Receiver detection in wireless power transmission

Abstract

Systems and methods for wireless power transfer systems are described. A wireless power transmitter can be used to perform frequency scanning of its transmitting coil at multiple frequencies. These multiple frequencies may include the resonant frequency of a detection capacitor connected in parallel with the receiving coil in a wireless power receiver. The wireless power transmitter can be used to determine the presence of a wireless power receiver in a charging region connected to the wireless power transmitter based on the phase response of the frequency scan.

Description

Background Technology

[0001] This disclosure generally relates to apparatus and methods for receiver detection in wireless power transmission.

[0002] A wireless power system may include a transmitter with a transmitting coil and a receiver with a receiving coil. The transmitting and receiving coils may be positioned close to each other to form a transformer that enables the inductive transfer of alternating current (AC) power. The receiver may include a rectifier circuit that converts AC power into direct current (DC) power for use by various loads or components that require DC power to operate. Summary of the Invention

[0003] In one embodiment, a semiconductor device for wireless power transfer is generally described. A controller can be used to perform frequency scanning of the transmitting coil of a wireless power transmitter at multiple frequencies. The multiple frequencies may include the resonant frequency of a detection capacitor connected in parallel with the receiving coil in a wireless power receiver. The controller can also be used to determine, based on the phase response of the frequency scan, the presence of a wireless power receiver in a charging region connected to the wireless power transmitter.

[0004] In one embodiment, a device for wireless power transfer is generally described. The device may include a transmitter and a controller. The transmitter may include a transmitting coil and a primary capacitor connected in series with the transmitting coil. The transmitting coil and the primary capacitor may form an LC resonant circuit. The controller may be used to perform frequency scanning of the LC resonant circuit at multiple frequencies. The multiple frequencies may include the resonant frequency of a detection capacitor connected in parallel with a receiving coil in a wireless power receiver. The controller may be used to determine, based on the phase response of the frequency scan, the presence of a wireless power receiver in a charging region connected to the transmitter.

[0005] In one embodiment, a method for wireless power transfer is generally described. The method may include performing a frequency scan of the transmitting coil of a wireless power transmitter at multiple frequencies. The multiple frequencies may include the resonant frequency of a detection capacitor connected in parallel with a receiving coil in a wireless power receiver. The method may also include determining the presence of a wireless power receiver in the charging region of the wireless power transmitter based on the phase response of the frequency scan.

[0006] More features, as well as the structure and operation of various embodiments, are described in detail below with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similarly functional elements. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating an example system for implementing receiver detection in wireless power transmission in one embodiment.

[0008] Figure 2A This is a schematic diagram illustrating an example implementation of receiver detection in wireless power transmission in one embodiment.

[0009] Figure 2B This is a schematic diagram illustrating an example phase response of an implementation of receiver detection in wireless power transmission in one embodiment.

[0010] Figure 2C This is a schematic diagram illustrating another example of the phase response of an implementation of receiver detection in wireless power transmission in one embodiment.

[0011] Figure 3 This is a schematic diagram illustrating an adaptive implementation of receiver detection in wireless power transmission in one embodiment.

[0012] Figure 4 This is a schematic diagram illustrating an embodiment that combines high-power technology with receiver detection in wireless power transmission.

[0013] Figure 5 This is a flowchart illustrating the process of implementing receiver detection in wireless power transmission in one embodiment. Detailed Implementation

[0014] The following description sets forth numerous specific details, such as particular structures, components, materials, dimensions, processing steps, and techniques, to facilitate understanding of the various embodiments of this application. However, those skilled in the art will understand that the various embodiments of this application can be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail to avoid obscuring the content of this application.

[0015] Figure 1 This is a schematic diagram illustrating an example system 100 for implementing receiver detection in wireless power transmission in one embodiment. System 100 may include a transmitter 110 and a receiver 120 for wirelessly transmitting electrical power and data between them via inductive coupling. Although described herein as transmitter 110 and receiver 120, each of transmitter 110 and receiver 120 can be used to receive or transmit electrical power or data between them via inductive coupling.

[0016] Transmitter 110 is used to receive electrical energy from one or more power sources and wirelessly transmit AC power 130 to receiver 120. For example, transmitter 110 can be used to connect to power source 116 such as an AC power source or a DC power source. Transmitter 110 may include controller 112 and analog front end (AFE) 118. AFE 118 may include various analog circuits and integrated circuits (ICs), such as driver circuitry or driver 114 for driving the coil TX of transmitter 110.

