Regulating rectifier with adaptive current boosting and operation method thereof

Abstract

The invention provides a regulating rectifier and an operating method thereof. The regulating rectifier includes an output switch circuit, an energy storage switch circuit, an energy storage capacitor and a crossbar switch circuit. In a charging mode, the output switch circuit and the crossbar switch circuit together form a rectifier circuit to convert the wireless power received by a wireless charging induction coil into output power. In a current boosting mode, the output switch circuit, the energy storage switch circuit and the crossbar switch circuit jointly perform iterative operations (including DC-DC conversion and AC-DC conversion). The DC-DC conversion uses the electric energy of the energy storage capacitor to enhance the current of the wireless charging induction coil. The AC-DC conversion converts the wireless power of the wireless charging induction coil into the output power.

Description

Technical Field

[0001] This invention relates to a power supply circuit, and more particularly to a voltage regulator and rectifier with adaptive current enhancement function and its operating method. Prior Technology

[0002] Wireless charging technology has been widely applied in many fields. Taking electronic shelf labels as an example, when a charging device wirelessly powers the label, the angle and distance of the charging device will affect the wireless charging energy received by the receiver (label). That is, during the period when the charging device wirelessly powers the receiver, the wireless charging energy received by the receiver's wireless charging induction coil may fluctuate. How to effectively utilize the wireless charging energy received by the wireless charging induction coil to provide a more stable power supply voltage to other circuits of the receiver has become one of the many technical challenges in this field. Summary of the Invention

[0003] This invention provides a voltage regulator and rectifier and its operating method to convert wireless energy received by a wireless charging induction coil into output electrical energy.

[0004] In one embodiment of the present invention, the aforementioned voltage regulator includes an output switching circuit, an energy storage switching circuit, an energy storage capacitor, and a cross switch circuit. The common terminal of the output switching circuit is coupled to the output terminal of the voltage regulator. The first and second terminals of the input terminals of the voltage regulator are respectively coupled to the first and second terminals of the wireless charging induction coil. The first selection terminal of the output switching circuit is coupled to the first terminal of the wireless charging induction coil. The second selection terminal of the output switching circuit is coupled to the second terminal of the wireless charging induction coil. The first selection terminal of the energy storage switching circuit is coupled to the first terminal of the wireless charging induction coil. The second selection terminal of the energy storage switching circuit is coupled to the second terminal of the wireless charging induction coil. The first terminal of the energy storage capacitor is coupled to the common terminal of the energy storage switching circuit. The second terminal of the energy storage capacitor is coupled to a first reference voltage source. The first terminal of the cross switch circuit is coupled to the first terminal of the wireless charging induction coil. The second terminal of the cross switch circuit is coupled to the second terminal of the wireless charging induction coil. In charging mode, the output switching circuit and the cross-switch circuit together form the first rectifier circuit to convert the wireless energy received by the wireless charging induction coil into output electrical energy for the output of the rectifier. In current boosting mode (CBM), the output switching circuit, energy storage switching circuit, and cross-switch circuit jointly perform iterative operations, including DC-DC conversion and AC-DC conversion. The DC-DC conversion utilizes the stored energy in the energy storage capacitor to boost the current in the wireless charging induction coil. The AC-DC conversion converts the wireless energy of the wireless charging induction coil into output electrical energy for the output of the rectifier.

[0005] In one embodiment of the present invention, the above-described operation method includes: in response to the voltage regulator rectifier operating in charging mode, forming a first rectifier circuit by the output switching circuit and the cross-switching circuit of the voltage regulator rectifier to convert the wireless power received by the wireless charging induction coil into output electrical energy to the output terminal of the voltage regulator rectifier; and in response to the voltage regulator rectifier operating in current enhancement mode, performing iterative operations by the output switching circuit, the energy storage switching circuit and the cross-switching circuit of the voltage regulator rectifier, wherein the iterative operations include DC-DC conversion and AC-DC conversion, the DC-DC conversion using the stored electrical energy of the energy storage capacitor to enhance the current of the wireless charging induction coil, and the AC-DC conversion converting the wireless power of the wireless charging induction coil into output electrical energy to the output terminal of the voltage regulator rectifier.

[0006] Based on the above, the voltage regulator and rectifier described in the embodiments of the present invention can operate in multiple modes, such as charging mode and current boosting mode. During the wireless power supply of the receiver by the charging device, the wireless energy received by the receiver's wireless charging induction coil may fluctuate. When the wireless energy received by the wireless charging induction coil is sufficiently large, the voltage regulator and rectifier can operate in charging mode to convert the wireless energy received by the wireless charging induction coil into output power for other circuits (load circuits) of the receiver. When the wireless energy received by the wireless charging induction coil weakens, the voltage regulator and rectifier can operate in current boosting mode to perform iterative operations, such as DC-DC conversion and AC-DC conversion. Current boosting mode can utilize the stored energy of the energy storage capacitor to boost the current of the wireless charging induction coil (transferring the energy of the energy storage capacitor to the wireless charging induction coil), and then convert the boosted energy of the wireless charging induction coil into output power. Therefore, the voltage regulator and rectifier can effectively utilize the wireless charging energy received by the wireless charging induction coil, thereby providing a more stable power supply voltage to other circuits of the receiver.

[0007] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Simple Explanation of the Diagram

[0008] Figure 1 is a schematic diagram of a circuit block of a wireless power receiver according to an embodiment of the present invention. Figure 2 is a circuit block diagram of a voltage regulator rectifier according to an embodiment of the present invention. Figure 3 is a schematic flowchart of an operation method of a voltage regulator rectifier according to an embodiment of the present invention. Figure 4 is a circuit diagram illustrating an output switch circuit, an energy storage switch circuit, and a cross switch circuit according to an embodiment of the present invention. Figure 5 is a schematic diagram of voltage waveforms in different operating modes according to an embodiment of the present invention. Figure 6 is a schematic diagram of the voltage waveform in current enhancement mode according to an embodiment of the present invention. Implementation

[0009] The term "coupled (or connected)" as used throughout this specification (including the claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted as the first device being directly connected to the second device, or the first device being indirectly connected to the second device through other devices or some means of connection. The terms "first," "second," etc., used throughout this specification (including the claims) are used to name elements or distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit of the number of elements, nor to limit the order of elements. Furthermore, wherever possible, elements / components / steps using the same reference numerals in the drawings and embodiments represent the same or similar parts. Elements / components / steps using the same reference numerals or the same terms in different embodiments may be referred to mutually in the relevant descriptions.

[0010] Figure 1 is a circuit block diagram of a wireless power receiver 100 according to an embodiment of the present invention. The wireless power receiver 100 can be applied to various electronic products. Taking electronic shelf applications as an example (but not limited to this), the wireless power receiver 100 can be an electronic shelf label. The wireless power receiver 100 shown in Figure 1 includes a wireless charging induction coil 110, a voltage regulator rectifier 120, and a functional circuit 130 (load circuit). The voltage regulator rectifier 120 can supply power to the functional circuit 130. A charging device (not shown) transmits wireless charging energy Ein1 to the wireless power receiver 100. When the charging device transmits wireless charging energy Ein1, the wireless charging induction coil 110 can sense the wireless charging energy Ein1 from the charging device and generate wireless energy Ein2 for the voltage regulator rectifier 120. The voltage regulator rectifier 120 converts the wireless energy Ein2 of the wireless charging induction coil 110 into output electrical energy Eout1 for the functional circuit 130.

