DC converter 301 may increase the charging current by a predetermined increment (e.g., 0.1 amps). The controller 305 may then allow a predetermined time for the charging current and the charging voltage level to stabilize. After another predetermined time has passed since the charging current was increased, the controller 305 may again determine whether the charging voltage level is within the charging voltage range and whether the charging current is within the charging current range.

[0045] This process can be repeated until the controller 305 determines that one or both of the charging voltage level and the charging current are not within their respective acceptable ranges. After the controller determines that one or both of the charging voltage level and the charging current are not within their respective acceptable ranges, the controller 305 can generate a control signal 315 indicating that one or both of the charging voltage level and the charging current are not within their respective acceptable ranges, and the DC-DC converter 301 can then reduce the charging current by a predetermined amount. For example, the charging current can be reduced by a single increment (e.g., the charging current generated in the immediately preceding cycle). By reducing the charging current by a single increment, a charging current value can be generated that has been determined by the controller 305 to be within the charging voltage range and results in a charging voltage level within the charging voltage range. The controller 305 can then add a flag indicating that the charging current has been sufficiently modified, and the rechargeable electronic device 100 can continue charging the rechargeable battery 302 until the charging cycle is complete.

[0046] Figure 4 A flow chart of a method for charging a rechargeable electronic device according to some embodiments is depicted. For example, Figure 1 、 Figure 2 or Figure 3 Method 400 may be applied to an example embodiment of a rechargeable electronic device 100 depicted in FIG. A first step may be detecting a voltage on a charging bus, as shown in block 401. When a charging device is connected to a rechargeable electronic device, the voltage on the charging bus may be determined at a bus node of the rechargeable electronic device. After detecting the voltage on the charging bus, the next step may be determining whether the voltage on the charging bus is within a charging voltage range, as shown in block 402. The charging voltage range may be an acceptable voltage range within which the rechargeable electronic device can safely and efficiently charge a rechargeable battery. If the voltage on the charging bus is within the charging voltage range, the next step may be to begin charging the rechargeable battery with a charging current, as shown in block 403. The rechargeable electronic device may reserve a predetermined time for the charging current and the voltage on the charging bus to stabilize.

[0047] If the voltage on the charging bus is not within the charging voltage range, the rechargeable electronic device may enter a low-power mode and display an error indicator (e.g., an error message or an error light), as shown in block 404. If the voltage on the charging bus is within the charging voltage range and the charging current has stabilized, the charging current level may be measured, as shown in block 405. As shown in block 406, the next step may be to determine whether the charging current is above a minimum threshold current level. If the charging current is above the minimum threshold current level, the next step may be to increase the charging current, as depicted in 409. For example, the charging current may be increased by a predetermined value.

[0048] If the charging current is not above the minimum threshold current level, the next step may be to determine whether any auxiliary circuits are active (e.g., enabled), as shown in block 407. Auxiliary circuits may include components such as a flashlight or USB output circuitry. Auxiliary circuits can draw current from the rechargeable battery and, therefore, may reduce the rechargeable electronic device's ability to charge the rechargeable battery. If one or more auxiliary circuits are active, the next step may be to shut down (e.g., disable) these auxiliary circuits, as shown in block 408. In some example embodiments, a single auxiliary circuit may be shut down in block 408, and a different auxiliary circuit may be shut down if the method subsequently returns to block 408. After shutting down the auxiliary circuits in block 408, the charging current may be measured again in step 405. If no auxiliary circuits are active, the rechargeable electronic device may enter a low-power mode and display an error indicator, as shown in block 404.

[0049] After increasing the charging current in block 409, the next step may be to allow a predetermined time for the rechargeable electronic device to stabilize, as shown in block 410. For example, the charging current and the voltage on the charging bus may stabilize (e.g., reach a substantially constant level). After the predetermined time for the rechargeable electronic device to stabilize, the voltage on the charging bus may be measured, as shown in block 410. As shown in block 411, the next step may be to determine whether the charging voltage level is within a charging voltage range and whether the charging current is within a charging current range. For example, the charging current range may be between a minimum threshold current level and an upper current limit, which represents the maximum current at which the rechargeable battery can be safely and effectively charged.

