Apparatus and methods for enhancing operation in a wireless charging receiver

Abstract

Various embodiments of this disclosure relate to apparatus and methods for enhancing operation in a wireless charging receiver. One method implemented via a wireless charging receiver (RX) includes: detecting via the wireless charging RX that the voltage potential of the output of the rectifier of the wireless charging RX reaches a boost mode threshold; placing the rectifier in boost mode via the wireless charging RX; and detecting via the wireless charging RX that the voltage potential of the output of the rectifier of the wireless charging RX reaches a specified threshold, and based thereon, negotiating with a wireless charging transmitter (TX) via the wireless charging RX to initiate power delivery.

Description

Technical Field

[0001] The present invention generally relates to methods and apparatus for enhancing operation in a wireless charging receiver. Background Technology

[0002] Powering electronic devices has always been a challenge for system designers. Early electronic devices were connected to a power source via power cords. Batteries were given the freedom of movement, but they still needed to be replaced or recharged. Recharging a battery required using a power cord to plug the battery or electronic device into a power source.

[0003] Wireless charging systems eliminate power cords by delivering electricity in free space, where the power can be used to charge rechargeable batteries or directly power electronic devices. Wireless charging systems eliminate the difficulties associated with plugging into electronic devices, such as figuring out the correct plug orientation, ensuring the correct power cord is used, physical connectors, and connection wear and tear. Therefore, wireless charging systems are attractive to end users.

[0004] The Wireless Power Consortium's (WPC) Qi standard is currently the protocol used in most wireless charging systems. Qi wireless charging systems are based on magnetic induction between a wireless charging transmitter (TX) and a wireless charging receiver (RX). The wireless charging TX initiates a power transfer session by periodically emitting digital pings to identify a wireless charging RX positioned close to the TX (e.g., placed on a surface of the TX). Upon detecting a digital ping, the wireless charging RX can begin negotiating with the TX. However, if the wireless charging RX is not properly coupled to the wireless charging TX (e.g., the charging resonant coil is misaligned, or a specific combination of the TX and RX charging resonant circuits causes a low rectifier output voltage due to a fixed predetermined TX operating point used during the ping phase and the identification and configuration phases), the digital ping may not be detected by the wireless charging RX. Therefore, there is a need for methods and apparatus to enhance ping-mode operation in the wireless charging RX. Summary of the Invention

[0005] According to an embodiment, a method implemented by a wireless charging receiver (RX) is provided. The method includes: the wireless charging RX detecting that the voltage potential of the output of the rectifier of the wireless charging RX has reached a boost mode threshold; the wireless charging RX placing the rectifier in boost mode; and the wireless charging RX detecting that the voltage potential of the output of the rectifier of the wireless charging RX has reached a specified threshold, and based thereon, the wireless charging RX negotiating with a wireless charging transmitter (TX) to initiate power transmission.

[0006] According to an embodiment, a wireless charging RX is provided. The wireless charging RX includes: a non-transitory memory storage device including instructions; and one or more processors communicating with the memory storage device, wherein the one or more processors execute the instructions to cause the wireless charging RX to: detect that the voltage potential of the output of the rectifier of the wireless charging RX has exceeded a boost mode threshold; place the rectifier in boost mode; and detect that the voltage potential of the output of the rectifier of the wireless charging RX has reached a specified threshold, and on this basis, negotiate with a wireless charging transmitter TX to initiate power delivery.

[0007] According to an embodiment, a wireless charging RX is provided. The wireless charging RX includes: a rectifier operably coupled to a receiving resonant circuit, the rectifier being configured to output a direct current (DC) voltage based on received energy received by the receiving resonant circuit from a wireless charging TX; a non-transitory memory storage device including instructions; and one or more controllers communicating with the memory storage device, wherein the one or more controllers execute instructions to cause the wireless charging RX to: detect that the voltage potential of the rectifier's output has exceeded a boost mode threshold; place the rectifier in boost mode; and detect that the voltage potential of the rectifier's output of the wireless charging RX has reached a specified threshold, and based thereon, negotiate with the wireless charging TX to initiate power delivery. Attached Figure Description

[0008] To gain a more complete understanding of the invention and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 The illustration shows a prior art wireless charging system;

[0010] Figure 2 The diagram shows... Figure 1 Detailed view of existing wireless charging systems;

[0011] Figure 3 The diagram illustrates a prior art phase diagram including the stages of power delivery involving a wireless charging transmitter (TX) and a wireless charging receiver (RX).

[0012] Figure 4 The diagram illustrates the signal traces of the wireless charging RX signal when the wireless charging RX participates in a ping operation.

[0013] Figure 5 The illustration shows an example wireless charging system with details of an example wireless charging RX provided according to an example embodiment presented herein;

[0014] Figure 6 The illustration shows a highlighted example embodiment presented herein. Figure 3 A portion of the phase diagram;

[0015] Figure 7 The illustration shows a flowchart of an example operation that occurs in a wireless charging RX capable of operating in boost mode according to the example embodiments presented herein;

[0016] Figure 8 The illustration shows a signal trace diagram representing the wireless charging RX participating in a ping operation in boost mode to enhance the signal of the wireless charging RX during the ping operation, according to the example embodiments presented herein; and

[0017] Figure 9 An example wireless charging RX is illustrated according to the example embodiments presented herein.

[0018] Unless otherwise stated, corresponding numbers and symbols in different figures generally refer to corresponding parts. These figures are drawn to clearly illustrate relevant aspects of the embodiments and are not necessarily drawn to scale. Feature edges drawn in the figures do not necessarily indicate the termination of feature ranges. Detailed Implementation

[0019] In the following description, one or more specific details are shown to provide an understanding of examples of the embodiments. These embodiments may be obtained without one or more of the specific details, or by other methods, components, materials, etc. In other instances, known structures, materials, or operations have not been shown or described in detail so as not to obscure certain aspects of the embodiments.

[0020] References to “embodiment” or “one embodiment” within the framework of this specification are intended to indicate that a particular configuration, structure, or feature described with respect to an embodiment is included in at least one embodiment. Therefore, phrases such as “in an embodiment” or “in one embodiment” that may appear at one or more points in this specification do not necessarily refer to one and the same embodiment. Furthermore, in one or more embodiments, particular conformations, structures, or features may be combined in any suitable manner.

[0021] The references used herein are for convenience only and therefore do not limit the scope of protection or the scope of embodiments.

