KR20200032458A - Wireless Power Transmitter and Data Communication Method In Wireless Power Transmitter - Google Patents

Abstract

According to an embodiment of the present invention, a wireless power transmitter comprises: an inverter which outputs an alternating current (AC) signal; a transmission coil connected to the inverter; a demodulator connected to the transmission coil to receive an amplitude modulated signal and demodulate the amplitude modulated signal; and a controller which controls operation of the inverter. The demodulator receives the amplitude modulated signal, detects a data signal obtained by removing an offset direct current (DC) voltage level from the amplitude modulated signal, and demodulates bit data encoded in the amplitude modulated signal by comparing a voltage or current of the detected data signal with a reference voltage or a reference current. The data signal has a data DC voltage level corresponding to the amplitude of vibration fluctuation of the amplitude modulated signal.

Description

Wireless power transmitter and its data communication method {Wireless Power Transmitter and Data Communication Method In Wireless Power Transmitter}

The present invention relates to a wireless power transmitter, and relates to a wireless power transmitter and a data communication method for demodulating the in-band signal transmitted from the wireless power receiver.

With the recent rapid development of information and communication technology, a ubiquitous society based on information and communication technology has been formed.

In order to access information and communication devices anytime, anywhere, sensors in the computer chip with communication functions must be installed in all social facilities.

Therefore, the problem of supplying power to these devices and sensors has become a new task. In addition, as the number of mobile devices, such as Bluetooth handsets and iPods, as well as mobile phones, has rapidly increased, charging the battery has required time and effort from users.

Currently, in-band communication is used in an electromagnetic induction type wireless charging system.

In particular, the wireless power transmission device periodically receives a feedback signal from the wireless power receiving device during charging, and performs power control based on the received feedback signal.

In the electromagnetic induction method, the wireless charging area of the wireless power transmission device may be defined as an area in which communication between wireless power transmission and reception devices is possible rather than intensity of power received by the wireless power reception device.

Therefore, demodulation performance of the wireless power transmission device is an essential element in maximizing the chargeable area.

Generally, the wireless charging interruption occurs when the feedback signal generated by the wireless power receiving device is not normally demodulated in the wireless power transmitting device than when the intensity of the power received by the wireless power receiving device is less than the reference value. .

Therefore, the conventional wireless power transmission apparatus has a problem in that the demodulation performance is deteriorated and the wireless charging is stopped despite the sufficient strength of the power received by the wireless power reception apparatus.

The present invention has been devised to solve the above-described problems of the prior art, and an object of the present invention is to provide a wireless power transmitter and a data communication method thereof.

Another object of the present invention is to provide a wireless power transmitter capable of expanding a chargeable area by improving demodulation performance for a feedback signal of in-band communication.

In addition, another object of the present invention is to provide a wireless power transmitter and a data communication method thereof that can maximize the chargeable area by improving the sensitivity of the demodulator in the wireless power transmitter.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description. Will be able to.

Wireless power transmitter according to an embodiment includes an inverter for outputting an AC signal; A transmission coil connected to the inverter; A demodulator connected to the transmitting coil to receive an amplitude modulated signal and demodulate the amplitude modulated signal; And a controller that controls the operation of the inverter, wherein the demodulator receives the amplitude modulated signal, detects a data signal obtained by removing an offset DC voltage level from the amplitude modulated signal, and the voltage of the detected data signal or The current is compared with a reference voltage or a reference current to demodulate the bit data encoded in the amplitude modulated signal, and the data signal has a data DC voltage level corresponding to the amplitude of vibration fluctuation of the amplitude modulated signal.

In addition, the demodulator has a peak detector that outputs a peak detection signal that detects a peak level from the amplitude modulated signal, and removes the offset DC voltage level from the peak detection signal of the peak detector, thereby having the data DC voltage level. And a voltage drop outputting the data signal.

In addition, the voltage drop, while maintaining the data DC voltage level, drops the offset DC voltage level based on the operating voltage of the demodulator.

In addition, the voltage drop removes the offset DC voltage level from the peak detection signal to 0, and outputs the data signal having the data DC voltage level.

In addition, the data signal is divided into a first data section having a DC voltage level of 0V and a second data section having a DC voltage level equal to the data DC voltage level.

In addition, the voltage drop includes a first resistor having one end connected to the output terminal of the peak detector, a second resistor having one end connected to ground, a collector terminal connected to the other end of the first resistor, and the second resistor. It includes a switching element including an emitter terminal connected to the other end of the, and a base terminal to which the base voltage is input.

In addition, the data DC voltage level of the data signal is a collector voltage level of the switching element, and a base voltage input to the base terminal of the switching element is variable according to a peak level of the amplitude modulation signal.

In addition, the demodulator includes: a first low-pass filter for low-pass filtering the data signal output from the voltage drop; And a comparator that compares the filtered signal with a reference voltage or a reference current to convert it into a digital signal.

In addition, the voltage drop further includes a base voltage input unit connected to the base terminal of the switching element and outputting the base voltage variable according to the peak level of the amplitude modulated signal, wherein the base voltage input unit is the peak detector. And a voltage divider resistor connected in series between the output terminal and the ground, and a second low-pass filter disposed between the voltage divider resistor and the base terminal of the switching element.

In addition, the controller determines whether to adjust the transmission power from the bit data, and changes the operating frequency of the AC signal to adjust the transmission power.

In addition, the controller determines whether to adjust the current intensity flowing in the transmitting coil from the bit data, and changes the operating frequency of the AC signal to adjust the current intensity of the transmitting coil.

Meanwhile, a data communication method of a wireless power transmitter according to an embodiment includes generating AC power through an inverter; Obtaining an amplitude modulated signal from a transmission antenna to which the AC power is input; Obtaining a peak detection signal that senses a peak level of the amplitude modulated signal; Obtaining a data signal obtained by removing an offset DC voltage level from the acquired peak detection signal; And comparing the voltage or current of the obtained data signal with a reference voltage or a reference current to demodulate the bit data encoded in the amplitude modulated signal, wherein the data signal is adjusted to the amplitude of vibration fluctuations of the amplitude modulated signal. It has a corresponding data DC voltage level.

In addition, the step of demodulating the bit data encoded in the amplitude modulated signal by comparing the voltage or current of the data signal with a reference voltage or a reference current includes low-pass filtering the data signal; And comparing the filtered signal with a reference voltage or a reference current to convert the digital signal into a digital signal.

In addition, the step of acquiring the data signal includes dropping the offset DC voltage level based on the operating voltage of the comparator while maintaining the DC voltage level of the DC voltage level of the peak detection signal. .

In addition, the step of acquiring the data signal includes removing the offset DC voltage level from the peak detection signal to 0 to obtain the data signal having a size corresponding to the data DC voltage level.

In addition, the data signal is divided into a first data section having a DC voltage level of 0V and a second data section having a DC voltage level equal to the data DC voltage level.

In addition, the step of obtaining the data signal includes removing the offset DC voltage level through a voltage drop including a first resistor, a second resistor, and a switching element, wherein the first resistor and the first The resistance value of the two resistors is set based on the offset DC voltage level, and the data DC voltage level of the data signal is a collector voltage of the switching element.

In addition, the method further includes varying the voltage applied to the base of the switching element according to the peak level of the amplitude modulated signal.

The method further includes determining whether to adjust the transmission power from the bit data, and changing the operating frequency of the AC signal to adjust the transmission power.

Further, it is determined whether the current intensity flowing from the bit data to the transmission antenna is adjusted, and the operating frequency of the AC signal is changed to adjust the current intensity of the transmission coil.

According to an embodiment of the present invention, only the data signal is output by removing the DC offset signal from the amplitude modulated carrier signal. At this time, the data signal includes the amplitude fluctuation amount according to the data value of the carrier signal. For example, when the amplitude variation according to the data value in the carrier signal is 1V, the amplitude variation amount according to the data value in the output data signal is also 1V.

Accordingly, in an embodiment according to the present invention, it is possible to provide a wireless power transmitter having improved demodulation performance for an in-band communication feedback signal in a wireless charging system, and to maximize a chargeable area of the wireless power transmitter. have.

In addition, in the embodiment according to the present invention, it is possible to minimize the charging interruption phenomenon due to deterioration of demodulation performance, and improve the sensitivity of the demodulator in the wireless power transmitter to improve the chargeable area.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description. will be.

1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.
2 is a view for explaining a power transmission control method in a wireless power transmission system according to an embodiment of the present invention.
3 is a view for explaining a detection signal transmission procedure in a wireless charging system according to an embodiment of the present invention.
4 is a state transition diagram for describing a wireless power transfer procedure according to an embodiment of the present invention.
5 is a state transition diagram for describing a wireless power transmission procedure according to another embodiment of the present invention.
6 is a block diagram illustrating a structure of a wireless power transmission apparatus according to an embodiment of the present invention.
7 is a view for explaining the structure of the transmission antenna of FIG. 6.
8 is a view for explaining the structure of a demodulator provided in a conventional wireless power transmitter.
9 is a block diagram illustrating a structure of a demodulator provided in a wireless power transmitter according to an embodiment of the present invention.
10 is a view for explaining a demodulation method in a wireless power transmitter according to an embodiment of the present invention.
11 is an equivalent circuit diagram for explaining the structure of an AC power transmitter according to an embodiment of the present invention.
12A is an equivalent circuit diagram for explaining a structure of a voltage drop provided in a demodulator of a wireless power transmitter according to an embodiment of the present invention.
12B is an equivalent circuit diagram for explaining a structure of a voltage drop provided in a demodulator of a wireless power transmitter according to another embodiment of the present invention.
12C is an equivalent circuit diagram for explaining the configuration of a low-pass filter and a comparator of a demodulator disposed in a wireless power transmitter according to an embodiment of the present invention.
13 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter of FIG. 6 according to an embodiment of the present invention.
14 is a flowchart illustrating a signal demodulation method in a demodulator disposed in a wireless power transmitter according to an embodiment of the present invention.
15 is a flowchart illustrating a method for improving demodulation performance in a wireless power transmitter according to an embodiment of the present invention.
16 is a flowchart illustrating a signal demodulation method in a wireless power transmitter according to another embodiment of the present invention.

