KR20210105588A - Apparatus and method for transmitting power wirelessly - Google Patents

Abstract

The present specification relates to an apparatus and method for transmitting power wirelessly. A method for transmitting power in an apparatus for transmitting power wirelessly according to an embodiment includes the steps of: wirelessly transmitting power to a receiving device through a wireless power signal; using a low-pass filter to obtain an analog signal loaded by a receiving device in an amplitude shift manner on a wireless power signal; generating a digital signal from an analog signal; extracting a data bit from the digital signal; checking whether an error occurs in the extracted data bit; and when an error occurs, changing a method used for generating a digital signal from an analog signal from a reference value comparison method to a peak value comparison method or from a peak value comparison method to a reference value comparison method.

Description

Wireless power transmission apparatus and method {Apparatus and method for transmitting power wirelessly}

This specification relates to an apparatus and method for wirelessly transmitting power, and more particularly, to a method for decoding a signal transmitted from a receiving apparatus.

With the development of communication and information processing technologies, the use of smart terminals such as smart phones and tablet PCs is gradually increasing. The charging method currently widely applied to smart terminals is to connect an adapter connected to a power source directly to the smart terminal to It is a method of charging by receiving power or by connecting to a smart terminal through the USB terminal of the host and receiving USB power from the host to charge.

Recently, in order to reduce the inconvenience of having to directly connect a smart terminal to an adapter or a host through a connection line, a wireless charging method of wirelessly charging a battery using magnetic coupling without electrical contact is gradually applied to smart terminals. .

There are several methods for wirelessly supplying or receiving electrical energy. Representatively, inductive coupling based on electromagnetic induction and resonant coupling based on electromagnetic resonance by a wireless power signal of a specific frequency. There is a coupling method.

Both methods form a communication channel between the wireless charging device and an electronic device such as a smart terminal to exchange data, thereby securing stability of power transmission and increasing transmission efficiency.

However, there are cases in which a large amount of noise enters the signal transmitted from the receiving device, resulting in an abnormal waveform, and it is difficult to extract accurate digital data from the signal of such a waveform. If data is not properly transmitted from the receiving device, the transmitting device does not detect a change in state of the receiving device and cannot transmit power with high efficiency.

This specification is in view of this situation, and an object of this specification is to provide a method for improving communication quality between a wireless power transmitter and a receiver.

Another object of the specification is to provide a method for accurately decoding data bits from a signal transmitted by a receiving device.

A method of transmitting power in a wireless power transmitting apparatus according to an embodiment for realizing the above object includes: wirelessly transmitting power to a receiving apparatus through a wireless power signal; using a low-pass filter to obtain an analog signal loaded by a receiving device in an amplitude shift manner on a wireless power signal; generating a digital signal from an analog signal; extracting data bits from the digital signal; checking whether an error occurs in the extracted data bit; and when an error occurs, changing a method used for generating a digital signal from an analog signal from a reference value comparison method to a peak value comparison method or from a peak value comparison method to a reference value comparison method .

A wireless power transmitter according to another embodiment includes an inverter for converting DC power into AC; a resonance circuit including a primary coil for transmitting a wireless power signal through magnetic inductive coupling with a secondary coil of a receiving device; a demodulator for extracting a message loaded by the receiving device in an amplitude shifting manner on the wireless power signal; and a control unit for controlling the inverter to generate a wireless power signal suitable for the message extracted by the demodulator, wherein the demodulator obtains an analog signal loaded on the wireless power signal in an amplitude shift method using a low-pass filter, and the analog signal The method used when generating a digital signal from, generating a digital signal from an analog signal, and generating a digital signal from an analog signal when an error occurs in the extracted data bits It is characterized in that the value comparison method is changed to the reference value comparison method.

Therefore, even if the ASK signal transmitted from the wireless power receiving device is distorted, it is possible to accurately decode or demodulate, so that stable communication quality can be maintained between the transmitting device and the receiving device, and the transmitting device can supply power to the receiving device with high efficiency. can be transmitted.

1 is a conceptual diagram illustrating that power is wirelessly transmitted from a wireless power transmission device to an electronic device;
2 is a schematic diagram of a circuit configuration of a power converter of a transmission device for wirelessly transmitting power in an electromagnetic induction method;
3 is a diagram illustrating a configuration for a wireless power transmitter and a receiver to exchange power and a message;
4 is a block diagram illustrating a loop for controlling power transfer between a wireless power transmitter and a receiver,
5 is a block diagram of a wireless power system in which a transmitting device demodulates an ASK signal transmitted by a receiving device receiving power wirelessly;
Figure 6a shows a configuration for demodulating the ASK signal,
Figure 6b shows the process of obtaining digital data by demodulating the ASK signal of a normal waveform,
7 shows an example in which digital data cannot be properly obtained by demodulating the ASK signal of an abnormal waveform;
8 shows an example of demodulating an ASK signal of an abnormal waveform by a peak value detection method;
9 is a flowchart illustrating an operation of demodulating an ASK signal while alternating a reference value comparison method and a peak value detection method according to an embodiment of the present invention;
10 shows a digital signal generated by a differential bi-phase encoding method and data bits corresponding thereto;
11a and 11b respectively show a normal digital signal and an abnormal digital signal among digital signals generated from the ASK signal,
12A and 12B show an algorithm for determining data bits from a digital signal generated from an ASK signal according to an embodiment of the present invention;
13 is an exploded perspective view of a charger to which the present invention is applied.

Hereinafter, an embodiment of a wireless power transmission apparatus and method will be described in detail based on the accompanying drawings.