[0022] Figure 1 The illustration shows a prior art wireless charging system 100. The wireless charging system 100 may comply with the Wireless Power Consortium (WPC) Qi standard. Details of the communication can be found in the Qi standard defined by the WPC.

[0023] The wireless charging system 100 includes a wireless charging transmitter (TX) 105 and a wireless charging receiver (RX) 110. The wireless charging TX 105, coupled to a power source 115, provides energy to the wireless charging RX 110, which in turn provides power to a device 120 coupled to the wireless charging RX 110. The power provided to the device 120 can be used to charge a rechargeable battery in the device 120, directly power the device 120, or both. The process of providing energy is referred to as power delivery.

[0024] The wireless charging TX 105 includes a transmitting resonant circuit 125. The resonant circuit is characterized by its inductance (L) and capacitance (C) (shown in the highlighted area 127 of the wireless charging TX 105), and the power transferred between the wireless charging TX 105 and the wireless charging RX 110 is a function of both the inductance and capacitance of the resonant circuits of the wireless charging TX 105 and the wireless charging RX 110. The capacitor (C) is used to improve the efficiency of power transfer, while the inductance L is used to transfer power (the transmitting coil converts current into magnetic flux and the receiving coil converts magnetic flux into electromotive force). The transmitting resonant circuit 125 uses the transmitting coil to transmit an excited wireless field (shown as line 135). The excited wireless field (line 135) is received by the receiving resonant circuit 130 of the wireless charging RX 110. The resonant circuit 130 is also characterized by its inductance (L) and capacitance (C), shown in the highlighted area 132.

[0025] In addition to transmitting and receiving the excited wireless field, changes in the parameters of the receiving resonant circuit 130 can be used to communicate from the wireless charging RX 110 to the wireless charging TX 105. For example, in communication between the wireless charging RX 110 and the wireless charging TX 105, the communicated information can be used to modulate the amplitude of the wireless field, thereby enabling the transmission or reception of information. For example, in communication between the wireless charging TX 105 and the wireless charging RX 110, the communicated information can be used to modulate the frequency of the wireless field, thereby enabling the transmission or reception of information. For example, the wireless charging TX 105 and the wireless charging RX 110 communicate to initiate a wireless charging session, set the charging mode, control the amount of energy transmitted by the wireless charging TX 105, control the amount of energy received by the wireless charging RX 110, and terminate the wireless charging session, etc. The communication performed is mainly in the uplink direction, for example, from the wireless charging RX 110 to the wireless charging TX 105.

[0026] Figure 2A detailed view of a prior art wireless charging system 100 is illustrated. The wireless charging system 100 includes a wireless charging TX 105 and a wireless charging RX 110. In operation, the wireless charging TX 105 provides power to the wireless charging RX 110 to charge devices coupled to the wireless charging RX 110.

[0027] The wireless charging TX 105 includes a resonant circuit 127 and an inverter 205. For example, the inverter 205 can be implemented as a full-bridge inverter or a half-bridge inverter. The inverter 205 converts the direct current (DC) supplied by power supply 115 into alternating current (AC). The wireless charging RX 110 includes a resonant circuit 132 and a rectifier 210.

[0028] The resonant circuits 127 and 132, coupled together, form an air-core current transformer. The wireless charging RX 110 receives AC power and uses rectifier 210 to convert the AC power back to DC. For example, DC voltage is supplied to charge a battery or power a device. Since batteries typically require a specific voltage to charge, the output voltage (VRECT) of the rectifier 210 of the wireless charging RX 110 needs to be within a specific range. If the output voltage (VRECT) of the rectifier 210 exceeds the specific range, the wireless charging RX 110 may be damaged due to overvoltage or battery charging may be slowed down due to undervoltage. Additionally, if VRECT falls below a threshold level (i.e., the minimum operating voltage threshold UVLO) under undervoltage conditions, the wireless charging RX 110 can be reset.

[0029] Based on the received power level, the wireless charging RX 110 communicates with the wireless charging TX 105 to request an increase or decrease in the power supplied by the wireless charging TX 105. In the Qi standard, the wireless charging RX 110 can communicate with the wireless charging TX 105 using one or more control error packets. Upon receiving one or more control error packets, the wireless charging TX 105 adjusts the power by controlling one or more of the following:

[0030] -AC frequency;

[0031] -AC duty cycle or AC phase shift;

[0032] - Input voltage (e.g., provided by power supply 115)

[0033] The aforementioned value, which can be changed to adjust the power received by the wireless charger RX 110, can be referred to as the operating point of the wireless charger TX 105.

[0034] Figure 3The illustration shows a prior art phase diagram 300, including phases involving wireless charging TX 105 and wireless charging RX 110. The Qi technology standard, hereby incorporated herein by reference in its entirety, specifies that power delivery from wireless charging TX 105 to wireless charging RX 110 comprises four phases: selection 305, ping 310, identification and configuration 315, and power delivery 320. Wireless charging TX 105 can transition between these four phases based on signals or events received or detected by wireless charging TX 105. Transitions between different phases can be initiated by wireless charging TX 105 (shown as solid arrow lines) or wireless charging RX 110 (shown as dashed arrow lines).

[0035] In selection phase 305, wireless charging TX 105 monitors the placement and removal of wireless charging RX. For example, wireless charging TX 105 can detect that wireless charging RX 110 is placed on or near its resonant circuit 127. After detecting the placement of wireless charging RX 110, wireless charging TX 105 determines whether to proceed to ping phase 310. For example, if wireless charging RX 110 has terminated a specified number of continuous power delivery attempts, then wireless charging TX 105 can determine not to proceed to ping phase 310.

[0036] In ping phase 310, the wireless charging TX 105 performs a digital ping to initiate power delivery in conjunction with the wireless charging RX 110 detected during selection phase 305. In ping phase 310, the wireless charging TX 105 applies a power signal at a fixed operating point defined by the Tx topology definition in the Qi standard and awaits a response (e.g., a signal strength packet) from the wireless charging RX 110. This power signal may be referred to as a ping. The wireless charging RX 110 detects a ping when the output voltage VRECT of the rectifier 210 exceeds the minimum operating voltage threshold UVLO. If the output voltage VRECT does not exceed the minimum operating voltage threshold UVLO, the wireless charging RX 110 does not activate and the ping is lost. A detailed discussion of ping phase 310 is provided below. Depending on the response of the wireless charging RX 110, the wireless charging TX 105 may proceed to identification and configuration phase 315.