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of its components between embodiments may be selectively selected. It can be used by bonding and substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless specifically defined and described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as a meaning, and terms that are commonly used, such as predefined terms, may be interpreted by considering the contextual meaning of the related technology. In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, a singular form may also include a plural form unless specifically stated in the phrase, and is combined as A, B, C when described as "at least one (or more than one) of A and B, C". It can contain one or more of all possible combinations. In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only for distinguishing the component from other components, and the term is not limited to the nature, order, or order of the component. And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also to the component It may also include a case of 'connected', 'coupled' or 'connected' due to another component between the other components.

Further, when described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other. It also includes a case in which another component described above is formed or disposed between two components. In addition, when expressed as "up (up) or down (down)", it may include the meaning of the downward direction as well as the upward direction based on one component.

In the description of the embodiment, a device equipped with a function for transmitting wireless power on a wireless charging system includes a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a transmitter, a transmitter, and a transmitter for convenience of description. , The transmitting side, a wireless power transmission device, a wireless power transmitter, etc. will be used interchangeably.

In addition, a wireless power receiving device, a wireless power receiver, a wireless power receiving device, a wireless power receiver, a receiving terminal, a receiving side, for convenience of description as an expression of a device equipped with a function for receiving wireless power from the wireless power transmitting device, A receiving device, a receiver, and the like can be used interchangeably.

The transmitter according to the present invention may be configured in a pad shape, a cradle shape, an AP (Access Point) shape, a small base station shape, a stand shape, a ceiling buried shape, a wall-mounted shape, etc., and one transmitter is provided with a plurality of wireless power receiving devices. You can also transmit power.

To this end, the transmitter may include at least one wireless power transmission means. Here, as the wireless power transmission means, various radio power transmission standards based on an electromagnetic induction method that generates a magnetic field in the coil of the power transmitting end and charges it using the electromagnetic induction principle in which electricity is induced in the coil of the receiving end under the influence of the magnetic field may be used.

In addition, the receiver according to an embodiment of the present invention may be provided with at least one wireless power receiving means, and may simultaneously receive wireless power from two or more transmitters.

The receiver according to the present invention is a mobile phone, a smart phone, a laptop computer, a terminal for digital broadcasting, PDA (Personal Digital Assistants), PMP (Portable Multimedia Player), navigation, MP3 player, electric It can be used in small electronic devices such as toothbrushes, electronic tags, lighting devices, remote controllers, fishing boats, wearable devices such as smart watches, but is not limited thereto, and if the device is equipped with a wireless power receiving means according to the present invention and can charge the battery Is enough.

1 is a block diagram illustrating a wireless charging system according to an embodiment of the present invention.

Referring to FIG. 1, the wireless charging system includes a wireless power transmitter 10 that wirelessly transmits power, a wireless power receiver 20 that receives the transmitted power, and an electronic device 20 that receives the received power. Can be configured.

For example, the wireless power transmitting end 10 and the wireless power receiving end 20 may perform in-band communication exchanging information in the same frequency band as the operating frequency used for wireless power transmission.

For example, information exchanged between the wireless power transmission end 10 and the wireless power reception end 20 may include control information as well as status information of each other.

Here, the state information and control information exchanged between the transmitting and receiving terminals will become clearer through the description of the embodiments to be described later.

The in-band communication and the out-of-band communication may provide two-way communication, but are not limited thereto, and in other embodiments, one-way communication or half-duplex communication may be provided.

For example, the unidirectional communication may be that the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10, but is not limited thereto, and the wireless power transmitting end 10 is only the wireless power receiving end 20. It may be sending information.

The half-duplex communication method may be two-way communication between the wireless power receiving end 20 and the wireless power transmitting end 10, but may be a communication method capable of transmitting information only by one device at any one time.

The wireless power receiver 20 according to an embodiment of the present invention may acquire various status information of the electronic device 30.

For example, the status information of the electronic device 30 may include current power usage information, information for identifying a running application, CPU usage information, battery charge status information, battery output voltage / current information, etc., but is not limited thereto. If not, it is sufficient if the information can be obtained from the electronic device 30 and can be used for wireless power control.

In particular, the wireless power transmitter 10 according to an embodiment of the present invention may transmit a predetermined packet indicating whether to support fast charging to the wireless power receiver 20.

In the in-band communication between the wireless power transmitting end 10 and the wireless power receiving end 20, the wireless power receiving end 20 changes the load through a switch control connected to the receiving antenna, thereby transmitting antenna of the wireless power transmitting end 10 Can generate an amplitude modulated signal. The wireless power transmitter 10 may demodulate the amplitude modulated signal from the transmit antenna.

Hereinafter, in-band communication in a wireless charging system supporting an electromagnetic induction method will be briefly described.

The wireless power transmitter outputs the generated AC power signal through a transmission coil. The wireless power receiver may transmit the feedback signal to the wireless power transmitter by changing the amplitude of the AC power signal received according to the feedback signal. Here, the feedback signal may be referred to as feedback bit data. Also, the amplitude change of the AC power signal may mean amplitude modulation of the received AC power signal. The wireless power transmitter can demodulate the feedback signal from the amplitude modulated signal and control internal operation according to the demodulated feedback signal.

For example, the feedback signal may be a control error packet for power control, and the wireless power transmitter may dynamically control the strength of transmission power based on the control error packet.

2 is a view for explaining a power transmission control method in a wireless power transmission system according to an embodiment of the present invention.

Referring to FIG. 2, the wireless power receiver 210 may receive AC power from the wireless power transmitter 210 (S211).

The wireless power receiver 210 may determine an actual control point based on the received power strength (S212).

Also, the wireless power receiver 210 may select a desired control point (S213).

Here, the request control point may be selected based on the type and power reception class of the corresponding wireless power receiver 210, but is not limited thereto, and the request control point is dynamic through a predetermined negotiation procedure with the wireless power transmitter 220. It may be selected as.

However, it should be noted that this is only an example, and the method of selecting the required control point may be different according to the design of a person skilled in the art.

The wireless power receiver 210 may calculate a control error value based on the determined actual control point and the selected request control point (S214).

The wireless power receiver 210 may generate a control error packet including a control error value and transmit it to the wireless power transmitter 220 (S230).

For example, the wireless power transmitter 220 may demodulate the in-band communication signal to identify the control error value included in the control error packet.

The wireless power transmitter 220 may determine the actual transmit coil current by measuring the intensity of the current flowing through the transmit coil (S221).

The wireless power transmitter 220 may determine a new transmission coil current based on the control error value included in the control error packet and the determined actual transmission coil current (S222).

The wireless power transmitter 220 may control the actual transmit coil current to converge to the determined new transmit coil current (S223).

At this time, the wireless power transmitter 220 may determine a control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current.

Here, the wireless power transmitter 220 may calculate a new operation point according to the determined control method.

The wireless power transmitter 220 may set the calculated new operation point (S224).

The wireless power transmitter 220 may convert power according to the set new operation point and transmit it to the wireless power receiver 210 (S225).

In the above-described embodiment of FIG. 2, the control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current may be determined by at least one of the following four control methods.

1) A voltage control method that controls the DC voltage input to the power converter, that is, the inverter operating voltage.

2) A phase control method for controlling the phase of the pulse width modulated signal applied to the inverter.

3) A duty control method for controlling the duty rate of the pulse width modulated signal applied to the inverter.

4) Frequency control method for controlling the frequency (operating frequency) of the pulse width modulated signal applied to the inverter.

3 is a view for explaining a detection signal transmission procedure in a wireless charging system according to an embodiment of the present invention.

For example, the wireless power transmitter may be equipped with three transmission coils 111, 112, and 113. Each transmitting coil may have some areas overlapping with other transmitting coils, and the wireless power transmitter may use predetermined sensing signals 117 and 127 to detect the presence of the wireless power receiver through each transmitting coil. The digital ping signal-is sequentially transmitted in a predefined order.

As shown in FIG. 3, the wireless power transmitter sequentially transmits the detection signals 117 through the primary detection signal transmission procedure shown in FIG. 110, and a signal strength indicator (Signal) from the wireless power receiver 115. Strength Indicator, 116 may identify the received transmission coil (111, 112).

Subsequently, the wireless power transmitter sequentially transmits the detection signals 127 through the secondary detection signal transmission procedure illustrated in FIG. 120, and transmits power among the transmission coils 111 and 112 in which the signal strength indicator 126 has been received. The efficiency (or charging efficiency) —that is, the alignment between the transmitting coil and the receiving coil—can identify a good transmitting coil, and control the power to be transmitted through the identified transmitting coil—that is, to achieve wireless charging. .

As shown in FIG. 3, the reason why the wireless power transmitter performs two detection signal transmission procedures is to more accurately identify which transmission coil is well-received in the receiving coil of the wireless power receiver.

If the signal strength indicators 116 and 126 are received at the first transmission coil 111 and the second transmission coil 112, as shown in the reference numerals 110 and 120 of FIG. 3, the wireless power transmitter Selects the most aligned transmission coil based on the signal strength indicator 126 received in each of the first transmission coil 111 and the second transmission coil 112, and performs wireless charging using the selected transmission coil. .

If the power transmission is stopped for some reason during charging, the wireless power transmitter may transmit a detection signal for identifying the wireless power receiver again after a certain time has elapsed.

The wireless power transmitter according to an embodiment of the present invention may stop power transmission when an overheating state of the wireless power receiver is confirmed during charging.

In particular, when the overheating state of the wireless power receiver is detected, the wireless power transmitter may delay transmission of the detection signal until the overheating state of the corresponding wireless power receiver is resolved.

For example, if the power transmission is stopped according to the detection of the overheating state, the wireless power transmitter may resume transmission of the detection signal after waiting for a preset first time.

Here, the first time may be determined through negotiation between the wireless power transmitter and the wireless power receiver. If the overheating state is detected again, the wireless power transmitter may resume transmission of the detection signal after waiting for the first time again.

As another example, if the power transmission is stopped according to the detection of the overheating state, the wireless power transmitter may resume transmission of the detection signal after waiting for a predefined second time.