[0011] The voltage regulator rectifier 120 can operate in various modes, such as, but not limited to, charging mode and current boost mode. In the embodiment shown in FIG1, the voltage regulator rectifier 120 includes a voltage regulator circuit 121 and an energy storage capacitor Csto1. When the wireless charging energy Ein1 received by the wireless charging induction coil 110 is sufficiently large, the voltage regulator circuit 121 can operate in charging mode to convert the wireless energy Ein2 of the wireless charging induction coil 110 into output energy Eout1 for the functional circuit 130. The angle and distance of the charging device (not shown) relative to the wireless energy receiver 100 will affect the wireless charging energy Ein1 received by the wireless charging induction coil 110. In other words, the wireless charging energy Ein1 received by the wireless charging induction coil 110 may vary. When the wireless charging energy Ein1 received by the wireless charging induction coil 110 is sufficiently large, the voltage regulator circuit 121 can also store the wireless energy Ein2 of the wireless charging induction coil 110 in the energy storage capacitor Csto1. When the wireless charging energy Ein1 received by the wireless charging induction coil 110 weakens, the voltage regulator circuit 121 can operate in current enhancement mode to perform iterative operation. This iterative operation uses the stored energy of the energy storage capacitor Csto1 to enhance the current of the wireless charging induction coil 110 (i.e., transfer the energy of the energy storage capacitor Csto1 to the wireless charging induction coil 110), and then converts the enhanced energy of the wireless charging induction coil 110 into output energy Eout1 for the functional circuit 130. Therefore, the voltage regulator rectifier 120 can effectively utilize the wireless charging energy Ein1 received by the wireless charging induction coil 110, thereby providing a more stable power supply voltage to the functional circuit 130.

[0012] Figure 2 is a circuit block diagram of a voltage regulator rectifier 200 according to an embodiment of the present invention. The first and second terminals of the input terminal pair of the voltage regulator rectifier 200 are respectively coupled to the first and second terminals of the wireless charging induction coil 20. The wireless charging induction coil 20 and the voltage regulator rectifier 200 shown in Figure 2 can be deduced by referring to the relevant descriptions of the wireless charging induction coil 110 and the voltage regulator rectifier 120 shown in Figure 1.

[0013] In the embodiment shown in Figure 2, the voltage regulator rectifier 200 includes an output switching circuit 210, an energy storage switching circuit 220, an energy storage capacitor Csto, and a cross switch circuit 230. The output switching circuit 210, energy storage switching circuit 220, and cross switch circuit 230 shown in Figure 2 can be considered as one of many implementation examples of the voltage regulator circuit 121 shown in Figure 1. The output switching circuit 210, energy storage switching circuit 220, and cross switch circuit 230 shown in Figure 2 can be deduced by referring to the relevant description of the voltage regulator circuit 121 shown in Figure 1.

[0014] The common terminal of the output switching circuit 210 is coupled to the output terminal of the voltage regulator rectifier 200 to provide output power Eout2 to the load circuit (not shown). The output power Eout2 shown in Figure 2 can be deduced from the relevant description of the output power Eout1 shown in Figure 1, and therefore will not be repeated. The first selection terminal of the output switching circuit 210 is coupled to the first terminal of the wireless charging induction coil 20. The second selection terminal of the output switching circuit 210 is coupled to the second terminal of the wireless charging induction coil 20.

[0015] The first selection terminal of the energy storage switch circuit 220 is coupled to the first terminal of the wireless charging induction coil 20. The second selection terminal of the energy storage switch circuit 220 is coupled to the second terminal of the wireless charging induction coil 20. The first terminal of the energy storage capacitor Csto is coupled to the common terminal of the energy storage switch circuit 220. The second terminal of the energy storage capacitor Csto is coupled to a reference voltage source (e.g., ground voltage source GND). The energy storage capacitor Csto shown in Figure 2 can be deduced from the relevant description of the energy storage capacitor Csto1 shown in Figure 1, and therefore will not be repeated. The first terminal of the cross switch circuit 230 is coupled to the first terminal of the wireless charging induction coil 20. The second terminal of the cross switch circuit 230 is coupled to the second terminal of the wireless charging induction coil 20.

[0016] Figure 3 is a schematic flowchart of an operation method of a voltage regulator rectifier according to an embodiment of the present invention. Referring to Figures 2 and 3, in response to the voltage regulator rectifier 200 operating in charging mode (CHM), the output switching circuit 210 and the cross-switch circuit 230 form a rectifier circuit (first rectifier circuit) to convert the wireless energy received by the wireless charging induction coil 20 into output electrical energy Eout2 and supply it to the output terminal of the voltage regulator rectifier 200 (step S310).

[0017] In response to the regulated rectifier 200 operating in current boosting mode (CBM), the output switching circuit 210, the energy storage switching circuit 220, and the crossover switching circuit 230 jointly perform an iterative operation (step S320). This iterative operation includes at least DC-DC conversion and AC-DC conversion. The DC-DC conversion utilizes the stored energy in the energy storage capacitor Csto to boost the current in the wireless charging induction coil 20. That is, the energy storage switching circuit 220 transfers the stored energy in the energy storage capacitor Csto to the wireless charging induction coil 20. Then, the AC-DC conversion converts the wireless power (boosted power) of the wireless charging induction coil 20 into output power Eout2, which is supplied to the output terminal of the regulated rectifier 200.

[0018] In summary, the voltage regulator rectifier 200 can operate in multiple modes, such as charging mode and current boosting mode. When the wireless power received by the wireless charging induction coil 20 is sufficiently large, the voltage regulator rectifier 200 can operate in charging mode to convert the wireless power received by the wireless charging induction coil 20 into output power Eout2 for other circuits (load circuit, not shown). When the wireless power received by the wireless charging induction coil 20 weakens, the voltage regulator rectifier 200 can operate in current boosting mode to perform iterative operations, such as DC-DC conversion and AC-DC conversion. The current boosting mode can utilize the stored energy of the energy storage capacitor Csto to boost the current of the wireless charging induction coil 20 (transferring the energy of the energy storage capacitor Csto to the wireless charging induction coil 20), and then convert the boosted energy of the wireless charging induction coil 20 into output power Eout2. Therefore, the voltage regulator rectifier 200 can effectively utilize the wireless charging energy received by the wireless charging induction coil 20, thereby providing a more stable power supply voltage to the load circuit.

[0019] Based on practical design, in some applications, the DC-DC conversion in current-boosting mode includes a first phase and a second phase. In the first phase, the energy storage switch circuit 220 uses the stored energy of the energy storage capacitor Csto to boost the current of the wireless charging induction coil 20. In the second phase, the output switch circuit 210 outputs the current of the wireless charging induction coil 20 to the output terminal of the voltage regulator rectifier 200.

[0020] In some applications, the regulated rectifier 200 can also operate in storage mode (STM) and free-wheeling mode (FWM). In storage mode, the energy storage switch circuit 220 and the cross switch circuit 230 together form a second rectifier circuit to store the wireless energy of the wireless charging induction coil 20 in the storage capacitor Csto. In free-wheeling mode, the energy storage switch circuit 220 and the output switch circuit 210 are turned off, and the cross switch circuit 230 grounds the first and second terminals of the wireless charging induction coil 20.