[0017] Controller 112 can be used to control and operate AFE 118. Controller 112 may include, for example, at least one processor (e.g., processor 154), a central processing unit (CPU), a field-programmable gate array (FPGA), or any other circuitry for controlling and operating power driver 114. Controller 112 may also include at least one memory device, such as read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), or other types of memory devices. Controller 112 may include any other circuitry for controlling and operating various operational components of transmitter 110. In an example embodiment, controller 112 can be used to control power driver 114 to drive coil TX to generate a magnetic field. The power driver 114 can be used to drive the coil TX in accordance with the frequency range and configuration defined by the wireless charging standard, such as the Wireless Power Consortium (Qi) standard, the Power Matters Alliance (PMA) standard, the Alliance for Wireless Power (A for WP or Rezence) standard, or any other wireless charging standard.

[0018] Receiver 120 can be used to receive AC power 130 transmitted from transmitter 110 and provide that power to one or more loads 126 or other components of target device 140. Load 126 may include, for example: a battery charger for charging the battery of target device 140; a DC-DC converter for powering the processor, display, or other electronic components of target device 140; or any other load of target device 140. Target device 140 may include, for example, a computing device, mobile device, mobile phone, smart device, tablet computer, wearable device, or any other electronic device for wirelessly receiving power. In an example embodiment, target device 140 may include receiver 120. In other embodiments, receiver 120 may be detachable from target device 140 and connected to target device 140 via wires or other components for providing power to target device 140.

[0019] Receiver 120 may include controller 122 and power rectifier 124 (“rectifier 124”). Controller 122 may include, for example, at least one processor, CPU, FPGA, or any other circuitry that can be used to control and operate power rectifier 124. Controller 122 may also include at least one memory device, such as ROM, RAM, EEPROM, or other types of memory devices. Power rectifier 124 includes a coil RX and is used to rectify the electrical energy received through the coil RX to the type of electrical energy required by load 126. Power rectifier 124 is used to rectify the AC electrical energy received from the coil RX into DC electrical energy 132, which is then supplied to load 126. In one embodiment, power rectifier 124 may be part of the AFE of receiver 120. Power rectifier 124 may help drive the coil RX to transmit signals of encoded messages to the coil TX of transmitter 110.

[0020] As an example, when receiver 120 is placed near transmitter 110, the magnetic field generated by coil TX of power driver 114 induces a current in coil RX of power rectifier 124. This induced current causes AC power 130 to be transferred from power driver 114 to power rectifier 124. Power rectifier 124 receives AC power 130 and converts it into DC power 132. DC power 132 is then supplied by power rectifier 124 to load 126.

[0021] Transmitter 110 and receiver 120 are also used to exchange information or data, such as messages, via the inductive coupling of power driver 114 and power rectifier 124. For example, before transmitter 110 begins transmitting power to receiver 120, receiver 120 and transmitter 110 may negotiate and establish a power protocol. For example, receiver 120 may send communication data packet 136 or other data to transmitter 110 to indicate power transmission information, such as the amount of power to be transmitted to receiver 120, instructions to increase / decrease or maintain the power level of AC power 130, instructions to stop power transmission, or other power transmission information. In another example, in response to receiver 120 being close to transmitter 110, such as to the extent that coils TX and RX constitute a transformer to facilitate power transmission, receiver 120 may be used to initiate communication by sending a signal requesting power transmission to transmitter 110. In this case, transmitter 110 may respond to receiver 120's request by establishing a power protocol or by beginning power transmission to receiver 120. For example, if an electrical protocol has been established, transmitter 110 and receiver 120 can transmit and receive communication data packets, data, or other information via inductive coupling of coils TX and RX.

[0022] On one hand, the coil TX and primary capacitor Cp in transmitter 110 can form a primary LC resonant circuit. The coil RX and secondary capacitor Cs in receiver 120 can form a secondary LC resonant circuit. The primary LC resonant circuit in transmitter 110 and the secondary LC resonant circuit in receiver 120 can resonate at the same resonant frequency. Receiver 120 may include a detection LC resonant circuit composed of coil RX and detection capacitor Cd. The resonant LC circuit composed of coil RX and coil Cd can resonate at a frequency different from the resonant frequencies of the primary and secondary LC resonant circuits. As an example, the primary and secondary LC resonant circuits can resonate at 100 kHz, while the detection LC resonant circuit can resonate at 1 MHz. The secondary LC resonant circuit in receiver 120 can receive AC power 130 supplied by transmitter 110 (through the primary LC resonant circuit). The detection LC resonant circuit in receiver 120 can be used for detection and communication. Therefore, the secondary LC resonant circuit in receiver 120 and the detection LC resonant circuit have different resonant frequencies. On the one hand, the bandwidth of the detection LC resonant circuit is greater than that of the secondary LC resonant circuit in order to generate effective data communication packets.

