KR20190114185A - Wireless charging device and wireless charging method - Google Patents

Abstract

According to an embodiment of the present invention, a wireless charging device comprises: an inverter; a switch connecting DC power inputted to the inverter to flow to the ground through a first load resistor or a second load resistor; and a control unit determining whether voltage of the DC power is greater than reference voltage in a state of being connected with the first load resistor or the second load resistor and selecting and storing guaranteed power corresponding to a load resistor having a low resistance value among load resistors having a higher voltage than the reference voltage. The first load resistor can have the resistance value less than the second load resistor.

Description

Wireless charging device and wireless charging method {WIRELESS CHARGING DEVICE AND WIRELESS CHARGING METHOD}

An embodiment relates to a wireless charging device and a wireless charging method for preventing a charging failure.

Portable terminals such as mobile phones and laptops include a battery that stores power and circuits for charging and discharging the battery. In order for the battery of the terminal to be charged, power must be supplied from an external charger.

In general, as an example of an electrical connection method between a charging device and a battery for charging power to a battery, the terminal is supplied with commercial power and converted into a voltage and a current corresponding to the battery to supply electrical energy to the battery through the terminal of the battery. Supply method. This terminal supply method is accompanied by the use of a physical cable (cable) or wire. Therefore, when handling a lot of terminal supply equipment, many cables occupy considerable working space, are difficult to organize, and are not good in appearance. In addition, the terminal supply method may cause problems such as instantaneous discharge phenomenon due to different potential difference between the terminals, burnout and fire caused by foreign matter, natural discharge, deterioration of battery life and performance.

In order to solve this problem, a charging system (hereinafter referred to as a "wireless charging system") and a control method using a method of transmitting power wirelessly have been proposed. In addition, the wireless charging system was not pre-installed in some portable terminals in the past, and consumers had to separately purchase a wireless charging receiver accessory, so the demand for the wireless charging system was low. It has a built-in function.

In general, the wireless charging system includes a wireless power transmitter for supplying electrical energy through a wireless power transmission method and a wireless power receiver for charging the battery by receiving the electrical energy supplied from the wireless power transmitter.

The wireless charging system may transmit power by at least one wireless power transmission method (eg, electromagnetic induction method, electromagnetic resonance method, RF wireless power transmission method, etc.).

Portable devices using 5V operating power sources such as mobile phones can be wirelessly charged using wireless chargers, usually designed for 5-15W. To ensure wireless power transfer at the designed power, an adapter that can supply enough power to supply enough input power must be used. For example, a wireless charger that guarantees 15W should use an adapter that can supply more than 15W.

However, if the adapter is not designed to be paired with a wireless charger, there are many types of adapters and some adapters may not provide 15W. If you charge the wireless charger using an adapter that does not provide 15W, the input power may not be enough when charging 15W, which may cause a problem that the charging is cut off.

An embodiment of the present invention is to provide a wireless charging device and a wireless charging method for preventing the charging is cut off regardless of the type of input power.

According to an embodiment of the present invention, a wireless charging device includes an inverter, a switch for connecting DC power input to the inverter to a ground through a first load resistor or a second load resistor, and the first load resistor or the second load resistor. And a controller configured to determine whether the voltage of the DC power is higher than a reference voltage in a connected state, and to select and store a guaranteed power corresponding to a load resistance having a lower resistance value among load resistances in which the voltage is higher than the reference voltage. The load resistance may have a lower resistance value than the second load resistance.

The guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver can be determined within the guaranteed power. The apparatus may further include a power supply unit receiving power from an external power supply terminal, wherein the DC power may be output from the power supply unit. The controller may control the magnitude of the DC power by varying the frequency of the input voltage. The controller may reduce the magnitude of the DC power by varying the frequency from 110KHz to 150Hz. The converter may supply 5V or 10V to the load resistor. It may include a transmission coil for transmitting the guarantee power.