[0037] In the identification and configuration phase 315, the wireless charging TX 105 identifies the wireless charging RX 110 and collects configuration information from the wireless charging RX 110, or the wireless charging RX 110 configures the wireless charging TX 105. For example, the identification and collection of configuration information may be based on packets received from the wireless charging RX 110. These two phases represent the minimum communication between the wireless charging TX 105 and the wireless charging RX 110 as defined by the Qi standard, and are required before power delivery begins. In other applications, additional communication may be performed for negotiation purposes, such as before power delivery is initiated at a predetermined ping frequency. In the power delivery phase 320, the wireless charging TX 105 controls power delivery (i.e., the point of operation) based on multiple requests from the wireless charging RX 110. The wireless charging RX 110 may send a Control Error Packet (CEP) for power control, a packet to terminate power delivery, a packet indicating an error, or any other packet as defined in the Qi specification.

[0038] As discussed above, during the ping phase 310, the wireless charging TX 105 transmits a power signal (i.e., ping) at a defined operating point and waits for a response from the wireless charging RX 110, where the defined operating point is fixed and cannot be changed by the wireless charging TX 105. Therefore, if the wireless charging RX 110 is not well coupled to the wireless charging TX 105, the output voltage VRECT of the rectifier 210 operating in diode mode may not exceed the minimum operating voltage threshold UVLO. The wireless charging RX 110 will not turn on and will not be able to send signal strength packets to the wireless charging TX 105, and the ping will be lost. Therefore, the wireless charging RX 110 does not respond to the ping, and the wireless charging TX 105 cannot proceed to the identification and configuration phase 315, and no power delivery occurs.

[0039] Figure 4 The diagram illustrates a signal trace 400 representing the signal of the wireless charging RX 110 during a ping operation. The first trace 405 represents the voltage potential at point AC1 of the rectifier 210 of the wireless charging RX 110; the second trace 410 represents the voltage potential at point AC2 of the rectifier 210 of the wireless charging RX 110; the third trace 415 represents the output voltage potential of the rectifier 210 of the wireless charging RX 110; and the fourth trace 417 represents the minimum operating voltage threshold UVLO, which is the minimum operating voltage required for the operation of the wireless charging RX 110. Points AC1 and AC2 are the inputs of the rectifier 210. (For simplicity...) Figure 4The first trace 405 and the second trace 410 show the signal envelopes of the AC signals at the positive point AC1 and the negative point AC2 of the rectifier 210, rather than the AC signals themselves, which will oscillate within the shown signal envelopes.

[0040] like Figure 4 As shown, pulses 407 and 412 correspond to a ping applied by the wireless charging TX 105. Pulses 407 and 412 cause an increase in the voltage potential of rectifier 210 (shown as pulse 419). However, the duration of the ping asserted by the wireless charging TX 105 is finite, and pulse 419 (the output voltage potential of rectifier 210) does not reach the minimum operating voltage threshold UVLO. Therefore, the wireless charging RX 110 does not detect the ping, and the wireless charging RX 110 does not wake up. If the output voltage potential of rectifier 210 does not exceed the minimum operating voltage threshold UVLO, then rectifier 210 operates in diode mode. For example, rectifier 210 operates as if it comprises multiple diodes. Rectifier 210 only enters active full-wave synchronous rectifier mode (also known as fully synchronous mode) when the voltage potential of rectifier 210 exceeds the minimum operating voltage threshold UVLO and the wireless charging RX 110 wakes up. When the wireless charging TX 105 stops applying ping, the voltage potential at points AC1 and AC2 (trace 405 and trace 410) drops and the output voltage potential of rectifier 210 also drops (shown as drop 418).

[0041] although Figure 4 Not shown, but the Qi standard specifies that the wireless charging TX applies a specified number of pings (e.g., three). However, each ping fails because the operating point of the ping does not change, and none of the pings causes the output voltage potential of the rectifier 210 to reach the minimum operating voltage threshold UVLO.

[0042] The inability of ping to raise the output voltage potential of rectifier 210 sufficiently to reach the minimum operating voltage threshold UVLO may be due to poor coupling between wireless charging TX 105 and wireless charging RX 110. Generally, if the corresponding resonant circuits (or coils therein) of wireless charging TX 105 and wireless charging RX 110 are misaligned, then poor coupling between wireless charging TX 105 and wireless charging RX 110, or a specific combination of the resonant coils of wireless charging TX 105 and wireless charging RX 110, results in a low output voltage of rectifier 210 due to a fixed predetermined operating point of wireless charging TX 105 used during ping phase 310 and identification and configuration phase 315. Since wireless charging TX 105 cannot change the operating point of ping (e.g., increase the transmit power level or duration of ping), ping and subsequent pings will be lost by wireless charging RX 110. Therefore, a method and apparatus for enhancing ping operation in wireless charging RX are needed.

[0043] According to the example embodiment, the output voltage potential of rectifier 210 is amplified to help ensure that the minimum operating voltage threshold UVLO is reached. Since the operating point of ping is immutable, the amplification of the output voltage potential (VRECT) of rectifier 210 makes it easier for the output voltage potential of rectifier 210 to reach (or exceed) the minimum operating voltage threshold UVLO. Amplifying the output voltage potential of rectifier 210 increases the voltage potential, making it potentially easier to reach the minimum operating voltage threshold.

[0044] According to an example embodiment, the output voltage potential of rectifier 210 is amplified by operating rectifier 210 in boost mode. Operating in boost mode increases the output voltage potential of rectifier 210. A detailed discussion of operating rectifier 210 in boost mode is provided below. In the embodiment, operating rectifier 210 in boost mode approximately doubles the output voltage potential of rectifier 210 compared to its voltage potential when not operating in boost mode (e.g., rectifier 210 operating in diode mode).

[0045] Figure 5 An example wireless charging system 500 according to an exemplary embodiment presented herein is illustrated, providing details of an example wireless charging RX 110. The wireless charging system 500 includes a wireless charging TX 105 and a wireless charging RX 110, wherein the wireless charging RX 110 includes a rectifier 210 that operates in boost mode to amplify the voltage potential of the rectifier 210.

[0046] The wireless charging RX 110 includes a resonant circuit 132, which in... Figure 5The coil and capacitor are shown in the diagram. The resonant circuit 132 of the wireless charging RX 110 and the resonant circuit 127 of the wireless charging TX 105 are very close to each other and have a certain degree of coupling between the respective resonant circuits.