[0023] Transmitter 110 may be connected to charging dock surface 150. Charging dock surface 150 may include charging area 152. Coil TX may be disposed adjacent to charging area 152 such that a receiver (e.g., receiver 120) placed on charging area 152 may receive AC power 130 from transmitter 110. Transmitter 110 may be used to monitor charging area 152 of charging dock surface 150 to detect whether an object is placed on or removed from charging area 152. Transmitter 110 may also be used to determine whether an object placed on charging area 152 is a foreign object or a wireless power receiver.

[0024] On one hand, when an object is placed on the charging area, the wireless power transmitter can determine whether the object is a foreign object or a wireless power receiver. Some techniques used for this determination may include low-power techniques, such as Q-factor (quality factor) detection. The Q-factor can be a parameter indicating the losses of a metallic structure at its resonant frequency. Q-factor detection may involve the wireless power transmitter sending a low-power signal to the object and using envelope detection techniques on the response from the object to determine the object's Q-factor. However, various metallic objects and coils, such as the receiving coil of a wireless power receiver, may have similar Q-factor values. Therefore, if the object is metallic, the wireless power transmitter may misjudge that a wireless power receiver is placed on the charging area. Furthermore, the low-power signal used in Q-factor detection may not be sufficient to wake up the wireless power receiver.

[0025] Another technique for determining whether an object is a foreign object or a wireless power receiver may include digital ping. Digital ping may involve sending a high-power signal to the object, strong enough to wake up the wireless power receiver. If the object is a foreign object, it will not respond to the high-power signal. If the object is a wireless power receiver, it will be woken up and send a response or data packet to the wireless power transmitter. The wireless power transmitter can receive this response and determine that the object is a wireless power receiver. However, in low-power applications, the high-power signal of digital ping can quickly deplete the transmitter's battery. Furthermore, certain energy levels in the high-power signal can sometimes cause other metal components in the wireless power receiver to overheat.

[0026] Another technique for determining whether an object is a foreign object or a wireless power receiver can include the use of a Hall effect sensor. A Hall effect sensor is a magnetic sensor that detects the strength and direction of a magnetic field generated by a permanent magnet or electromagnet, and its output changes proportionally to the detected magnetic field strength. Hall effect sensors can be attached to or integrated into a wireless power transmitter so that the transmitter can detect the presence of a wireless power receiver. However, when using a Hall effect sensor, the transmitter of the wireless power transmitter needs to be turned off to save power. Furthermore, Hall sensors occupy circuit board space and incur additional cost.

[0027] To address the shortcomings of conventional technologies (the aforementioned and other conventional technologies not mentioned herein), transmitter 110 can be used to determine whether an object placed on charging region 152 is a foreign object or a wireless power receiver by detecting the presence of a detection capacitor Cd in receiver 120. Transmitter 110 can perform a frequency scan within a frequency range including the resonant frequency of the detection capacitor Cd. Transmitter 110 can analyze the phase response obtained from the frequency scan to determine the presence of the detection capacitor Cd in charging region 152. The frequency scan can be performed periodically and continuously to monitor changes in charging region 152 and detect the presence of a wireless power receiver on charging region 152. Since foreign objects do not possess the ability to detect the presence of a wireless power receiver at resonant frequency f... Cd The transmitter 110 uses a resonant detection capacitor, allowing it to distinguish between foreign objects and the wireless power receiver by detecting the presence of Cd. Furthermore, the transmitter 110 can perform frequency scanning at any time without shutting down. Moreover, the transmitter 110 can combine frequency scanning with one or more conventional techniques to achieve multi-level verification and detection of the wireless power receiver.

[0028] Figure 2A This is a schematic diagram illustrating an example implementation of receiver detection in wireless power transmission in one embodiment. Figure 2A The description can be found in [reference]. Figure 1 The components shown are described. To perform frequency scanning, the controller 112 of transmitter 110 can generate a control signal (e.g., a pulse width modulation (PWM) signal) to control driver 114 to drive or excite the primary LC resonant circuit composed of coils TX and Cp. Driver 114 can apply a scanning voltage V. sweep To excite the primary LC resonant circuit, the scanning voltage uses different frequencies within the range of frequency f1 to frequency f2. The resonant frequency f... Cd It can be greater than f1 and less than f2. It should be noted that the frequency range {f1:f2} does not include the resonant frequency of the primary LC resonant circuit in transmitter 110 and the secondary LC resonant circuit composed of coils RX and Cs in receiver 120.