In addition, the wireless charging device according to the embodiment includes a converter for outputting direct current power, an inverter for receiving the direct current power and converting it into alternating current power, and a switch for connecting the direct current power to ground through a load resistance; And controlling the converter so that the output voltage of the DC power becomes a first voltage or a second voltage, determining whether the output voltage of the DC power is higher than a reference voltage while the load resistance is connected, and outputting higher than the reference voltage. It may include a control unit for selecting and storing the guaranteed power corresponding to the output voltage having a high voltage value of the voltage. The guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver can be determined within the guaranteed power.

In addition, the wireless charging method according to the embodiment measuring the DC voltage input to the first or second load resistance connected to the input terminal of the inverter, comparing the DC voltage is higher than the reference voltage, and the DC voltage is The method may include selecting a guaranteed power corresponding to a load resistance having a lower resistance value among load resistances higher than a reference voltage.

The guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver can be determined within the guaranteed power. The DC power may output power receiving input power from an external power supply terminal. The magnitude of the DC power may be controlled by varying the frequency of the input power.

In an embodiment, the input power checking unit is configured to check the power available from the input power, and thus, the wireless power receiver determines the available power that can be transmitted accurately and provides the power to the wireless power receiver. Available power) can be requested, thereby preventing charging from being lost.

According to the embodiment, the input power checking unit is configured using a resistor having a low value, thereby reducing the cost and minimizing the failure of the resistor.

The embodiment has an effect of reducing the number of resistors and switch components by configuring the input power confirmation unit using a variable resistor.

According to the embodiment, the input power is measured while varying the variable resistor, so that the timing at which the input voltage is cut can be measured more effectively.

1 is a block diagram illustrating a wireless charging apparatus according to an embodiment.
2 is a state transition diagram for explaining a wireless power transmission procedure.
3 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment.
4 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 3.
FIG. 5 is a diagram illustrating a configuration of load resistors of FIG. 3.
6 is a flowchart for describing an operation of measuring guaranteed power of a wireless charging device, according to an exemplary embodiment.
7 and 8 are views illustrating a configuration according to another embodiment of the load resistors of FIG. 3.
9 is a block diagram illustrating a structure of a wireless power transmitter according to a second embodiment.
10 is a block diagram illustrating a structure of a wireless power transmitter according to a third embodiment.
11 is a diagram for describing an operation of a controller of a wireless charging apparatus, according to an exemplary embodiment.
12 is a diagram for explaining a negotiation step between a wireless power transmitter and a wireless power receiver.

Hereinafter, an apparatus and various methods to which the embodiments are applied will be described in more detail with reference to the accompanying drawings. The suffixes "module" and "unit" for components used in the following description are given or used in consideration of ease of specification, and do not have distinct meanings or roles from each other.

In the above description, all elements constituting the embodiments are described as being combined or operating in combination, but are not necessarily limited to the embodiments. In other words, all of the components may be selectively operated in combination with one or more within the scope of the embodiments. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art of the embodiments. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing the embodiments. The storage medium of the computer program may include a magnetic recording medium, an optical recording medium, a carrier wave medium, and the like.

In the description of the embodiments, in the case of being described as being formed at "up (up) or down (down)", "before (front) or back (back)" of each component, "up (up) or down (Below) " and " before (front) or back (back) " include both formed by direct contact of two components or one or more other components disposed between two components.

In addition, the terms "comprise", "comprise" or "having" described above mean that the corresponding component may be included, unless otherwise stated, and thus excludes other components. It should be construed that it may further include other components instead. All terms, including technical and scientific terms, have the same meanings as commonly understood by one of ordinary skill in the art to which the embodiments belong, unless otherwise defined. Terms commonly used, such as terms defined in a dictionary, should be interpreted to coincide with the contextual meaning of the related art, and shall not be construed in an ideal or overly formal sense unless explicitly defined in the examples.

In addition, in describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It should be understood that the elements may be "connected", "coupled" or "connected".

In the following description of the embodiments, it will be apparent to those skilled in the art that the related art can be unnecessarily obscured.