If the overheating state is detected again after resuming transmission of the detection signal, the wireless power transmitter may increase the standby time by a predetermined time. The wireless power transmitter may increase the standby time up to a predetermined maximum time whenever the overheating state is detected again.

In the above-described embodiment of FIG. 3, it is described as an example that the wireless power transmitter is provided with a plurality of transmission coils, but this is only one embodiment, and the wireless power transmitter may be configured with only one transmission coil. It should be noted that there is.

4 is a state transition diagram for describing a wireless power transfer procedure according to an embodiment of the present invention.

4, the power transmission from the transmitter to the receiver is largely a selection phase (Selection Phase, 410), a ping phase (Ping Phase, 420), identification and configuration phase (Identification and Configuration Phase, 430), power transmission phase ( Power Transfer Phase, 440).

The selection step 410 may be a transition step when a specific error or specific event is detected while starting or maintaining the power transmission.

Here, specific errors and specific events will be clarified through the following description.

In addition, in the selection step 410, the transmitter may monitor whether an object is present on the interface surface.

If the transmitter detects that an object is placed on the interface surface, it may transition to the ping step 420 (S401).

In the selection step 410, the transmitter transmits a very short pulse analog ping signal, and an object is present in the active area of the interface surface based on the current change of the transmitting coil, that is, load change. Can detect.

In the ping step 420, when an object is detected, the transmitter activates the receiver, and transmits a digital ping to identify whether the receiver is a receiver compliant with the corresponding standard.

In the ping step 420, if the transmitter does not receive a response signal for digital ping-for example, a signal strength indicator-from the receiver, the transmitter may transition to the selection step 410 again (S402).

In addition, in the ping step 420, the transmitter may transition to the selection step 410 when receiving a signal indicating that power transmission is completed from the receiver, that is, a charging completion signal (S403).

When the ping step 420 is completed, the transmitter may transition to the identification and configuration step 430 for collecting the receiver identification and receiver configuration and status information (S404).

In the identification and configuration step 430, the transmitter may receive an unexpected packet, an undesired packet for a predefined time (time out), a packet transmission error (transmission error), or a power transmission contract. If this is not set (no power transfer contract), the process may transition to the selection step 410 (S405).

When identification and configuration of the receiver is completed, the transmitter may transition to a power transmission step 240 of transmitting wireless power (S406).

In the power transmission step 440, the transmitter may receive an unsolicited packet (unexpected packet), or receive a desired packet for a predefined time (time out), or a violation of a preset power transmission contract (power). transfer contract violation), when charging is completed, the process may transition to the selection step 410 (S407).

In addition, in the power transmission step 440, the transmitter may transition to the identification and configuration step 430 when it is necessary to reconfigure the power transmission contract according to a change in the transmitter state (S408).

The above-described power transmission contract may be established based on the state and characteristic information of the transmitter and receiver. For example, the transmitter status information may include information on the maximum transmittable power, information on the maximum number of receivers that can be accommodated, and receiver status information may include information on the required power.

5 is a state transition diagram for explaining a wireless power transmission procedure according to an embodiment of the present invention.

5, the power transmission from the transmitter to the receiver is largely a selection phase (Selection Phase, 510), a ping phase (Ping Phase, 520), identification and configuration phase (Identification and Configuration Phase, 530), negotiation phase (Negotiation) Phase, 540), a calibration phase (Calibration Phase, 550), a power transfer phase (Power Transfer Phase, 560) phase and a renegotiation phase (Renegotiation Phase, 570).

The selection step 510 may be a transition step when a specific error or specific event is detected while starting or maintaining the power transmission.

Here, specific errors and specific events will be clarified through the following description. In addition, in the selection step 510, the transmitter may monitor whether an object is present on the interface surface.

If the transmitter detects that an object is placed on the interface surface, it may transition to ping step 520. In the selection step 510, the transmitter transmits a very short pulse analog ping signal, and an object in the active area of the interface surface based on the current change of the transmitting coil or the primary coil. Can detect if exists.

In ping step 520, when an object is detected, the transmitter activates the receiver and transmits a digital ping to identify whether the receiver is a WPC standard compliant receiver. In the ping step 520, if the transmitter does not receive a response signal for digital ping-for example, a signal strength packet-from the receiver, the transmitter may transition to the selection step 510 again.

In addition, in the ping step 520, the transmitter may transition to the selection step 510 upon receiving a signal indicating that power transmission is completed from the receiver, that is, a charging complete packet.

When the ping step 520 is complete, the transmitter can transition to the identification and configuration step 530 to identify the receiver and collect receiver configuration and status information.

In the identification and configuration step 530, the transmitter may receive an unexpected packet, an undesired packet for a predefined time (time out), a packet transmission error (transmission error), or a power transmission contract. If this is not set (no power transfer contract), it may transition to the selection step 510.

The transmitter may check whether entry into the negotiation step 540 is necessary based on the value of the negotiation field of the configuration packet received in the identification and configuration step 530.

As a result of the verification, if negotiation is required, the transmitter may enter a negotiation step 540 to perform a predetermined foreign object detection (FOD) procedure.

On the other hand, as a result of the check, if negotiation is not required, the transmitter may immediately enter the power transmission step 560.

In a negotiation step 540, the transmitter may receive a FOD status packet including a reference quality factor value. At this time, the transmitter may determine a threshold for FO detection based on the reference quality factor value.

The transmitter may detect whether the FO is present in the charging area using the determined threshold for FO detection and the currently measured quality factor value, and may control power transmission according to the FO detection result. For example, when a FO is detected, power transmission may be stopped, but is not limited thereto.

If a FO is detected, the transmitter can return to selection step 510. On the other hand, if the FO is not detected, the transmitter may enter the power transmission step 560 through a correction step 550.

In detail, when the FO is not detected, the transmitter determines the strength of the power received at the receiving end in the correction step 550, and the power loss at the receiving end and the transmitting end is determined to determine the strength of the power transmitted from the transmitting end. Can be measured.

That is, the transmitter may predict power loss based on the difference between the transmission power of the transmitting end and the receiving power of the receiving end in the correction step 550.

The transmitter according to an embodiment may correct the threshold for FO detection by reflecting the predicted power loss.

In the power transmission step 540, the transmitter may receive an unsolicited packet (unexpected packet), or receive a desired packet for a predefined time (time out), or a violation of a preset power transmission contract (power). transfer contract violation), when charging is completed, the process may transition to the selection step 510.

In addition, in the power transmission step 440, the transmitter may transition to the renegotiation step 570 when it is necessary to reconfigure the power transmission contract according to a change in the transmitter state.

At this time, if the renegotiation is normally completed, the transmitter may return to the power transmission step 560.

The above-described power transmission contract may be established based on the state and characteristic information of the transmitter and receiver. For example, the transmitter status information may include information on the maximum transmittable power, information on the maximum number of receivers that can be accommodated, and receiver status information may include information on the required power.

The wireless power receiver according to the present invention may transmit a power transmission end packet including a ripping code or an overheat protection code to the wireless power transmitter when overheating is detected in the power transmission step.

In this case, when a power transmission end packet including a ripping code or an overheat protection code is received, the wireless power transmitter may stop power transmission and enter a selection step 510 to drive a ripping timer.

Here, the ripping timer driving time may be determined based on the ripping time negotiation result in the negotiation step 540 and the renegotiation step 570.

If the ripping time negotiation is successful, the ripping timer may be driven with the negotiated ripping time. On the other hand, if the ripping time negotiation fails, the ripping timer may be driven with a predefined default ripping time.

When the ripping timer expires, the wireless power transmitter may enter ping step 520 to start digital ping transmission and receive a signal strength packet.

The wireless power transmitter may increase the ripping time when the power transmission end packet including the ripping code or the overheat protection code is received from the wireless power receiver in the identification and configuration step 530.

 For example, if the overheating phenomenon of the wireless power receiver is not resolved, the wireless power transmitter may gradually increase the ripping time to a predefined maximum time.

When the overheating phenomenon of the wireless power receiver is resolved, the wireless power transmitter may resume charging to the wireless power receiver.

The ripping time control method in the wireless power transmitter according to the present invention will be more apparent through the description of the drawings to be described later.

6 is a block diagram illustrating a structure of a wireless power transmission apparatus according to an embodiment of the present invention.

Referring to FIG. 6, the wireless power transmitter 600 includes a controller (Controller 610), a gate driver (Gate Driver 620), an inverter (Invertor, 630), a transmission antenna (Trasmission Antenna, 640), and a power source (Power Source). , 650), a power supply (Power Supply, 660) and a demodulator 670. In the following description, the inverter 630 and the transmission antenna 640 are integrated to be referred to as an AC power transmitter 680.

The power supply 660 may convert power applied from the power 650 to supply operating power of the inverter 630.

For example, the power supply 660 may convert the first DC voltage V_in applied from the power source 650 to a second DC voltage, that is, V_rail.

As another example, the power supply 660 may rectify the first AC voltage applied from the power source 650 and convert the rectified DC voltage into a second DC voltage.

The intensity of the output DC voltage of the power supply 660 may be controlled by the controller 610.

The method for the controller 610 to control the intensity of the AC power transmitted through the transmission antenna (or transmission coil) 640 can be largely classified into three types. First, the controller 660 is a power supply 660 The intensity of the AC power transmitted through the transmission antenna 640 may be controlled by adjusting the intensity of the DC voltage output from.

Second, the controller 660 may control the operating frequency to adjust the strength of AC power transmitted through the transmission antenna 640. For example, the intensity of power is controlled by controlling the operating frequency to be closer to or farther away from the self-resonance frequency of the transmitting antenna while the resonance frequency of the transmitting antenna or the wireless power receiver is placed in the charging area.

Third, the controller 660 may control the phases of the plurality of PWM signals SC_0 to SC_N applied to the inverter 630 to adjust the intensity of AC power transmitted through the transmission antenna 640.

The controller 610 may determine an operating point based on a power control signal received from the wireless power receiver, including, for example, a control error packet of the WPC standard.