1 is a conceptual diagram illustrating wireless power transmission from a wireless power transmission device to an electronic device.

The wireless power transmitter 100 is a power transmitter that wirelessly transmits power required by the wireless power receiver or the electronic device 200, or charges the battery of the electronic device 200 by wirelessly transferring power. It may be a wireless charging device for this purpose, or may be implemented as various types of devices that deliver power to the electronic device 200 that requires power in a non-contact state.

The electronic device 200 is a device capable of wirelessly receiving power from the wireless power transmitter 100 to operate, and may charge a battery using the wirelessly received power. Electronic devices that receive power wirelessly include portable electronic devices, for example, smart phones, smart terminals, tablet computers, multimedia terminals, keyboards, mice, input/output devices such as video or audio auxiliary devices, and auxiliary batteries. can do.

Resonance occurs in the electronic device 200 by the inductive coupling method based on electromagnetic induction by the wireless power signal of the wireless power transmitter 100 , that is, the wireless power signal transmitted from the wireless power transmitter 100 , and the resonance phenomenon Power can be wirelessly transferred from the wireless power transmitter 100 to the electronic device 200 without contact by the It transmits power by induction.

When the intensity of the current flowing in the primary coil of the wireless power transmitter 100 changes, the magnetic field passing through the primary coil or transmission coil (primary coil, TX coil) is changed by the current, and the changed magnetic field is the electronic device An induced electromotive force is generated on the side of the secondary coil or the receiving coil in 200 (secondary coil, RX coil).

The wireless power transmitter 100 and the electronic device 200 are arranged so that the primary coil of the wireless power transmitter 100 and the receiving coil of the electronic device 200 are close to each other, and the wireless power transmitter 100 is When the current of the primary coil is controlled to change, the electronic device 200 supplies power to a load such as a battery by using the electromotive force induced in the receiving coil.

Since the efficiency of wireless power transfer by the inductive coupling method is affected by the arrangement and distance between the wireless power transmitter 100 and the electronic device 200, the wireless power transmitter 100 is configured to include a flat interface surface. and a primary coil mounted on a lower portion of the interface surface, and one or more electronic devices may be placed on the interface surface. By making the space between the primary coil mounted below the interface surface and the receiving coil located above the interface surface sufficiently small, the efficiency of wireless power transfer by inductive coupling can be increased.

A mark indicating a position where the electronic device is to be placed may be displayed on the upper portion of the interface surface, and may indicate the position of the electronic device so that the arrangement between the primary coil and the receiving coil mounted below the interface surface is properly made. A protrusion-shaped structure for guiding the position of the electronic device may be formed on the interface surface, and a magnetic material such as a magnet is formed under the interface surface to form a primary coil by attraction with a magnetic material of another pole provided inside the electronic device. and may guide the receiving coil to be well aligned.

2 is a conceptual diagram illustrating a circuit configuration of a power converter of a transmission device for wirelessly transmitting power in an electromagnetic induction method.

The wireless power transmitter may be largely configured to include a power source and a power conversion unit composed of an inverter and a resonance circuit, the power source may be a voltage source or a current source, and the power conversion unit converts the power supplied from the power source into a wireless power signal and receives pass to the device. The wireless power signal is formed in the form of a magnetic or electromagnetic field having resonance characteristics, and the resonance circuit includes a coil for generating a wireless power signal.

The inverter converts a DC input into an AC waveform of a desired voltage and frequency through a switching element and a control circuit. FIG. 2 shows a full-bridge inverter, and other types of inverters such as half-bridge inverters are also possible .

The resonant circuit is configured to include a primary coil (Lp) and a capacitor (Cp) to transmit power in a magnetic induction method, and the coil and the capacitor determine a fundamental resonant frequency of power transmission. The primary coil forms a magnetic field corresponding to a wireless power signal according to a change in current, and may be implemented in the form of a flat plate or a solenoid.

The AC current converted by the inverter drives the resonance circuit, thereby forming a magnetic field in the primary coil. The inverter generates AC with a frequency close to the resonance frequency of the resonance circuit, thereby increasing the transmission efficiency of the transmission device and controlling the inverter. By doing so, the transmission efficiency of the transmission device can be changed.

3 is a diagram illustrating a configuration for a wireless power transmitter and a receiver to exchange power and a message.

Since the power converter only unilaterally transmits power regardless of the reception state of the receiving device, a configuration for receiving feedback related to the reception state from the receiving device is required in order to transmit power to match the state of the receiving device. do.

The wireless power transmitter 100 may include a power converter 110 , a communicator 120 , a controller 130 , and a power source 140 , and the wireless power receiver 200 includes a power receiver 210 . , may be configured to include the communication unit 220 and the control unit 230, and may be configured to further include a load 250 to be supplied with the received power.

The power converter 110 may be configured to include an inverter and a resonance circuit of FIG. 2 , and further include a circuit capable of adjusting characteristics such as a frequency, voltage, and current used to form a wireless power signal.

The communication unit 120 is connected to the power conversion unit 110 and demodulates a wireless power signal modulated by the receiving device 200 wirelessly receiving power according to magnetic induction from the transmitting device 100 to receive a power control message. can be detected.

The control unit 130, based on the message detected by the communication unit 120, determines one or more characteristics of the operating frequency, voltage, and current of the power conversion unit 110, and controls the power conversion unit 110 to convert power It may cause the unit 110 to generate a wireless power signal suitable for the message. The communication unit 120 and the control unit 130 may be configured as one module.

The power receiving unit 210 includes a matching circuit consisting of a receiving coil and a capacitor generating an induced electromotive force according to a change in a magnetic field generated in the primary coil of the power converting unit 110, and an alternating current flowing in the receiving coil. It may include a rectifier circuit for rectifying and outputting a direct current.