[0047] The wireless charging RX 110 includes a rectifier 210. The rectifier 210 is implemented using four field-effect transistors (FETs) 505-508 arranged on two parallel branches 502 and 503. On the first branch 502, FET 505 couples the first rectifier input (AC1) to the rectifier output (VRECT), and FET 506 couples the first rectifier input (AC1) to ground. On the second branch 503, FET 507 couples the first rectifier input (AC2) to the rectifier output (VRECT), and FET 508 couples the second rectifier input (AC1) to ground. FETs 505-508 are designated HS1, HS2, LS1, and LS2, respectively. FETs 505-508 can be p-type FETs or n-type FETs. FETs 505-508 can be junction FETs (JFETs), metal-oxide-semiconductor FETs (MOSFETs), etc.

[0048] FETs 505-508 are controlled by signals SR1, SR2, SR3, and SR4, respectively. The values ​​of the control signals may vary, for example, depending on the type of FETs 505-508. However, regardless of the type of FET, the states of FETs 505-508 are similar. FETs in the ON position are conductive, while FETs in the OFF position are non-conductive. The first terminal of resonant circuit 132 is coupled to point AC1 between FETs 505 and FET 506 of rectifier 210, and the second terminal of resonant circuit 132 is coupled to point AC2 between FETs 507 and FET 508 of rectifier 210.

[0049] Figure 5 The parasitic diodes 510-513 shown are inherent to the FET transistor. The output voltage potential (VRECT) of rectifier 210 can be measured across capacitor 515. As discussed above, the FET conducts when it is ON and does not conduct when it is OFF.

[0050] Rectifier 210 can operate in diode mode, where all FETs 505-508 are OFF, and rectifier 210 behaves as if it were formed solely by diodes 510-513, because the AC signal is rectified by the parasitic body diodes of the FETs. In diode mode, rectifier 210 behaves as a diode bridge rectifier.

[0051] Rectifier 210 can operate in active full-wave synchronous rectifier mode. To operate rectifier 210 in full-synchronous mode, rectifier 210 is configured such that only one of HS1 (FET 505) or LS1 (FET 506) is ON at any given time (HS2 (FET 507) and LS2 (FET 508) are similarly configured). For example, if HS1 (FET 505) is ON, then LS1 (FET 506) is OFF, and vice versa. HS2 (FET 507) operates similarly to LS2 (FET 508).

[0052] Furthermore, if the voltage potential at AC1 is higher than the AC high-side (HS) voltage threshold, then HS1 (FET 505) is ON (and therefore LS1 (FET 506) is OFF), while if the voltage potential at AC1 is lower than the AC low-side (LS) voltage threshold, then LS1 (FET 506) is ON (and therefore HS1 (FET 505) is OFF). Similarly, if AC2 is higher than the AC HS voltage threshold, then HS2 (FET 507) is ON (and therefore LS2 (FET 508) is OFF), while if AC2 is lower than the AC LS voltage threshold, then LS2 (FET 508) is ON (and therefore HS2 (FET 507) is OFF). During active full-wave synchronous rectifier mode, four comparators can be used to perform this control of the HS FET and LS FET (as switching operations). Figure 5 The comparator is not shown in the diagram. A similar function can be achieved if the rectifier 210 is controlled in two comparator modes (with AC1 HS threshold and AC2 HS threshold or AC1 LS threshold and AC2 LS threshold, wherein the thresholds control two FETs (HS1 (FET 505) and LS2 (FET 508) are controlled by the first threshold while HS2 (FET 507) and LS1 (FET 506) are controlled by the second threshold).

[0053] In addition to full-wave synchronous rectifier mode, rectifier 210 can operate in boost mode. For example, in boost mode, when rectifier 210 operates in diode mode (where FETs 505-508 are off), the output voltage potential of rectifier 210 is approximately twice that of rectifier 210. To operate rectifier 210 in boost mode, rectifier 210 is configured such that only one of HS1 (FET 505) or LS1 (FET 506) is ON at any given time, and HS2 (FET 507) is configured to always be OFF while LS2 (FET 508) is configured to always be ON. Furthermore, if AC1 is higher than the AC HS voltage threshold, then HS1 (FET 505) is ON (and therefore LS1 (FET 506) is OFF), and if AC1 is lower than the AC LS voltage threshold, then LS1 (FET 506) is ON (and therefore HS1 (FET 505) is OFF). Alternatively, rectifier 210 is configured such that only one of HS2 (FET 507) or LS2 (FET 508) is ON at any given time, and HS1 (FET 505) is always OFF and LS1 (FET 506) is always ON. In this alternative, if AC2 is above the AC HS voltage threshold, then HS2 (FET 507) is ON (and therefore LS2 (FET 508) is OFF), and if AC2 is below the AC LS voltage threshold, then LS2 (FET 508) is ON (and therefore HS2 (FET 507) is OFF). In either configuration, the output voltage potential of rectifier 210 operating in boost mode is approximately twice the output voltage potential of rectifier 210 when configured to operate in diode mode. The AC HS voltage threshold and AC LS voltage threshold for boost mode may be the same as or different from the AC HS voltage threshold and AC LS voltage threshold used in active full-wave synchronous rectifier mode.

[0054] According to the example embodiment, rectifier 210 operates in boost mode throughout the ping phase 310 and the identification and configuration phase 315. Rectifier 210 operates in boost mode during these phases to amplify the output voltage potential of rectifier 210. When not in the ping phase 310 and the identification and configuration phase 315 (or other phases completed at the ping TX operating point prior to the power delivery phase), rectifier 210 may operate in active full-wave synchronous mode or diode mode (or some modes other than boost mode). Operation in active full-wave synchronous mode allows rectifier 210 to operate more efficiently, for example, improving the efficiency of the power delivery phase 320.

[0055] According to an example embodiment, rectifier 210 begins operation in boost mode when its voltage potential reaches a boost threshold. The boost threshold can be a specified voltage value, and rectifier 210 begins operation in boost mode when the voltage potential is below, for example, a minimum operating voltage threshold UVLO. The boost threshold can be specified by design objectives or capabilities. An example design objective is to minimize the boost threshold to help improve ping detection performance.

[0056] In an alternative embodiment, the boost threshold can be set dynamically. For example, if the wireless charging RX 110 detects a series of pings, but none of them exceed a specified threshold UVLO and the wireless charging RX 110 cannot respond to the pings, then the wireless charging RX 110 can reduce the boost threshold.

