Rectifier, wireless power transfer system and method for a rectifier

Abstract

The present disclosure relates to a rectifier, a wireless power transfer system, and a method for a rectifier. A rectifier modulates a signal in the rectifier by turning on low side field effect transistors to create a load at a coil network in response to low side field effect transistors turning on in alternating diagonals. The system measures a signal quality to determine a modulation depth required for ASK communication, then determines a switching time and amplitude of a ballast signal applied to the low side field effect transistors to achieve the modulation depth.

Description

Technical Field

[0001] This disclosure relates to a fast load ballast for a rectifier, and also to a rectifier, a wireless power delivery system, and a method for using a rectifier. Background Technology

[0002] Wireless power transmission systems utilizing communication power transmission links include modulators and modulators that require modulation depth for fast and accurate communication. Typically, amplitude shift keying (ASK) modulation in wireless power transmission systems requires switching capacitors in the rectifier coil network (capacitive load modulation) or adjusting the load on the rectifier output (e.g., constant current load modulation) to facilitate communication. Capacitive modulation is power-friendly but introduces instability, requires additional components, and is unsuitable for multi-frequency systems. Load modulation on the rectifier output is too slow to prohibit high-speed communication.

[0003] It does not affect the rectified voltage (V) RECT Systems and methods for ASK modulation that improve system stability or adjust communication speed will be advantageous. Summary of the Invention

[0004] On the one hand, embodiments of the inventive concept disclosed herein relate to a system and method for modulating a signal in a rectifier by turning on a low-side field-effect transistor in response to the switching on of low-side field-effect transistors on alternating diagonals to generate a load at a coil network.

[0005] On the other hand, the system measures signal quality to determine the modulation depth required for ASK communication, and then determines the switching time and amplitude of the ballast signal applied to the low-side field-effect transistor to achieve the modulation depth.

[0006] It should be understood that the above general description and the following detailed description are for illustrative purposes only and should not limit the scope of the claims. The accompanying drawings, which are incorporated in and form a part of the specification, illustrate exemplary embodiments of the inventive concepts disclosed herein and, together with the general description, serve to explain the principles. Attached Figure Description

[0007] Those skilled in the art will better understand the many advantages of the embodiments of the inventive concepts disclosed herein by referring to the accompanying drawings, in which:

[0008] Figure 1 A block diagram showing a rectifier according to an exemplary embodiment;

[0009] Figure 2 A block diagram showing a system according to an exemplary embodiment; and

[0010] Figure 3 The graph shows the turn-on and turn-off times of the FET when ASK modulation is present. Detailed Implementation

[0011] Before explaining in detail the various embodiments of the inventive concepts disclosed herein, it should be understood that the inventive concepts are not limited to the arrangement of components, steps, or methods to be set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments of the invention, numerous specific details are set forth to provide a more thorough understanding of the invention. However, those skilled in the art to which this disclosure pertains will understand that the inventive concepts disclosed herein can be practiced without these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the disclosure. The inventive concepts disclosed herein can be implemented in other embodiments or practiced or carried out in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0012] As used herein, the letters following the element symbol are intended to refer to embodiments of features or elements that are similar to, but not necessarily identical to, the aforementioned element or feature having the same element symbol (e.g., 1, 1a, 1b). These shorthand symbols are used for convenience only and should in no way be construed as limiting the inventive concepts disclosed herein, unless expressly stated otherwise.

[0013] Furthermore, unless explicitly stated otherwise, "or" refers to inclusive or rather, not exclusive or. For example, condition A or B is satisfied by any of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); and both A and B are true (or exist).

[0014] Additionally, the use of "a" is for describing elements and components of embodiments of the present invention. This is for convenience only and to give a general meaning of the inventive concept, and "a" is intended to include one or at least one and the singular includes the plural, unless it is obvious otherwise.

[0015] Furthermore, although various components may be depicted as directly connected, direct connection is not required. Components may communicate data with intervening components that are not specified or described.

[0016] Finally, as used herein, any reference to “one embodiment” or “some embodiments” means that a particular element, feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the inventive concept disclosed herein. The phrase “in at least one embodiment” appearing in the specification does not necessarily refer to the same embodiment. Embodiments of the disclosed inventive concept may include any combination or sub-combination of one or more, or two or more, of the features expressly described herein or inherently present.