The controller 610 may dynamically adjust the intensity of AC power transmitted through the transmission antenna 640 by transmitting a predetermined control signal to the lower module according to the determined operation point. Here, the lower module may include a power supply 660, but is not limited thereto.

As an example, the operation point is a phase of a plurality of PWM signals SC_0 to SC_N supplied to the inverter 630 and a first operation parameter corresponding to the operation frequency, a second operation parameter corresponding to the operation frequency, required to adjust the output voltage of the power supply 660 It may be determined based on at least one of the third operating parameters corresponding to.

The controller 610 may generate and provide a plurality of PWM signals with a plurality of switches provided in the inverter 630 for generating an AC signal. At this time, the phase of the plurality of PWM signals of the controller 610-that is, the inverter control signal-may be controlled.

Hereinafter, for convenience of description, the DC voltage supplied from the power supply 660 to the inverter 630 will be specified by mixing an inverter input voltage, an inverter operating voltage, an inverter driving voltage, or a V rail.

The power supply 660 may be configured to include at least one of an AC / DC converter and a DC / DC converter, depending on the type of power applied from the power source 650. .

For example, the power supply 660 may be a switching mode power supply (SMPS), and a switch control method that converts AC power to DC power using a switching transistor, filter, and rectifier may be used. . Here, the rectifier and the filter may be independently configured to be disposed between the AC power supply and the SMPS.

SMPS is a power supply device that controls the on / off time ratio of a semiconductor switch element to supply a DC power supply whose output is stabilized to a corresponding device or circuit element. It is widely used in equipment and equipment.

The controller 610 according to an embodiment may control the intensity of a current flowing through the transmission antenna 640 by controlling the duty of the PWM signal for controlling the switching transistor when the power supply 660 is a switching mode power supply. have.

In many cases, the stability or precision of the operation of the electronic circuit depends on the quality of the power supply. In general, there are two types of a method of converting and supplying stable power from a battery and commercial AC power, and there are a series regulator method and a switched mode method.

As another example, the variable power supply 660 may be a variable SMPS (Variable Switching Mode Power Supply).

The variable SMPS generates DC voltage by switching and rectifying AC voltage in the tens of Hz band output from an AC power supply.

Variable SMPS (Variable SMPS) may output a DC voltage of a constant level or adjust the output level of the DC voltage according to a predetermined control of the controller 610.

The variable SMPS controls the supply voltage according to the output power level of the power amplifier-that is, the inverter 530-so that the power amplifier of the wireless power transmitter always operates in a highly efficient saturation region, thereby maximizing efficiency at all output levels. You can also keep it.

When a commercially available SMPS is used instead of the variable SMPS, a variable DC / DC converter (Variable DC / DC) may be additionally used.

Commercial SMPS and variable DC / DC converters can control the supply voltage according to the output power level of the power amplifier so that the power amplifier can operate in a highly efficient saturation region, thereby maintaining maximum efficiency at all output levels.

The inverter 630 receives a DC voltage of a constant level by a switching pulse signal in the band of several KHz to several tens of MHz received through the gate driver 620, that is, a pulse width modulated signal for controlling the inverter switch ( V_rail) to AC voltage to generate an AC power signal to be transmitted through the transmission antenna 640.

When the pulse width modulated signal is received from the controller 610, the gate driver 620 may amplify to an appropriate voltage required for driving a plurality of switches included in the inverter 630. That is, the gate driver 620 is an inverter The pulse width modulated signal input to the 630 may function as a buffer to amplify to have an appropriate driving voltage.

Hereinafter, for convenience of description, the pulse width modulation signal input to the inverter switch to generate the AC power signal will be referred to as an inverter control signal or an inverter switch control signal.

When the inverter 630 includes a half bridge circuit, N is 1, and when the inverter 630 includes a full bridge circuit, N may be 3.

The operating frequency may be set to a fixed value in advance, but this is only one embodiment, and the controller 610 according to another embodiment may dynamically determine the operating frequency according to the determined operating point.

The controller 610 according to an embodiment determines whether to adjust the transmission power based on the demodulated feedback signal, and controls the operating frequency according to the determination result to determine the strength of the AC power signal transmitted through the transmission antenna 640. You can also adjust.

In addition, the controller 610 determines whether to adjust the transmission power based on the demodulated feedback signal, and controls the operating frequency according to the determination result to determine the intensity of the current flowing through the transmission antenna 640-that is, the transmission coil. You can also adjust.

In the embodiment of FIG. 6, when the inverter 630 includes a full bridge circuit including four switches, the inverter 630 includes four PWM signals SC_0, SC_1, for controlling each switch provided. SC_2 and SC_3) may be received through the gate driver 620.

At this time, the PWM signals SC_0, SC_1, SC_2, and SC_3 are generated by the controller 610 and then provided to the gate driver 620, amplified to an appropriate driving voltage and then supplied to the inverter 630.

In the embodiment of FIG. 6, when the inverter 630 includes a half bridge circuit including two switches, the inverter 630 gates two PWM signals SC_0 and SC_1 for controlling each switch. It can be received through the driver 620.

The transmission antenna 640 may include an LC resonance circuit for wirelessly transmitting an AC power signal output from the inverter 630.

Here, the LC resonance circuit may include one transmission coil, but this is only one embodiment, and the LC resonance circuit according to another embodiment may include a plurality of transmission coils.

The transmission antenna 640 may further include a matching circuit (not shown) for impedance matching as well as the LC resonance circuit in which the capacitor C and the inductor L are connected in series.

In addition, when a plurality of transmission coils are provided in the transmission antenna 640, the transmission antenna 640 is a coil selection circuit (not shown) for selecting a transmission coil to be actually used for power transmission to a corresponding wireless power receiver among the plurality of transmission coils City) may be further included.

The wireless power transmitter according to another embodiment of the present invention may further include a sensor (not shown) connected to the controller 610.

At this time, the sensor includes various sensing circuits for measuring the strength of the power input / output to / from the inverter 630 or (and) the strength of the current flowing in the transmission coil, the temperature at a specific location inside the wireless power transmitter, and the like. Can be configured.

Here, the information sensed by the sensor may be transmitted to the controller 610, and the controller 610 may control the operation of the wireless power transmitter based on the sensing information.

For example, when the temperature measured by the sensor exceeds a reference value or the intensity of a voltage or current measured at a specific location exceeds a predetermined reference value, the controller 610 lowers the strength of the transmission power or temporarily suspends the power transmission. You can also control.

In addition, the sensor may measure the intensity of the current flowing through the transmitting coil while the analog ping is being transmitted in the above-described selection steps 410 and 510 of FIGS. 4 to 5 and transmit it to the controller 610.

In the selection step, the controller 610 may compare the intensity information of the power flowing in the transmission coil with a predetermined reference value to detect the presence of an object disposed in the charging area.

When the wireless power transmitter 600 performs in-band communication with the wireless power receiver, the wireless power transmitter 600 may include a demodulator 680 connected to the transmission antenna 640.

The demodulator 680 can demodulate and transmit the in-band signal to the controller 610.

The demodulator 670 according to an embodiment of the present invention may demodulate a feedback signal transmitted by a wireless power receiver by extracting only a data signal from an amplitude modulated signal received through a transmission coil. Here, the size of each amplitude-modulated signal may be determined according to a data value transmitted from the wireless power receiver. That is, the amplitude modulated signal has a constant amplitude fluctuation width based on the maximum amplitude of the carrier signal.

In other words, the size of each section of the amplitude modulated signal may be reduced with the amplitude fluctuation width according to the data value based on the maximum amplitude. Accordingly, the amplitude modulated signal includes a first section having a first magnitude corresponding to the maximum amplitude according to the data value, and a second section having a second magnitude at which the amplitude fluctuation width is reduced at the maximum amplitude. can do. Here, in order to demodulate the in-band signal, a signal corresponding to the amplitude fluctuation width that changes according to the data value is required. Then, the demodulation performance of the demodulator 680 is determined according to the size of the signal corresponding to the amplitude fluctuation width.

Therefore, in the present invention, the signal size of the portion corresponding to the amplitude fluctuation width is maintained, and the size of the signals other than this is removed, so that the demodulation performance of the amplitude-modulated feed times signal can be improved.

That is, in the amplitude modulated signal, a section including a first data value has a first signal size. In addition, differently, in the amplitude modulated signal, a section including a second data value has a second signal size smaller than the first signal size. Here, the difference value between the first signal size and the second signal size corresponds to the amplitude fluctuation width. Here, the first data value may be high level data '1', and the second data value may be low level data '0'.

In a conventional conventional technique, the amplitude modulated signal is attenuated to a voltage level recognizable by a differential amplifier (OP-AMP). At this time, the amplitude modulated signal has a constant amplitude fluctuation width according to the data value based on the maximum amplitude. However, as described above, according to the attenuation of the voltage level, the maximum amplitude is also reduced by the attenuation amount, and the amplitude fluctuation width is also reduced by the attenuation amount. Accordingly, in the related art, since the amplitude fluctuation width decreases with the amount of attenuation, accurate data demodulation has been difficult.

On the other hand, the demodulator 670 in the present invention, while maintaining the size of the amplitude fluctuation width required for data demodulation, removes the size of the remaining portions, thereby enabling accurate data demodulation. This will be described in more detail below.

The wireless power receiver may transmit the feedback signal to the wireless power transmitter through an amplitude modulation technique that changes the voltage or current amplitude of the AC signal received through the receiving coil using a switch. The wireless power transmitter may obtain a feedback signal by demodulating the amplitude modulated signal on the transmit antenna 640.

The detailed structure of the demodulator 680 will be more apparent through the description of the drawings to be described later.

For example, the controller 610 may check whether a signal strength indicator is received based on a demodulation signal received from the demodulator 680.

When the controller 610 detects the object disposed in the charging area in the selection step, the controller 610 may enter the ping step and control the digital ping to be transmitted through the transmission antenna 640.

When the reception of the signal strength indicator is confirmed in the ping step, the controller 610 may stop the digital ping transmission and enter the identification and configuration step.

When the power transmission end packet is received in the power transmission step, the controller 610 according to the present invention may stop power transmission and enter the selection step.