The communication unit 220 of the receiving device is connected to the power receiving unit 210, and by adjusting the load of the power receiving unit in a manner that adjusts a resistive load in DC and/or a capacitive load in AC, the transmitting device and the receiving device The power control message may be transmitted to the transmitting device by changing the wireless power signal between the two.

The control unit 230 of the receiving device controls each component included in the receiving device, measures the output of the power receiving unit 210 in the form of current or voltage, and controls the communication unit 220 based on this to wirelessly transmit power A power control message may be transmitted to the device 100 . The message may instruct the wireless power transmitter 100 to start or end the transmission of the wireless power signal, and may also adjust the characteristics of the wireless power signal.

The wireless power signal formed by the power conversion unit 110 of the transmitting device is received by the power receiving unit 210, the control unit 230 of the receiving device controls the communication unit 220 to modulate the wireless power signal, the control unit ( The 230 may perform a modulation process to change the amount of power received from the wireless power signal by changing the reactance of the communication unit 220 . When the amount of power received from the wireless power signal is changed, the current and/or voltage of the power converter 110 that forms the wireless power signal also changes, and the communication unit 120 of the wireless power transmitter 100 is the power converter of the power converter 110 . A demodulation process may be performed by sensing a change in current and/or voltage.

The controller 230 of the receiving device generates a packet including a message to be transmitted to the wireless power transmitter 100 and modulates the wireless power signal to include the generated packet, and the controller 130 of the transmitter generates a communication unit The packet extracted through 120 may be decoded to obtain a power control message, and the controller 230 of the receiving device controls the received power based on the amount of power received through the power receiver 210 to control the wireless power signal. You can send a message requesting to change the properties of

4 is a block diagram illustrating a loop for controlling power transmission between a wireless power transmitter and a receiver.

A current is induced in the power receiver 210 of the receiver 200 according to a change in the magnetic field generated by the power converter 110 of the transmitter 100 to transmit power, and the controller 230 of the receiver A control point, that is, a desired output current and/or voltage is selected, and an actual control point of power received through the power receiver 210 is determined.

The control unit 230 of the receiving device calculates a control error value using a desired control point and an actual control point while power is transmitted. For example, a difference between two output voltages or currents may be taken as a control error value. The control error value can be determined so that if less power is required to reach the desired control point, for example, it will be a negative value, and if more power is needed to reach the desired control point, it will be a positive value. The control unit 230 of the receiving device may generate a packet including the calculated control error value in a manner that changes the reactance of the power receiving unit 210 over time through the communication unit 220 and transmit it to the transmitting device 100 . .

The communication unit 120 of the transmitting device detects a message by demodulating a packet included in the wireless power signal modulated by the receiving device 200 , and may demodulate a control error packet including a control error value.

The control unit 130 of the transmitting device decodes the control error packet extracted through the communication unit 120 to obtain a control error value, and the receiving device uses the actual current value and the control error value that actually flow through the power conversion unit 110 . A new current value for transmitting the desired power can be determined.

When the system is stabilized from the process of receiving the control error packet from the receiving device, the control unit 130 of the transmitting device is a new operating point, that is, applied to the primary coil so that the actual current value flowing through the primary coil becomes a new current value. The power converter 110 is controlled so that the magnitude, frequency, duty ratio, etc. of the AC voltage reach a new value, and a new operating point is continuously maintained so that the receiving device can additionally communicate control information or state information.

The interaction between the wireless power transmitter 100 and the wireless power receiver 200 has four steps, including selection, ping, identification & configuration, and power transfer. can be made with The selecting step is for the transmitting device to discover an object placed on the interface surface, the ping step is to check whether the object contains the receiving device or not, and the identifying/configuring step is the preparation step for sending power to the receiving device to receive appropriate information from the receiving device and conclude a power transfer contract with the receiving device based on this is a step

In the ping step, the receiving device 200 transmits a signal strength packet (Signal Strength Packet, SSP) indicating the magnetic flux coupling degree of the primary coil and the receiving coil to the transmitting device 100 through modulation of the resonance waveform, the signal strength The packet SSP is a message generated by monitoring the voltage rectified by the receiving device, and the transmitting device 100 may receive it from the receiving device 200 and use it to select an initial driving frequency for power transmission.

In the identification/configuration step, an identification packet including the version, manufacturer code, device identification information, etc. of the receiving device 200, the maximum power of the receiving device 200, a configuration including information such as a power transmission method The receiving device 200 transmits a configuration packet or the like to the transmitting device 100 .

In the power transmission step, a control error packet (Control Error Packet, CEP) indicating the difference between the operating point at which the receiving device 200 receives the power signal and the operating point determined in the power transmission contract, the receiving device 200 connects to the interface surface The receiving device 200 transmits, to the transmitting device 100 , a received power packet (RPP) indicating an average value of power received through .

The reception power packet (RPP) is reception power amount data in consideration of the rectified voltage, load current, offset power, etc. of the power reception unit 210 of the reception device, and the transmission device 100 continues while receiving power by the reception device 200 . ), and the transmission device 100 receives it and uses it as an operation factor for power control.

The communication unit 120 of the transmitting device extracts a packet from the change in the resonance waveform, respectively, and the control unit 130 decodes the extracted packet to obtain a message, and controls the power converter 110 based on the decoded packet to control the receiving device 200. Power can be transmitted wirelessly while changing the power transmission characteristics as requested.