[0017] Embodiments of the inventive concept disclosed herein generally relate to a system and method for modulating a signal in a rectifier by turning on a low-side field-effect transistor in response to the switching on of low-side field-effect transistors on alternating diagonals to generate a load at a coil network. The system measures signal quality to determine the modulation depth required for ASK communication, and then determines the switching time and amplitude of the ballast signal applied to the low-side field-effect transistor to achieve the modulation depth.

[0018] refer to Figure 1 A block diagram of a rectifier according to an exemplary embodiment is shown. To enable data communication in a wireless power transmission system, load modulation may occur simultaneously with the power signal; a carrier signal may also be present for modulation.

[0019] The rectifier in the wireless power transmission system includes field-effect transistors (FETs) 116, 118, 120, and 122, which switch according to a carrier signal (e.g., receiving a signal at the gate to set the state of FETs 116, 118, 120, and 122 to conduct or deconduct) to generate a rectified voltage (V). RECT A rectifier (e.g., controlled or uncontrolled) can be any device that converts alternating current (AC) to direct current (DC). A FET (e.g., a junction FET, a metal-oxide-semiconductor FET, or an insulated-gate FET) is a transistor type that can be used for weak signal amplification (e.g., amplifying wireless signals). During normal operation, FETs 116, 118, 120, and 122 are turned on by a current comparator. Generally, the diagonal FETs 116, 118, 120, and 122 (e.g., the first diagonal including the first high-side FET 116 and the first low-side FET 118, and the second diagonal including the second high-side FET 120 and the second low-side FET 122) are either simultaneously turned on or off; for example, the first high-side FET 116 and the first low-side FET 118 are turned on, while the second high-side FET 120 and the second low-side FET 122 are not turned on. It should be understood that the high-side FETs 116 and 120 may be FETs arranged and configured to supply current from the FET to the load on a diagonal. The low-side FETs 118 and 122 may be FETs arranged and configured to supply current from the load to ground on a diagonal.

[0020] In at least one embodiment, the rectifier can be configured to change the conduction state of one or more FETs 116, 118, 120, 122; for example, when the first high-side FET 116 and the first low-side FET 118 are turned on, the second low-side FET 122 can be turned on (e.g., turned on) to apply current 124 from coil 114 (e.g., field coil) to ground. The signal used to control this conduction can modulate a carrier signal for ASK data communication. Alternatively, a resistor can be applied from coil 114 to ground to achieve a similar result. In at least one embodiment, the modulation can be characterized by the amount of time the two low-side FETs 118, 122 are turned on; wherein the amount of time can be less than the switching time of the rectifier typically generated by the carrier signal. In at least one embodiment, the rectifier changes the current or resistance or overlap pulse width in the two low-side FETs 118, 122 in response to the turn-on of the two low-side FETs 118, 122.

[0021] In at least one embodiment, some rectifiers may include FETs 116, 118, 120, and 122 organized into FET groups 106, 108, 110, and 112, wherein the first group of high-side FETs 106 includes a plurality of individual parallel FETs 116. Similarly, the second group of high-side FETs 110, the first group of low-side FETs 108, and the second group of low-side FETs 112 also each include a plurality of individual parallel FETs 118, 120, and 122 within their respective groups 108, 110, and 112. In at least one embodiment, a single FET 122 or a subset of the second group of low-side FETs 112 may be switched to control the gate voltage and generate a desired load.

[0022] In one example, when a high voltage may be present at a set of high-side FETs 106 and a low voltage may be present at a set of low-side FETs 108, both the high-side FET group 106 and the low-side FET group 108 are in a conducting mode (e.g., FETs on). During this conduction, a ballast signal is turned on (e.g., weakly turned on) a second set of low-side FETs 112 to conduct current from the node between the first set of high-side FETs 106 and the second set of low-side FETs 112 to ground, thereby effectively applying load from the second set of low-side FETs 112 to the coil 114 until ground. Typical loads can be in the range of 50 to 100 mA. It should be understood that, in the context of this disclosure, the ballast signal refers to a signal applied to one or more FETs 116, 118, 120, 122 (which were originally in a non-conducting state) to cause the FETs 116, 118, 120, 122 to conduct current from the node to ground.