[0057] According to an example embodiment, after the output voltage potential of rectifier 210 reaches or exceeds a specified threshold UVLO and the ping phase 310 and identification and configuration phase 315 are completed, and after any other negotiation begins at the ping operation point of wireless charging TX 105 before power delivery phase 320, rectifier 210 exits boost mode, where wireless charging TX 105 adjusts power based on the needs of wireless charging RX 110. Rectifier 210 may exit boost mode based on a dynamically selected VRECT threshold, such as a full sync threshold. For example, when the output voltage potential of rectifier 210 (which operates in boost mode) reaches the full sync threshold, rectifier 210 switches to active full-wave synchronous rectifier mode operation. The full sync threshold can be set to reflect a point when, for example, the output voltage potential of rectifier 210 is sufficiently high for effective operation. For example, when rectifier 210 exits boost mode, rectifier 210 enters active full-wave synchronous mode. Alternatively, rectifier 210 can remain in boost mode throughout the entire power delivery phase 320.

[0058] Figure 6Figure 600 illustrates a portion of a highlighted phase diagram 300 according to an exemplary embodiment presented herein. Figure 600 shows possible modes of the rectifier 210 for different phases of phase diagram 300. During ping phase 310, the rectifier 210 operates in boost mode 605. As disclosed herein, operation in boost mode is not limited to the different phases of Qi power delivery discussed above. Boost mode can also be used for any other negotiation performed at a fixed predetermined ping point of the wireless charging TX 105, where the wireless charging TX 105 is not allowed to change the operating point. As previously discussed, for example, the rectifier 210 can exit boost mode 605 during power delivery phase 320 and the rectifier 210 can enter active full-wave synchronous rectifier mode 610. This transition may occur when VRECT exceeds a full synchronization threshold. In another embodiment, rectifier 210 remains in boost mode until after power delivery phase 320, for example, for all ping phases 310, identification and configuration phase 315 and power delivery phase 320, it remains in boost mode 605.

[0059] Figure 7 A flowchart illustrating an example operation 700 occurring in a wireless charging RX 110 capable of operating in boost mode, according to an example embodiment presented herein. Operation 700 may indicate operations occurring in the wireless charging RX 110 when the wireless charging RX 110 engages in power delivery. Operation 700 may begin when a ping operation starts.

[0060] Operation 700 begins with the wireless charging RX 110 performing a check to determine if the output voltage potential of rectifier 210 has reached the boost threshold (box 705). Rectifier 210 can operate in diode mode at this time, for example, by turning all FETs off. If the voltage potential of rectifier 210 reaches the boost threshold, then rectifier 210 enters boost mode (box 707). Rectifier 210 can enter boost mode by, for example, reconfiguring the FETs of rectifier 210 as previously discussed. For example, operating in boost mode causes the output voltage potential of rectifier 210 to approximately double compared to its output voltage potential when operating in diode mode.

[0061] The wireless charging RX 110 performs a check to determine whether the output voltage potential of the rectifier 210 has reached the minimum operating voltage threshold UVLO (box 709). If the voltage potential of the rectifier 210 reaches the minimum operating voltage threshold UVLO, the wireless charging RX 110 can determine that a ping has been received from the wireless charging TX 105 and respond. In response to the ping, communication with the wireless charging TX 105 is initiated to allow power delivery (box 711). Responding to the ping may include waking up the wireless charging RX 110 and communicating with the wireless charging TX 105. Waking up the wireless charging RX 110 may include removing the wireless charging RX 110 from a low-power state or sleep state and placing it in a higher power state that supports the execution of, for example, firmware, software, or applications, and communications. Communication between the wireless charging RX 110 and the wireless charging TX 105 may include packet communication to identify the wireless charging RX 110, obtain configuration information about the wireless charging RX 110, etc.

[0062] The wireless charging RX 110 completes the ping phase 310 and the identification and configuration phase 315 (box 713). Once the ping phase 310 and the identification and configuration phase 315 are completed (as well as any other communication completed at the fixed ping operation point of the wireless charging TX 105 before power conditioning is permitted), the wireless charging RX 110 participates in power delivery (box 715). The wireless charging RX 110 participates in power delivery together with the wireless charging TX 105.

[0063] The wireless charging RX 110 can request changes to the operating point of the wireless charging TX 105 as needed (box 717). The wireless charging RX 110 can request changes by transmitting packets to the wireless charging TX 105. Packets can cause the wireless charging TX 105 to increase its transmission power, decrease its transmission power, respond to the occurrence of an error, terminate power delivery, etc.

[0064] The wireless charging RX 110 performs a check to determine whether a switch from boost mode to active full-wave synchronous rectifier mode has been achieved (box 719). This check may examine values ​​stored in memory locations, flags, or registers, where setting a memory location, flag, or register to a first specified value indicates that a switch from boost mode to active full-wave synchronous rectifier mode has been achieved, while setting a memory location, flag, or register to a second specified value indicates that a switch has not been achieved. If a switch from boost mode to active full-wave synchronous rectifier mode has not been achieved, the wireless charging RX 110 continues to operate rectifier 210 in boost mode (box 721).

[0065] If the switch is successful, the wireless charging RX 110 can perform a check to determine whether the output voltage potential of the rectifier 210 has reached the full synchronization threshold (box 723). Reaching the full synchronization threshold indicates that the output voltage potential of the rectifier 210 is high enough to achieve more efficient operation in active full-wave synchronous rectifier mode. If the full synchronization threshold is reached, the wireless charging RX 110 can switch to active full-wave synchronous rectifier mode if active full-wave synchronous rectifier mode is implemented (box 725). If the full synchronization threshold is not reached, the wireless charging RX 110 can remain in boost mode and continue to check whether the full synchronization threshold has been reached (box 723).

[0066] If the output voltage potential of rectifier 210 does not reach the minimum operating voltage threshold (box 709), then the wireless charging RX 110 operates in boost mode (box 727) and continues to check the VRECT level.

[0067] If the output voltage potential of rectifier 210 does not reach the boost threshold (box 705), then the wireless charging RX 110 operates in diode mode (box 729) and continues to check the VRECT level.