[0029] Exciting the primary LC resonant circuit can cause the current (e.g., the coil current I) to... ac The current flows through the primary LC resonant circuit, via coils TX and Cp, from node AC1 to node AC2. If there is a foreign object in charging region 152, or if there is no object in charging region 152, then for the target frequency range, I... ac The phase and the voltage difference V between nodes AC1 and AC2 acThe phase difference between the phases is approximately -90 degrees. If a wireless power receiver (e.g., receiver 120) is present on the charging area 152, the coil current I of coil TX will... ac At the resonant frequency f Cd A phase change occurs at f because a capacitor Cd present in the charging region 152 is detected to be at f Cd The current I flowing through the primary LC resonant circuit ac A reaction occurs and resonance occurs.

[0030] exist Figure 2A The example shown illustrates the phase response 202 for a frequency sweep performed over the frequency range {f1:f2} in two scenarios: 1) no coil; 2) presence of coil RX. The phase response 202 can show the phase I under both scenarios. ac θ(I ac ) and phase V ac θ (V) ac The relationship between the phases, such as the phase difference Δθ, is shown. The phase response 202 can show the phase difference at different frequencies within the frequency range {f1:f2}. When the coil RX is absent, I... ac With V ac The phase difference Δθ between them can be -90 degrees or close to -90 degrees. When coil RX is present, in a phase relatively close to f... Cd At the frequency, I ac With V ac The phase difference Δθ between the phases will decrease. The resonant frequency f of the capacitor Cd is detected. Cd The phase drop at that point can cause Δθ (when RX is present) to produce a peak value of 204. Figure 2A In the phase response 202 shown, at the resonant frequency f Cd At this point, when RX is present, the phase difference Δθ can change from approximately -90 degrees to approximately -36 degrees (for example, a change toward zero degrees indicates a phase drop at AC2).

[0031] Controller 112 can analyze phase response 202 and determine whether there is a peak in the current at node AC2 in phase response 202. The absence of a peak in the phase difference Δθ indicates that no object is present at f. Cd The phase difference Δθ at a specific frequency indicates the presence of an object in the charging region 152, and that the object resonates at that specific frequency. As an example, in response to the receiver 120 and / or the detection capacitor Cd being located within the charging region 152, the phase response 202 will show a peak at f... Cd place or f Cd A peak value 204 appears nearby. In response to the presence of peak value 204 in phase response 202, controller 112 can determine that an object on charging region 152 is at f CdThe object that resonates at the point of contact can be the detection capacitor Cp of receiver 120. Therefore, transmitter 110 can detect the presence of the detection capacitor of wireless power receiver or the wireless power receiver itself on charging region 152 by analyzing the phase response obtained from the frequency scan.

[0032] In one embodiment, the controller 112 can detect whether a peak value detected in the phase difference Δθ exceeds a phase drop threshold. If the peak value does not exceed the phase drop threshold, the controller 112 can determine that the detection capacitor Cd is not present in the charging region 152. If the peak value exceeds the phase drop threshold, the controller 112 can determine that the detection capacitor Cd is present in the charging region 152. The phase drop threshold can be arbitrarily set and can be programmed in the controller 112 to adjust the sensitivity of Cd detection.

[0033] In one embodiment, voltage V sweep The voltage level may be insufficient to wake up receiver 120 or to turn on rectifier 124. Therefore, voltage V sweep The load equivalent resistance Rleq of rectifier 124, which is connected in parallel with Cd and spans between nodes AC1' and AC2', can be selected or programmed. On the one hand, the load equivalent resistance Rleq will still exist even if rectifier 124 remains in an unawakable state (e.g., ideally rectifier 124 could be completely turned off, but this is practically impossible). Therefore, a smaller V... sweep While minimizing the effect of Rleq can increase the difficulty of resolution, it may also reduce the overall impact. On one hand, Rleq can act as a damping resistor. For example, Figure 2A The phase response 202 shown corresponds to Rleq = 4000 ohms. Figure 2B The phase response shown corresponds to Rleq = 700 ohms. Figure 2C The phase response shown corresponds to Rleq = 400 ohms. Figure 2B The peak value of 220 can be less than the peak value of 204. Figure 2C The peak value of 222 in the phase response can be less than the peak value of 220. Therefore, in the phase response at f Cd The nearby peak value will increase or become more significant as Rleq increases. In one embodiment, the controller 112 can obtain f Cd And the value of Rleq. Controller 112 can utilize the known f Cd The value of Rleq determines V. sweep .

[0034] Figure 3 This is a schematic diagram illustrating an adaptive implementation of receiver detection in wireless power transmission in one embodiment. Figure 3 The description can be found in [reference]. Figures 1 to 2CThe components are shown. In one embodiment, controller 112 may adaptively execute different techniques other than frequency scanning to detect a wireless power receiver on charging area 152 based on detection success rate and / or power consumption. Controller 112 may monitor the detection success rate of the wireless power receiver and determine, based on the success rate, which technique to use to detect the presence of the wireless power receiver.