In the description of the embodiment, the apparatus for transmitting wireless power on the wireless power charging system is a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a transmitter, a transmitter, a transmitter, a transmitter, a wireless power transmitter for convenience of description. A wireless power transmitter, a wireless charging device, etc. will be used interchangeably. In addition, as a representation of a device for receiving the wireless power from the wireless power transmitter, for convenience of description, a wireless power receiver, a wireless power receiver, a wireless power receiver, a wireless power receiver, a receiver, a receiver, a receiver, a receiver Terminals and the like may be used interchangeably.

Wireless charging apparatus according to the embodiment may be configured in the form of a pad, a cradle, an access point (AP), a small base station, a stand, a ceiling buried, a wall, etc., one transmitter receives a plurality of wireless power It may also transmit power to the device.

For example, the wireless power transmitter may not only be used on a desk or a table, but also may be developed and applied to an automobile and used in a vehicle. The wireless power transmitter installed in the vehicle may be provided in the form of a cradle that can be fixed and mounted simply and stably.

Terminal according to the embodiment is a mobile phone (smart phone), smart phone (smart phone), laptop computer (laptop computer), digital broadcasting terminal, PDA (Personal Digital Assistants), PMP (Portable MultimediaPlayer), navigation, MP3 player, electric toothbrush , An electronic tag, a lighting device, a remote control, and a small electronic device such as a bobber, but are not limited thereto. A mobile device device (hereinafter, referred to as “device”) capable of charging a battery with a wireless power receiver according to an embodiment is provided. The term "terminal" or "device" may be used interchangeably. The wireless power receiver according to another embodiment may be mounted in a vehicle, an unmanned aerial vehicle, an air drone, or the like.

The wireless power receiver according to the embodiment may be provided with at least one wireless power transmission scheme, and may simultaneously receive wireless power from two or more wireless power transmitters. Here, the wireless power transmission method may include at least one of the electromagnetic induction method, electromagnetic resonance method, RF wireless power transmission method. In general, the wireless power transmitter and the wireless power receiver constituting the wireless power system may exchange control signals or information through in-band communication or Bluetooth low energy (BLE) communication. Here, in-band communication and BLE communication may be performed by a pulse width modulation method, a frequency modulation method, a phase modulation method, an amplitude modulation method, an amplitude and phase modulation method, or the like. For example, the wireless power receiver may transmit various control signals and information to the wireless power transmitter by generating a feedback signal by switching ON / OFF the current induced through the receiving coil in a predetermined pattern. The information transmitted by the wireless power receiver may include various state information including received power strength information. In this case, the wireless power transmitter may calculate the charging efficiency or the power transmission efficiency based on the received power strength information.

1 is a block diagram illustrating a wireless charging apparatus according to an embodiment, FIG. 2 is a state transition diagram for explaining a wireless power transmission procedure, and FIG. 3 illustrates a structure of a wireless power transmitter according to an embodiment. 4 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 3, FIG. 5 is a diagram illustrating a configuration of load resistors of FIG. 3, and FIG. 7 is a flowchart illustrating an operation for measuring the guaranteed power of the wireless charging apparatus according to an embodiment, and FIGS. 7 and 8 are views illustrating a configuration of another embodiment of the load resistors of FIG. 3.

Referring to FIG. 1, a wireless charging system (wireless charger) includes a wireless power transmitter 10 that wirelessly transmits power wirelessly, a wireless power receiver 20 that receives the transmitted power, and an electronic device that receives the received power. 30.

For example, the wireless power transmitter 10 and the wireless power receiver 20 may perform in-band communication for exchanging information using the same frequency band as the operating frequency used for wireless power transmission. In another example, the wireless power transmitter 10 and the wireless power receiver 20 perform out-of-band communication in which information is exchanged using a separate frequency band different from an operating frequency used for wireless power transmission. It can also be done.

For example, the information exchanged between the wireless power transmitter 10 and the wireless power receiver 20 may include control information as well as status information of each other. Here, the status information and control information exchanged between the transmitting and receiving end will be more clear 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 is not limited thereto. In another embodiment, the in-band communication and the out-of-band communication may provide one-way communication or half-duplex communication.