[0023] refer to Figure 2This diagram illustrates a block diagram of a system according to an exemplary embodiment. The rectifier 200 may include a controller 202 or control logic (such as a state machine, field-programmable gate array, programmable processor, or the like) associated with one or more FETs 206, 208, 210, 212. In at least one embodiment, the controller 202 may be configured to change the on-state of one or more FETs 206, 208, 210, 212; for example, the controller 202 may be configured to switch one or more low-side FETs 208, 212 on in response to the on-state of a corresponding high-side FET 206, 210.

[0024] In one example, when a high voltage may be present at a set of high-side FETs 206 and a low voltage may be present at a set of low-side FETs 208, both the high-side FET group 206 and the low-side FET group 208 are in a conducting mode (e.g., FETs on). During this conduction period, the controller 202 also briefly turns on (e.g., weakly turns on) a second set of low-side FETs 212 to conduct current from the node to ground, thereby effectively applying the load from the second set of low-side FETs 212 to the coil 214 to ground. Typical loads can be in the range of 50 to 100 mA.

[0025] Some rectifiers may include FETs organized into FET groups, wherein a first group of high-side FETs 206 includes a plurality of individual parallel FETs. Similarly, a second group of high-side FETs 210, a first group of low-side FETs 208, and a second group of low-side FETs 212 also each include a plurality of individual parallel FETs. In at least one embodiment, a controller 202 activates one or more subsets of the second group of low-side FETs 212 to control the gate voltage and generate a desired load. In at least one embodiment, the controller 202 modulates the current or resistance or overlap pulse width in the low-side FETs 208, 212, wherein two low-side FETs 208, 212 are turned on.

[0026] Data communication in wireless power transmission systems (such as ASK data communication) requires modulation depth for fast and accurate communication. Modulation depth refers to the ratio of the amplitude of the unmodulated carrier signal to the amplitude deviation that makes the modulated carrier signal reach a threshold minimum (e.g., the amplitude of the modulated carrier signal divided by the amplitude of the unmodulated carrier signal). The required modulation depth can vary depending on the noise, which in turn varies at least partly with the power. As the power of wireless power transmission systems increases, data communication via the power transmission link becomes noisier, requiring greater modulation depth.

[0027] ASK modulator 204 can apply a ballast signal to one or more low-side FETs 208, 212 according to the desired modulation. In at least one embodiment, the modulation depth can be dynamically adjusted. For example, measurements from the device receiving the ASK modulated signal (such as signal-to-noise ratio (SNR) measurement, bit error rate (BER) measurement, parity error rate measurement, or the like) can be used to increase or decrease the modulation depth. In at least one embodiment, controller 202 can determine the number of low-side FETs 208, 212 to be turned on or the magnitude of their turn-on based on signal quality metrics such as SNR measurement to provide dynamic modulation depth of ASK.

[0028] Furthermore, the controller 202 can be relative to signal quality metrics (such as V). RECT Fidelity or carrier signal oscillator (F CLK The quality of V determines the modulation depth. RECT The fidelity can be determined by the controller 202 based on V. RECT The high-frequency oscillation is used to determine this; and F CLK The fidelity can be determined by the controller 202 with reference to the switching time of a known good oscillator or FETs 206, 208, 210, 212. Such determination can be made with reference to measurements such as instantaneous or time-accumulated average error, root mean square error, variance, trend, or the like. The controller 202 can also measure the down-conversion signal from coil 214 to generate a noise estimate for ASK.

[0029] In at least one embodiment, the impedance from the receiver is changed when both sets of low-side FETs 208, 212 are turned on. Turning on both sets of low-side FETs 208, 212 for a period of time (e.g., half a millisecond) sets ASK to one level; turning off one set of low-side FETs 208, 212 sets ASK to another level. For example, Figure 3 The graph shows the turn-on and turn-off times of each FET 206, 208, 210, and 212 when ASK modulation 308 is present. During the ASK modulation cycle, each low-side FET 208 and 212 can be placed in a constant current or constant resistance state 300, 302, 304, and 306, respectively. The constant current or constant resistance states 300, 302, 304, and 306 can coincide with the cycle in which the low-side FETs 208 and 212 are originally "off".