7 is a view for explaining the configuration of the transmission antenna of FIG. 6 according to an embodiment of the present invention.

7 is a view for explaining the configuration of the transmission antenna of FIG. 6 according to an embodiment of the present invention.

Referring to FIG. 7, the transmission antenna 640 may include a coil selection circuit 710, a coil assembly 720, and a resonant capacitor 730.

The coil assembly 720 may include at least one transmitting coil, that is, first to Nth coils.

The coil selection circuit 710 may include a switching circuit configured to transmit the output current I_coil of the inverter 630 to any one or at least one of the transmission coils included in the coil assembly 720.

The controller 610 may select a transmission coil to be used for wireless power transmission among transmission coils included in the coil assembly 720.

The controller 610 may control the wireless power to be transmitted only through a specific transmission coil by shorting (ON) the switch corresponding to the selected transmission coil and opening (OFF) the switch corresponding to the remaining transmission coil.

The coil selection circuit 710 may include first to Nth switches. Here, N may be a natural number of 2 or more.

The switch included in the coil selection circuit 710 may have one end connected to the output terminal of the inverter 630 and the other end connected to the coil corresponding to it.

The first to Nth coils included in the coil assembly 720 may have one end thereof connected to a corresponding switch of the coil selection circuit 710, and the other end thereof connected to the resonant capacitor 730.

The demodulator 680 removes the second DC voltage value from the signal between the coil assembly 720 and the resonant capacitor 730, ie, the amplitude modulated signal, except for the first DC voltage value corresponding to the data signal. Then, the demodulator 680 outputs a data signal having a size corresponding to the first DC voltage value of the data component according to the removal of the second DC voltage value. In addition, the demodulator 680 may allow the data signal to pass through a low-pass filter, thereby performing demodulation to a digital signal. At this time, the demodulated signal may be transmitted to the controller 610.

If the coil assembly 720 is composed of one transmission coil, it should be noted that the coil selection circuit 710 of FIG. 7 described above may be excluded from the configuration of the transmission antenna 640.

In this case, the demodulator 680 uses a low-pass filter (not shown) and a comparator (not shown) for the data signal from which the DC voltage value is removed from the signal between the transmitting coil (not shown) and the resonant capacitor 730-that is, the amplitude modulated signal. (Not shown) to output a digital signal.

It should be noted that the demodulator 680 according to an embodiment of the present invention does not include the attenuator 810 disclosed in FIG. 8 to be described later to demodulate a high voltage amplitude modulated signal.

The detailed configuration of the demodulator 680 according to the embodiment of the present invention will become more clear through the description of the drawings to be described later.

8 is a view for explaining the structure of a demodulator provided in a conventional wireless power transmitter.

Referring to FIG. 8, the conventional demodulator 800 may include an attenuator (Attenuator, 810), a peak detector (Peak Detector, 820), and a comparator (Comparator, 830).

The amplitude modulated signal input to the demodulator 800 may be attenuated by the attenuator 810. As shown in FIG. 840, the amplitude modulated signal input to the attenuator 810 shows that the maximum amplitude is 100 V and the amplitude fluctuation width is 1 V.

However, the amplitude modulated signal that has passed through the attenuator 810 is not only the maximum amplitude is reduced to 10V, but also the amplitude fluctuation width is reduced to 0.1V in proportion to the decrease in the maximum amplitude, as shown in FIG.

When the amplitude fluctuation width of the amplitude modulated signal is rapidly decreased, demodulation performance in the demodulator 800 for the amplitude modulated signal is rapidly dropped, and thus there is a problem that normal signal recovery is difficult.

That is, when the amplitude fluctuation width of the amplitude modulated signal is rapidly decreased by the attenuator 810, the voltage level difference of the output signal of the peak detector 820 also rapidly decreases.

Accordingly, the conventional demodulator 800 has a problem in that the probability of occurrence of a signal discrimination error in the comparator 830 is increased even if a small noise is mixed with the amplitude modulated signal.

In particular, when the alignment state between the transmitting coil and the receiving coil is poor, the amplitude change of the signal A (t) is reduced, and thus the probability of demodulation error of the feedback data can be increased.

In addition, in a wireless charging / receiving system with high transmission power-for example, the amplitude deviation of a 60-watt (class) amplitude modulated signal must be large so that the difference between data '0' and '1' becomes apparent, so amplitude modulation is You need to increase your level.

However, if the amplitude modulation level is increased, EMI or EMC problems may occur, and thus there is a problem in that the value cannot be greatly increased.

The present invention has an advantage of providing a demodulator structure and a feedback signal demodulation method for improving the demodulation performance of a feedback signal in in-band communication while reducing the amplitude modulation level very small.

9 is a block diagram illustrating a structure of a demodulator provided in a wireless power transmitter according to an embodiment of the present invention.

9, the demodulator 900 includes a peak detector (Peak Detector, 910), a voltage drop (Voltage dropper, 920), a first low-pass filter (Low Pass Filter, 930) and a comparator (Comparator, 940) Can be configured.

The demodulator 900 may be connected to the AC power transmitter 680 and the controller 610.

The peak detector 910 may receive the amplitude modulated signal A (t) cos (W ₀ t-θ _inv ) from the transmission antenna 640 of the AC power transmitter 680.

Here, θ _inv means the phase delay generated internally when the inverter 630 is driven, and A (t) is the magnitude of alternating current (amplitude component of the feedback signal) flowing in the transmission antenna modulated by the wireless power receiver, W ₀ is 2πf _o and f _o is the operating frequency.

For convenience of description below, the amplitude modulated signal received from the transmission antenna 640 will be referred to as V _AM .

For example, the amplitude modulated signal (V _AM ) may be a signal sensed between the resonant capacitor 730 of the transmit antenna 680 and the coil assembly 720 (or transmit coil), as shown in FIG. 7 above. However, it is not limited thereto.

The peak detector 910 may detect a peak level from the received amplitude modulation signal (V _AM ). The peak level may be expressed as a DC voltage level corresponding to the amplitude magnitude of the amplitude modulated signal V _AM .

That is, the amplitude modulated signal (V _AM ) is an AC signal, and may have a constant frequency or a frequency that fluctuates within a certain range. Accordingly, the demodulator 900 according to the present invention can detect the peak level of the amplitude modulated signal V _AM and restore the feedback signal using the detected peak level. Here, in the description of the embodiment, the output value of the peak detector 910 is referred to as a peak detection signal for convenience of description. In addition, the peak detection signal may have a maximum value of the input voltage level of the amplitude modulation signal V _AM , that is, a DC voltage level corresponding to the maximum amplitude of the input. Hereinafter, for convenience of description, the peak detection signal output from the peak detector 910 will be referred to as V _D.

At this time, the output value of the peak detector 910 may have a DC voltage level corresponding to 1/2 of the maximum amplitude of the amplitude modulated signal V _AM . For example, when the maximum amplitude of the amplitude modulated signal V _AM is 100 V, the output value of the peak detector 910 may be 50 V.

Here, the peak detection signal may have different DC voltage levels for each section. Here, the section may correspond to a symbol period of a digital signal finally output through the demodulator 900.

For example, within the peak detection signal, a section corresponding to data '1' may have a first DC voltage level. Also, a section corresponding to data '0' in the peak detection signal may have a second DC voltage level. In addition, the difference between the first and second DC voltage levels may be a voltage level corresponding to the amplitude variation width of the amplitude modulated signal V _AM .

In conclusion, the peak detection signal V _D output from the peak detector 910 is a signal converted from the amplitude modulation signal, and may be a signal having a change in a DC voltage level according to a data value.

The voltage drop 920 drops the level of the peak detection signal V _D output from the peak detector 910 to an arbitrary level.

That is, the peak detection signal V _D may include a DC voltage component and a data voltage component. Here, the DC voltage component may have an offset DC voltage level, and the data voltage component may have a data DC voltage level. At this time, the peak detection signal has the offset DC voltage level as a reference level. In addition, the peak detection signal V _D has a change amount corresponding to a data DC voltage level based on the reference level. For example, the peak detection signal V _D may have a DC voltage level of 50V. In addition, the data DC voltage level may be 1V, and the offset DC voltage level may be 49V. Accordingly, within the peak detection signal V _D , the DC voltage level of the section corresponding to the data '1' may be 50V, and the DC voltage level of the section corresponding to the data '0' may be 49V. That is, the difference value of the DC voltage level according to the data value may be 1V corresponding to the Data DC voltage level.

That is, the peak detection signal V _D output from the peak detector 910 has a change amount of the data DC voltage level based on the offset DC voltage level. This may be a changing signal.

Here, a part necessary for demodulating the demodulator 900 to demodulate the amplitude modulated signal is the data DC voltage level that changes according to data values (data '0' and '1'). That is, in the peak detection signal V _D , the offset DC voltage level is not an essential part for data demodulation, and the data DC voltage level is the data demodulation. It is a necessary part for.

Therefore, the voltage drop 920 removes the offset DC voltage level from the peak detection signal V _D output from the peak detector 910. That is, the voltage drop 920 acquires and outputs only the data signal corresponding to the data DC voltage level from the peak detection signal V _D. The voltage drop 920 may output a data signal obtained by removing an offset DC voltage signal from the peak detection signal V _D.

At this time, the DC voltage level of the peak detection signal V _D is the sum of the offset DC voltage level and the data DC voltage level.

Further, the DC voltage level of the data signal output from the voltage drop 920 may correspond to the data DC voltage level. Hereinafter, for convenience of description, the data signal output from the voltage drop 920 will be referred to as Vc.

Here, the offset DC voltage level removed from the voltage drop 920 may be determined by resistance values of the resistors R _C and R _E constituting the voltage drop 920. This will be described in more detail below.

The voltage drop 920 provides a data signal from which the offset DC voltage level is removed to the first low-pass filter 930.

The first low-pass filter 930 may remove a high-frequency component included in the data signal and output only a baseband signal.