[0021] In response to a situation where the input power of the wireless power received by the wireless charging induction coil 20 is greater than the output power of the voltage regulator 200, the voltage regulator 200 adjusts its output voltage between a first threshold voltage and a second threshold voltage, wherein the first threshold voltage is greater than the second threshold voltage. The first and second threshold voltages can be determined based on the actual design and application. In response to a situation where the input power of the wireless charging induction coil 20 is less than the output power of the voltage regulator 200, the voltage regulator 200 adjusts its output voltage between a second threshold voltage and a third threshold voltage, wherein the second threshold voltage is greater than the third threshold voltage. The third threshold voltage can be determined based on the actual design and application.

[0022] In response to the input power of the wireless power received by the wireless charging induction coil 20 being greater than the output power of the voltage regulator 200, the voltage regulator 200 selectively operates in one of the following modes: charging mode, energy storage mode, and idling mode. In response to the input power being less than the output power, the voltage regulator selectively operates in one of the following modes: charging mode and current enhancement mode, so as to generate the output power of the voltage regulator 200 using the wireless power received by the wireless charging induction coil 20 and the stored energy in the energy storage capacitor Csto.

[0023] When the output voltage at the output terminal of the voltage regulator 200 exceeds the first threshold voltage, the voltage regulator 200 enters the energy storage mode. When the stored voltage of the energy storage capacitor Csto exceeds the first threshold voltage, the voltage regulator 200 transitions from the energy storage mode to the idle mode. When the output voltage of the voltage regulator 200 falls below the second threshold voltage, the voltage regulator 200 transitions from the idle mode to the charging mode.

[0024] When the output voltage at the output terminal of the voltage regulator 200 is less than the hysteresis window defined by the first and second threshold voltages, the voltage regulator 200 enters charging mode. When the output voltage of the voltage regulator 200 is less than the third threshold voltage, the voltage regulator 200 transitions from charging mode to current boosting mode. When the output voltage of the voltage regulator 200 is greater than the first threshold voltage, the voltage regulator 200 exits current boosting mode.

[0025] Figure 4 is a circuit diagram illustrating the output switch circuit 210, energy storage switch circuit 220, and cross switch circuit 230 according to an embodiment of the present invention. The output switch circuit 210, energy storage switch circuit 220, and cross switch circuit 230 shown in Figure 4 can be one of many embodiments of the output switch circuit 210, energy storage switch circuit 220, and cross switch circuit 230 shown in Figure 2. In the embodiment shown in Figure 4, the voltage regulator further includes a resonant capacitor Cc and an output capacitor Cout. The first end of the resonant capacitor Cc is coupled to the first end of the wireless charging induction coil 20. The second end of the resonant capacitor Cc is coupled to the second end of the wireless charging induction coil 20. The first end of the output capacitor Cout is coupled to the common terminal of the output switch circuit 210. The second end of the output capacitor Cout is coupled to a reference voltage source (e.g., ground voltage source GND).

[0026] In the embodiment shown in Figure 4, the output switch circuit 210 includes switches MP1 and MP2. Switch MP1 is controlled by control signal VGP1, while switch MP2 is controlled by control signal VGP2. A first terminal of the first switch MP1 is coupled to a first selection terminal of the output switch circuit 210, that is, coupled to a first terminal of the wireless charging induction coil 20. A second terminal of switch MP1 is coupled to a common terminal of the output switch circuit 210. The common terminal of the output switch circuit 210 is used to provide an output voltage Vout to a load circuit (not shown). A first terminal of switch MP2 is coupled to a second selection terminal of the output switch circuit 210, that is, coupled to a second terminal of the wireless charging induction coil 20. A second terminal of switch MP2 is coupled to a common terminal of the output switch circuit 210.

[0027] In response to the regulated rectifier 200 operating in charging mode, switches MP1 and MP2 are alternately turned on to convert the AC power of the wireless charging induction coil 20 into DC power and output the DC power to the common terminal of the output switching circuit 210. In response to the regulated rectifier 200 operating in current-boosting mode and the crossover switching circuit 230 performing DC-DC conversion, one of switches MP1 and MP2 is turned on while the other is turned off. The "DC-DC conversion performed by the crossover switching circuit 230" will be explained later.

[0028] In response to the regulated rectifier 200 operating in current-boosting mode and the crossover switch circuit 230 performing AC-DC conversion, switches MP1 and MP2 are alternately turned on to convert the AC power of the wireless charging induction coil 20 into DC power. The "AC-DC conversion performed by the crossover switch circuit 230" will be explained later. In response to the regulated rectifier 200 operating in energy storage mode and idling mode, switches MP1 and MP2 are turned off.

[0029] In the embodiment shown in Figure 4, the energy storage switch circuit 220 includes switches MP3 and MP4. Switch MP3 is controlled by control signal VGP3, while switch MP4 is controlled by control signal VGP4. A first terminal of switch MP4 is coupled to a first selection terminal of the energy storage switch circuit 220, i.e., coupled to a first terminal of the wireless charging induction coil 20. A first terminal of switch MP3 is coupled to a second selection terminal of the energy storage switch circuit 220, i.e., coupled to a second terminal of the wireless charging induction coil 20. The second terminals of switches MP3 and MP4 are coupled to a common terminal of the energy storage switch circuit 220. A second terminal of switch MP3 is coupled to the common terminal of the energy storage switch circuit 220, i.e., coupled to the energy storage capacitor Csto. A first terminal of the energy storage capacitor Csto provides a storage voltage Vsto. A second terminal of the energy storage capacitor Csto is coupled to a reference voltage source (e.g., ground voltage source GND).

[0030] In response to the rectifier 200 operating in charging mode, switches MP3 and MP4 are off. In response to the rectifier 200 operating in current boost mode and the cross switch circuit 230 performing DC-DC conversion, one of switches MP3 and MP4 is on while the other is off. The "cross switch circuit 230 performing AC-DC conversion" will be explained later. In response to the rectifier 200 operating in current boost mode and the cross switch circuit 230 performing AC-DC conversion, switches MP3 and MP4 are off. The "cross switch circuit 230 performing AC-DC conversion" will be explained later. In response to the rectifier 200 operating in energy storage mode, switches MP3 and MP4 are alternately turned on to convert the AC power of the wireless charging induction coil 20 into DC power and store the DC power in the energy storage capacitor Csto. In response to the rectifier 200 operating in idling mode, switches MP3 and MP4 are off.

[0031] In the embodiment shown in Figure 4, the cross switch circuit 230 includes switches MN1, MN2, SW1, and SW2. A first terminal of switch MN1 is coupled to a first terminal of the wireless charging induction coil 20. A first terminal of switch MN2 is coupled to a second terminal of the wireless charging induction coil 20. The second terminals of switches MN1 and MN2 are coupled to a reference voltage source (e.g., ground voltage source GND). Switch SW1 has a first selection terminal, a second selection terminal, and a common terminal. The common terminal of switch SW1 is coupled to the control terminal of switch MN1. The first selection terminal of switch SW1 is coupled to the second terminal of the wireless charging induction coil 20. The second selection terminal of switch SW1 receives a gate control signal VGN1. Switch SW2 has a first selection terminal, a second selection terminal, and a common terminal. The common terminal of switch SW2 is coupled to the control terminal of switch MN2. The first selection terminal of switch SW2 is coupled to the first terminal of the wireless charging induction coil 20. The second selection terminal of switch SW2 receives a gate control signal VGN2.