For example, the unidirectional communication may be performed by the wireless power receiver 20 only transmitting information to the wireless power transmitter 10, but is not limited thereto. The wireless power transmitter 10 may transmit information to the wireless power receiver 20. It may be to transmit.

In the half-duplex communication method, bidirectional communication between the wireless power receiver 20 and the wireless power transmitter 10 is possible, but at one time, only one device may transmit information.

The wireless power receiver 20 according to the embodiment may obtain various state information of the electronic device 30. For example, the state 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, and the like. The information may be obtained from the electronic device 30 and may be utilized for wireless power control.

2 is a state transition diagram for explaining a wireless power transmission procedure.

Referring to FIG. 2, power transmission from a transmitter to a receiver according to a wireless power transmission procedure is largely performed in a selection phase 210, a ping phase 220, and an identification and configuration phase 230. ), A negotiation phase (Negotiation Phase 240), a calibration phase (Calibration Phase 250), a power transfer phase (Power Transfer Phase 260) and a renegotiation phase (Renegotiation Phase 270).

The selection step 210 transitions if a specific error or a specific event is detected while initiating or maintaining the power transfer, for example, including reference numerals S202, S204, S208, S210, and S212. Can be. Here, specific errors and specific events will be apparent from the following description. In addition, in the selection step 210, the transmitter may monitor whether an object exists on the interface surface. If the transmitter detects that an object is placed on the interface surface, it may transition to ping step 220. In the selection step 210, the transmitter transmits a very short pulse of an 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 the presence of

If an object is detected in the selection step 210, the wireless power transmitter may measure quality factors at one and / or other end of the wireless power resonant circuit, eg, a transmission coil and / or resonant capacitor for wireless power transmission. .

The wireless power transmitter can measure the peak frequency of the wireless power resonant circuit (eg, power transmission coil and / or resonant capacitor).

The quality factor and / or peak frequency may be used to determine the presence of foreign matter in the future negotiation step 240.

When an object is detected in the ping step 220, the transmitter wakes up the receiver and transmits a digital ping for identifying whether the detected object is a wireless power receiver (S201). If in ping step 220 the transmitter does not receive a response signal (eg, a signal strength packet) to the digital ping from the receiver, it may transition back to selection step 210. In addition, in the ping step 220, when the transmitter receives a signal indicating that the power transmission is completed, that is, the charging completion packet, the transmitter may transition to the selection step 210 (S202).

When the ping step 220 is completed, the transmitter may transition to the identification and configuration step 230 for identifying the receiver and collecting receiver configuration and status information (S203).

In the identification and configuration step 230, the transmitter receives an unexpected packet, an outgoing desired packet for a predefined time, a packet transmission error, or a power transmission agreement. If this is not set (no power transfer contract) it may transition to the selection step 210 (S204).

The transmitter may determine whether entry into the negotiation step 240 is necessary based on a negotiation field value of the configuration packet received in the identification and configuration step 230.

As a result of the check, if negotiation is necessary, the transmitter may enter the negotiation step 240 (S205). In the negotiation step 240, the transmitter may perform a predetermined foreign matter detection procedure.

On the other hand, if it is determined that negotiation is not necessary, the transmitter may immediately enter the power transmission step 260 (S206).

In the negotiation step 340, the transmitter may receive a Foreign Object Detection (FOD) status packet including a reference quality factor value. Alternatively, the FOD status packet including the reference peak frequency value may be received. Alternatively, a status packet including a reference quality factor value and a reference peak frequency value may be received. In this case, the transmitter may determine the threshold quality factor value for FO detection based on the reference quality factor value. The transmitter may determine a threshold peak frequency value for FO detection based on the reference peak frequency value.

The transmitter may detect whether the FO is present in the charging region by using the threshold quality factor value for the determined FO detection and the currently measured quality factor value, which may be, for example, the quality factor value measured before the ping step, Power transmission may be controlled according to the FO detection result. For example, when the FO is detected, power transmission may be stopped, but is not limited thereto.