For example, when the operating frequency range of the wireless charging system according to the present embodiment is about 90 KHz to 180 KHz, the cut-off frequency of the first low-pass filter 930 may be designed to be about 20 KHz, but this is in one embodiment. It should be noted that the cutoff frequency of the first low-pass filter 930 may be designed differently according to the operating frequency range of the corresponding wireless charging system and the design of a person skilled in the art. That is, in general, the operating frequency range of the wireless charging system is 110 KHz or more, and the frequency of the data signal is 1 KHz (2 kbps). Accordingly, the cut-off frequency of the first low-pass filter 930 may be designed as an arbitrary frequency between the 110KHz and 1KHz frequencies, even if it is not the 20KHz. Here, the cut-off frequency may mean a maximum frequency that can pass through the first low-pass filter 930.

The signal that has passed through the first low-pass filter 930 is input to the comparator 940.

For example, the comparator 940 may compare the voltage of the input baseband signal and a reference voltage to output a digital signal.

As another example, the comparator 940 may output a digital signal by comparing the current of the input baseband signal with a reference current.

In particular, in the above-described embodiment of FIG. 9, the feedback signal component A (t) using only the data DC voltage level by removing the offset DC voltage level from the amplitude modulated signal ) Can be demodulated correctly.

That is, the amplitude fluctuation width according to the data value of the amplitude modulated signal received by the demodulator 900 is the same as the amplitude fluctuation width of the data signal output from the voltage drop 920. Here, the amplitude fluctuation width may mean a change amount of the DC voltage level. Consequently, in the present invention, while maintaining the amplitude fluctuation width according to the data value, the amplitude of the amplitude modulated signal is decreased. Accordingly, the peak level of the dropped signal is lowered to a predetermined level, but the amplitude fluctuation range is maintained, and thus the feedback signal component can be accurately demodulated.

10 is a view for explaining a demodulation method in a wireless power transmitter according to an embodiment of the present invention.

9 to 10, the demodulator 900 receives the amplitude modulated signal V _AM received from the transmit antenna 640 and is input to the peak detector 910. Then, the peak detector 910 may detect and output a peak detection signal (V _D , 1020) that detects the peak level of the amplitude modulation signal.

Next, the peak detection signal V _D is provided to the voltage drop 920.

The voltage drop 920 removes the offset DC voltage level from the peak detection signal V _D. The level of the peak detection signal V _D may be determined by the offset DC voltage level and the data DC voltage level. In addition, demodulation of the amplitude modulated signal may be performed with a change amount of the data DC voltage level. Thus, the voltage strong 920 to drop the level of the peak detection signal (V _D), to remove the offset DC voltage level (offset DC voltage level) in the peak detecting signal (V _D), the data The data signals V _c and 1030 including only the DC voltage level may be output.

At this time, the amplitude variation width 1011 according to the data value in the amplitude modulation signal may be 1V, and the amplitude variation width 1031 of the data signal output from the voltage drop 920 may also be 1V. That is, the voltage drop 920 may drop the overall signal level while maintaining the amplitude fluctuation width.

At this time, the data signal may include a multiplication frequency component of the operating frequency and a baseband component.

Accordingly, the data signal passes through the first low-pass filter 930. When the data signal passes through the first low-pass filter 930, the multiplication frequency component is removed and only the baseband signal may remain.

In addition, when the baseband signal passing through the first low-pass filter 930 passes through the comparator 940, digital signals a [Tn] and 1040 may be output. Here, the output signal of the comparator 940 may be a digital signal having a symbol period T.

Accordingly, as shown in reference numerals 1011, 1021, and 1031, the demodulator 900 according to the present invention modulates the amplitude fluctuation width of the data signal 1030 output from the voltage drop 920 to the amplitude It is possible to maintain the same amplitude variation width of the signal 1010.

In FIG. 1011, although the maximum amplitude level of the amplitude modulated signal 1010 is shown to be 100 V and the amplitude fluctuation width is 1 V, this is only for understanding, depending on the alignment state in which the wireless power receiver is placed in the charging area. Can be different.

For example, the more well-aligned the transmitting coil and the receiving coil-for example, the wireless power receiver is disposed in the center of the chargeable area-the larger the amplitude fluctuation width 1011 of the amplitude modulated signal 1010 may be.

At this time, since the amplitude variation width 1011 of the amplitude modulated signal 1010 influences the demodulation performance of the wireless power transmitter 600, it may be important to maintain the amplitude variation width 1011 at the maximum during demodulation.

As shown in FIG. 1031, it should be noted that the amplitude variation width of the data signal 1030 output from the voltage drop 920 can be maintained the same as the amplitude variation width of the amplitude modulation signal 1010. .

Meanwhile, the voltage drop 920 is said to remove the offset DC voltage level to 0 while maintaining the data DC voltage level, but this is only an example. . That is, according to an embodiment, the voltage drop 920 decreases the offset DC voltage level to a certain level other than 0 while maintaining the data DC voltage level. I can do it. That is, the operating voltage of the comparator 940 is within 30V. Accordingly, the level of the data signal output from the voltage drop 920 may have a level that can be processed by the comparator 940. Accordingly, the voltage drop 920 may output a data signal in which the offset DC voltage level is dropped below a certain level while maintaining the data DC voltage level. . At this time, the reference voltage or reference current input to the comparator 940 may be changed according to the degree of drop of the offset DC voltage level.

11 is an equivalent circuit diagram for explaining the structure of an AC power transmitter according to an embodiment of the present invention.

Referring to FIG. 11, the AC power transmitter 1100 may include a full bridge inverter 1110 and an LC resonant circuit 1120.

The full bridge inverter 1110 may include first to third switches 1111, 1112, 1113, and 1114.

The LC resonance circuit 1120 may include an inductor (L, 1120) connected in series and the first capacitors (C1, 1122).

Each of the first to third switches 1111, 1112, 1113, and 1114 may be applied with first switch control signals to third switch control signals SC_0 to SC_3, which are pulse width modulation signals for controlling the inverter switch.

Here, the first switch control signal to the third switch control signal SC_0 to SC_3 may be pulse width modulation signals generated by the controller 610.

11, one end of the LC resonant circuit 1120 is connected between the first switch 1111 and the second switch 1112, the other end is the second switch 1113 and the third switch 1114 Can be connected between.

In this case, the amplitude modulated signal (V _AM ) input to the demodulator 900 in FIG. 9 may be a signal flowing between the inductors (L, 1120) and the first capacitors (C1, 1122).

12A is an equivalent circuit diagram for explaining a structure of a voltage drop provided in a demodulator of a wireless power transmitter according to an embodiment of the present invention, and FIG. 12B is provided in a demodulator of a wireless power transmitter according to another embodiment of the present invention Is an equivalent circuit diagram for explaining the structure of the voltage drop, Figure 12c is an equivalent circuit diagram for explaining the configuration of a low-pass filter and a comparator of a demodulator disposed in a wireless power transmitter according to an embodiment of the present invention.

Referring to FIG. 12A, the peak detector 910 may include first diodes D1 and 911 and third capacitors C3 and 912.

In addition, the voltage drop 920 may include first resistors Rc and 922, second resistors R _E and 923 and first transistors TR1 and 921.

In the first diode D1 constituting the peak detector 910, an anode terminal is connected between the inductors L, 1120 and the first capacitors C1, 1122, and a cathode terminal is connected to the third capacitor C3. , 912).

The third capacitor (C3, 912) constituting the peak detector 910 may be connected to the cathode terminal of the first diode (D1, 911) and the input terminal of the voltage drop (920), the other terminal is grounded Can be.

Looking at the operation of the peak detector 910, the voltage across the third capacitors C3 and 912 is maintained at the peak level of the input signal (for example, the amplitude modulated signal).

In addition, when the voltage level of the input amplitude modulation signal is greater than the voltage across the third capacitors C3 and 912, the first diodes D1 and 911 are forward-biased to conduct. At this time, the third capacitors C3 and 912 are charged to the voltage level of the amplitude modulated signal by the output currents of the first diodes D1 and 911.

Conversely, when the voltage level of the input amplitude modulated signal falls after the voltage across the third capacitors C3 and 912, the first diodes D1 and 911 are reverse-biased and the Charging of the third capacitors C3 and 912 is stopped.

In conclusion, the third capacitors C3 and 912 constituting the peak detector 910 are charged to the peak level of the amplitude modulated signal.

Accordingly, the peak detection signal V _D , which is the output signal of the peak detector 910, has a peak level of the amplitude modulated signal corresponding to the voltage across the third capacitors C3 and 912.

The voltage drop 920 includes first resistors Rc and 922 connected to the peak detector 910, second resistors R _E and 923 connected to ground, and the first resistors Rc and 922. And first transistors TR1 and 921 disposed between the second resistors R _E and 923.

The first resistors Rc and 922 have one end connected to the output terminal of the peak detector 910 and the other terminal connected to the collector terminals of the first transistors TR1 and 921.

One end of the second resistors R _E and 923 is connected to the emitter ends of the first transistors TR1 and 921, and the other end is grounded.

In the first transistors TR1 and 921, a collector terminal is connected to the other end of the first resistors Rc and 922, an emitter terminal is connected to one end of the second resistors R _E and 923, and a base terminal is provided. It is connected to this base voltage supply (not shown).

The operation principle of the voltage drop 920 is as follows.

The peak detection signal output from the peak detector 910 is input to one end of the first resistors Rc and 922 constituting the voltage drop 920.

In addition, a constant base voltage V _B is applied to the base ends of the first transistors TR1 and 921. At this time, the base voltage V _B may have a constant voltage level of about 1V.

In the configuration of the voltage drop 920 as described above, the output signal Vc of the voltage drop 920 will be described as follows.

The peak detection signal may be as shown in Equation 1 below.

[Equation 1]

Here, V _D is a peak detection signal (more specifically, the DC voltage level of the peak detection signal) output from the peak detector 910, and V _offset-DC is the offset DC voltage level (offset DC voltage) level), and the V _Data A (t) is the data DC voltage level.

That is, the DC voltage level of the peak detection signal consists of the sum of the offset DC voltage level and the data DC voltage level.

In addition, the emitter voltage V _E and the emitter current I _{E of} the first transistors TR1 and 921 may be as shown in Equation 2 below.