On the other hand, in the method of wirelessly transmitting power by inductive coupling, the efficiency has little effect on the frequency characteristic, but is affected by the arrangement and distance between the transmitter 100 and the receiver 200 .

The area that the wireless power signal can reach can be divided into two types. When the transmitting device 100 wirelessly transmits power to the receiving device 200, the portion of the interface surface through which a high-efficiency magnetic field can pass is activated. It may be referred to as an area, and the area in which the transmitting device 100 can detect the presence of the receiving apparatus 200 may be referred to as a sensing area.

The control unit 130 of the transmitting device may detect whether the receiving device 200 is disposed in or removed from the active area or the sensing area, using a wireless power signal formed by the power conversion unit 110 or provided separately. It is possible to detect whether the receiving device 200 is disposed in the active area or the sensing area by the corresponding sensor.

For example, the control unit 130 of the transmitting device is affected by the wireless power signal due to the receiving device 200 existing in the sensing area, and the power characteristic for forming the wireless power signal of the power converter 110 is changed. It is possible to detect the presence of the receiving device 200 by monitoring whether or not. The controller 130 of the transmitting device may perform a process of identifying the receiving device 200 or determine whether to start wireless power transmission, etc. according to a result of detecting the presence of the receiving device 200 .

The power conversion unit 110 of the transmitting device may further include a position determining unit, the position determining unit may move or rotate the primary coil in order to increase the efficiency of wireless power transfer by the inductive coupling method, in particular, the receiving device ( 200) may be used when the transmission device 100 does not exist in the active area.

The positioning unit moves the primary coil so that the distance between the center of the primary coil of the transmitting device 100 and the center of the receiving coil of the receiving device 200 is within a predetermined range, or 1 so that the centers of the primary coil and the receiving coil overlap. It may be configured to include a driving unit for moving the car coil. To this end, the transmitting device 100 may further include a sensor or a sensing unit for detecting the position of the receiving device 200 , and the control unit 130 of the transmitting device is configured to control the receiving device 200 that receives from the sensor of the sensing unit. The positioning unit may be controlled based on the location information.

Alternatively, the control unit 130 of the transmitting device may receive control information on the arrangement or distance to the receiving device 200 through the communication unit 120 and control the positioning unit based on this.

In addition, the transmitting device 100 is formed to include two or more of a plurality of primary coils and selectively using some of the coils that are suitably arranged with the receiving coil of the receiving device 200 among the plurality of primary coils to increase the transmission efficiency. In this case, the positioning unit may determine which of the plurality of primary coils will be used for power transmission.

A single primary coil or a combination of one or more primary coils that form a magnetic field passing through the active region may be referred to as a primary cell. Detects and determines an active area based on this, connects a transmission module constituting a main cell corresponding to the active area, and controls so that the primary coil of the transmission module and the receiving coil of the receiving device 200 are inductively coupled can do.

On the other hand, the receiving device 200 is embedded in an electronic device such as a smart phone or a smart device including a smart phone or a multimedia playback terminal, the electronic device is not constant in the vertical or horizontal direction on the interface surface of the transmitting device 100 Depending on the orientation or location, the transmission device requires a large active area.

When a plurality of transmitting coils are used to expand the active area, a driving circuit is required as many as the number of transmitting coils and control of the plurality of transmitting coils becomes complicated, resulting in an increase in the cost of a transmitting device, that is, a wireless charger when commercialized. In addition, even when a method of changing the position of the transmission coil to expand the active area is applied, a transport mechanism for moving the position of the transmission coil must be provided, so that there is a problem in that the volume and weight increase and the manufacturing cost increases.

It is effective if there is a method to expand the active area even with one primary coil with a fixed position, but if the size of the primary coil is simply increased, the magnetic flux density per unit area of the primary coil decreases and the magnetic coupling force between the transmitting and receiving coils decreases. It is weakened, so that the active area does not increase as expected and the transmission efficiency decreases.

As such, it is important to determine an appropriate shape and size of the primary coil in order to expand the active area and improve transmission efficiency. A multi-coil method employing two or more primary coils may be effective as a method of expanding an active area of a wireless power transmitter.

5 is a block diagram illustrating a wireless power system in which a transmitting device demodulates an ASK signal transmitted by a receiving device wirelessly receiving power.

The wireless power system of FIG. 5 is composed of a transmitter (PTx) and a receiver (PRx), the transmitter (PTx) wirelessly transmits power to the receiver (PRx) (Power), and the receiver (PRx) wirelessly transmits a message. Feedback to (PTx) (Communication).

The transmitter (PTx) switches the power supplied by the power supply (Power Supply) to generate an AC electric field to form a magnetic field, whereby AC power is induced in the coil of the receiver (PRx) and the rectifier (Rectifier) converts it into DC and LDO (Low Drop Out) changes the voltage to supply power to the load.

In the receiver (PRx), an ASK signal modulator (ASK Signal Modulator) corresponding to the communication unit 220 of the receiving device 200 of FIG. 3 transmits a wireless power signal transmitted by the transmitter (PTx) to an amplitude shift method (ASK) keying) and transmit it to the transmitter (PTx). In the transmitter (PTx), an ASK signal demodulator corresponding to the communication unit 120 of the transmission device 100 of FIG. 3 transmits an ASK signal loaded with an amplitude shift keying (ASK) to a wireless power signal. Demodulates and decodes the message transmitted by the receiver (PRx).

The ASK signal transmitted by the receiver PRx includes information related to the receiver and information on the strength of power during power transmission. The transmitter (PTx) may demodulate the message carried in the ASK signal and change the characteristics of the wireless power signal transmitted to the receiver (PRx) based on this demodulation.