[0050] If the charging voltage level is within the charging voltage range and the charging current is within the charging current range, the next step may be to add a charging flag, as shown in block 414. For example, the charging flag may be added by software within the rechargeable electronic device. After adding the charging flag, the next step may be to determine whether the charging flag is active, as shown in block 414. If the charging flag is not active, the method may return to the step of increasing the charging current, as shown in block 409. If the charging flag is active, the rechargeable electronic device may continue to charge the rechargeable battery with the existing charging current until the charging cycle is complete (e.g., until the rechargeable battery is fully charged, or until the charging device is disconnected from the rechargeable electronic device), as shown in block 415.

[0051] If the charging voltage level is not within the charging voltage range or the charging current is not within the charging current range at the step shown in block 411, the next step may be to reduce the charging current, as shown in block 413. After reducing the charging current, the next step may be to allow a predetermined time for the rechargeable electronic device to stabilize, as shown by returning to block 410. After the predetermined time for the rechargeable electronic device to stabilize, the voltage on the charging bus may be measured, as shown in block 410. This process may be repeated until the charging voltage level is within the charging voltage range and the charging current is within the charging current range, as shown by the path between blocks 410, 411, and 413.

[0052] Figure 5 A flow chart of a method for charging a rechargeable electronic device according to some embodiments is depicted. For example, Figure 1 、 Figure 2 or Figure 3 Method 500 may be applied to an example embodiment of a rechargeable electronic device 100 depicted in FIG. A first step may be detecting a voltage on a charging bus, as shown in block 501. When a charging device is connected to a rechargeable electronic device, the voltage on the charging bus may be determined at a bus node of the rechargeable electronic device. After detecting the voltage on the charging bus, the next step may be determining whether the voltage on the charging bus is within a charging voltage range, as shown in block 502. The charging voltage range may be an acceptable voltage range within which the rechargeable electronic device can safely and efficiently charge a rechargeable battery. If the voltage on the charging bus is within the charging voltage range, the next step may be to begin charging the rechargeable battery with a charging current, as shown in block 503. The rechargeable electronic device may reserve a predetermined time for the charging current and the voltage on the charging bus to stabilize.

[0053] If the voltage on the charging bus is not within the charging voltage range, the rechargeable electronic device may enter a low power mode and display an error indicator (e.g., an error message or an error light), as shown in block 504. If the voltage on the charging bus is within the charging voltage range and the charging current has stabilized, the charging current level may be measured, as shown in block 505. As shown in block 506, the next step may be to determine whether the charging current is above a minimum threshold current level. If the charging current is above the minimum threshold current level, the next step may be to increase the charging current in increments, as depicted in 509. For example, the charging current may be increased by a predetermined value. The predetermined value for increasing the charging current in increments, as shown in block 509, may be a value greater than Figure 4 The block 409 shown is used to increase the charging current to a smaller value than the predetermined value.

[0054] If the charging current is not above the minimum threshold current level, the next step may be to determine whether any auxiliary circuits are active (e.g., enabled), as shown in block 507. Auxiliary circuits may include components such as a flashlight or USB output circuitry. Auxiliary circuits can draw current from the rechargeable battery and, therefore, may reduce the rechargeable electronic device's ability to charge the rechargeable battery. If one or more auxiliary circuits are active, the next step may be to shut down (e.g., disable) these auxiliary circuits, as shown in block 508. In some example embodiments, a single auxiliary circuit may be shut down in block 508, and a different auxiliary circuit may be shut down if the method subsequently returns to block 508. After shutting down the auxiliary circuits in block 508, the charging current may be measured again in step 505. If no auxiliary circuits are active, the rechargeable electronic device may enter a low-power mode and display an error indicator, as shown in block 504.