[0030] In at least one embodiment, to mitigate any electromagnetic interference, the controller 202 may cycle alternately. For example, during a first cycle, the low-side FETs 208, 212 are controlled to apply a load to the coil 214; during a second cycle, the high-side FETs 206, 210 are controlled to apply a load to the coil 214. It should be understood that although the exemplary embodiments described herein are specifically for using the low-side FETs 208, 212 for conduction, the principle can also be applied to the high-side FETs 206, 210.

[0031] In at least one embodiment, controller 202 may deactivate the low-side FET for signal modulation. Temporarily deactivating the low-side FET may be desirable to establish interference-free rectifier signal quality or to adjust rectifier parameters, such as switching the current threshold (I0). LIM ), rectifier gain, continuous conduction mode or similar.

[0032] Overvoltage protection can also be achieved by applying a load at the input of the rectifier. When V RECT When the voltage on the rectifier exceeds a certain predefined threshold, some rectifier input load can be applied until V... RECT The temperature drops below the predefined threshold. Additionally, temperature monitoring can be used to determine when the chip temperature also falls below the threshold. This threshold monitoring prevents overvoltage. Modulation at the rectifier input allows communication at a rate greater than the carrier frequency, with multiple pulses per cycle duration.

[0033] In at least one embodiment, controller 202 may simultaneously apply a modulated load and any additional load for overvoltage protection via one or more individual parallel FETs within low-side FETs 212, 208. Alternatively or additionally, load 216 may be placed on the rectifier output to apply modulation to the rectifier input and an overvoltage load to the rectifier output. In at least one embodiment, the rectifier input load may include a composite waveform, such as a ramp, to cancel electromagnetic interference.

[0034] Switching with V using a brief low-side FET conduction. RECT The load modulation is as fast as that of conventional modulation modulators, thus enabling faster ASK communication; existing systems with conventional modulators operate at approximately 2K baud rates, while embodiments of this disclosure can achieve 10K or 20K baud rates. Furthermore, because the embodiments employ resistor switching, the system avoids the limitations of capacitor switching; additionally, the modulation strength can be easily changed, making the modulation depth programmable. Furthermore, resistor modulation is suitable for any frequency. In multi-band systems using capacitor modulation, the system is only optimally suited to a specific frequency band at any given time.

[0035] Embodiments of this disclosure implement a fast load (e.g., a ballast device placed in series with the load to limit the amount of current in the circuit) at the input of the rectifier. The rectifier FET and / or additional FETs are configured to provide resistance switching. Utilizing FETs for resistance switching at the rectifier input allows for dynamic modification of the modulation intensity and is suitable for multi-band applications.

[0036] Embodiments of this disclosure enable high-frequency (e.g., baud rate) fast ASK communication, adjustable / programmable signal strength (e.g., higher voltage) based on various conditions / environments, and multi-band communication.

[0037] It is believed that the inventive concept disclosed herein and its many accompanying advantages will be understood through the above description of embodiments of the inventive concept, and it will be appreciated that various changes can be made to the form, construction, and arrangement of its components without departing from the broad scope of the inventive concept disclosed herein or without sacrificing all its material advantages; and individual features from various embodiments can be combined to achieve other embodiments. The forms described above are merely illustrative embodiments, and the appended claims are intended to cover and include such changes. Furthermore, any feature disclosed with respect to any of the individual embodiments may be incorporated into any other embodiment.

Claims

1. A rectifier comprising: First high-side field-effect transistor (FET); Second high-side FET; First low-side FET; Second low-side FET; A second set of low-side FETs, wherein the second low-side FETs are in the second set of low-side FETs; coil; and Controller in: The first high-side FET, the second high-side FET, the first low-side FET, and the second low-side FET are configured to generate a rectified voltage (V) based on a carrier signal. RECT ); The controller is configured to apply a control signal to the second low-side FET in response to the first low-side FET being turned on to generate a load at the coil, and the controller is further configured to: Measure one or more signal quality metrics of the carrier signal; The modulation depth is determined based on one or more signal quality metrics; and The number of FETs in the second group of low-side FETs to which the control signal is applied to achieve the determined modulation depth is determined.