FIG. 6A shows a configuration for demodulating an ASK signal, and FIG. 6B shows a process of obtaining digital data by demodulating an ASK signal of a normal waveform.

The demodulator of the transmitter (PTx) is generally composed of a low pass filter (LPF) and a comparator to demodulate the ASK signal. The LPF removes the high frequency component of the wireless power signal to obtain a low frequency analog signal , a comparator compares it with a reference voltage and changes it to a digital signal depending on whether it is greater than or less than the reference voltage.

The comparator, for example, outputs a high-level signal when the analog input signal is greater than the reference voltage, and outputs a low-level signal when the analog input signal is less than the reference voltage. can

When the receiver (PRx) loads the data bit of the message to the ASK signal in a differential bi-phase method, a transition occurs from the high level to the low level in the middle of a predetermined time interval for the data bit '1'. and the level may not be changed for a predetermined time interval for data bit '0'.

7 illustrates an example in which digital data cannot be properly obtained by demodulating an ASK signal having an abnormal waveform.

Since the receiver PRx modulates the amplitude of transmission power to transmit a message, the ASK signal transmitted from the receiver PRx is often affected by noise and the like, resulting in an abnormal waveform. These abnormal waveforms cannot be accurately converted to digital signals through conventional comparators.

When the ASK signal is demodulated as shown in FIG. 7 , if it is compared with a reference voltage through a comparator and output as a digital signal composed of a low level and a high level, data bits that are digital data cannot be properly extracted from the digital signal. That is, the timing at which the transition occurs from the high level to the low level or from the low level to the high level in the digital signal deviates from the reference time interval for detecting the data bit from the digital signal, so that the data bit cannot be accurately determined.

8 shows an example of demodulating an ASK signal of an abnormal waveform by a peak value detection method.

When converting an ASK signal to a digital signal, instead of generating a high level and low level digital signal by comparing the ASK signal with a reference voltage, a digital signal is generated with a high level when the ASK signal is at its maximum value. A peak value detection method that generates a digital signal with a low level at the minimum value can be used.

In some cases, if the ASK signal is converted into a digital signal using the peak value detection method as shown in FIG. 8, data bits may be more accurately extracted from the ASK signal than the reference value comparison method.

9 is a flowchart illustrating an operation of demodulating an ASK signal while alternately performing a reference value comparison method and a peak value detection method according to an embodiment of the present invention.

The transmitter PTx generates an ASK signal carried on the wireless power signal through LPF (Filtering (LPF)), and extracts data bits from the ASK signal through a demodulator.

The demodulator compares the ASK signal with a reference voltage using a reference value comparison method to generate a digital signal having a high level and a low level, and extracts data bits using the transition timing of the digital signal (Extracting digital data by reference) comparing method).

If an error does not occur in the data bit extracted by the reference value comparison method (Error occurring?: NO), the demodulator continuously extracts the data bits from the ASK signal by using the reference value comparison method.

However, if an error occurs in the data bit extracted by the reference value comparison method (Error occurring?: YES), the demodulator generates a digital signal from the ASK signal using the peak value detection method instead of the reference value comparison method, and the transition timing of the digital signal is used to extract data bits (Extracting digital data by peak detecting method).

If an error does not occur in the data bit extracted by the peak value detection method (Error occurring?: NO), the demodulator continuously extracts the data bit from the ASK signal by using the peak value detection method.

However, if an error occurs in the data bit extracted by the peak value detection method (Error occurring?: YES), the demodulator extracts the data bit from the ASK signal by applying the reference value comparison method again instead of the peak value detection method.

The demodulator of the transmitter (PTx) uses the reference value comparison method and the peak value comparison method alternately depending on whether an error occurs, and the receiver (PRx) extracts data bits from the ASK signal loaded with the amplitude shift method on the wireless power signal. have.

FIG. 10 shows a digital signal generated by a differential bi-phase encoding method and data bits corresponding thereto, and FIGS. 11A and 11B are normal digital signals among digital signals generated from an ASK signal, respectively. and an abnormal digital signal.

In the differential bi-phase encoding method, one data bit is transmitted in one cycle (tclk) of a clock, and a digital signal is is a transition, and when the data bit is '1' (ONE), the transition occurs at the center of the bit time, and when the data bit is '0' (ZERO), the transition does not occur at the center of the bit time.

In FIGS. 11A and 11B, the cycle of the clock is 500 us. 11A, when the digital signal generated from the ASK signal is normal, the digital signal transitions at the boundary of the bit time, and if the transition does not occur at the center of the bit time, the corresponding bit time is determined as data bit '0', , when a transition occurs at the center of the bit time, the corresponding bit time is determined as data bit '1'.

However, as shown in FIG. 11B , when the digital signal generated from the ASK signal is abnormal, there is a case where the digital signal transition does not occur at the boundary of the digital bit time. Occasionally, it may occur at a skewed position, or there may be two transitions between beat times. In this case, it is difficult to determine the data bit of the corresponding bit time.

In fact, when the receiver (PRx) modulates and converts the ASK signal extracted from the wireless power signal into a digital signal, a digital signal that is out of period frequently occurs, and the transmitter (PTx) receives the message transmitted by the receiver (PRx) with the correct value. can't do it

12A and 12B show an algorithm for determining data bits from a digital signal generated from an ASK signal according to an embodiment of the present invention, wherein the data bits are encoded in the ASK signal by a differential bi-phase method.

When it is difficult to determine the data bit of the bit time as 0 or 1 because the digital signal converted from the ASK signal by the reference value comparison method or the peak value detection method does not accurately transition at the edge of the bit time or the center of the bit time, Determination of the data bit may be withheld and the data bit may be determined based on the timing of one or two transitions occurring in the digital signal thereafter.