[0055] After increasing the charging current at block 509, the next step may be to allow a predetermined time for the rechargeable electronic device to stabilize, as shown in block 510. For example, the charging current and the voltage on the charging bus may stabilize (e.g., reach a substantially constant level). After the predetermined time for the rechargeable electronic device to stabilize, the voltage on the charging bus may be measured, also as shown in block 510. The next step may be to determine whether the voltage on the charging voltage bus is within a charging voltage range and whether the charging current is within a charging current range, as shown in block 511. For example, the charging current range may be between a minimum threshold current level and an upper current limit, which represents the maximum current at which the rechargeable battery can be safely and effectively charged.

[0056] If the voltage on the charging voltage bus is within the charging voltage range and the charging current is within the charging current range, method 500 may return to the step shown in block 509 to increase the charging current in an incremental manner. If the voltage on the charging bus is not within the charging voltage range or the charging current is not within the charging current range, or if the voltage on the charging bus is not within the charging voltage range and the charging current is not within the charging current range, the next step may be to reduce the charging current to the previous charging current value. The charging current may be reduced to the previous charging current value because method 500 may have previously verified at the step shown in block 506 that the charging current at the previous time was greater than the minimum charging current threshold and was therefore sufficient to charge the rechargeable battery.

[0057] After reducing the charging current at block 512, the next step may be to add a charging flag, as shown in block 513. For example, the charging flag may be added by software within the rechargeable electronic device. After adding the charging flag, the next step may be to determine whether the charging flag is active, as shown in block 514. If the charging flag is active, the rechargeable electronic device may continue to charge the rechargeable battery with the existing charging current until the charging cycle is complete (e.g., until the rechargeable battery is fully charged, or until the charging device is disconnected from the rechargeable electronic device), as shown in block 515. If the charging flag is not active, the next step may be to gradually increase the charging current again, as shown in block 509.

[0058] Figure 6 Methods of charging a rechargeable electronic device according to some embodiments are described. Figure 6 In the example embodiment depicted in , the first step 601 of the method is to compare the charging voltage level of the charging device with the charging voltage range of the rechargeable electronic device. The second step 602 can be based on determining that the charging voltage level of the charging device is within the charging voltage range of the rechargeable electronic device, charging the battery of the rechargeable electronic device with the charging current. The third step 603 can be to compare the charging current with a minimum current threshold of the rechargeable electronic device. The fourth step 604 can be based on determining that the charging current is higher than the minimum current threshold, increasing the charging current. The fifth step 605 can be to compare the charging voltage level of the charging device with the charging voltage range again, and to compare the charging current with the charging current range. The sixth step 606 can be based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, continuing to charge the rechargeable electronic device with the charging current. In some example embodiments, the steps of: Figure 6 In addition, Figure 6 The steps shown in Figure 6 The order in which they are depicted is different from the order in which they are executed.

[0059] Figure 7 Methods of charging a rechargeable electronic device according to some embodiments are described. Figure 7 In the example embodiment depicted in , the first step 701 of the method is to compare the charging voltage level of the charging device with the charging voltage range of the rechargeable electronic device. The second step 702 can be based on determining that the charging voltage level of the charging device is within the charging voltage range of the rechargeable electronic device, charging the battery of the rechargeable electronic device with the charging current. The third step 703 can be to compare the charging current with a minimum current threshold of the rechargeable electronic device. The fourth step 704 can be based on determining that the charging current is higher than the minimum current threshold, increasing the charging current. The fifth step 705 can be to compare the charging voltage level of the charging device with the charging voltage range again, and to compare the charging current with the charging current range. The sixth step 706 can be based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, increasing the charging current again. In some example embodiments, the method may be omitted. Figure 7 In addition, Figure 7 The steps shown in Figure 7 The order in which they are depicted is different from the order in which they are executed.