[0035] As an example, controller 112 continuously monitors charging area 152 to determine the presence of a wireless power receiver on charging area 152. Controller 112 may record a success rate, such as the number of times a wireless power receiver is correctly detected. Controller 112 may also record the number of times an object is falsely detected as a wireless power receiver. The success rate may be the ratio of the number of times a wireless power receiver is correctly detected to the number of times an object is falsely detected as a wireless power receiver. If the success rate is below a preset threshold, controller 112 may perform one or more additional techniques to detect a wireless power receiver on charging area 152 in addition to frequency scanning. In one embodiment, if the success rate is below the preset threshold, controller 112 may employ low-power techniques, such as Q-factor detection, or schedule the execution of low-power techniques between multiple frequency scans.

[0036] The controller 112 can also monitor the power consumption of the transmitter 110. If the power consumption exceeds a preset threshold, the controller 112 can perform low-power techniques, such as Q-factor detection, outside of frequency scanning to detect the wireless power receiver on the charging area 152. If the power consumption is less than the preset threshold, the controller 112 can perform high-power techniques, such as digital ping, outside of frequency scanning to detect the wireless power receiver on the charging area 152.

[0037] Figure 3 An example process 300 is shown. A controller 112 can be used to execute process 300 to determine a technique for detecting Cd that can be used in conjunction with frequency scanning techniques, based on the power consumption of the transmitter 110 and / or the success rate of wireless power receiver detection. The controller 112 can execute process 300 iteratively and periodically (e.g., at time T). N (Execute the Nth iteration). Process 300 may begin at block 302. In block 302, controller 112 may set the iteration index N to an initial value, such as N=1.

[0038] Process 300 can proceed from block 302 to block 304. In block 304, controller 112 can supply V to the primary LC resonant circuit consisting of coil TX and primary capacitor Cp. sweepTo perform a frequency scan. Controller 112 can analyze the phase response of the frequency scan to determine whether a detection capacitor of the wireless receiver (e.g., Cd of receiver 120) is present on charging region 152. The Cd detection performed in block 304 is described above in conjunction with Figure 2.

[0039] Process 300 can proceed from block 304 to block 306. In block 306, controller 112 can determine whether Cd was detected in block 304. If Cd was not detected in block 304, process 300 can proceed to block 308. In block 308, controller 112 can record the result of a failed Cd detection to, for example, a storage device or register of transmitter 110. If Cd was detected in block 304, process 300 can proceed to block 310. In block 310, controller 112 can record the result of a successful Cd detection to, for example, a storage device or register of transmitter 110. Process 300 can proceed from block 308 and / or block 310 to block 312.

[0040] In block 312, controller 112 may determine and / or update the success rate. The success rate updated in block 312 may be the success rate of detecting Cd on charging region 152. In one embodiment, the success rate may be the ratio of the number of successful detections recorded in block 310 to the number of failed detections recorded in block 308. In another embodiment, the success rate may be the percentage obtained by dividing the number of successful detections recorded in block 310 by N.

[0041] Process 300 can proceed from box 312 to box 314. In box 314, controller 112 can compare the updated success rate in box 312 with a preset success rate threshold S. TH Compare the results. Preset success rate threshold S. TH It can be arbitrarily set and programmed. If the success rate is greater than or equal to S... TH Then process 300 can proceed to box 316. If the success rate is less than S... TH Then process 300 can proceed to frame 318.

[0042] In block 316, controller 112 may increment the iteration index N by one. Process 300 may proceed from block 316 to block 304, and may repeat blocks 304, 306, 308 or 310, 312, and 314 until process 300 proceeds from block 314 to block 318, or until the success rate is less than S. TH .

[0043] In block 318, controller 112 can compare the power consumption of transmitter 110 with a preset power consumption threshold P. TH Compare. If the power consumption is greater than or equal to P... TH Then process 300 can proceed to step 320. If the success rate is less than P... THThen process 300 can proceed to block 316. In block 320, controller 112 can combine low-power technology with frequency scanning Cd detection in block 304. The combination method in block 320 will combine... Figure 4 To provide a more detailed description.

[0044] Alternatively, if the success rate is less than P TH Then process 300 can proceed to block 322, where the controller can perform a high-power technique, such as the digital ping described above, as an alternative to Cd detection. Alternatively, if Cd is detected in block 306, process 300 can proceed to block 318 to detect the power consumption of transmitter 110. If Cd is detected in block 306 and the power consumption is less than P... TH Then controller 112 can execute block 322 to perform high-power techniques such as digital ping to further verify the results of Cd detection (e.g., verify the presence of a wireless power receiver).