[0068] Figure 8 Figure 800 illustrates the signal traces of the wireless charging RX 110 signal when it participates in a ping operation in boost mode to enhance the ping operation, according to the example embodiment presented herein. The first trace 805 represents the voltage potential at point AC1 of the rectifier 210 of the wireless charging RX 110, the second trace 810 represents the voltage potential at point AC2 of the rectifier 210 of the wireless charging RX 110, and the third trace 815 represents the output voltage potential of the rectifier 210 of the wireless charging RX 110. Furthermore, the first dashed line 820 represents the boost threshold, the second dashed line 825 represents the minimum operating voltage threshold UVLO at which the wireless charging RX 110 detects a ping and can communicate with the wireless charging TX 105, and the third dashed line 845 represents the full synchronization threshold at which the wireless charging RX 110 can switch to active full-wave synchronous rectifier mode. For simplicity... Figure 8 The first trace 805 and the second trace 810 show the signal envelopes of the AC signals at the positive point AC1 and the negative point AC2 of the rectifier 210, rather than the AC signals themselves.

[0069] like Figure 8 As shown, pulses 807 and 812 correspond to the ping applied by the wireless charging TX 105. Pulses 807 and 812 cause an increase in the output voltage potential of rectifier 210 (shown as pulse 817).

[0070] At approximately the time indicated by the vertical dashed line 830, the voltage potential of rectifier 210 reaches the boost threshold (first dashed line 820). As discussed, when the boost threshold is reached, rectifier 210 is placed in boost mode (shown as boost mode interval 832). Prior to the vertical dashed line 830, rectifier 210 operates in diode mode (shown as diode mode interval 834). A first technique for placing rectifier 210 in boost mode is to force HS2 (FET 507) to always be OFF and LS2 (FET 508) to always be ON, while only one of HS1 (FET 505) or LS1 (FET 506) is ON at any given time based on the voltage potential at point AC1 (first trace 805). A second technique for putting rectifier 210 into boost mode is to force HS1 (FET 505) to always be OFF and LS1 (FET 506) to always be ON, while only one of HS2 (FET 507) or LS2 (FET 508) is ON at any given time based on the voltage potential at point AC2 (second trace 810).

[0071] Figure 8 The case where rectifier 210 is placed in boost mode using the first technique discussed above is illustrated. When rectifier 210 is placed in boost mode according to the first technique discussed above, the first side of rectifier 210, including HS1 (FET 505) and LS1 (FET 506), continues to change depending on the signal applied by wireless charging TX 105, while the second side of rectifier 210, including HS2 (FET 507) and LS2 (FET 508), is coupled to electrical ground by keeping HS2 (FET 507) always OFF and LS2 (FET 508) always ON, and does not change depending on the signal applied by wireless charging TX 105. If rectifier 210 is placed in boost mode using the second technique discussed above, then the behavior of points AC1 and AC2, as shown in the first trace AC1 805 and the second trace AC2 810, will be reversed.

[0072] When rectifier 210 is operating in boost mode, the amplitude of the signal at point AC1 (first trace AC1805) increases (shown as span 835). The increase in the amplitude of the signal at point AC1 also causes an increase in the voltage potential of rectifier 210.

[0073] At approximately the time indicated by the vertical dashed line 840, the voltage potential of rectifier 210 reaches the minimum operating voltage threshold UVLO (second dashed line 825). When the voltage potential of rectifier 210 reaches the minimum operating voltage threshold UVLO, wireless charging RX 110 has detected a ping asserted by wireless charging TX 105, and wireless charging RX 110 can send a response to the detected ping. For example, wireless charging RX 110 and wireless charging TX 105 can communicate to initiate power delivery. For example, wireless charging RX 110 and wireless charging TX 105 can communicate in response to pings (e.g., signal strength (SS) packets 850), identification (e.g., identification (ID) packets 852), configuration (e.g., configuration (CFG) packets 854), power conditioning and error switching (e.g., CEP 856 and CEP 858), and to perform power delivery. The waveforms shown are for illustrative purposes and provide a simplified representation of packets communicating from the wireless charging RX 110 to the wireless charging TX 105, and do not reflect the actual waveforms on AC1, AC2, and VRECT during modulation.

[0074] In this embodiment, while the rectifier 210 remains in boost mode, communication regarding identification and configuration can continue, such as... Figure 8 As shown. In an embodiment, when the output voltage potential of rectifier 210 reaches a programmable threshold (e.g., a full synchronization threshold), rectifier 210 can be placed in an active full-wave synchronous rectifier mode during the power transmission phase. If rectifier 210 is in active full-wave synchronous rectifier mode, then the envelope of the voltage potential at AC1 (first trace 805) and AC2 (second trace 810) can have a similar... Figure 8 The appearance of the first trace AC1 805. In fact, the voltage potentials at AC1 and AC2 are opposite, where when AC1 is high, AC2 is low, and vice versa. However, the signal envelopes of these voltage potentials have similar appearances. At time 860, rectifier 210 enters active full-wave synchronous rectifier mode (shown as full synchronization interval 862, which can extend beyond...). Figure 8 (As shown) and the envelope of the voltage potential at AC2 (second trace 810) begins to mirror the envelope of the voltage potential at AC1 (first trace 805).

[0075] like Figure 8 As shown, power delivery continues after rectifier 210 switches to active full-wave synchronous rectifier mode. Power delivery is still in progress when rectifier 210 switches from boost mode to active full-wave synchronous rectifier mode, and the wireless charging RX 110 is using a CEP, such as CEP 864, to regulate the power emitted by the wireless charging TX 105.

[0076] Figure 9 An example wireless charging RX 110 according to an exemplary embodiment presented herein is illustrated. The wireless charging RX 110 includes an integrated circuit 905 that controls the operation of the wireless charging RX 110, including communicating with a wireless charging TX 105, establishing a wireless charging session, controlling the power supplied to electronic devices coupled to the wireless charging RX 110, etc. Integrated circuit 905 includes: a microcontroller 910 that executes a program to control the operation of the wireless charging RX 110; a frequency shift keying (FSK) demodulation circuit 912 that demodulates FSK communication from the wireless charging transmitter; an RX rectifier / TX driver circuit 914 that rectifies AC signals wirelessly received by the wireless charging RX 110 (from the wireless charging TX 105) or drives signals transmitted by the wireless charging TX 105 when operating as a wireless charging TX; a sensing and amplitude shift keying (ASK) demodulator circuit 916 that senses and demodulates ASK modulated signals (when operating as a wireless charging TX); an RX low dropout (LDO) circuit 918 that regulates the voltage; and a memory (including a read-only memory (ROM) 920 for storing code executed by the microcontroller 910, a random access memory (RAM) 922 for storing data, and a non-volatile (NV) memory 924 for storing configuration information).