[0032] In response to the regulated rectifier 200 operating in charging mode, switch SW1 couples the second terminal of the wireless charging induction coil 20 to the control terminal of switch MN1, and switch SW2 couples the first terminal of the wireless charging induction coil 20 to the control terminal of switch MN2. At this time, switch MN1 is controlled by the AC voltage VAC2 at the second terminal of the wireless charging induction coil 20, while switch MN2 is controlled by the AC voltage VAC1 at the first terminal of the wireless charging induction coil 20.

[0033] In response to the regulated rectifier 200 operating in current-boosting mode and the cross-switch circuit 230 performing DC-DC conversion, switch SW1 transmits a gate control signal VGN1 to the control terminal of switch MN1, and switch SW2 transmits a gate control signal VGN2 to the control terminal of switch MN2. At this time, switch MN1 is controlled by control signal VGN1, and switch MN2 is controlled by control signal VGN2. In the current-boosting mode DC-DC conversion, one of switches MN1 and MN2 is on while the other is off. For example, the current-boosting mode DC-DC conversion includes a first phase and a second phase. In the first phase, switch MN1 is on and switch MN2 is off to utilize the stored energy in the energy storage capacitor Csto to boost the current of the wireless charging induction coil 20. In the second phase, switch MN1 is off and switch MN2 is on to output the current of the wireless charging induction coil 20 to the output terminal of the regulated rectifier 200.

[0034] In response to the regulated rectifier 200 operating in current-boosting mode and the cross-switch circuit performing AC-DC conversion, switch SW1 couples the second terminal of the wireless charging induction coil 20 to the control terminal of switch MN1, and switch SW2 couples the first terminal of the wireless charging induction coil 20 to the control terminal of switch MN2. At this time, switch MN1 is controlled by the AC voltage VAC2 at the second terminal of the wireless charging induction coil 20, while switch MN2 is controlled by the AC voltage VAC1 at the first terminal of the wireless charging induction coil 20.

[0035] In response to the regulated rectifier 200 operating in energy storage mode, switch SW1 couples the second terminal of the wireless charging induction coil 20 to the control terminal of switch MN1, and switch SW2 couples the first terminal of the wireless charging induction coil 20 to the control terminal of switch MN2. At this time, switch MN1 is controlled by the AC voltage VAC2 at the second terminal of the wireless charging induction coil 20, while switch MN2 is controlled by the AC voltage VAC1 at the first terminal of the wireless charging induction coil 20.

[0036] In response to the regulated rectifier 200 operating in idling mode, switch SW1 transmits the gate control signal VGN1 to the control terminal of switch MN1, and switch SW2 transmits the gate control signal VGN2 to the control terminal of switch MN2, so that switches SW1 and SW2 are turned on.

[0037] In summary, switches MN1 and MN2 can automatically switch between cross-coupling and gate drive control, while switches MP1, MP2, MP3, and MP4 can each generate two outputs (output voltage Vout and stored voltage Vsto). The output voltage Vout has priority for charging. Therefore, while providing a stable output voltage Vout, the voltage regulator rectifier 200 can effectively store excess energy in the energy storage capacitor Csto and reuse the energy stored in Csto when needed.

[0038] When the receiving power of the wireless charging induction coil 20 is sufficient, the system controls the voltage regulator rectifier 200 to preferentially enter the charging mode, providing the output voltage Vout through the rectifier. For example, in the charging mode, switch MN1 is controlled by the AC voltage VAC2 at the second terminal of the wireless charging induction coil 20, while switch MN2 is controlled by the AC voltage VAC1 at the first terminal of the wireless charging induction coil 20. In the first AC phase, switches MP1 and MN2 are on, while switches MP2, MP3, MP4, and MN1 are off, allowing the current from the wireless charging induction coil 20 to be output to the output terminal of the voltage regulator rectifier 200. In the second AC phase, switches MP2 and MN1 are on, while switches MP1, MP3, MP4, and MN2 are off, allowing the current from the wireless charging induction coil 20 to be output to the output terminal of the voltage regulator rectifier 200.

[0039] Once the output voltage Vout reaches the target voltage, the system switches the operating mode of the voltage regulator rectifier 200 to energy storage mode. Through the rectifier's operation, the voltage regulator rectifier 200 stores excess received power from the wireless charging induction coil 20 in the energy storage capacitor Csto as backup energy. For example, in energy storage mode, switch MN1 is controlled by the AC voltage VAC2 at the second terminal of the wireless charging induction coil 20, while switch MN2 is controlled by the AC voltage VAC1 at the first terminal of the wireless charging induction coil 20. In the first AC phase, switches MP3 and MN1 are on, while switches MP1, MP2, MP4, and MN2 are off, allowing the current from the wireless charging induction coil 20 to be output to the energy storage capacitor Csto. In the second AC phase, switches MP4 and MN2 are on, while switches MP1, MP2, MP3, and MN1 are off, allowing the current from the wireless charging induction coil 20 to be output to the energy storage capacitor Csto.

[0040] Once the output voltage Vout reaches the target voltage and the energy storage capacitor Csto is fully charged, the system controls the voltage regulator rectifier 200 to enter idle mode, stopping the supply of output voltage Vout and stored voltage Vsto. For example, in idle mode, switch MN1 remains on under control signal VGN1, and switch MN2 remains on under control signal VGN2. Switches MP1, MP2, MP3, and MP4 remain off in idle mode.

[0041] When the received power of the wireless charging induction coil 20 is insufficient to support the output load, the system controls the voltage regulator rectifier 200 to enter current enhancement mode. In current enhancement mode, the voltage regulator rectifier 200 utilizes the reserve energy of the energy storage capacitor Csto to increase the output current of the voltage regulator rectifier 200, thereby maintaining the voltage regulation function of the output voltage Vout. The iterative operations performed by the voltage regulator rectifier 200 in current enhancement mode include DC-DC conversion and AC-DC conversion, wherein the DC-DC conversion includes a first phase and a second phase. In current enhancement mode, switch MN1 is controlled by control signal VGN1, and switch MN2 is controlled by control signal VGN2. In the first phase, switches MP3 and MN1 are turned on, while switches MP1, MP2, MP4, and MN2 are turned off, allowing the current of the energy storage capacitor Csto to be output to the wireless charging induction coil 20. In the second phase, switches MP1 and MN2 are on while switches MP2, MP3, MP4, and MN1 are off, allowing the current from the wireless charging induction coil 20 to be output to the output terminal of the voltage regulator rectifier 200. The operation of the voltage regulator rectifier 200 in the AC-DC conversion process can be referred to the relevant description of the charging mode, and therefore will not be repeated here.