The transmitter may detect whether the FO is present in the charging region by using the threshold peak frequency value for the determined FO detection and the currently measured peak frequency value, which may be, for example, the peak frequency value measured before the ping step, Power transmission may be controlled according to the FO detection result. For example, when the FO is detected, power transmission may be stopped, but is not limited thereto.

If the FO is detected, the transmitter may return to the selection step 210 (S208). On the other hand, when the FO is not detected, the transmitter may enter the power transmission step 260 via the correction step 250 (S207 and S209). Specifically, when the FO is not detected, the transmitter receives the strength of the power received at the receiving end in the calibrating step 250, and measures the power loss at the receiving end and the transmitting end in comparison with the strength of the power transmitted at the transmitting end. can do. That is, the transmitter may predict the power loss based on the difference between the transmit power of the transmitter and the receive power of the receiver in the correction step 250. The transmitter according to an embodiment may correct the power loss threshold for FOD detection by reflecting the predicted power loss. That is, since there is no FO in the correction phase, power loss due to the coupling state of the receiver and the friendly metal component of the receiver is determined, and foreign matter exists when additional power loss other than the predetermined power loss occurs. You can judge that.

In addition, the negotiation step 240 may transmit the power transmitter capability in response to the general request packet of the receiver. The transmitter may measure and transmit the maximum transmittable power measured from the input power source, for example, guarantee power. The measurement of the guarantee power may be performed during the initialization process when the power is turned on and the transmitter may transmit the previously measured guarantee power.

Measuring the guaranteed power will be described in detail later with reference to the drawings.

In power transmission step 260, the transmitter receives an unexpected packet, an outgoing desired packet for a predefined time, or a violation of a predetermined power transmission contract occurs. transfer contract violation), if the filling is completed, the transition to the selection step (210) (S210).

In addition, in the power transmission step 260, if it is necessary to reconfigure the power transmission contract according to a change in the transmitter state, the transmitter may transition to the renegotiation step 270 (S211). At this time, if the renegotiation is normally completed, the transmitter may return to the power transmission step 260 (S213).

The power transmission contract may be set based on state and characteristic information of the transmitter and the receiver. For example, the transmitter state information may include information about the maximum amount of power that can be transmitted, information about the maximum number of receivers that can be accommodated, and the receiver state information may include information about required power.

If the renegotiation is not normally completed, the transmitter may stop power transmission to the corresponding receiver and transition to the selection step 210 (S212).

3 is a block diagram illustrating a structure of a wireless power transmitter according to an embodiment.

Referring to FIG. 3, the wireless power transmitter 300 includes a power supply unit 360, a DC-DC converter 310, an inverter 320, a resonant circuit 330, a sensing unit 350, It may be configured to include a communication unit 340, alarm unit 370 and the control unit 380.

The resonant circuit 330 includes a resonant capacitor 331 and an inductor (or transmitting coil) 332, and the communication unit 340 includes at least one of a demodulator 341 and a modulator 342. Can be. The transmitting coil may generate magnetic flux from the applied AC power.

The power supply unit 360 may receive DC power from an external power supply terminal or a battery and transmit the DC power to the DC-DC converter 310. In another embodiment, the battery may be mounted inside the wireless power transmitter 300 to be chargeable, but this is only one embodiment, and the battery may be provided in the form of an auxiliary battery or an external battery of the wireless power transmitter 300. The power supply unit 360 may be connected through a predetermined cable.

The DC-DC converter 310 may convert the intensity of the DC power input from the power supply unit 360 into the DC power of a specific intensity under the control of the controller 380. For example, the DC-DC converter 310 may be configured as a variable voltage device capable of adjusting the strength of the voltage, but is not limited thereto.

The inverter 320 may convert the converted DC power into AC power.

The inverter 320 may convert a DC power signal input through a plurality of switch controls provided into an AC power signal and output the converted AC power signal.