[Equation 2]

The V _E is the emitter voltage of the first transistors TR1 and 921, V _B is the base voltage of the first transistors TR1 and 921, and 0.7V is the first transistor TR1 and 921 operating. Voltage.

In addition, I _E is the emitter current of the first transistors TR1 and 921, V _E is the emitter voltage, and R _E is the resistance value of the second resistors R _E and 923.

At this time, the output signal of the voltage drop 920 is substantially the collect voltage Vc applied to the collect terminal of the first transistors TR1 and 921. Therefore, the collect voltage Vc may be referred to as an output signal of the voltage drop 920. At this time, in the present invention, the collect voltage Vc has the same value as the data DC voltage level.

Here, according to Equations 1 and 2, the collect voltage Vc may be equal to Equation 3.

[Equation 3]

The Rc is a resistance value of the first resistor (Rc, 922).

That is, the collect voltage Vc may be equal to a difference between a DC voltage level of the peak detection signal and a DC voltage level according to resistance values of the first resistors Rc and 922.

Therefore, when the above expressions 1 to 3 are combined, the collect voltage Vc can be summarized as in the following expression 4.

[Equation 4]

값을 감산하고, 그에 따라 여기에 상기 데이터 직류 전압 레벨(V_DataA(t))을 가산한 직류 전압 레벨을 가질 수 있다. As such, the collector voltage Vc corresponding to the output signal of the first transistors TR1 and 921 in the present invention is obtained from the offset DC voltage level (V _offset-DC ).

The DC voltage level may be obtained by subtracting a value and adding the data DC voltage level (V _Data A (t)) thereto.

At this time, the voltage drop 920 in the present invention outputs a data signal including only the data DC voltage level obtained by removing the offset DC voltage level from the peak detection signal detected by the peak detector 910.

값이 동일한 값을 가져야 한다.To this end, in the present invention, the Vc and the data DC voltage level (V _Data A (t)) have the same value. For this, the offset DC voltage level (V _offset-DC ) and

The values must have the same value.

값이 동일한 값을 가지도록 상기 제 1 저항(Rc, 922) 및 제 2 저항(R_E, 923)의 저항 값을 결정하도록 한다. Therefore, in the present invention, the offset DC voltage level (V _offset-DC ) and

The resistance values of the first resistors Rc and 922 and the second resistors R _E and 923 are determined so that the values have the same value.

In conclusion, the collect voltage Vc in the present invention can be determined as shown in Equation 5 below.

[Equation 5]

In conclusion, in the present invention, the first resistors Rc and 922 and the second resistors R _E and 923 such that the collect voltage Vc and the data DC voltage level V _Data A (t) have the same value. ) To determine the resistance value. Accordingly, the signal that has passed through the voltage drop 920 is a signal in which the offset DC voltage level (V _offset-DC ) is removed from the peak detection signal detected by the peak detector 910.

Therefore, the offset DC voltage level is removed from the DC voltage level of the peak detection signal in the collect voltage Vc corresponding to the output values of the first transistors TR1 and 921 in the present invention. It can also be referred to as the DC voltage level. Also, the collect voltage Vc may be the data DC voltage level.

On the other hand, to remove the offset DC voltage level (offset DC voltage level) included in the peak detection signal, a high pass filter (High Pass Filter) or a series capacitor (Series Capacitor) may be used. However, when a circuit such as a high pass filter or a series capacitor is applied, a certain time delay occurs between the input signal and the output signal. In addition, there is a problem in that it is difficult to accurately restore data initially input by the time delay.

Therefore, in the present invention, the initial input data can be accurately restored without the time delay by using the voltage drop 920 as described above.

Meanwhile, a base voltage fixed to the base ends of the first transistors TR1 and 921 is applied to the voltage drop 920 constituting the demodulator in one embodiment of the present invention.

At this time, the size of the transmission power transmitted from the wireless power transmitter varies according to the type or location of the wireless power receiver. In addition, as the size of the transmission power changes, the size of the peak detection signal output from the peak detector 910 also changes. At this time, when the magnitude of the peak detection signal changes, the magnitude of the offset DC voltage level included in the peak detection signal also changes.

Accordingly, the signal output from the voltage drop 920 includes a constant offset DC voltage level in addition to the data DC voltage level. That is, when the base voltage is fixed as described above and the size of the transmission power changes, the offset DC voltage level may not be accurately removed from the voltage drop 920.

Therefore, in another embodiment of the present invention, the base voltage input to the first transistors TR1 and 921 is adaptively changed according to the size of the transmission power, that is, the level of the peak detection signal.

12B, the voltage drop 920 in another embodiment of the present invention may further include a base voltage input device 924.

That is, in the voltage drop 920 of FIG. 12B, in the voltage drop of FIG. 12A, the base voltage input unit 924 may be further added. Accordingly, a detailed description of the connection relationship and operation principle of the first resistor 922, the second resistor 923, and the first transistors TR1 and 921 already described in FIG. 12A will be omitted.

The base voltage input unit 924 has _one end connected to a contact between the third resistors R ₁ and 925 and the fourth resistors R ₂ and 926 connected in series with the third and fourth resistors, and the other end is the first resistor. And a second low-pass filter 927 connected to the base ends of the transistors TR1 and 921.

The third resistor 925 and the fourth resistor 926 may be divided voltage resistors. The partial pressure resistance may divide and output a peak detection signal detected by the peak detector 910. The third resistor 925 and the fourth resistor may have constant resistance values.

In addition, the signal divided through the divided resistor may be input to the base terminal of the first transistors TR1 and 921 through the second low-pass filter 927. The second low-pass filter 927 may pass only a baseband component from the partial pressure signal. Preferably, the second low-pass filter 927 may have a cut-off frequency of 0.2KHz. However, it should be noted that this is only an example, and the cut-off frequency of the second low-pass filter 927 may be designed differently according to the operating frequency range of the wireless charging system and the design of a person skilled in the art. The cut-off frequency may mean a maximum frequency that can pass through the second low-pass filter 927.

The operation of the voltage drop 920 including the base voltage input unit 924 is as follows.

The input signal input to the voltage drop 920, that is, the peak detection signal output from the peak detector 910 may be as shown in Equation 1 below.

[Equation 6]

In addition, the output signal of the base voltage input unit 924, that is, the base voltage V _B input to the base terminal of the first transistors TR1 and 921 may be as shown in Equation 7 below.

[Equation 7]

Here, R ₁ is the resistance value of the third resistor 925 and R ₂ is the resistance value of the fourth resistor 926.

Accordingly, the emitter voltage V _E and the emitter current I _{E of} the first transistors TR1 and 921 may be expressed by Equation 8 below.

[Equation 8]

The V _E is the emitter voltage of the first transistors TR1 and 921, V _B is the base voltage of the first transistors TR1 and 921, and 0.7V is the first transistor TR1 and 921 operating. Voltage.

In addition, I _E is the emitter current of the first transistors TR1 and 921, V _E is the emitter voltage, and R _E is the resistance value of the second resistors R _E and 923.

At this time, the output signal of the voltage drop 920 is substantially the collect voltage Vc applied to the collect terminal of the first transistors TR1 and 921. Therefore, the collect voltage Vc may be referred to as an output signal of the voltage drop 920.

Here, according to Equations 6 to 8, the collect voltage Vc may be the same as Equation 9.

[Equation 9]

The Rc is a resistance value of the first resistor (Rc, 922).

Therefore, when the above expressions 6 to 9 are combined, the collect voltage Vc can be summarized as in the following expression 10.

[Equation 10]

Accordingly, the voltage drop 920 including the base voltage input unit 924 includes a first offset DC voltage level and a second offset DC voltage level, and the first and second offset DC voltage levels are zero. The resistance values of the first resistor 922, the second resistor 923, the third resistor 925, and the fourth resistor 926 are set, respectively.

일 수 있고, 상기 제 2 오프셋 직류 전압 레벨은

일 수 있다. That is, in Equation 10, the first offset DC voltage level is

The second offset DC voltage level may be

Can be

Therefore, even if the offset DC voltage level of the peak detection signal outputted from the peak detector 910 changes, the third resistor (so that the second offset DC voltage level becomes 0 to make the offset DC voltage component zero. 925) and the resistance values of the fourth resistor 926. Then, when the resistance values of the third resistor 925 and the fourth resistor 926 are determined, resistance values of the first resistor 922 and the second resistor 923 such that the first offset DC voltage level is 0. Respectively.

12C is an equivalent circuit diagram illustrating the configuration of a low-pass filter and a comparator of a demodulator disposed in a wireless power transmitter according to an embodiment of the present invention.

Referring to FIG. 12C, the first low-pass filter 1210 is composed of an RC circuit including resistors R, 1211 and second capacitors C2, 1212 to remove high-frequency components and pass only the base-band components.

The signal that has passed through the first low pass filter 1210 is applied to the first input terminal of the comparator 1220-for example, the '+' terminal-and the second input terminal of the comparator 1220-for example, A reference voltage Vref may be applied to the '-' terminal-.

The output of the comparator 1220 during a unit symbol period may be a digital signal having a HIGH or LOW value.

13 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter of FIG. 6 according to an embodiment of the present invention.

Referring to FIG. 13, the wireless power receiver 1300 includes a receiving antenna 1310, a rectifier 1320, a DC / DC converter (1330), a switch 1340, a load 1350, and a sensing unit ( 1360), a modulator 1370, and a main control unit 1370.

The wireless power receiver 1300 shown in the embodiment of FIG. 13 may exchange information with the wireless power transmitter 600 through in-band communication.

The receiving antenna 1310 may include an inductor (not shown) that is a receiving coil and at least one capacitor (not shown).

The AC power transmitted by the wireless power transmitter 600 may be transmitted to the rectifier 1320 through the reception antenna 1310.

The rectifier 1320 may convert AC power into DC power and transmit it to the DC / DC converter 1330.

The DC / DC converter 1330 may convert the intensity of the output DC power of the rectifier 1320 into a specific intensity required by the load 1350 and output the converted intensity.

The sensing unit 1340 may measure the intensity of the output DC power of the rectifier 1320 and provide it to the main control unit 1380.

