Power regulation in non-adjustable wireless charging systems
By dynamically changing the antenna resonant frequency of the portable device and manipulating the detuning stage to obtain the appropriate amount of power during wireless charging, the problem of overheating of the portable device is solved, and a stable and safe charging process is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RENESAS DESIGN AUSTRIA GMBH
- Filing Date
- 2022-01-31
- Publication Date
- 2026-05-26
AI Technical Summary
Existing wireless charging systems cause a significant increase in the junction temperature (TL) of portable devices during the transition period (TR), leading to a potential risk of device damage, and the long response time of the feedback loop can cause charging interruptions.
By dynamically changing the antenna resonant frequency of a portable device, the detuning stage is used to manipulate the antenna resonant frequency to obtain the appropriate amount of power from the magnetic field at different charging stages, thereby reducing heat conversion and feedback loop response time.
It effectively prevents portable devices from overheating, shortens the transition time (TR), ensures the stability and safety of the charging process, and reduces heat generation.
Smart Images
Figure CN116830419B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a system for wirelessly charging a battery of a portable device and a power device. The power device includes an antenna for emitting a magnetic field with a carrier frequency to power the portable device. The portable device includes an antenna exposed to the magnetic field and the antenna is connected via a matching stage to a rectifier stage to rectify the antenna signal. The portable device also includes a charging stage for sensing and limiting the rectified antenna signal. An input voltage is provided at an input pin of a charger IC of the portable device. The charger IC provides a first charging current at an output pin connected to the battery. The battery is charged for a first time period with a constant first charging current as a power source. The portable device includes a detuning stage for changing the resonant frequency of the antenna of the portable device, and the charging stage is configured to limit the input voltage of the charger IC by manipulating the detuning stage to detune the resonant frequency of the antenna of the portable device away from the carrier frequency of the magnetic field. Background Technology
[0002] Wireless charging is used for a variety of portable devices, such as mobile phones or headphones. The portable device simply needs to be placed near a power source, which generates and radiates a magnetic field through its antenna. The advantage is that no wires are needed to charge the portable device. In some such systems, the power source only radiates the magnetic field, and some newer systems include a feedback loop from the portable device to the power source to modulate the power of the magnetic field.
[0003] Figure 1 A system is shown that includes an electrical device 1 and a portable device 2 with a battery 3, as is known to those skilled in the art. For example, the NFC Forum... TM This system is described in technical specification version 1.0. The power device 1, referred to as a "poller," includes an antenna 4 that radiates a magnetic field with a carrier frequency of 13.56 MHz. The portable device 2, referred to as a "listener," includes an antenna 5 exposed to the magnetic field emitted by the power device 1. A matching circuit 15 matches the impedance of the output pin of antenna 5 to the input pin of rectifier 6, which uses a bridge rectifier to rectify the antenna signal and provide a DC voltage. The charging stage 7 of the portable device 2 is used to charge the battery 3. The charging stage 7 requires a power voltage of 5V + / - 10% as its input voltage U. I The charger IC 8, so the DC / DC converter and limiter 9 are used to sense the DC voltage provided by the rectifier 6 to limit it, and provide an appropriate input voltage U at the input pin 10 of the charger IC 8. I .
[0004] Battery 3 needs to be charged by charging stage 7 at different charging currents I. CA lithium-ion battery that is charged with a charging voltage at different time intervals. The charging stage 7 also includes a digital control stage 13, which receives an input voltage U at input pin 10. I And / or the charging current I used to charge battery 3 C In cases where the power level is too low or too high, power adjustment information 16 is generated. This power adjustment information 16 is provided by the digital control level 13 to the Cless communication level 14, which follows the NFC communication protocol to transmit the power adjustment information 16 to the power device 1. Utilizing this feedback loop from the portable device 2 to the power device 1, the charging level 7 can request more or less power from the magnetic field provided by the power device 1.
[0005] Figure 2 The charging current I is shown during two different time periods T1 and T2 when battery 3 is loaded. C Timeline. Figure 2 It also shows the constant first charging current I during the time periods T1 and T2 when battery 3 is loaded, and from the first time period T1. C The higher constant second charging current I during the second time period T2 C The actual battery voltage U during the ramp-up period TR. BAT The input voltage U at pin 10 of charger IC 8 I . Figure 2 It also shows that in portable device 2, power P is generated from a magnetic field to power battery 3. L The power P L It can be approximated as P L =U I *I C ,and Figure 2 This shows the electric current P generated by electrical device 1 in a magnetic field. P . Figure 2 The bottom box shows power adjustment information 16 from portable device 2 to power device 1, used to increase the power P generated by power device 1 in the magnetic field at the end of time period T1. P .