[0060] Figure 8 Depicted is a circuit diagram of a rechargeable electronic device according to some embodiments. Figure 8 One or more components of the rechargeable electronic device depicted in FIG. 4 may be substantially similar to Figure 3 Components of an example rechargeable electronic device are depicted in FIG. Figure 8 In the example depicted in FIG, the rechargeable electronic device 100 includes an adjustable R SENSE Circuit 801. For example, the DC-DC converter 301 may be a Renesas Electronics ISL9238 CIRTZ-T unit. The adjustable R SENSE The circuit 801 can be coupled to a first pin 803 (eg, CSON pin) and a second pin 804 (eg, CSOP pin) of the DC-DC converter 301. Depending on the specific DC-DC converter 301 implemented in the rechargeable electronic device 100, the R SENSE The number or type of pins to which the circuit 801 is connected may vary. SENSE Circuit 801 may also be coupled to a battery input node 802 .

[0061] Adjustable R SENSE Circuit 801 can be used to control the current output of DC-DC converter 301. For example, R SENSE Circuit 801 can be coupled to controller 305 and can receive control signal 315. Based on control signal 315, RSENSE Circuit 801 can adjust its internal resistance. For example, R SENSE Circuit 801 can adjust the resistance by turning on a resistor in parallel with the current sense resistor. SENSE The internal resistance of the circuit 801 can be detected by the first pin 803 and the second pin 804. SENSE As the internal resistance of circuit 801 increases, DC-DC converter 301 can sense the reduced charging current and can increase its current output (eg, charging current) accordingly. SENSE As the internal resistance of circuit 801 decreases, DC-DC converter 301 can sense the increased charging current and can reduce its current output accordingly.

[0062] Figure 9 Depicted is a circuit diagram of a rechargeable electronic device according to some embodiments. Figure 9 One or more components of the example rechargeable electronic device 100 depicted in FIG. 1 may be substantially similar to Figure 3 Components of the example rechargeable electronic device 100 are depicted in FIG. Figure 9 In the example depicted in FIG, the rechargeable electronic device 100 includes an adjustable current-limiting resistor circuit 901. The adjustable current-limiting resistor circuit 901 can be coupled to the DC-DC converter 301. For example, the DC-DC converter 301 can be a Feeling Technology FP6293 unit. The Feeling Technology FP6293 unit includes a current-limit input channel that controls its current output (e.g., charging current). Therefore, the adjustable current-limiting resistor circuit can be used to control the current output of the DC-DC converter 301 by controlling the input received at the current-limit input channel. For example, the adjustable current-limiting resistor circuit 901 can receive a control signal 315 from the controller 305. Based on the control signal 315, the adjustable current-limiting resistor circuit 901 can select from two or more current-limiting inputs 902 received at the current-limiting input channel of the DC-DC converter 301. The DC-DC converter 301 can increase or decrease the generated current output based on the received current-limiting input 902.

[0063] Those skilled in the art will appreciate that changes may be made to the above embodiments without departing from the broad inventive concept of the above embodiments. Therefore, it will be understood that the invention disclosed herein is not limited to the specific embodiments disclosed, and is intended to cover various modifications within the spirit and scope of the invention.

Claims

1. A method for charging a rechargeable electronic device having a USB interface, comprising: comparing a charging voltage level of the charging device with a charging voltage range of the rechargeable electronic device; charging a battery of the rechargeable electronic device with a charging current based on determining that the charging voltage level of the charging device is within the charging voltage range of the rechargeable electronic device; comparing the charging current with a minimum current threshold of the rechargeable electronic device; increasing the charging current based on determining that the charging current is greater than the minimum current threshold; again comparing the charging voltage level of the charging device with the charging voltage range and comparing the charging current with a charging current range; as well as Based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, the rechargeable electronic device continues to be charged with the charging current.

2. The method according to claim 1, wherein The method is performed without requiring power negotiation between the charging device and the rechargeable electronic device.

3. The method according to claim 1, further comprising: Based on determining that the charging current is equal to or below the minimum current threshold, it is determined whether an auxiliary circuit of the rechargeable electronic device is enabled or disabled.

4. The method according to claim 3, further comprising: Based on determining that the auxiliary circuit is enabled, the auxiliary circuit is disabled.

5. The method according to claim 3, further comprising: Based on determining that the auxiliary circuit is disabled, the rechargeable electronic device is placed in a low power mode or an error indicator is displayed on the rechargeable electronic device.