[0042] Figure 5 is a schematic diagram of voltage waveforms in different operating modes according to an embodiment of the present invention. The horizontal axis of Figure 5 represents time t. The operating mode presented in Figure 5 includes a voltage regulation mechanism consisting of three threshold voltages VRH1, VRL1, and VRB1 (VRH1 > VRL1 > VRB1) to automatically detect the received power and activate the current enhancement mode as appropriate. The voltage regulation of the storage voltage Vsto is achieved through two threshold voltages VRH2 and VRL2 (VRH2 > VRL2). The system adopts an energy reuse design, prioritizing the voltage regulation requirements of the output voltage Vout and storing excess energy in the energy storage capacitor Csto.

[0043] The system operates in two states: "sufficient received power" and "insufficient received power". When the received power of the wireless charging induction coil 20 is sufficient, the output voltage Vout is regulated between the threshold voltage VRH1 and the threshold voltage VRL1. The threshold voltages VRH1 and VRL1 define a hysteresis window. In the "sufficient received power" state, the operating mode of the voltage regulator rectifier 200 is switched between charging mode CHM, energy storage mode STM, and idle mode FWM to maintain the regulated state of the output voltage Vout and the stored voltage Vsto. These mode switching occurs when the received power of the wireless charging induction coil 20 is sufficient to meet the load demand.

[0044] When the output voltage Vout is lower than the threshold voltage VRL1, the regulated rectifier 200 enters charging mode CHM to charge the output capacitor Cout until the output voltage Vout exceeds the threshold voltage VRH1. In response to the regulated rectifier 200 operating in charging mode CHM, the output switching circuit 210 and the cross-switch circuit 230 form a rectifier circuit to convert the wireless power received by the wireless charging induction coil 20 into an output voltage Vout for the energy storage capacitor Csto. Specifically, when the regulated rectifier 200 operates in charging mode, switches MP1 and MP2 are alternately turned on (other switches are off) to convert the AC power of the wireless charging induction coil 20 into DC power and output the DC power to the energy storage capacitor Csto.

[0045] If the output capacitor Cout does not need charging and the storage voltage Vsto is lower than the threshold voltage VRL2, the regulated rectifier 200 enters energy storage mode STM to charge the energy storage capacitor Csto until the storage voltage Vsto exceeds VRH2. If neither the output capacitor Cout nor the energy storage capacitor Csto needs charging, the regulated rectifier 200 enters idle mode FWM to stop charging both. Specifically, in response to the storage voltage Vsto of the energy storage capacitor Csto being greater than the threshold voltage VRH2, the regulated rectifier 200 enters idle mode FWM from energy storage mode STM. In response to the output voltage Vout of the regulated rectifier 200 being less than the hysteresis window defined by the threshold voltages VRH1 and VRL1, the regulated rectifier 200 returns from idle mode FWM to charging mode CHM.

[0046] When the received power of the wireless charging induction coil 20 is insufficient, the output voltage Vout will drop from the hysteresis window originally formed by the threshold voltages VRH1 and VRL1 to between the threshold voltages VRL1 and VRB1. In the "insufficient received power" state, the voltage regulator rectifier 200 periodically switches to the current boost mode CBM on top of the charging mode CHM to compensate for the insufficient received power of the wireless charging induction coil 20. Specifically, when the output voltage Vout is lower than the threshold voltage VRB1, the voltage regulator rectifier 200 switches from the charging mode CHM to the current boost mode CBM to charge the output capacitor Cout. In addition to the wireless power received by the wireless charging induction coil 20, the voltage regulator rectifier 200 also uses the energy in the energy storage capacitor Csto to supplement the energy of the wireless charging induction coil 20 in the current boost mode CBM, causing the output voltage Vout to gradually rise. The voltage regulator rectifier 200 ends the current boost mode CBM and switches back to the charging mode CHM only when the output voltage Vout exceeds the threshold voltage VRL1.

[0047] When changes in the transmission environment cause a temporary shortage of received power, the output voltage Vout will continue to decrease even if all the received power of the wireless charging induction coil 20 is used to charge the output voltage Vout. This can be detected by checking if the output voltage Vout is below the threshold voltage VRB1 to activate the current boost mode. At this time, the voltage regulator rectifier 200 operates in both charging mode and current boost mode to charge the output voltage Vout. Therefore, once the received power of the wireless charging induction coil 20 is sufficient to handle the output power again, the output voltage Vout will continue to be charged and increase until it reaches the threshold voltage VRH1.

[0048] If the received power of the wireless charging induction coil 20 is still insufficient to support the load, the output voltage Vout will continue to decrease in charging mode until it falls below the threshold voltage VRB1 again and restarts the current boost mode. Conversely, when the received power is sufficient, the output voltage Vout will gradually rise until it exceeds the threshold voltage VRH1, at which point the charging mode will end and the system will switch to energy storage mode or idling mode as needed.

[0049] Figure 6 is a waveform diagram of voltage in current enhancement mode according to an embodiment of the present invention. The horizontal axis of Figure 6 represents time. The current enhancement mode is used to address situations where the received power is insufficient to load the output power. It injects the energy stored in the energy storage capacitor Csto into the original inductor current IL, thereby enhancing the charging current for the output voltage Vout. The iterative operation performed in the current enhancement mode includes DC-DC conversion and AC-DC conversion Ø3, wherein the DC-DC conversion includes a first phase Ø1 and a second phase Ø2. Referring to Figures 4 and 6, in the first phase Ø1, the control switches MN1 and MN are controlled by control signals VGN1 and VGN2. Switches MP3 and MN1 are turned on based on the control signals VGP1 and VGN1 (the other switches remain off). At this time, the energy in the energy storage capacitor Csto is transferred to the wireless charging induction coil 20 to increase the inductor current IL.

[0050] In the second phase Ø2, the gates of switches MN1 and MN2 continue to be controlled by control signals VGN1 and VGN2. At this time, control signals VGP1 and VGN2 turn on switches MP1 and MN2, while the remaining switches remain closed. The energy accumulated in the wireless charging induction coil 20 in the first phase Ø1 is released to the output capacitor Cout. That is, the inductor current IL charges the output voltage Vout through the charging path formed by switches MP1 and MN2. At this time, the charging current for the output capacitor Cout no longer depends solely on the AC power received by the wireless charging induction coil 20, but can utilize the energy in the energy storage capacitor Csto to replenish the charge of the output capacitor Cout (further increasing the charging current for the output voltage Vout).

[0051] Finally, in AC-DC conversion Ø3, the gates of switches MN1 and MN2 will switch to cross-coupled control, meaning switch MN1 is controlled by AC voltage VAC2, and switch MN2 is controlled by AC voltage VAC1. During this stage, the circuit operates as if it were rectifying in charging mode (refer to the relevant description of charging mode). Charging mode (AC-DC conversion Ø3) converts the AC power received by the wireless charging induction coil 20 from AC to DC to charge the output capacitor Cout.

[0052] Adjusting the duration of the first phase Ø1 controls the increase in inductor current IL. In other words, the longer the first phase Ø1 lasts, the more energy stored in the capacitor Csto is transferred to the wireless charging induction coil 20, further enhancing the inductor current IL and the output charging current. When the first phase Ø1 ends, the system (control circuit, not shown) triggers the start of the second phase Ø2; the end time of the second phase Ø2 is determined by the control circuit detecting when the inductor current IL drops to zero. Subsequently, AC-DC conversion Ø3 begins, and the end of AC-DC conversion Ø3 is determined by the control circuit when to trigger the first phase Ø1 again.