For example, the inverter 320 may include a full bridge circuit, but is not limited thereto, and may include a half bridge.

As another example, the inverter 320 may include both a half bridge circuit and a full bridge circuit. In this case, the controller 380 may operate the interlock 320 as a half bridge or a full bridge. Can be determined and controlled.

The wireless power transmitter according to an embodiment may adaptively control the bridge mode of the inverter 320 according to the strength of power required by the wireless power receiver.

Here, the bridge mode includes a half bridge mode and a full bridge mode. For example, when the wireless power receiver requires 5W of low power, the controller 380 may control the inverter 320 to operate in a half bridge mode.

On the other hand, when the wireless power receiver requires 15W of power, the controller 380 may control to operate in the full bridge mode. As another example, the wireless power transmitter may adaptively determine the bridge mode according to the sensed temperature and drive the inverter 320 according to the determined bridge mode.

For example, when the temperature of the wireless power transmitter exceeds a predetermined reference value while transmitting wireless power through the half bridge mode, the controller 380 may deactivate the half bridge mode and control the full bridge mode to be activated. That is, the wireless power transmitter increases the voltage through the full bridge circuit and decreases the strength of the current flowing through the resonant circuit 330 for power transmission of the same intensity, so that the internal temperature of the wireless power transmitter decreases below a predetermined reference value. Can be controlled to maintain.

In general, the amount of heat generated in an electronic component mounted on an electronic device may be more sensitive to the strength of the current than the strength of the voltage applied to the electronic component.

In addition, the inverter 320 may not only convert DC power into AC power, but also change the strength of AC power.

For example, the inverter 320 may adjust the intensity of the AC power output by adjusting the frequency of a reference alternating current signal used to generate AC power under the control of the controller 380. To this end, the inverter 320 may be configured to include a frequency oscillator for generating a reference AC signal having a specific frequency, which is just one embodiment, another example is that the frequency oscillator is separate from the inverter 320 Is configured to be mounted on one side of the wireless power transmitter 300.

As another example, the wireless power transmitter 300 may further include a gate driver (not shown) for controlling a switch provided in the inverter 320. In this case, the gate driver may receive at least one pulse width modulation signal from the controller 380, and control the switch of the inverter 320 according to the received pulse width modulation signal. The controller 880 may control the intensity of the output power of the inverter 320 by controlling a duty cycle of the pulse width modulated signal, that is, a duty rate and a phase. The controller 360 may adaptively control the duty cycle and the phase of the pulse width modulated signal based on the feedback signal received from the wireless power receiver.

The sensing unit 350 may measure the voltage / current of the DC-converted power and provide the same to the controller 380. In addition, the sensing unit 350 may measure the internal temperature of the wireless power transmitter 300 or the inside of the charging interface (surface) to determine whether overheating occurs, and provide the measurement result to the controller 380. For example, the controller 380 may adaptively block the power supply from the power supply unit 380 based on the voltage / current value or the internal temperature value measured by the sensing unit 350. To this end, one side of the DC-DC converter 310 may be further provided with a predetermined power cut-off circuit for cutting off the power supplied from the power supply unit 360.

The controller 380 may receive the power reception state information and / or the power control signal of the wireless power receiver through the communication unit 340, and adjust the amplification factor based on the received power reception state information or the power control signal. It can be adjusted dynamically. For example, the power reception state information may include, but is not limited to, strength information of the rectifier output voltage and strength information of a current applied to the receiving coil. The power control signal may include a signal for requesting power increase, a signal for requesting power reduction, and the like.

The modulator 342 may modulate the control signal generated by the controller 380 and transmit the modulated control signal to the resonance coil 330. Here, the modulation scheme for modulating the control signal is a frequency shift keying (FSK) modulation scheme, a Manchester coding modulation scheme, a PSK (Phase Shift Keying) modulation scheme, a pulse width modulation scheme, a differential 2 Differential bi-phase modulation schemes may be included, but is not limited thereto.