6. The method according to claim 1, further comprising: Based on determining that the charging voltage level of the charging device is not within the charging voltage range or the charging current is not within the charging current range, the charging current is reduced, and the charging voltage level of the charging device is compared with the charging voltage range again and the charging current is compared with the charging current range again.

7. A method for charging a rechargeable electronic device having a USB interface, comprising: comparing a charging voltage level of the charging device with a charging voltage range of the rechargeable electronic device; charging a battery of the rechargeable electronic device with a charging current based on determining that the charging voltage level of the charging device is within the charging voltage range of the rechargeable electronic device; comparing the charging current with a minimum current threshold of the rechargeable electronic device; increasing the charging current based on determining that the charging current is greater than the minimum current threshold; again comparing the charging voltage level of the charging device with the charging voltage range and comparing the charging current with a charging current range; as well as Based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, the charging current is increased again.

8. The method according to claim 7, further comprising: Based on determining that the charging voltage level of the charging device is not within the charging voltage range or the charging current is not within the charging current range, the charging current is reduced to a previous charging current level, and the rechargeable electronic device is continued to be charged at the previous charging current level.

9. The method according to claim 7, further comprising: After starting to charge the battery of the rechargeable electronic device with the charging current, a predetermined time is reserved before comparing the charging current with the charging current range of the rechargeable electronic device, and the predetermined time is based on the stabilization time of the charging device or the stabilization time of the rechargeable electronic device.

10. A rechargeable electronic device having a USB interface, the rechargeable electronic device being configured to be attached to and detached from a charging device, the rechargeable electronic device comprising: a rechargeable battery configured to receive a charging current and to be charged with the charging current; a current sensor coupled to the rechargeable battery, the current sensor configured to measure the charging current; a voltage sensor configured to measure a charging voltage level of the charging device when the charging device is attached to the rechargeable electronic device; a controller coupled to the voltage sensor and the current sensor, the controller being configured to: comparing the charging voltage level to a charging voltage range of the rechargeable electronic device; charging the battery with the charging current based on determining that the charging voltage level is within the charging voltage range; measuring the charging current; increasing the charging current based on determining that the charging current is greater than a minimum current threshold; again comparing the charging voltage level of the charging device with the charging voltage range and again comparing the charging current with the charging current range; as well as Based on determining that the charging voltage level of the charging device is within the charging voltage range and the charging current is within the charging current range, the rechargeable electronic device continues to be charged with the charging current.

11. The rechargeable electronic device according to claim 10, wherein: The charging device is not configured to perform power negotiation between the charging device and the chargeable electronic device.

12. The rechargeable electronic device according to claim 10, wherein: The controller is further configured to determine whether auxiliary circuitry of the rechargeable electronic device is enabled or disabled based on determining that the charging current is equal to or below the minimum current threshold.

13. The rechargeable electronic device according to claim 12, wherein: The controller is further configured to disable the auxiliary circuit based on determining that the auxiliary circuit is enabled.

14. The rechargeable electronic device according to claim 12, wherein: The controller is further configured to place the rechargeable electronic device in a low power mode or display an error indicator on the rechargeable electronic device based on determining that the auxiliary circuit is disabled.

15. The rechargeable electronic device according to claim 10, wherein: The controller is further configured to, based on determining that the charging voltage level of the charging device is not within the charging voltage range or the charging current is not within the charging current range, reduce the charging current, and again compare the charging voltage level of the charging device with the charging voltage range and again compare the charging current with the charging current range.

16. The rechargeable electronic device according to claim 10, wherein: The controller is also configured to, after starting to charge the battery of the rechargeable electronic device with the charging current, reserve a predetermined time before comparing the charging current with the charging current range of the rechargeable electronic device, wherein the predetermined time is based on the stabilization time of the charging device or the stabilization time of the rechargeable electronic device.

17. The rechargeable electronic device according to claim 10, further comprising: A DC-DC converter is coupled to the controller, wherein the DC-DC converter is configured to generate the charging current.

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