[0053] In summary, the above embodiments propose a voltage regulator rectifier 200 with adaptive current enhancement, which can utilize the energy in the energy storage capacitor Csto to increase the output charging current, thereby enhancing the charging capability of the output. When the received power is sufficient, it operates similarly to a typical single-stage voltage regulator rectifier, but the system can adaptively activate this current enhancement mode according to the current input power conditions. This technology is applicable to various short-term situations with insufficient received power and is not limited by the relationship between the stored voltage Vsto and the output voltage Vout. Therefore, in addition to more efficiently utilizing input power, it further improves the ability to withstand input power variations, expands the maximum loadable output power, and enables more flexible circuit specification design.

[0054] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0055] 100: Wireless Power Receiver 110, 20: Wireless charging induction coil 120, 200: Voltage Regulator / Rectifier 121: Voltage Regulator Circuit 130: Functional Circuit 210: Output switching circuit 220: Energy storage switch circuit 230: Cross switch circuit CBM: Current Enhancement Mode Cc: Resonant capacitor CHM: Charging Mode Cout: Output capacitor Csto, Csto1: Energy storage capacitors Ein1: Wireless charging energy Ein2: Wireless power Eout1, Eout2: Output electrical energy FWM: Idle Mode GND: Grounding voltage source IL: Inductor current MN1, MN2, MP1, MP2, MP3, MP4, SW1, SW2: Switches S310, S320: Steps STM: Energy Storage Mode t: time VGN1, VGN2, VGP1, VGP2, VGP3, VGP4: Control signals VAC1, VAC2: AC voltage Vout: Output voltage VRH1, VRH2, VRL1, VRL2, VRB1: Threshold voltage Vsto: Stored voltage Ø1: First phase Ø2: Second phase Ø3: AC to DC conversion

Claims

1. A voltage regulator and rectifier, comprising: An output switch circuit has a first selection terminal, a second selection terminal, and a common terminal, wherein the common terminal of the output switch circuit is coupled to an output terminal of a voltage regulator and rectifier, a first terminal and a second terminal of an input terminal pair of the voltage regulator and rectifier are respectively coupled to a first terminal and a second terminal of a wireless charging induction coil, the first selection terminal of the output switch circuit is coupled to the first terminal of the wireless charging induction coil, and the second selection terminal of the output switch circuit is coupled to the second terminal of the wireless charging induction coil; an energy storage switch circuit has a first selection terminal, a second selection terminal, and a common terminal, wherein the first selection terminal of the energy storage switch circuit is coupled to the first terminal of the wireless charging induction coil, and the second selection terminal of the energy storage switch circuit is coupled to the second terminal of the wireless charging induction coil; An energy storage capacitor, wherein a first terminal of the energy storage capacitor is coupled to a common terminal of the energy storage switching circuit, and a second terminal of the energy storage capacitor is coupled to a first reference voltage source; and a cross switch circuit having a first terminal and a second terminal, wherein the first terminal of the cross switch circuit is coupled to the first terminal of the wireless charging induction coil, and the second terminal of the cross switch circuit is coupled to the second terminal of the wireless charging induction coil. In response to the regulated rectifier operating in a charging mode, the output switching circuit and the cross switch circuit together form a first rectifier circuit to convert wireless power received by the wireless charging induction coil into output power for the output terminal of the regulated rectifier; and in response to the regulated rectifier operating in a current boosting mode, the output switching circuit, the energy storage switching circuit, and the cross switch circuit together perform an iterative operation, wherein the iterative operation includes DC-DC conversion and AC-DC conversion, the DC-DC conversion using a stored energy in the energy storage capacitor to boost the current of the wireless charging induction coil, and the AC-DC conversion converting the wireless power of the wireless charging induction coil into output power for the output terminal of the regulated rectifier.

2. The voltage regulator rectifier as claimed in claim 1, wherein the DC-DC conversion in the current enhancement mode includes a first phase and a second phase, wherein in the first phase the energy storage switch circuit uses the stored energy of the energy storage capacitor to enhance the current of the wireless charging induction coil, and in the second phase the output switch circuit outputs the current of the wireless charging induction coil to the output terminal of the voltage regulator rectifier.

3. The voltage regulator and rectifier as claimed in claim 1, wherein in response to the voltage regulator and rectifier operating in an energy storage mode, the energy storage switch circuit and the cross switch circuit together form a second rectifier circuit to store the wireless energy of the wireless charging induction coil in the energy storage capacitor; and in response to the voltage regulator and rectifier operating in an idle mode, the energy storage switch circuit and the output switch circuit are turned off, and the cross switch circuit grounds the first terminal and the second terminal of the wireless charging induction coil.

4. The voltage regulator as claimed in claim 1, wherein in response to an input power of the wireless power received by the wireless charging induction coil being greater than an output power at the output terminal of the voltage regulator, the voltage regulator adjusts an output voltage at the output terminal of the voltage regulator between a first threshold voltage and a second threshold voltage, the first threshold voltage being greater than the second threshold voltage; and in response to an input power being less than the output power, the voltage regulator adjusts the output voltage at the output terminal of the voltage regulator between the second threshold voltage and a third threshold voltage, the second threshold voltage being greater than the third threshold voltage.

5. The voltage regulator as claimed in claim 1, wherein, in response to an input power of the wireless power received by the wireless charging induction coil being greater than an output power at the output of the voltage regulator, the voltage regulator selectively operates in one of a charging mode, an energy storage mode, and an idle mode; and in response to an input power being less than the output power, the voltage regulator selectively operates in one of the charging mode and the current enhancement mode to generate the output power using the wireless power received by the wireless charging induction coil and the stored energy in the energy storage capacitor.

6. The voltage regulator rectifier as claimed in claim 5, wherein the voltage regulator rectifier enters the energy storage mode in response to an output voltage at the output terminal of the voltage regulator rectifier being greater than a first threshold voltage; the voltage regulator rectifier enters the idle mode in response to a storage voltage in the energy storage capacitor being greater than the first threshold voltage; and the voltage regulator rectifier enters the charging mode in response to an output voltage being less than a second threshold voltage, wherein the first threshold voltage is greater than the second threshold voltage.

7. The voltage regulator rectifier as claimed in claim 5, wherein in response to an output voltage at the output terminal of the voltage regulator rectifier being less than a hysteresis window defined by a first threshold voltage and a second threshold voltage, the voltage regulator rectifier enters the charging mode, wherein the first threshold voltage is greater than the second threshold voltage; in response to the output voltage being less than a third threshold voltage, the voltage regulator rectifier enters the current boost mode from the charging mode, wherein the second threshold voltage is greater than the third threshold voltage; and in response to the output voltage being greater than the first threshold voltage, the voltage regulator rectifier exits the current boost mode.

8. The voltage regulator and rectifier as described in claim 1, further comprising: A resonant capacitor, wherein a first end of the resonant capacitor is coupled to the first end of the wireless charging induction coil, and a second end of the resonant capacitor is coupled to the second end of the wireless charging induction coil.

9. The voltage regulator and rectifier as described in claim 1, further comprising: An output capacitor, wherein a first terminal of the output capacitor is coupled to the common terminal of the output switching circuit, and a second terminal of the output capacitor is coupled to a second reference voltage source.