[0045] Process 300 allows controller 112 to adaptively determine whether additional techniques are needed, and / or to be used in conjunction with Cd detection in block 304. If the success rate of Cd detection is relatively low and the power consumption of the transmitter is relatively high, controller 112 may employ low-power techniques to save energy, because using low-success-rate Cd detection alone may cause unnecessary power consumption by transmitter 110. Conversely, if the success rate of Cd detection is relatively low and the power consumption of the transmitter is relatively low, controller 112 may continue to use frequency scanning to detect Cd.

[0046] Figure 4 This is a schematic diagram illustrating an embodiment that combines high-power technology with receiver detection in wireless power transmission. Figure 4 The description can be found in [reference]. Figures 1 to 3The components are shown. In one embodiment, to save power consumption of transmitter 110, controller 112 may be used to perform low-power techniques, such as Q-factor detection, before performing Cd detection. As an example, controller 112 may be used to perform Q-factor detection to detect the presence of an object with a Q-factor on charging area 152. If controller 112 determines that no object with a Q-factor is present on charging area 152, controller 112 may continue monitoring charging area 152 without performing a frequency scan. If controller 112 determines that an object with a Q-factor is present on charging area 152, controller 112 may perform a frequency scan to verify whether the object includes Cd. If Cd is not detected, controller 112 may determine that the object with a Q-factor is a foreign object. If Cd is detected, controller 112 may determine that the object with a Q-factor is a wireless power receiver. In response to the detection of Cd, controller 112 may further verify the presence of a wireless power receiver on the charging area by performing high-power techniques, such as digital ping. In one embodiment, controller 112 can be used to combine Cd detection with digital ping without performing Q factor detection.

[0047] By performing Q-factor detection first, then Cd detection, and finally digital ping, transmitter 110 can save power. If Cd is not detected, digital ping can be skipped, thus saving power. Adding Cd detection reduces the number of times controller 112 performs digital ping. For example, if Cd detection is not performed before digital ping, transmitter 110 will perform N digital pings regardless of how many times the wireless power receiver is detected in N digital pings. However, if Cd detection is performed before digital ping, transmitter 110 can perform N Cd detections. If Cd is detected X times out of N, transmitter 110 can perform X digital pings instead of N, thus saving power.

[0048] Figure 4 An example process 400 is shown. Process 400 could be an example of combining low-power techniques, such as Q-factor detection, and high-power techniques, such as digital ping, with Cd detection using frequency scanning. Process 400 can begin at box 402, if process 400 continues Figure 3 In box 320, controller 112 can increment the iteration index N by one. It should be noted that process 400 can also be executed as an independent process without being combined with process 300, and box 402 can start from N=1.

[0049] Process 400 can proceed from block 402 to block 404. In block 404, controller 112 can perform low-power techniques, such as Q-factor detection described above. The low-power techniques performed in block 404 consume less power than the frequency-scanning Cd detection described herein.

[0050] Process 400 can proceed from block 404 to block 406. In block 406, controller 112 can determine whether an object is present in charging area 152. If the Q-factor detection result indicates that no Q-factor is detected, process 400 can proceed to block 410. No Q-factor detection may indicate that there is no object in charging area 152, or that the object in charging area 152 does not contain metal, and therefore no wireless power receiver is present in charging area 152. If the Q-factor detection result indicates that a Q-factor is detected, process 400 can proceed to block 408.

[0051] In block 408, controller 112 can provide V to the primary LC resonant circuit consisting of coil TX and primary capacitor Cp. sweep To perform a frequency scan. Controller 112 can analyze the phase response of the frequency scan to determine whether a detection capacitor of the wireless receiver (e.g., Cd of receiver 120) is present on charging region 152. The Cd detection performed in block 408 is described above in conjunction with Figure 2.

[0052] Process 400 can proceed from block 408 to block 412. In block 412, controller 112 can determine whether Cd is detected in block 408. If Cd is not detected in block 408, process 400 can proceed to block 414. In block 414, controller 112 can record the result of Cd detection failure to, for example, a storage device or register of transmitter 110. Process 400 can proceed from block 414 to block 410. If Cd is detected in block 408, process 400 can proceed to block 416. In block 416, controller 112 can perform high-power techniques such as digital ping to verify the presence of the wireless power receiver on charging area 152. Process 400 can proceed from block 416 to block 418.

[0053] In block 418, controller 112 may determine whether the high-power technique performed in block 416 has successfully detected or communicated with a wireless power receiver. If controller 112 fails to detect or communicate with a wireless power receiver in block 416, process 400 may proceed to block 410. If controller 112 successfully detects or communicates with a wireless power receiver in block 416, process 400 may proceed to block 420. In block 420, in response to the successful detection or communication with a wireless power receiver in block 416, transmitter 110 may perform wireless power transfer with the detected wireless power receiver.