[0006] like Figure 2 As shown, during the first time period T1, the charger IC 8 charges with a constant first charging current I. C Load battery 3 until U BAT A specific voltage is reached. From that time onwards, a higher second charging current I can be applied during the second time period T2. C Load lithium-ion battery 3 until U BAT The target voltage is reached, and during the third time period, the charging stage switches to constant voltage charging. At the end of the first time period T1, the charging current I of charging stage 7 ramps up. CThis will generate power P in portable device 2 L Insufficient to achieve a high second charging current I during the second time period T2 C Reduce input voltage U when battery 3 is loaded I Therefore, the charging stage 7 sends power adjustment information 16 to the power device 1 to increase the power P generated by the power device 1 in the magnetic field. P Because this feedback loop requires some time to activate the charger IC 8, the input voltage U... I Further decline and reach V 复位充电器 Voltage level, which causes charger IC 8 to malfunction due to input voltage U I The power is cut off and reset due to excessively low voltage. Therefore, the charging of battery 3 is interrupted for a short period of time, which can be seen from the charging current I at the beginning of the transition period TR. C This is a drawback, as can be seen from the decline.
[0007] Due to the advance communication of power adjustment information 16, power equipment 1 increases its output power P at the start of the transition period TR. P In portable device 2, this increased power P L This causes the junction temperature TL to rise because the high power must be consumed internally until the charging state leaves the reset state and reaches its second high charging current I. C The point is that after the transition time TR, the junction temperature TL within portable device 2 will decrease again because most of the power is delivered to battery 3. The high junction temperature TL during the transition period TR can cause problems because it may exceed the maximum permissible junction temperature TL of portable device 2, which is a drawback.
[0008] US 2017 / 0025897A1 discloses a system for a power device and a portable device, wherein the power device is configured to wirelessly charge the battery of the portable device. The portable device includes a charger stage for charging the battery using energy from a rectified antenna signal from the portable device's antenna. For maximum power transfer, a matching stage resonantly tunes the antenna, and the charging stage is configured to manipulate a detuning stage to detune the portable device's antenna away from the carrier frequency of the magnetic field, thereby limiting the rectified antenna signal as the input voltage of the charger stage. A drawback of this known system is that the portable device can only detune the antenna to reduce the power transferred from the power device, but may not request more power if a battery charging is required.
[0009] US 2019 / 334367 A1 discloses a system similar to the one described above, but with more than one receiver. Several of these receivers receive power wirelessly and simultaneously charge the battery of a portable device with even greater power.
[0010] US 2018 / 272130 A1 discloses a system in which a receiver sends a request to interrupt power transmission at an electrical device in the event of detuning.
[0011] In addition, WO 2015 / 080517 A1 and US2019 / 097448 A1 disclose wireless charging of batteries. Summary of the Invention
[0012] The purpose of this invention is to provide a system for a power device and a portable device with a charger IC for wirelessly charging the battery of the portable device to avoid a significant increase in the junction temperature TL of the portable device during the transition period TR.
[0013] This objective is achieved in the system according to claim 1.
[0014] This invention enables portable devices to dynamically change the resonant frequency of their antennas to draw more or less power from the magnetic field generated by the power source during battery charging. Since the amount of power required to charge the battery is drawn primarily from the magnetic field during different charging phases, less or no waste power is converted into heat in the portable device. Furthermore, PCB size can be reduced because such a low temperature coefficient is not required for heat removal compared to existing solutions.
[0015] A feedback loop can manipulate electrical devices to generate more or less power in a magnetic field. Because the feedback loop requires some time to affect the generation of more or less power (P) within a portable device... L Therefore, a major advantage of the detuning provided by the present invention is the dynamic reduction of the power obtained from the magnetic field during the change of power in the magnetic field.
[0016] These and other aspects of the invention will be apparent from and set forth in the embodiments described below. Those skilled in the art will understand that various embodiments can be combined. Attached Figure Description
[0017] Figure 1 A system known to those skilled in the art is shown, comprising a power device and a portable device with a charger IC for wirelessly charging a battery.