[0077] The wireless charging RX 110 also includes a receiving resonant circuit 132, which includes an actual coil and a capacitor. The coil and capacitor define the resonant circuit of the wireless charging RX 110, and this coil is coupled to the coil of the resonant circuit of the wireless charging TX 105. The output from the wireless charging RX 110 includes the output voltage (VRECT) of the RX rectifier / TX driver circuit 914 and an output voltage (VOUT) for recharging a rechargeable battery of an electronic device coupled to the wireless charging RX 110 or for directly powering the electronic device.

[0078] The RX rectifier / TX driver 914 includes a rectifier 210 as described herein. The microcontroller 910 executes code stored in memory (e.g., ROM 920, RAM 922, and NV memory 924) to compare the voltage potential of the rectifier 210 with thresholds (e.g., boost threshold, specified threshold UVLO, and full sync threshold), compare the voltage potentials at points AC1 and AC2 of the rectifier 210 with thresholds, such as the AC HS voltage threshold and the AC LS voltage threshold (used to set the state of FETs 505-508 of the rectifier 210), set the mode of the rectifier 210 (e.g., full sync mode, boost mode, etc.), and set the state of FETs 505-508 of the rectifier 210, etc. The microcontroller 910 can also execute code stored in memory to dynamically set the boost threshold, as previously described.

[0079] Exemplary embodiments of the invention are summarized herein. Other embodiments may also be understood from the entire specification and the claims filed herein.

[0080] Example 1. A method implemented by a wireless charging receiver (RX), the method comprising: detecting by the wireless charging RX that the voltage potential of the output of the rectifier of the wireless charging RX has reached a boost mode threshold; placing the rectifier in boost mode by the wireless charging RX; and detecting by the wireless charging RX that the voltage potential of the output of the rectifier of the wireless charging RX has reached a specified threshold, and on this basis, negotiating with a wireless charging transmitter (TX) to initiate power delivery.

[0081] Example 2. The method of Example 1, wherein the detection that the output voltage potential has reached the boost mode threshold occurs when the rectifier is in diode mode.

[0082] Example 3. The method according to either Example 1 or 2 further includes: when in boost mode: the wireless charging RX and the wireless charging TX negotiate to initiate power delivery at a fixed predetermined operating point of the wireless charging TX; and the wireless charging RX and the wireless charging TX participate in the power delivery.

[0083] Example 4. A method according to any one of Examples 1 to 3, wherein negotiating to initiate power delivery includes: identifying the wireless charging RX by the wireless charging RX; and configuring at least one of the wireless charging RX or the wireless charging TX by the wireless charging RX.

[0084] Example 5. The method according to any one of Examples 1 to 4, wherein negotiating to initiate power delivery includes: waking up the wireless charging RX by the wireless charging RX; and transmitting packets from the wireless charging RX to the wireless charging TX.

[0085] Example 6. The method of any one of Example 1 in 5, wherein the specified threshold includes the minimum operating voltage threshold (UVLO).

[0086] Example 7. The method of any one of Examples 1 to 6, wherein the minimum operating voltage threshold is greater than the boost mode threshold.

[0087] Example 8. The method according to any one of Examples 1 to 7, wherein participating in power delivery includes: determining by the wireless charging RX that the voltage potential of the rectifier's output has reached a full synchronization threshold, and on this basis, placing the rectifier in an active full-wave synchronous rectifier mode by the wireless charging RX.

[0088] Example 9. The method according to any one of Examples 1 to 8 further includes transmitting packets from the wireless charging RX to the wireless charging TX during at least one of the ping phase or the identification and configuration phase.

[0089] Example 10. A wireless charging receiver (RX) comprising: a non-transitory memory storage device including instructions; and one or more processors communicating with the memory storage device, wherein the one or more processors execute the instructions to cause the wireless charging RX to: detect that the voltage potential of the output of the rectifier of the wireless charging RX has exceeded a boost mode threshold; place the rectifier in boost mode; and detect that the voltage potential of the output of the rectifier of the wireless charging RX has reached a specified threshold, and on this basis, negotiate with a wireless charging transmitter (TX) to initiate power delivery.

[0090] Example 11. The wireless charging RX according to Example 10, wherein the rectifier is in diode mode before the output voltage potential exceeds the boost mode threshold.

[0091] Example 12. According to any one of Examples 10 or 11, the instruction also causes the wireless charging RX to: negotiate with the wireless charging TX when in boost mode to initiate power delivery at a fixed predetermined operating point of the wireless charging TX; and participate in power delivery with the wireless charging TX.

[0092] Example 13. According to any one of Examples 10 to 12, the instructions also cause the wireless charging RX to: identify the wireless charging RX; and configure at least one of the wireless charging RX or the wireless charging TX.

[0093] Example 14. Wireless charging RX according to any of Examples 10 to 13, wherein the specified thresholds include the minimum operating voltage threshold (UVLO).

[0094] Example 15. According to any of Examples 10 to 14, the wireless charging RX is further instructed to: determine that the voltage potential of the rectifier output has reached the full synchronization threshold, and on this basis, put the rectifier into active full-wave synchronous rectifier mode.

[0095] Example 16. A wireless charging receiver (RX) comprising: a rectifier operably coupled to a receiving resonant circuit, the rectifier being configured to output a direct current (DC) voltage based on received energy received by the receiving resonant circuit from a wireless charging transmitter (TX); a non-transitory memory storage device including instructions; and one or more controllers communicating with the memory storage device, wherein the one or more controllers execute instructions to cause the wireless charging RX to: detect that the voltage potential of the rectifier's output has exceeded a boost mode threshold; place the rectifier in boost mode; and detect that the voltage potential of the rectifier's output of the wireless charging RX has reached a specified threshold, and on this basis, negotiate with the wireless charging transmitter (TX) to initiate power delivery.

[0096] Example 17. According to the wireless charging RX of Example 16, the instruction also causes the wireless charging RX to: negotiate with the wireless charging TX when in boost mode to initiate power delivery at a fixed predetermined operating point of the wireless charging TX; and participate in power delivery with the wireless charging TX.

[0097] Example 18. According to the wireless charging RX of any one of Examples 16 or 17, the instructions also cause the wireless charging RX to: identify the wireless charging RX; and configure at least one of the wireless charging RX or the wireless charging TX.