[0054] Using frequency scanning to detect Cd, whether as a standalone technique or in combination with Q-factor detection and / or digital ping, offers several advantages. For example, Cd detection consumes less power than digital ping while providing a higher success rate than Q-factor detection. Furthermore, frequency scanning for Cd detection requires no additional components. Moreover, frequency scanning for Cd detection can be performed without shutting down transmitter 110.

[0055] Figure 5 This is a flowchart illustrating a process for implementing receiver detection in wireless power transmission in one embodiment. Process 500 may include one or more operations, actions, or functions, as shown in one or more of blocks 502 and / or 504. Although illustrated as discrete blocks, the individual blocks may be divided into more blocks, combined into fewer blocks, deleted, executed in parallel, and / or executed in a different order, depending on the desired implementation.

[0056] Process 500 can be performed by a wireless power transmitter in a wireless power transfer system (e.g., Figure 1 The process 500 is performed by the transmitter 110 in the wireless power transmitter. The process 500 may begin at block 502. In block 502, the controller of the wireless power transmitter performs a frequency scan of the transmitter coil at multiple frequencies. These multiple frequencies may include the resonant frequency of a detection capacitor connected in parallel with the receiver coil in the wireless power receiver.

[0057] In one embodiment, the controller can perform a frequency scan by supplying a voltage to the transmit coil. The voltage may be based on the load equivalent resistance of the rectifier of the wireless power receiver.

[0058] Process 500 can proceed from block 502 to block 504. In block 504, the controller can determine, based on the phase response of the frequency scan, whether the wireless power receiver is present in the charging area of ​​the wireless power transmitter.

[0059] In one embodiment, the controller can detect the absence of a phase drop in the phase response at the resonant frequency of the detection capacitor. In response to detecting the absence of a phase drop, the controller can determine that the wireless power receiver is not present in the charging region. Alternatively, the controller can detect a phase drop in the phase response at the resonant frequency of the detection capacitor. In response to detecting the presence of a phase drop, the controller can determine that the wireless power receiver is present in the charging region.

[0060] In one embodiment, the controller may detect the Q factor of an object present in the charging area. In response to detecting the presence of a Q factor, the controller may perform a frequency scan.

[0061] In one embodiment, the controller may periodically perform frequency scans. The controller may determine the success rate of detecting a wireless power receiver in the charging area based on the phase response of the frequency scan. If the success rate is greater than a preset threshold, the controller may continue to periodically perform frequency scans. If the success rate is less than the preset threshold, the controller may perform Q-factor detection to detect the presence of an object in the charging area. If an object is detected in the charging area, the controller may perform a frequency scan.

[0062] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or part of an instruction, containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than indicated in the figures. For example, depending on the function involved, two consecutively shown blocks may actually execute substantially simultaneously, or these blocks may sometimes execute in reverse order. It will also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system or a combination of dedicated hardware and computer instructions that performs the specified function or action.

[0063] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that, when used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0064] All means or steps plus functional elements (if any) in the following claims, and their corresponding structures, materials, actions, and equivalents, are intended to include any structure, material, or action used to perform the function in conjunction with other explicitly claimed elements. The description of the invention is presented for illustrative and descriptive purposes and is not intended to be exhaustive or limiting to the invention as disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments were chosen and described in order to best explain the principles and practical application of the invention and to enable those skilled in the art to understand the various embodiments of the invention with various modifications suitable for the particular intended use.

Claims

1. A semiconductor device, comprising: Controller, used for: Frequency scanning is performed on the transmitting coil of the wireless power transmitter at multiple frequencies, wherein the multiple frequencies include the resonant frequency of a detection capacitor connected in parallel with the receiving coil of the wireless power receiver; and Based on the phase response of the frequency scan, it is determined whether the wireless power receiver exists in the charging area connected to the wireless power transmitter.

2. The semiconductor device of claim 1, wherein, The controller is part of the wireless power transmitter.

3. The semiconductor device of claim 1, wherein, The controller is used to perform the frequency scan by providing a voltage to the transmitting coil, the voltage being based on the load equivalent resistance of the rectifier of the wireless power receiver.

4. The semiconductor device of claim 1, wherein, The controller is used for: The phase response is detected to show no phase drop at the resonant frequency of the detection capacitor; In response to the detection of no phase drop, it is determined that the wireless power receiver is not present in the charging area; A phase drop is detected at the resonant frequency of the detection capacitor in the phase response; as well as In response to the detection of the phase drop, it is determined that the wireless power receiver is present in the charging area.

5. The semiconductor device according to claim 1, wherein, The controller is used for: Detecting the Q factor of the presence of an object in the charging area; and In response to the detection of the Q factor, the frequency scan is performed.