2. The rectifier of claim 1, further comprising an amplitude shift keying (ASK) modulator, the ASK modulator being configured to: Determine the signal modulation method used for ASK communication; and The signal modulation method is provided to the controller.

3. The rectifier according to claim 1, further comprising: A first set of high-side FETs, wherein the first high-side FET is in the first set of high-side FETs; A second set of high-side FETs, wherein the second high-side FET is in the second set of high-side FETs; and The first low-side FET is in the first group of low-side FETs.

4. The rectifier of claim 1, wherein the controller is configured to: Determine the V RECT The voltage threshold has been exceeded; and The load at the rectifier output applies a modulation operation to the rectifier input.

5. The rectifier of claim 1, wherein the controller is further configured to apply a control signal to the second high-side FET in response to the first low-side FET being turned on to generate a load at the coil.

6. The rectifier of claim 1, wherein the controller is further configured to apply a control signal to the first low-side FET in response to the first low-side FET being turned on to generate a load at the coil.

7. A method for a rectifier, comprising: A rectified voltage (V) is generated by turning on the first high-side field-effect transistor (FET) and the first low-side FET in the rectifier based on a carrier signal, while turning off the second high-side FET and the second low-side FET. RECT ); A control signal is applied to the second low-side FET to temporarily generate a load at the coil; Measure one or more signal quality metrics of the carrier signal; The modulation depth is determined based on one or more signal quality metrics; and The number of FETs in the second group of low-side FETs, which is one of the second group of low-side FETs, is determined for applying the control signal to achieve the determined modulation depth.

8. The method of claim 7, further comprising determining a signal modulation scheme for ASK communication, wherein the control signal is used to implement the signal modulation scheme.

9. The method according to claim 7, wherein: The first high-side FET is one of the first group of high-side FETs; The second high-side FET is one of the second group of high-side FETs; and The first low-side FET is one of the first group of low-side FETs.

10. The method of claim 7, further comprising: Based on the carrier signal, the first high-side FET and the first low-side FET in the rectifier are placed in a non-conducting state; The second high-side FET and the second low-side FET are put into the on state based on the carrier signal; and A control signal is applied to the first low-side FET to temporarily generate a load at the coil.

11. The method of claim 7, further comprising: Based on the carrier signal, the first high-side FET and the first low-side FET in the rectifier are placed in a non-conducting state; The second high-side FET and the second low-side FET are put into the on state based on the carrier signal; and A control signal is applied to the first high-side FET to temporarily generate a load at the coil.

12. A wireless power transmission system, comprising: A rectifier, which has the following characteristics: First high-side field-effect transistor (FET); Second high-side FET; First low-side FET; Second low-side FET; A second set of low-side FETs, wherein the second low-side FETs are in the second set of low-side FETs; and coil; and Controller in: The first high-side FET, the second high-side FET, the first low-side FET, and the second low-side FET are configured to generate a rectified voltage (V) based on a carrier signal. RECT ); The controller is configured to apply a control signal to the second low-side FET in response to the first low-side FET being turned on to generate a load at the coil, and the controller is further configured to: Measure one or more signal quality metrics of the carrier signal; The modulation depth is determined based on one or more signal quality metrics; and The number of FETs in the second group of low-side FETs used to apply the control signal to achieve the determined modulation depth is determined.

13. The wireless power transmission system of claim 12, further comprising an amplitude shift keying (ASK) modulator, the ASK modulator being configured to: Determine the signal modulation method used for ASK communication; and The signal modulation method is provided to the controller.

14. The wireless power transmission system according to claim 12, further comprising: A first set of high-side FETs, wherein the first high-side FET is in the first set of high-side FETs; A second set of high-side FETs, wherein the second high-side FET is in the second set of high-side FETs; and The first low-side FET is in the first group of low-side FETs.

15. The wireless power transmission system of claim 14, wherein the controller is configured to: Determine the V RECT The voltage threshold has been exceeded; and Apply the input load to the rectifier input until V... RECT The voltage drops below a predefined threshold.

16. The wireless power delivery system of claim 15, wherein the controller is further configured to determine at least one FET in the first set of low-side FETs and to apply the input load via the at least one FET.

17. The wireless power transmission system of claim 12, wherein the controller is further configured to apply a control signal to the first low-side FET in response to the second low-side FET being turned on to generate a load at the coil.

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