[0098] Example 19. Wireless charging RX according to any of Examples 16 to 18, wherein the specified thresholds include the minimum operating voltage threshold (UVLO).

[0099] Example 20. A wireless charging RX according to any one of Examples 16 to 19, wherein the rectifier includes: a first input of the rectifier coupled to the output of the rectifier via a first high-side transistor and coupled to electrical ground via a coupled first low-side transistor; and a second input of the rectifier coupled to the output of the rectifier via a second high-side transistor and coupled to electrical ground via a second low-side transistor, wherein in boost mode, the state of the first high-side transistor and the state of the first low-side transistor are set according to the voltage potential of the first input of the rectifier, and wherein the state of the second high-side transistor is off and the state of the second low-side transistor is on.

[0100] Although the invention has been described with reference to illustrative embodiments, this description is not intended to be limiting. Various modifications and combinations of the illustrative embodiments and other embodiments of the invention will be apparent to those skilled in the art upon reference to this specification. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A method implemented by a wireless charging receiver RX, the method comprising: The wireless charging receiver RX detects that the output voltage potential of the rectifier of the wireless charging receiver RX has reached the boost mode threshold; The rectifier is placed in boost mode by the wireless charging receiver RX; as well as The wireless charging receiver RX detects that the voltage potential of the output of the rectifier of the wireless charging receiver RX has reached a specified threshold, and based on this, the wireless charging receiver RX negotiates with the wireless charging transmitter TX to initiate power transmission.

2. The method of claim 1, wherein the detection that the output voltage potential has reached the boost mode threshold occurs when the rectifier is in diode mode.

3. The method according to claim 1, further comprising: When in the boost mode: the wireless charging receiver RX and the wireless charging transmitter TX complete the negotiation to initiate the power transmission at a fixed predetermined operating point of the wireless charging transmitter TX; and the wireless charging receiver RX and the wireless charging transmitter TX participate in the power transmission.

4. The method of claim 3, wherein negotiating to initiate the power transmission comprises: The wireless charging receiver RX is identified by the wireless charging receiver RX; as well as The wireless charging receiver RX is configured with at least one of the wireless charging transmitter TX.

5. The method of claim 1, wherein negotiating to initiate the power transmission comprises: The wireless charging receiver RX is awakened by the wireless charging receiver RX; as well as The wireless charging receiver RX transmits packets to the wireless charging transmitter TX.

6. The method of claim 1, wherein the specified threshold includes a minimum operating voltage threshold UVLO.

7. The method of claim 6, wherein the minimum operating voltage threshold is greater than the boost mode threshold.

8. The method of claim 1, wherein participating in the power transmission comprises: The wireless charging receiver RX determines that the output voltage potential of the rectifier has reached the full synchronization threshold, and based on this, the wireless charging receiver RX puts the rectifier into active full-wave synchronous rectifier mode.

9. The method according to claim 8, further comprising: During at least one of the ping phase or the identification and configuration phase, the wireless charging receiver RX transmits packets to the wireless charging transmitter TX.

10. A wireless charging receiver RX, comprising: Non-transitory memory storage device, including instructions; and One or more processors communicate with the memory storage device, wherein the one or more processors execute the instructions to cause the wireless charging receiver RX: The voltage potential output of the rectifier of the wireless charging receiver RX has been detected to exceed the boost mode threshold. Set the rectifier to boost mode; as well as The voltage potential at the output of the rectifier of the wireless charging receiver RX has been detected to have reached a specified threshold, and based on this, the wireless charging transmitter TX is negotiated to initiate power transmission.

11. The wireless charging receiver RX of claim 10, wherein the rectifier is in diode mode before the output voltage potential exceeds the boost mode threshold.

12. The wireless charging receiver RX of claim 10, wherein the instruction further causes the wireless charging receiver RX to: negotiate with the wireless charging transmitter TX when in the boost mode to initiate the power delivery at a fixed predetermined operating point of the wireless charging transmitter TX; and participate in the power delivery with the wireless charging transmitter TX.

13. The wireless charging receiver RX of claim 12, wherein the instructions further cause the wireless charging receiver RX to: identify the wireless charging receiver RX; and configure at least one of the wireless charging receiver RX or the wireless charging transmitter TX.

14. The wireless charging receiver RX of claim 10, wherein the specified threshold includes a minimum operating voltage threshold UVLO.

15. The wireless charging receiver RX according to claim 10, wherein the instruction further causes the wireless charging receiver RX to: determine that the voltage potential of the output of the rectifier has reached the full synchronization threshold, and on this basis, to place the rectifier in an active full-wave synchronous rectifier mode.

16. A wireless charging receiver RX, comprising: A rectifier is operatively coupled to a receiving resonant circuit, the rectifier being configured to output a DC voltage based on received energy received by the receiving resonant circuit from the wireless charging transmitter TX. Non-transitory memory storage device, including instructions; and One or more controllers communicate with the memory storage device, wherein the one or more controllers execute the instructions to cause the wireless charging receiver RX: The voltage potential at the output of the rectifier has been detected to exceed the boost mode threshold. Set the rectifier to boost mode; as well as The system detects that the voltage potential of the output of the rectifier of the wireless charging receiver RX has reached a specified threshold, and based on this, negotiates with the wireless charging transmitter TX to initiate power transmission.

17. The wireless charging receiver RX of claim 16, wherein the instruction further causes the wireless charging receiver RX to: negotiate with the wireless charging transmitter TX when in the boost mode to initiate the power delivery at a fixed predetermined operating point of the wireless charging transmitter TX; and participate in the power delivery with the wireless charging transmitter TX.

18. The wireless charging receiver RX of claim 17, wherein the instructions further cause the wireless charging receiver RX to: identify the wireless charging receiver RX; and configure at least one of the wireless charging receiver RX or the wireless charging transmitter TX.

19. The wireless charging receiver RX of claim 16, wherein the specified threshold includes a minimum operating voltage threshold UVLO.

20. The wireless charging receiver RX of claim 16, wherein the rectifier comprises: The first input of the rectifier is coupled to the output of the rectifier through a first high-side transistor, and is coupled to electrical ground through a coupled first low-side transistor; as well as The second input of the rectifier is coupled to the output of the rectifier via a second high-side transistor, and is coupled to electrical ground via a second low-side transistor. In the boost mode, the state of the first high-side transistor and the state of the first low-side transistor are set according to the voltage potential of the first input of the rectifier, wherein the state of the second high-side transistor is off and the state of the second low-side transistor is on.

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