[0018] Figure 2 Shown to the basis Figure 1 A time-varying graph of the charging current and other parameters of the battery charging of a portable device in the system.
[0019] Figure 3A system according to the invention is shown, comprising an electrical device and a portable device with a detuning stage for wirelessly charging a battery.
[0020] Figure 4 Shown to the basis Figure 3 A time-varying graph of the charging current and other parameters of the battery charging of a portable device in the system. Detailed Implementation
[0021] Figure 3 A first embodiment of a system 17 comprising a power device 1 and a portable device 18 with a battery 3 according to the present invention is shown. The same reference numerals are used for those having features known to those skilled in the art. Figure 1 The same technical function as described in the system is used in the charging stage 20. The power device 1, referred to as the "poller," includes an antenna 4 that radiates a magnetic field at a frequency of 13.56 MHz. The power device 1 can be a charging device connected to the power grid or powered by a battery pack. The portable device 18, referred to as the "listener," includes an antenna 5 exposed to the magnetic field emitted by the power device 1. The portable device 18 can be any device, such as a headset or mobile phone with a wireless interface and a battery 3. Matching circuit 15 matches the impedance of the output pin of antenna 5 to the input pin of rectifier 6 via detuning stage 19. Rectifier 6 uses a bridge rectifier to rectify the antenna signal and provides a DV voltage as the input voltage at charging stage 20. Since charging stage 20 includes a power supply voltage requiring 5V + / - 10% as the input voltage U... I The charger IC 8 uses a voltage limiter 21 to sense and limit the DC voltage provided by the rectifier 6 to provide an appropriate input voltage U at the input pin 10 of the charger IC 8. I .
[0022] Battery 3 needs to be charged by charging stage 20 at different times with different charging currents I. C A lithium-ion battery that is charged with a charging voltage. The charging stage 20 also includes a digital control stage 24, which receives an input voltage U at input pin 10. I And / or the charging current I used to charge battery 3 C In cases where the power level is too low or too high, power adjustment information 16 is generated. This power adjustment information 16 is provided by the digital control level 24 to the Cless communication level 14, which follows the NFC communication protocol to transmit the power adjustment information 16 to the power device 1. Utilizing this feedback loop from the portable device 18 to the power device 1, the charging level 20 can request more or less power from the magnetic field provided by the power device 1.
[0023] like Figure 4As shown, during the first time period T1, battery 3 is charged by charger IC8 with a constant first charging current I. C Loading is performed, and the first charging current I C Approximately the maximum charging current I required for a specific battery 3 C 10%, until U BAT A specific voltage is reached. From this point onward, during the second time period T2, a higher second charging current I can be achieved. C Lithium-ion battery 3 is loaded, and the second charging current I is applied. C Approaching the maximum charging current I to be used for a specific battery 3 C 100%, until U BAT The target voltage is reached. From this point onward, during the third time period, the load is switched to constant voltage charging, and the charging current I... C The charging current automatically decreases based on the battery's charging conditions until the charger stops charging, for example, when the charging current has decreased to 10% of the maximum charging current. The principle of loading a lithium-ion battery during these time periods is known to those skilled in the art.
[0024] At the end of the first time period T1, the charging stage 20 causes the charging current I to... C The inclined plane will generate power P in portable device 2. L Insufficient to achieve a high second charging current I during the second time period T2 C Reduce input voltage U when battery 3 is loaded I Therefore, the charging stage 20 sends power adjustment information 16 to the power device 1 to increase the power P generated by the power device 1 in the magnetic field. P Because the feedback loop takes some time, the input voltage U... I Further decline and reach V 复位充电器 Voltage level, which causes the charger IC to be affected by the input voltage U I If the temperature drops too low and a power-off reset occurs, this will raise the junction temperature TL because no power is being used to charge the battery 3 and all the power generated by P will be used to recharge it. L All of these must be converted to heat. To prevent this, the digital control level 24 is constructed to utilize... Figure 4 The detuning information D shown I The detuning stage 19 is manipulated to change the resonant frequency of the antenna of the portable device 18, and is thus configured to limit power P by detuning the resonant frequency of the antenna 5. L and the input voltage U of charger IC 8 IThe detuning stage 19 may include one or more discrete capacitors connected in parallel with the matching stage 15 and the antenna 5, which are switched and change the resonant frequency of the antenna 5. Therefore, the detuning stage 19 includes at least two tuning configurations: in a first tuning configuration, the resonant frequency of the antenna 5 is tuned to a carrier frequency closer to or more precisely to the magnetic field generated by the power device 1; in a second tuning configuration, a carrier frequency further away from the magnetic field than the resonant frequency of the antenna 5 is provided, resulting in a higher power PL and thus a higher input voltage U at the input pin 10 of the charger IC8. I .