In the embodiment of FIG. 12 , a data bit may be determined based on a timing at which three transitions occurring in a digital signal occur or a time interval between transitions.

In the embodiment of Fig. 12, the length of the bit time is 500 us.

It starts when a transition occurs in the digital signal according to the start boundary or start timing of the first bit time (BT#1) (Start) (①).

When the first transition (1 ^st T) occurs, the interval between the start boundary of the first bit time (or the timing at which the transition that determines the data bit of the previous bit time occurs) and the timing at which the first transition (1 ^st T) occurs The first time interval t1 is checked, and as shown in FIG. 12B , it branches into first to seventh cases (case1 to case7) according to the value of the first time interval t1 .

For example, if the first time interval t1 is 500us, ^{the timing of the first transition 1st} T belongs to the time band of the fourth case (case4) developed from 424us to 625us in FIG. 12A, so the first bit time Determines the data bit of (BT#1) as '0' and ends regardless of the next transition (End) (②), and restarts the operation for the second bit time (BT#2), which is the next bit time, from ① do.

For example, if the first time interval t1 is 400us, ^{the timing of the first transition (1 st} T) belongs to the time band of the third case (case3) developed from 375us to 425us in FIG. 12A, so that the next second transition The judgment of the data bit of the first bit time (BT#1) is suspended until (2 ^{nd T) occurs (③)}

When the second transition (2 ^nd T) occurs, a second time interval t2 between the timing at which the ^{first transition (1 st} T) occurs and the timing at which the second transition (2 ^{nd T) occurs is identified, and the first} The data bit is determined based on the sum (t1+t2) of the time interval t1 and the second time interval t2.

For example, (t1 + t2) is 500us is, the second transition (2 ^nd T) is in the timing at which the Figure 12a occurs 424us to time strip in the fourth case (case4) that is deployed on 625us belongs, the first bit time (BT It is determined that the data bit of #1) is '1' and ends regardless of the next transition (④), and the operation for the second bit time (BT#2), which is the next bit time, starts again from ①.

For example, even when (t1+t2) is smaller than 425us ^{, and the timing at which the second transition (2 nd} T) occurs falls back to the time band of the third case (case3) in FIG. 12A , the first bit time (BT#1 ) is determined to be '1', and it ends regardless of the next transition, and the operation for the second bit time (BT#2), which is the next bit time, starts again from ①.

Also, for instance (t1 + t2) if 650us with belonging time strip of the fifth case (case5) that is deployed on 625us to 875us, the third transition (3 ^rd T) to determine the data bit further consider the timing has occurred do.

When the third transition (3 ^rd T) occurs, a third time interval t3 between the timing at which the ^{second transition (2 nd} T) occurs and the timing at which the third transition (3 ^{rd T) occurs is identified, and the first} The data bit is determined based on the sum (t1+t2+t3) of the time interval t1, the second time interval t2, and the third time interval t3.

For example, if (t1+t2+t3) belongs to the time band of the fifth case (case5) that develops from 625us to 875us, by comparing the sizes of the first time interval t1 and the second time interval t2, If the first time interval t1 is greater than or equal to the second time interval t2 (t2>=t2), the data bits of the first and second bit times BT#1 and BT#2 are determined as '01', and the next The operation for the third bit time (BT#3), which is the bit time, is restarted from ① (⑤), and if the first time interval (t1) is smaller than the second time interval (t2) (t2>=t2), the second The data bits of the first and second bit times BT#1 and BT#2 are determined as '10', and the operation for the third bit time (BT#3), which is the next bit time, is restarted from ①.

For example, if (t1+t2+t3) belongs to the time band of the sixth case (case6) that develops from 875us to 1250us, by comparing the sizes of the first time interval t1 and the second time interval t2, If the first time interval t1 is greater than or equal to the second time interval t2 (t2>=t2), the data bits of the first and second bit times BT#1 and BT#2 are determined to be '01' and again Starting from ①, if the first time interval (t1) is smaller than the second time interval (t2) (t2>=t2), the data bits of the first and second bit times (BT#1, BT#2) are ' 10', and the operation for the third bit time (BT#3), which is the next bit time, starts again from ①.

On the other hand, for example, if (t1 + t2 + t3) belongs to the time band of the seventh case (case7) that develops to 1250 us or more, the data bits of the first and second bit times (BT#1, BT#2) are When it is determined as '00' (⑥), and the operation for the third bit time (BT#3), which is the next bit time, the first transition occurs before half of the bit time (pre-half) ( ⑦) starts again.

On the other hand, the first transition (1 ^st T) corresponds to ②, and ^{(t1+t2), which is the timing at which the second transition (2 nd} T) occurs, belongs to the time band of the sixth case (case6) that develops between 875us and 1250us. In this case, the data bits of the first and second bit times BT#1 and BT#2 are determined as '00', and the operation for the third bit time (BT#3), which is the next bit time, is restarted from ①. do.

When the first transition (1 ^st T) corresponds to ② and the ^{timing at which the second transition (2 nd} T) occurs (t1+t2) belongs to the time band of the seventh case (case7) of 1250us or more, it is generated from the ASK signal It is determined that there is an abnormality in the digital signal, and it is reset without determining the data bit, and the demodulation operation for the ASK signal is restarted.

On the other hand, a sixth ^{time interval t1 between the start boundary of the first bit time and the timing at which the first transition (1 st} T) occurs due to the occurrence of the first transition (1 ^st T) is developed from 875us to 1250us. If it belongs to the case (case6) or the seventh case (case7) developed in 1250us or more, it is determined that there is an abnormality in the digital signal generated from the ASK signal, and it is reset without determining the data bit, and the ASK signal is Restart the demodulation operation.