When a signal received through the transmission coil is detected, the demodulator 341 may demodulate the detected signal and transmit the demodulated signal to the controller 380. For example, the demodulated signal may include a signal strength indicator, an error correction (EC) indicator for controlling power during wireless power transmission, an end of charge (EOC) indicator, an overvoltage / overcurrent / overheat indicator, and the like. However, the present invention is not limited thereto and may include various state information for identifying a state of the wireless power receiver. As another example, the demodulated signal may include FOD state information including at least one of a reference quality factor value and a reference frequency value.

For example, the wireless power transmitter 300 may obtain the signal strength indicator through in-band communication using the same frequency used for wireless power transmission to communicate with the wireless power receiver.

In the description of FIG. 3, the wireless power transmitter 300 and the wireless power receiver perform in-band communication by way of example. However, this is only one embodiment, and is a frequency band used for wireless power signal transmission. Short-range bidirectional communication may be performed through a frequency band different from that of FIG. For example, the short-range bidirectional communication may be any one of low power Bluetooth communication, RFID communication, UWB communication, and Zigbee communication.

4 is a block diagram illustrating a structure of a wireless power receiver interworking with the wireless power transmitter according to FIG. 3.

Referring to FIG. 4, the wireless power receiver 400 includes a receiving coil 410, a rectifier 420, a DC / DC converter 430, a load 440, a sensing unit 450, and a communication unit ( 460, the main controller 470 may be configured. Here, the communicator 460 may include at least one of a demodulator 461 and a modulator 462.

Although the wireless power receiver 400 illustrated in the example of FIG. 4 is illustrated as being capable of exchanging information with the wireless power transmitter through in-band communication, this is only one embodiment, and in another embodiment. The communication unit 460 may provide short-range bidirectional communication through a frequency band different from the frequency band used for wireless power signal transmission.

AC power received through the receiving coil 410 may be transferred to the rectifier 420. The rectifier 420 may convert AC power into DC power and transmit the DC power to the DC / DC converter 430. The DC / DC converter 430 may convert the strength of the rectifier output DC power into a specific strength required by the load 440 and then transfer the power to the load 440. In addition, the receiving coil 410 may include a plurality of receiving coils (not shown), that is, the first to nth receiving coils. Frequency of AC power delivered to each receiving coil (not shown) according to one embodiment may be different from each other, another embodiment is a predetermined frequency controller with a function to adjust the LC resonance characteristics differently for each receiving coil It is also possible to set a different resonant frequency for each receiving coil by using a.

The sensing unit 450 may measure the intensity of the output DC power of the rectifier 420 and provide it to the main controller 470. For example, the sensing unit 450 may measure the strength of the current applied to the receiving coil 410 according to the wireless power reception, and may transmit the measurement result to the main controller 470. As another example, the sensing unit 450 may measure the internal temperature of the wireless power receiver 400 and provide the measured temperature value to the main controller 470.

As an example, the main controller 470 may determine whether the overvoltage is generated by comparing the measured intensity of the rectifier output DC power with a predetermined reference value. As a result of the determination, when the overvoltage is generated, a predetermined packet indicating that the overvoltage has occurred may be generated and transmitted to the modulator 462. Here, the signal modulated by the modulator 462 may be transmitted to the wireless power transmitter through the receiving coil 410 or a separate coil (not shown). In addition, the main controller 470 may determine that the detection signal is received when the intensity of the rectifier output DC power is greater than or equal to a predetermined reference value. When the detection signal is received, a signal strength indicator corresponding to the detection signal may be modulated by the modulator 462. Can be transmitted to the wireless power transmitter. As another example, the demodulator 461 demodulates an AC power signal or a rectifier 420 output DC power signal between the receiving coil 410 and the rectifier 420 to identify whether a detection signal is received, and then, the main controller identifies the identification result. It may be provided to the unit 470. In this case, the main controller 470 may control the signal strength indicator corresponding to the detection signal to be transmitted through the modulator 462.

In addition, the main controller 470 may control the FOD status packet including any one or more of a pre-stored reference quality factor value and a reference frequency value to be transmitted to the wireless power transmitter through the modulator 462.