[0025] Due to the advance communication of power adjustment information 16, power equipment 1 will increase its output power P. P On the two sides of the portable device, this high-power P L This will cause the junction temperature TL to rise. To overcome this problem, the detuning stage 19 changes the resonant frequency of the portable device 2 to a frequency far removed from the system resonant frequency, and the input power P L The current will be reduced until charging stage 20 leaves the reset state and reaches its second charging current I, which switches back to high. C At that point in time, digital control level 24 is configured to utilize the detuning information D. I By manipulating the detuned stage 19, the resonant frequency is changed back to the optimal value for power transmission. Through this detuning and retuning during the transition time TR, the system 17 can overcome the problem of high junction temperature TL.
[0026] In the same or another embodiment of the invention, the charging stage 20 includes a temperature sensor, and wherein the charging stage 20 is configured to manipulate the detuning stage 19 to detune the resonant frequency of the antenna 5 of the portable device 18 away from the carrier frequency of the magnetic field generated by the power device 1 if the sensed temperature TL reaches a maximum temperature limit. In this embodiment, the detuning stage 19 is used to ensure that the portable device 18 and / or the charger IC 8 are prevented from overheating to avoid damage. As a possible next step, if the detuning stage 19 must detune the resonant frequency of the antenna 5 of the portable device 18 to reduce the sensed temperature T... L Then, charging stage 20 can generate power adjustment information 16 for power device 1 to reduce the power of the magnetic field. In another embodiment of the invention, if detuning stage 19 must detune the resonant frequency of antenna 5 of portable device 18 to reduce the input voltage U at input pin 10 of charger IC 8... I Then, power adjustment information 16 is generated for power equipment 1 to reduce the power of the magnetic field.
[0027] In another embodiment not covered by this invention, two or more portable devices of the system are exposed to the magnetic field of power device 1 to load the batteries of these portable devices. Since all these portable devices may enter the magnetic field at different times, and all their batteries may be under different charging conditions, the feedback loop described above with power adjustment information 16 from the portable devices cannot increase or decrease the power P generated by power device 1 in the magnetic field. P Therefore, portable devices must handle the electricity P generated by electrical device 1 as is. P To achieve this, a method can be used where the charger IC 8 uses a first charging current I. C When charging battery 3, the detuning stage causes the resonant frequency of antenna 5 of the portable device to detune from the carrier frequency of the magnetic field, and the charger IC 8 charges at a current higher than the first charging current I. C The second charging current I C When charging battery 3, the resonant frequency of antenna 5 of portable device 18 is tuned to the carrier frequency of the magnetic field. It is assumed that for a typical charging cycle of battery 3, battery 3 is never depleted to the point that it must be charged with a low initial charging current I. C If charging is performed for a long time, the electrical equipment may already be at a high power level (P). P The state begins, and during the first time period T1, the portable device 2 is detuned to the second tuning configuration from the start. When the digital control stage 24 switches to a high second charging current Ic at the end of the first time period T1, the digital control stage 24 only needs to switch the detuned stage 19 to the tuned first tuning configuration state, and thus the system 17 can overcome the reset of the charger IC 8 and can shorten the transition time TR without any temperature issues.