On the other hand, if the first time interval t1 belongs to the first case (case1) developed from 0us to 125us or the second case (case2) developed from 125us to 375us, the next second transition (2 ^nd T) will occur. The judgment of the data bit of the first bit time (BT#1) is suspended until (7).

The first time interval t1 belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the timing at which the ^{second transition (2 nd T) occurs, develops between 0us and 125us.} If it belongs to one case (case1) or the time band of the second case (case2) developed from 125us to 375us, it is determined that there is an abnormality in the digital signal generated from the ASK signal, and reset without determining the data bit, Restart the demodulation operation for the ASK signal.

The first time interval t1 belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the timing at which the ^{second transition (2 nd T) occurs, develops between 375us and 425us.} If it belongs to case 3 (case3) or the time band of case 4 (case4) that develops from 424us to 625us, the data bit of the first bit time (BT#1) is determined as '1' and ends regardless of the next transition, (End), the operation for the second bit time (BT#2), which is the next bit time, starts again from ①.

The first time interval (t1) belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the timing at which the ^{second transition (2 nd T) occurs, is 650us and develops from 625us to 875us} In the case of belonging to the time band of the fifth case (case5), the data bit is determined by further considering the timing ^{at which the third transition (3 rd T) occurs.}

The first time interval t1 belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the sum of the first time interval t1 and the second time interval t2, is the fifth ^{When the third transition (3 rd} T) occurs in the state belonging to case 5, the third time interval between the timing at which the second transition (2 ^nd T) occurs and the timing at which the third transition (3 ^{rd T) occurs} (t3) is checked, and the data bit is determined based on the sum (t1+t2+t3) of the first time interval t1, the second time interval t2, and the third time interval t3.

For example, if (t1+t2+t3) belongs to the time band of the fifth case (case5) developed from 625us to 875us or the sixth case (case6) developed from 875us to 1250us, the first time interval (t1) and The size of the second time interval t2 is compared, and if the first time interval t1 is equal to or greater than the second time interval t2 (t2>=t2), the first and second bit times BT#1 and BT# The data bit of 2) is determined as '01', and the operation for the third bit time (BT#3), which is the next bit time, is restarted from ① (⑤), and the first time interval (t1) is the second time interval If it is less than (t2) (t2>=t2), the data bit of the first and second bit times (BT#1, BT#2) is determined as '10', and the third bit time (BT#3), which is the next bit time, is determined as '10'. ), start again from ①.

The first time interval t1 belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the timing at which the ^{second transition (2 nd T) occurs, develops between 875us and 1250us.} When belonging to the time band of case 6, the data bits of the first and second bit times (BT#1, BT#2) are determined as '00', and the third bit time (BT#3), which is the next bit time, is determined as '00'. ), start again from ①.

The seventh time interval t1 belongs to the first case (case1) or the second case (case2), and (t1+t2), which is the timing at which the ^{second transition (2 nd T) occurs, expands to 1250 us or more} If it belongs to the time band of case 7, it is determined that there is an abnormality in the digital signal generated from the ASK signal, and the data bit is reset without determining the data bit, and the demodulation operation for the ASK signal is restarted.

As such, when extracting data bits from a digital signal generated from an ASK signal in which data is encoded in a differential bi-phase method, data bits are selected based on two or more or, if necessary, three or more transition timings and a time interval between the transition timings. By determining this, even if the ASK signal is distorted, it is possible to maintain stable communication quality between the receiver and the transmitter, and based on this, it is possible to transmit power with high efficiency.

13 is an exploded perspective view of a charger to which the present invention is applied.

The charger 300 of FIG. 13 includes a wireless power transmitter providing inductive power, and an electronic device including a receiving device to be charged is placed on the upper surface and a seating surface having an operation area may be formed, the seating surface When an electronic device is placed on the charger, the charger can detect it and initiate wireless charging.

The charger 300 may be equipped with a transmission coil 320 constituting the resonance circuit 111 of the transmission device between the front case 311 and the rear case 312 , and a shielding part under the transmission coil 320 . 330 may be formed. That is, the shielding unit 330 may be formed between the rear case 312 of the charger 300 and the transmitting coil 320 , and at least a portion of the transmitting coil 320 may be formed to exceed. can

The shielding unit 330 is mounted on a circuit board (not shown) by the operation of the transmitting coil 320 so that elements such as an inverter, a microprocessor, and a memory constituting the communication unit 120 and the control unit 130 are electromagnetically affected. It is possible to prevent the multi-transmission coil 320 from being affected by electromagnetic waves by receiving or by the operation of the elements mounted on the circuit board, and may be made of stainless or titanium material that does not require plating.

In addition, a ferrite sheet (not shown) is provided between the transmission coil 320 and the circuit board (not shown), and electromagnetic disturbances such as eddy currents generated in the transmission coil 320 or the circuit board affect other components. can be avoided.

The charger 300 is formed in a structure in which a power converter including a transmitting coil, a communication unit, a control unit, a power supply, etc. are provided in one body, or a first body in which the transmitting coil 320 and the shielding unit 330 are mounted. and a second body connected to the first body and including a conversion unit, a communication unit, a control unit, a power supply unit, and the like for controlling the operation of the transmitting coil 320 .

In addition, an output unit such as a display or a speaker, a user input unit, a socket for supplying power, or an interface to which an external device is coupled may be disposed on the body of the charger 300 . The display may be formed on the upper surface of the front case 311 , and the user input unit and the socket may be disposed on the side of the body.