10. The voltage regulator and rectifier as claimed in claim 1, wherein the output switching circuit includes: A first switch, wherein a first terminal of the first switch is coupled to the first selection terminal of the output switch circuit, and a second terminal of the first switch is coupled to the common terminal of the output switch circuit; The system includes a second switch, wherein a first terminal of the second switch is coupled to the second selection terminal of the output switch circuit, and a second terminal of the second switch is coupled to the common terminal of the output switch circuit. In response to the regulated rectifier operating in the charging mode, the first switch and the second switch are alternately turned on to convert AC power from the wireless charging induction coil into DC power, and to output the DC power to the common terminal of the output switch circuit. In response to the regulated rectifier operating in the current enhancement mode and the cross-switch circuit performing the DC-DC conversion, one of the first switch and the second switch is turned on while the other is turned off. In response to the regulated rectifier operating in the current enhancement mode and the cross-switch circuit performing the AC-DC conversion, the first switch and the second switch are alternately turned on to convert the AC power from the wireless charging induction coil into DC power.

11. The voltage regulator and rectifier as claimed in claim 10, wherein the first switch and the second switch are off in response to the voltage regulator and rectifier operating in an energy storage mode; and the first switch and the second switch are off in response to the voltage regulator and rectifier operating in an idle mode.

12. The voltage regulator and rectifier as claimed in claim 1, wherein the energy storage switching circuit comprises: A first switch, wherein a first terminal of the first switch is coupled to the first selection terminal of the energy storage switch circuit, and a second terminal of the first switch is coupled to the common terminal of the energy storage switch circuit; And a second switch, wherein a first terminal of the second switch is coupled to the second selection terminal of the energy storage switch circuit, and a second terminal of the second switch is coupled to the common terminal of the energy storage switch circuit; in response to the voltage regulator operating in the charging mode, the first switch and the second switch are off; in response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the DC-DC conversion, one of the first switch and the second switch is on and the other is off; and in response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the AC-DC conversion, the first switch and the second switch are off.

13. The voltage regulator and rectifier as claimed in claim 12, wherein in response to the voltage regulator and rectifier operating in an energy storage mode, the first switch and the second switch are alternately turned on to convert AC power of the wireless charging induction coil into DC power and store the DC power in the energy storage capacitor; and in response to the voltage regulator and rectifier operating in an idle mode, the first switch and the second switch are turned off.

14. The voltage regulator and rectifier as claimed in claim 1, wherein the cross-switch circuit comprises: A first switch, wherein a first terminal of the first switch is coupled to the first terminal of the wireless charging induction coil, and a second terminal of the first switch is coupled to a second reference voltage source; a second switch, wherein a first terminal of the second switch is coupled to the second terminal of the wireless charging induction coil, and a second terminal of the second switch is coupled to a third reference voltage source; a third switch having a first selection terminal, a second selection terminal and a common terminal, wherein the common terminal of the third switch is coupled to a control terminal of the first switch, the first selection terminal of the third switch is coupled to the second terminal of the wireless charging induction coil, and the second selection terminal of the third switch receives a first gate control signal; And a fourth switch having a first selection terminal, a second selection terminal and a common terminal, wherein the common terminal of the fourth switch is coupled to a control terminal of the second switch, the first selection terminal of the fourth switch is coupled to the first terminal of the wireless charging induction coil, and the second selection terminal of the fourth switch receives a second gate control signal, wherein in response to the voltage regulator operating in the charging mode, the third switch couples the second terminal of the wireless charging induction coil to the control terminal of the first switch, and the fourth switch couples the first terminal of the wireless charging induction coil to the control terminal of the second switch; In response to the voltage regulator operating in the current boost mode and the cross switch circuit performing the DC-DC conversion, the third switch transmits the first gate control signal to the control terminal of the first switch, and the fourth switch transmits the second gate control signal to the control terminal of the second switch; and in response to the voltage regulator operating in the current boost mode and the cross switch circuit performing the AC-DC conversion, the third switch couples the second terminal of the wireless charging induction coil to the control terminal of the first switch, and the fourth switch couples the first terminal of the wireless charging induction coil to the control terminal of the second switch.

15. The voltage regulator rectifier as claimed in claim 14, wherein in the DC-DC conversion of the current enhancement mode, one of the first switch and the second switch is on while the other is off.

16. The voltage regulator and rectifier as claimed in claim 14, wherein the DC-DC conversion in the current enhancement mode includes a first phase and a second phase, wherein in the first phase the first switch is on and the second switch is off to enhance the current of the wireless charging induction coil using the stored energy of the energy storage capacitor, and in the second phase the first switch is off and the second switch is on to output the current of the wireless charging induction coil to the output terminal of the voltage regulator and rectifier.

17. The voltage regulator and rectifier as claimed in claim 14, wherein in response to the voltage regulator and rectifier operating in an energy storage mode, the third switch couples the second terminal of the wireless charging induction coil to the control terminal of the first switch, and the fourth switch couples the first terminal of the wireless charging induction coil to the control terminal of the second switch; and in response to the voltage regulator and rectifier operating in an idle mode, the third switch transmits a first gate signal to the control terminal of the first switch, and the fourth switch transmits a second gate signal to the control terminal of the second switch to enable the third switch and the fourth switch to conduct.

18. A method for operating a voltage regulator rectifier, comprising: In response to the voltage regulator operating in a charging mode, a first rectifier circuit is formed by an output switching circuit and a cross-switching circuit of the voltage regulator to convert wireless power received by a wireless charging induction coil into output electrical energy at an output terminal of the voltage regulator. A first selection terminal of the output switching circuit and a first terminal of the cross-switching circuit are coupled to a first terminal of the wireless charging induction coil; a second selection terminal of the output switching circuit and a second terminal of the cross-switching circuit are coupled to a second terminal of the wireless charging induction coil; a common terminal of the output switching circuit is coupled to the output terminal of the voltage regulator; and a first selection terminal of an energy storage switching circuit of the voltage regulator is coupled to the first terminal of the wireless charging induction coil. At one end, a second selection terminal of the energy storage switch circuit is coupled to the second terminal of the wireless charging induction coil, a first terminal of an energy storage capacitor of the voltage regulator is coupled to a common terminal of the energy storage switch circuit, and a second terminal of the energy storage capacitor is coupled to a first reference voltage source; and in response to the voltage regulator operating in a current enhancement mode, the output switch circuit of the voltage regulator, the energy storage switch circuit and the cross switch circuit perform an iterative operation, wherein the iterative operation includes DC-DC conversion and AC-DC conversion, the DC-DC conversion using a stored energy of the energy storage capacitor to enhance the current of the wireless charging induction coil, and the AC-DC conversion converting the wireless power of the wireless charging induction coil into the output power for the output terminal of the voltage regulator.

19. The operating method as claimed in claim 18, wherein the DC-DC conversion in the current enhancement mode includes a first phase and a second phase, the operating method further comprising: The energy storage switch circuit uses the stored energy of the energy storage capacitor to enhance the current of the wireless charging induction coil during the first phase. And the output switching circuit outputs the current of the wireless charging induction coil to the output terminal of the voltage regulator rectifier in the second phase.