Claims
1. A system (17) for wirelessly charging a battery (3), the system (17) comprising a power device (1) and a portable device (18), wherein the portable device (18) includes the battery (3) and the power device (1) is configured to wirelessly charge the battery, wherein the power device (1) includes a first antenna (4) configured to transmit a magnetic field having a carrier frequency to power the portable device (18), and wherein the portable device further includes a second antenna (5), a matching stage, a rectifier stage and a charging stage, wherein the charging stage is configured to sense and limit the rectified antenna signal, and further includes a charger IC, the charger IC including an input pin connected to the rectifier stage and an output pin connected to the battery, wherein the antenna of the portable device is configured to be exposed to the magnetic field and via The matching stage (15) is connected to the rectifier stage (6) to rectify the antenna signal, providing an input voltage at the input pin (10) of the charger IC (8), wherein the charger IC (8) is configured to provide a first charging current at the output pin as a power source to charge the battery (3) for a first time period (T1) with a constant first charging current, and wherein the portable device (18) includes a detuning stage (19) for changing the resonant frequency of the second antenna (5) of the portable device (18), and the charging stage (20) is configured to limit the input voltage of the charger IC (8) by manipulating the detuning stage (19) to detune the resonant frequency of the second antenna (5) of the portable device (18) away from the carrier frequency of the magnetic field, wherein the system (17) is characterized in that... The system (17) includes a unique portable device, wherein the power device (1) is configured to receive and process power adjustment information (16) from the unique portable device (18) exposed to the magnetic field to increase or decrease the power of the magnetic field emitted by the first antenna (4) of the power device (1), and wherein the charging stage (20) of the portable device (18) is configured to generate the power adjustment information (16) for causing the power device (1) to increase or decrease the power of the magnetic field to manipulate the input voltage of the charger IC (8) within the voltage range of the charger IC (8)'s specifications, and wherein The portable device (18) is configured to provide a second charging current at the output pin of the charger IC (8) to charge the battery (3) for a second time period (T2) with a constant second charging current higher than the first charging current, and to provide sufficient power for ramping from the first charging current to the second charging current. The charging stage (20) is configured to send power adjustment information (16) to the power device (1) to increase the power of the magnetic field, and simultaneously detun the second antenna (5) during the ramping time period (TR) to avoid the sensed temperature (TL) from reaching the maximum temperature limit.
2. The system (17) of claim 1, wherein the detuning stage (19) includes at least two tuning configurations to tune the resonant frequency of the second antenna (5) to a carrier frequency closer to the magnetic field in a first tuning configuration to provide a higher input voltage at the input pin (10) of the charger IC (8) compared to a second tuning configuration in which the resonant frequency of the antenna is further away from the carrier frequency of the magnetic field.
3. The system (17) according to claim 1 or 2, wherein the charging stage (20) includes a temperature sensor, and wherein the charging stage (20) is configured to manipulate the detuned stage (19) to detune the resonant frequency of the second antenna (5) of the portable device (18) away from the carrier frequency of the magnetic field if the sensed temperature (TL) reaches a maximum temperature limit.
4. The system (17) according to claim 1, wherein the charging stage (20) is configured to generate power adjustment information (16) for the power device (1), and to reduce the power of the magnetic field if the detuning stage (19) must detune the resonant frequency of the second antenna (5) of the portable device (18) to reduce the input voltage at the input pin (10) of the charger IC (8).
5. The system (17) of claim 2, wherein the portable device (18) is configured to provide a second charging current at the output pin of the charger IC (8) to charge the battery (3) for a second time period (T2) with a constant second charging current higher than the first charging current, and to provide sufficient power to ramp up from the first charging current to the second charging current, and the charging stage (20) is configured to switch the detuned stage (19) from the second tuning configuration to the first tuning configuration at the end of the first time period (T1).
6. The system (17) according to any one of claims 1 to 5, wherein the power device (1) includes a battery power supply configured to provide power to other components of the power device (1).
7. A method of wirelessly charging a battery (3) of a portable device (18) by a power device (1) and the portable device (18) using the system (17) according to any one of claims 1 to 6, characterized in that, The detuning stage (19) changes the resonant frequency of the second antenna (5) of the portable device (18) to a carrier frequency that is far from the magnetic field, thereby limiting the input voltage of the charger IC (8).
8. The method of claim 7, wherein, If the sensed temperature (TL) reaches the maximum temperature limit, the resonant frequency of the second antenna (5) of the portable device (18) is detuned away from the carrier frequency of the magnetic field.
9. The method according to claim 7 or 8, characterized in that, While the charger IC (8) charges the battery (3) with a first charging current, the resonant frequency of the second antenna (5) of the portable device (18) is detuned away from the carrier frequency of the magnetic field, and while the charger IC (8) charges the battery (3) with a second charging current higher than the first charging current, the resonant frequency of the second antenna (5) of the portable device (18) is tuned to the carrier frequency of the magnetic field.