The display may indicate whether the receiving device is aligned or not, and when the receiving device is misaligned, the display may notify the user through a speaker.

The wireless power transmission apparatus and method described in this specification may be described as follows.

A method of transmitting power in a wireless power transmission device according to an embodiment includes: wirelessly transmitting power to a receiving device through a wireless power signal; using a low-pass filter to obtain an analog signal loaded by a receiving device in an amplitude shift manner on a wireless power signal; generating a digital signal from an analog signal; extracting data bits from the digital signal; checking whether an error occurs in the extracted data bit; and when an error occurs, changing a method used for generating a digital signal from an analog signal from a reference value comparison method to a peak value comparison method or from a peak value comparison method to a reference value comparison method.

In an embodiment, the analog signal may include information on the intensity of power being transmitted.

In an embodiment, the analog signal may be encoded with data bits in a differential bi-phase manner.

In an embodiment, the extracting of the data bit may determine the data bit based on timing at which three transitions occur in the digital signal.

In one embodiment, the step of extracting the data bit comprises: when the third transition occurs, a first time interval until the first transition occurs and a second time interval between the timing at which the first transition occurs and the timing at which the second transition occurs can be compared to determine two data bits for two bit times.

In one embodiment, the step of extracting the data bits includes determining two data bits as '01' if the first time interval is greater than or equal to the second time interval, and if the first time interval is smaller than the second time interval, Two data bits may be determined as '10'.

A wireless power transmitter according to another embodiment includes an inverter for converting DC power into AC; a resonance circuit including a primary coil for transmitting a wireless power signal through magnetic inductive coupling with a secondary coil of a receiving device; a demodulator for extracting a message loaded by the receiving device in an amplitude shifting manner on the wireless power signal; and a control unit for controlling the inverter to generate a wireless power signal suitable for the message extracted by the demodulator, wherein the demodulator obtains an analog signal loaded on the wireless power signal in an amplitude shift method using a low-pass filter, and the analog signal The method used when generating a digital signal from, generating a digital signal from an analog signal, and generating a digital signal from an analog signal when an error occurs in the extracted data bits The value comparison method can be changed to the reference value comparison method.

The present invention is not limited to the described embodiments, and it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Accordingly, it should be said that such modifications or variations are included in the claims of the present invention.

100: wireless power transmitter 110: power conversion unit
120: communication unit 130: control unit
140: power unit 200: wireless power receiver
210: power receiving unit 220: communication unit
230: control unit 250: charging unit
300: charger 311: front case
312: rear case 320: transmission coil
330: shield

Claims (11)

transmitting power wirelessly to a receiving device via a wireless power signal;
obtaining an analog signal loaded by the receiving device in an amplitude shift manner on the wireless power signal by using a low-pass filter;
generating a digital signal from the analog signal;
extracting data bits from the digital signal;
checking whether an error occurs in the extracted data bit; and
when the error occurs, changing a method used for generating a digital signal from the analog signal from a reference value comparison method to a peak value comparison method or from the peak value comparison method to the reference value comparison method A method of transmitting power in a power transmission device. According to claim 1,
The analog signal is a power transmission method in a wireless power transmission device, characterized in that it includes information about the intensity of the power being transmitted. According to claim 1,
The analog signal is a power transmission method in a wireless power transmission device, characterized in that the data bits are encoded in a differential bi-phase method. 4. The method of claim 3,
The extracting of the data bit comprises determining the data bit based on a timing at which three transitions occur in the digital signal. 5. The method of claim 4,
The step of extracting the data bit may include comparing a first time interval until the first transition occurs when the third transition occurs and a second time interval between the timing at which the first transition occurs and the timing at which the second transition occurs. A method of transmitting power in a wireless power transmission device, comprising determining two data bits for two bit times. 6. The method of claim 5,
The extracting of the data bits may include determining the two data bits as '01' if the first time interval is greater than or equal to the second time interval, and if the first time interval is smaller than the second time interval, the Power transmission method in a wireless power transmission device, characterized in that determining two data bits as '10'. an inverter for converting DC power into AC;
a resonance circuit including a primary coil for transmitting a wireless power signal through magnetic inductive coupling with a secondary coil of a receiving device;
a demodulator for extracting a message loaded by the receiving device in an amplitude shift method on the wireless power signal; and
and a control unit for controlling the inverter to generate a wireless power signal suitable for the message extracted by the demodulator,
The demodulator obtains an analog signal loaded in the amplitude shift method on the wireless power signal using a low-pass filter, generates a digital signal from the analog signal, generates a digital signal from the analog signal, and the extracted data Wireless power, characterized in that when an error occurs in a bit, a method used for generating a digital signal from the analog signal is changed from a reference value comparison method to a peak value comparison method or from the peak value comparison method to the reference value comparison method transmission device. 8. The method of claim 7,
The analog signal is a wireless power transmitter, characterized in that the data bits are encoded in a differential bi-phase method. 9. The method of claim 8,
The demodulator determines the data bit based on a timing at which three transitions occur in the digital signal. 10. The method of claim 9,
When the third transition occurs, the demodulator compares a first time interval until the first transition occurs and a second time interval between the timing at which the first transition occurs and the timing at which the second transition occurs for two bit times. A wireless power transmitter, characterized in that determining two data bits. 11. The method of claim 10,
The demodulator determines the two data bits as '01' if the first time interval is greater than or equal to the second time interval, and sets the two data bits as '01' if the first time interval is smaller than the second time interval. 10 'Wireless power transmission device, characterized in that determined.

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