6. The semiconductor device according to claim 1, wherein, The controller is used to perform the frequency scan periodically.

7. The semiconductor device according to claim 1, wherein, The controller is used for: The frequency scan is performed periodically; Based on the phase response of the frequency scan, the success rate of detecting the wireless power receiver in the charging region is determined; In response to the success rate being greater than a preset threshold, the frequency scan continues to be performed periodically; In response to the success rate being less than a preset threshold, Q-factor detection is performed to detect whether there is an object on the charging area; as well as In response to the detection of the object on the charging area, the frequency scan is performed.

8. The semiconductor device according to claim 7, wherein, The controller is used for: In response to the success rate being less than a preset threshold, it is determined whether the power consumption of the wireless power transmitter is greater than or less than a preset power consumption threshold. In response to the power consumption being less than the preset power consumption threshold, the frequency scan continues to be performed periodically; as well as In response to the power consumption being greater than the preset power consumption threshold, the Q factor detection is performed.

9. An apparatus comprising: A transmitter includes a transmitting coil and a primary capacitor connected in series with the transmitting coil, wherein the transmitting coil and the primary capacitor form an LC resonant circuit; Controller, used for: A frequency scan is performed on the LC resonant circuit at multiple frequencies, wherein the multiple frequencies include the resonant frequency of a detection capacitor connected in parallel with the receiving coil in a wireless power receiver; and Based on the phase response of the frequency scan, it is determined whether the wireless power receiver exists in the charging area connected to the transmitter.

10. The apparatus according to claim 9, wherein, The controller is used to perform the frequency scan by providing a voltage to the LC resonant circuit, the voltage being based on the load equivalent resistance of the rectifier of the wireless power receiver.

11. The apparatus according to claim 9, wherein, The controller is used for: The phase response is detected to show no phase drop at the resonant frequency of the detection capacitor; In response to the detection of no phase drop, it is determined that the wireless power receiver is not present in the charging area; A phase drop is detected at the resonant frequency of the detection capacitor in the phase response; as well as In response to the detection of the phase drop, it is determined that the wireless power receiver is present in the charging area.

12. The apparatus according to claim 9, wherein, The controller is used for: Detecting the Q factor of the presence of an object in the charging area; and In response to the detection of the Q factor, the frequency scan is performed.

13. The apparatus according to claim 9, wherein, The controller is used to perform the frequency scan periodically.

14. The apparatus according to claim 9, wherein, The controller is used for: The frequency scan is performed periodically; Based on the phase response of the frequency scan, the success rate of detecting the wireless power receiver in the charging region is determined; In response to the success rate being greater than a preset threshold, the frequency scan continues to be performed periodically; In response to the success rate being less than a preset threshold, Q-factor detection is performed to detect whether there is an object on the charging area; as well as In response to the detection of the object on the charging area, the frequency scan is performed.

15. The apparatus according to claim 14, wherein, The controller is used for: In response to the success rate being less than the preset threshold, determine whether the power consumption of the transmitter is greater than or less than the preset power consumption threshold; In response to the power consumption being less than the preset power consumption threshold, the frequency scan continues to be performed periodically; as well as In response to the power consumption being greater than the preset power consumption threshold, the Q factor detection is performed.

16. A method comprising: Frequency scanning is performed on the transmitting coil of the wireless power transmitter at multiple frequencies, wherein the multiple frequencies include the resonant frequency of a detection capacitor connected in parallel with the receiving coil of the wireless power receiver; and Based on the phase response of the frequency scan, it is determined whether the wireless power receiver is present in the charging area of ​​the wireless power transmitter.

17. The method according to claim 16, wherein, The step of performing the frequency scan includes supplying a voltage to the transmitting coil, the voltage being based on the load equivalent resistance of the rectifier of the wireless power receiver.

18. The method of claim 16, further comprising: The phase response is detected to show no phase drop at the resonant frequency of the detection capacitor; In response to the detection of no phase drop, it is determined that the wireless power receiver is not present in the charging area; A phase drop is detected at the resonant frequency of the detection capacitor in the phase response; as well as In response to the detection of the phase drop, it is determined that the wireless power receiver is present in the charging area.

19. The method of claim 16, further comprising: Detect the Q factor of the presence of an object in the charging area; as well as In response to the detection of the Q factor, the frequency scan is performed.

20. The method of claim 16, further comprising: The frequency scan is performed periodically; Based on the phase response of the frequency scan, the success rate of detecting the wireless power receiver in the charging area is determined; In response to the success rate being greater than a preset threshold, the frequency scan continues to be performed periodically; In response to the success rate being less than the preset threshold, Q-factor detection is performed to detect whether there is an object on the charging area; as well as In response to the detection of the object on the charging area, the frequency scan is performed.

Images