The main control unit 1380 may perform power control based on the output DC power of the rectifier 1320.

The feedback signal for power control may be achieved by the main control unit 1380 controlling the modulation unit 1370.

Also, the sensing unit 1340 may measure and output the output voltage and current of the DC / DC converter 1330 to the main control unit 1380.

The main control unit 1380 may control the switch 1340 to block overvoltage / overcurrent from being applied to the load 1350 when the output voltage and / or current of the DC / DC converter 1330 exceeds a corresponding reference value. have.

In addition, the sensing unit 1340 may measure the intensity of the current applied to the receiving antenna 1310 according to wireless power reception, and may transmit the measurement result to the main control unit 1380.

In addition, the sensing unit 1340 may measure the internal temperature of the wireless power receiver 1300 or the electronic device equipped with the wireless power receiver 1300, and provide the measured temperature value to the main control unit 1380.

For example, the main control unit 1380 may determine whether overvoltage is generated by comparing the measured intensity of the output DC power of the rectifier with a predetermined reference value.

As a result of the determination, when an overvoltage is generated, the main control unit 1380 may control the modulator 1370 so that a predetermined control signal indicating that an overvoltage has occurred can be detected by the wireless power transmitter 600.

For example, the modulator 1370 may modulate the amplitude of the AC power signal received by controlling a switch provided according to a control signal received from the main controller 1380.

That is, the current flow through the transmitting coil of the wireless power transmitter 600 may change in correspondence to the switch control of the modulator 1370.

The wireless power transmitter detects a change in a signal flowing in the transmission coil and demodulates the feedback signal generated by the wireless power receiver 1300.

14 is a flowchart illustrating a signal demodulation method in a demodulator disposed in a wireless power transmitter according to an embodiment of the present invention.

9 and 14, the demodulator 900 may output a data signal from an amplitude modulated signal input to the peak detector 910 (S1410).

That is, the signal input to the peak detector 910 is an amplitude modulated signal input from the transmit antenna 640, and the signal output from the peak detector 910 detects a peak that detects a peak level from the amplitude modulated signal. It is a signal.

Then, when the peak detection signal is output, the voltage drop 920 outputs a data signal obtained by removing the offset DC voltage level excluding the data DC voltage level from the peak detection signal. . The data signal may be a signal in which the offset DC voltage level is removed while the data DC voltage level is maintained.

At this time, the data signal output through the voltage drop 920 includes a multiplication frequency signal component of the operating frequency and a baseband signal component.

Accordingly, the output signal of the voltage drop 920 may be input to the first low-pass filter 930 provided in the demodulator 900.

The demodulator 900 may filter the output signal of the voltage drop 920 using the first low-pass filter 930 (S1420).

Here, the multiplication frequency component of the signal components included in the output signal of the voltage drop 920 is removed by the first low-pass filter 930, and only the baseband signal component passes through the first low-pass filter 930. You can.

The output signal of the first low-pass filter 930 may be applied to the first input terminal of the comparator 940 provided in the demodulator 900. At this time, a predetermined reference voltage may be applied to the second input terminal of the comparator 940.

The demodulator 900 may convert the baseband signal that is the output of the first low-pass filter 930, that is, the amplitude modulated signal that is an analog signal, into a digital signal using the provided comparator 940 (S1430). The comparator 940 may compare the filtered signal with a predetermined reference voltage and output a digital signal.

The demodulator 900 may transmit the digital signal converted through the comparator 940 to the controller 610 (S1440).

15 is a flowchart illustrating a demodulation method in a wireless power transmitter according to an embodiment of the present invention.

15, the wireless power transmitter may acquire an amplitude modulated signal through a transmission antenna (S1510).

The obtained amplitude modulated signal is input to the peak detector 910 constituting the demodulator 900. Then, the peak detector 910 outputs a peak detection signal that detects the peak level of the amplitude modulation signal.

The peak detection signal is input to a voltage drop (920).

The voltage drop 920 extracts and outputs only the data signal from the peak detection signal (S1520).

The level of the peak detection signal may include an offset DC voltage level and a data DC voltage level. Here, the data DC voltage level may have a value of 0V to 1V according to the data value. In addition, according to an embodiment, the data DC voltage level may have a value of 0V to 2V, which may be changed according to design.

In addition, the voltage drop 920 may output a data signal from which the offset DC voltage level is removed from the peak detection signal.

When the data signal is output, the data signal is input to the first low-pass filter 930 and the comparator 940, respectively, and a digital signal may be output accordingly (step 1530).

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential features of the present invention.

Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Features, structures, effects, and the like described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, and the like exemplified in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiments have been mainly described above, these are merely examples and do not limit the present invention, and those skilled in the art to which the present invention pertains are exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

Claims (20)

An inverter that outputs an AC signal;
A transmission coil connected to the inverter;
A demodulator connected to the transmitting coil to receive an amplitude modulated signal and demodulate the amplitude modulated signal; And
It includes a controller for controlling the operation of the inverter,
The demodulator,
Receiving the amplitude modulated signal,
A data signal obtained by removing the offset DC voltage level from the amplitude modulated signal is detected,
Comparing the voltage or current of the detected data signal with a reference voltage or a reference current to demodulate the bit data encoded in the amplitude modulated signal,
The data signal,
Having a data DC voltage level corresponding to the amplitude of vibration fluctuation of the amplitude modulated signal
Wireless power transmitter. According to claim 1,
The demodulator,
A peak detector outputting a peak detection signal that detects a peak level from the amplitude modulated signal,
And removing the offset DC voltage level from the peak detection signal of the peak detector to output a voltage signal having the data DC voltage level.
Wireless power transmitter. According to claim 2,
The voltage drop is,
In the state where the data DC voltage level is maintained, the offset DC voltage level is dropped based on the operating voltage of the demodulator.
Wireless power transmitter. According to claim 2,
The voltage drop is,
Outputting the data signal having the data DC voltage level by removing the offset DC voltage level from the peak detection signal to zero.
Wireless power transmitter. The method of claim 4,
The data signal
A first data section having a DC voltage level of 0V,
The data DC voltage level is divided into a second data section having the same DC voltage level.
Wireless power transmitter. According to claim 2,
The voltage drop is,
A first resistor having one end connected to the output terminal of the peak detector,
A second resistor having one end connected to ground,
And a switching element including a collector terminal connected to the other terminal of the first resistor, an emitter terminal connected to the other terminal of the second resistor, and a base terminal to which a base voltage is input.
Wireless power transmitter. The method of claim 6,
The data DC voltage level of the data signal is
Is the collector voltage level of the switching element,
The base voltage input to the base terminal of the switching element,
Variable according to the peak level of the amplitude modulated signal
Wireless power transmitter. According to claim 2,
The demodulator,
A first low-pass filter for low-pass filtering the data signal output from the voltage drop; And
Further comprising a comparator for comparing the filtered signal with a reference voltage or a reference current to convert to a digital signal
Wireless power transmitter. The method of claim 6,
The voltage drop is,
Further connected to the base terminal of the switching element, and further comprising a base voltage input unit for outputting the base voltage variable according to the peak level of the amplitude modulation signal,
The base voltage input device,
A partial voltage resistance connected in series between the peak detector and the output terminal and ground,
And a second low-pass filter disposed between the divided resistance and the base end of the switching element.
Wireless power transmitter. According to claim 1,
The controller
Determine whether to adjust the transmission power from the bit data, and to change the operating frequency of the AC signal to adjust the transmission power
Wireless power transmitter. According to claim 1,
The controller
A wireless power transmitter for determining whether to adjust the current intensity flowing in the transmission coil from the bit data, and changing the operating frequency of the AC signal to adjust the current intensity of the transmission coil. Generating AC power through an inverter;
Obtaining an amplitude modulated signal from a transmission antenna to which the AC power is input;
Obtaining a peak detection signal that senses a peak level of the amplitude modulated signal;
Obtaining a data signal obtained by removing an offset DC voltage level from the acquired peak detection signal; And
And comparing the voltage or current of the obtained data signal with a reference voltage or reference current to demodulate the bit data encoded in the amplitude modulated signal,
The data signal,
Having a data DC voltage level corresponding to the amplitude of vibration fluctuation of the amplitude modulated signal
Data communication method of wireless power transmitter. The method of claim 12,
The step of demodulating the bit data encoded in the amplitude modulated signal by comparing the voltage or current of the data signal with a reference voltage or a reference current
Low-pass filtering the data signal; And
Comprising the step of comparing the filtered signal with a reference voltage or a reference current to a digital signal
Data communication method of wireless power transmitter. The method of claim 12,
Acquiring the data signal,
And lowering the offset DC voltage level based on the operating voltage of the comparator while maintaining the data DC voltage level among the DC voltage levels of the peak detection signal.
Data communication method of wireless power transmitter. The method of claim 12,
Acquiring the data signal,
And removing the offset DC voltage level from the peak detection signal to 0 to obtain the data signal having a size corresponding to the data DC voltage level.
Data communication method of wireless power transmitter. The method of claim 15,
The data signal
A first data section having a DC voltage level of 0V,
The data DC voltage level is divided into a second data section having the same DC voltage level.
Data communication method of wireless power transmitter. The method of claim 16,
Acquiring the data signal,
And removing the offset DC voltage level through a voltage drop including a first resistor, a second resistor, and a switching element,
The resistance values of the first resistor and the second resistor are
Is set based on the offset DC voltage level,
The data DC voltage level of the data signal is
Collect voltage of the switching element
Data communication method of wireless power transmitter. The method of claim 17,
And varying a voltage applied to the base of the switching element according to the peak level of the amplitude modulated signal.
Data communication method of wireless power transmitter. The method of claim 12,
Further comprising the step of determining whether to adjust the transmission power from the bit data, and changing the operating frequency of the AC signal to adjust the transmission power
Data communication method of wireless power transmitter. The method of claim 12,
It is determined from the bit data whether or not the current intensity flowing through the transmission antenna is adjusted, and the operating frequency of the AC signal is changed to adjust the current intensity of the transmission coil.
Data communication method of wireless power transmitter.

Images