20. The operating method as described in claim 18, further comprising: In response to the regulated rectifier operating in an energy storage mode, a second rectifier circuit is formed by the energy storage switch circuit and the cross switch circuit to store the wireless energy of the wireless charging induction coil in the energy storage capacitor; and in response to the regulated rectifier operating in an idle mode, the energy storage switch circuit and the output switch circuit are turned off, and the first terminal and the second terminal of the wireless charging induction coil are grounded by the cross switch circuit.

21. The method of operation as described in claim 18, further comprising: In response to an input power of wireless energy received by the wireless charging induction coil being greater than an output power of the output terminal of the voltage regulator, the voltage regulator adjusts an output voltage of the output terminal of the voltage regulator between a first threshold voltage and a second threshold voltage, wherein the first threshold voltage is greater than the second threshold voltage; and in response to an input power being less than the output power, the voltage regulator adjusts the output voltage of the output terminal of the voltage regulator between the second threshold voltage and a third threshold voltage, wherein the second threshold voltage is greater than the third threshold voltage.

22. The method of operation as described in claim 18 further includes: In response to an input power of the wireless power received by the wireless charging induction coil being greater than an output power of the output terminal of the voltage regulator, the voltage regulator selectively operates in one of the charging mode, an energy storage mode, and an idle mode; and in response to an input power being less than the output power, the voltage regulator selectively operates in one of the charging mode and the current enhancement mode, so as to generate the output power using the wireless power received by the wireless charging induction coil and the stored energy of the energy storage capacitor.

23. The operating method as described in claim 22 further includes: In response to an output voltage at the output terminal of the voltage regulator being greater than a first threshold voltage, the voltage regulator enters the energy storage mode; in response to a storage voltage in the energy storage capacitor being greater than the first threshold voltage, the voltage regulator enters the idle mode from the energy storage mode; and in response to an output voltage being less than a second threshold voltage, the voltage regulator enters the charging mode from the idle mode, wherein the first threshold voltage is greater than the second threshold voltage.

24. The operating method as described in claim 22 further includes: In response to an output voltage at the output terminal of the voltage regulator being less than a hysteresis window defined by a first threshold voltage and a second threshold voltage, the voltage regulator enters the charging mode, wherein the first threshold voltage is greater than the second threshold voltage; in response to an output voltage being less than a third threshold voltage, the voltage regulator enters the current boost mode from the charging mode, wherein the second threshold voltage is greater than the third threshold voltage; and in response to an output voltage being greater than the first threshold voltage, the voltage regulator exits the current boost mode.

25. The operating method as described in claim 18 further includes: In response to the voltage regulator operating in the charging mode, a first switch and a second switch of the output switching circuit are alternately turned on to convert AC power from the wireless charging induction coil into DC power and output the DC power to the common terminal of the output switching circuit, wherein a first terminal of the first switch is coupled to the first selection terminal of the output switching circuit, a second terminal of the first switch is coupled to the common terminal of the output switching circuit, a first terminal of the second switch is coupled to the second selection terminal of the output switching circuit, and a second terminal of the second switch is coupled to the common terminal of the output switching circuit; In response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the DC-DC conversion, one of the first switch and the second switch is turned on while the other is turned off; and In response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the AC-DC conversion, the first switch and the second switch are alternately turned on to convert the AC power from the wireless charging induction coil into DC power.

26. The method of operation as described in claim 25 further includes: In response to the voltage regulator rectifier operating in an energy storage mode, the first switch and the second switch are turned off; And in response to the voltage regulator rectifier operating in an idle mode, the first switch and the second switch are turned off.

27. The operating method as described in claim 18 further includes: In response to the voltage regulator operating in the charging mode, a first switch and a second switch of the energy storage switch circuit are turned off, wherein a first terminal of the first switch is coupled to the first selection terminal of the energy storage switch circuit, a second terminal of the first switch is coupled to the common terminal of the energy storage switch circuit, a first terminal of the second switch is coupled to the second selection terminal of the energy storage switch circuit, and a second terminal of the second switch is coupled to the common terminal of the energy storage switch circuit; In response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the DC-DC conversion, one of the first switch and the second switch is turned on while the other is turned off; and In response to the voltage regulator operating in the current enhancement mode and the cross switch circuit performing the AC-DC conversion, the first switch and the second switch are turned off.

28. The method of operation as described in claim 27, further comprising: In response to the voltage regulator operating in an energy storage mode, the first switch and the second switch are alternately turned on to convert AC power from the wireless charging induction coil into DC power and store the DC power in the energy storage capacitor; and in response to the voltage regulator operating in an idle mode, the first switch and the second switch are turned off.

29. The operating method as described in claim 18, wherein the cross switch circuit includes a first switch, a second switch, a third switch, and a fourth switch, the operating method further comprising: In response to the operation of the voltage regulator in the charging mode, the second terminal of the wireless charging induction coil is coupled to the control terminal of the first switch by the third switch, and the first terminal of the wireless charging induction coil is coupled to the control terminal of the second switch by the fourth switch. A first terminal of the first switch is coupled to the first terminal of the wireless charging induction coil, a second terminal of the first switch is coupled to a second reference voltage source, a first terminal of the second switch is coupled to the second terminal of the wireless charging induction coil, a second terminal of the second switch is coupled to a third reference voltage source, a common terminal of the third switch is coupled to a control terminal of the first switch, a first selection terminal of the third switch is coupled to the second terminal of the wireless charging induction coil, and a second selection terminal of the third switch receives a first gate control signal. A common terminal of the fourth switch is coupled to a control terminal of the second switch, a first selection terminal of the fourth switch is coupled to the first terminal of the wireless charging induction coil, and a second selection terminal of the fourth switch receives a second gate control signal. In response to the voltage regulator operating in the current boost mode and the cross switch circuit performing the DC-DC conversion, the third switch transmits the first gate control signal to the control terminal of the first switch, and the fourth switch transmits the second gate control signal to the control terminal of the second switch; and in response to the voltage regulator operating in the current boost mode and the cross switch circuit performing the AC-DC conversion, the third switch couples the second terminal of the wireless charging induction coil to the control terminal of the first switch, and the fourth switch couples the first terminal of the wireless charging induction coil to the control terminal of the second switch.

30. The method of operation as described in claim 29, further comprising: In this DC-DC conversion of the current enhancement mode, one of the first switch and the second switch is turned on while the other is turned off.

31. The operating method as claimed in claim 29, wherein the DC-DC conversion in the current enhancement mode includes a first phase and a second phase, the operating method further comprising: In the first phase, the first switch is turned on and the second switch is turned off to enhance the current of the wireless charging induction coil using the stored energy of the energy storage capacitor; and in the second phase, the first switch is turned off and the second switch is turned on to output the current of the wireless charging induction coil to the output terminal of the voltage regulator.

32. The operating method as described in claim 29 further includes: In response to the voltage regulator operating in an energy storage mode, the third switch couples the second terminal of the wireless charging induction coil to the control terminal of the first switch, and the fourth switch couples the first terminal of the wireless charging induction coil to the control terminal of the second switch; and in response to the voltage regulator operating in an idle mode, the third switch transmits the first gate control signal to the control terminal of the first switch, and the fourth switch transmits the second gate control signal to the control terminal of the second switch, so that the third switch and the fourth switch are turned on.

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