Returning to FIG. 3, the wireless power transmitter according to the embodiment may further include a load resistor 390 to measure guaranteed power.

The load resistor 390 may be connected to the DC-DC converter 310. A switch may be further included between the load resistor 390 and the DC-DC converter 310. The power consumption of the load resistor 390 may be equal to the guaranteed power previously stored in the wireless power transmitter. Here, the guaranteed power may be 15W, but is not limited thereto.

The DC-DC converter 310 may supply a specific voltage to a Vrail value, which is an output voltage of the DC-DC converter 310. For example, if the DC-DC converter supplies a Vrail value of 5V, the power consumption of the load resistor 390 may have a resistance value of 1.6 ohms to have a value of 15W.

When the input power input from the power supply unit 360 is 15W or more and the power consumption of the load resistor 390 is set to 15W, the input voltage does not drop rapidly, and the guaranteed power may be set to 15W.

On the other hand, if the input power input from the power supply unit 360 is less than 15W, and the power consumption of the load resistor 390 is set to 15W, the input voltage drops sharply and the guaranteed power does not satisfy 15W. Accordingly, the controller 380 may determine that power transmission is impossible at the preset guaranteed power. The wireless power transmitter may recognize a user that charging is impossible through a separate user interface.

Embodiments may connect a plurality of load resistors to determine that power transmission is not possible with preset power, for example, correction power, while simultaneously measuring the guaranteed power that can be transmitted.

As shown in FIG. 5, the load resistor may include a first load resistor 390a, a second load resistor 390b, and a third load resistor 390c having different power consumptions. The first to third load resistors 390a, 390b, and 390c may be connected in parallel to the DC-DC converter 310. In addition, the first switch to the third switch (391a, 391b, 391c) to selectively connect the load resistors (390a, 390b, 390c) having different power consumption to the DC-DC converter (310). Can be. The switch 391 may connect power to the ground via the load resistor 390.

Power consumption of the first load resistor 390a may be greater than power consumption of the second load resistor 390b and the third load resistor 390c. Power consumption of the second load resistor 390b may be greater than power consumption of the third load resistor 390c. For example, the power consumption of the first load resistor 390a may be 15W, the power consumption of the second load resistor 390b may be 7.5W, and the power consumption of the third load resistor 390c may be 5W. It is not limited to this. Since the smaller the resistance value, the higher the power consumption, the resistance value of the first load resistor 390a may be smaller than the resistance value of the second load resistor 390b, and the resistance value of the second load resistor 390c is equal to the third load. It may be smaller than the resistance value of the resistor 390c.

The first switch 391a may be disposed between the DC-DC converter 310 and the first load resistor 390a. The second switch 391b may be disposed between the DC-DC converter 310 and the second load resistor 390b. The third switch 391c may be disposed between the DC-DC converter 310 and the third load resistor 390c.

In the above, three resistors and switches are disposed, but the present invention is not limited thereto, and may be disposed below three or four or more.

The load resistors 390a, 390b, 390c may be selectively connected to the DC-DC converter 310. For example, when the first switch 391a is turned on and the second switch 391b and the third switch 391c are turned off, the DC-DC converter 310 and the first load resistor 390a may be electrically connected. When the second switch 391b is turned on and the first switch 391a and the third switch 391c are turned off, the DC-DC converter 310 and the second load resistor 390b may be electrically connected to each other. When the third switch 391c is turned on and the first switch 391a and the second switch 391b are turned off, the DC-DC converter 310 and the third load resistor 390c may be connected.

The controller 380 detects that the voltage drops by comparing the voltage of the DC power with the reference voltage while any one of the load resistors 390a, 390b, and 390c is connected, and load resistors 390a and 390b that do not drop the voltage. , 390c may be selected and stored as guaranteed power.

The control unit 380 may be provided with a storage unit 381 (memory) to store the guaranteed power, and the storage unit 381 may be disposed in a separate space from the control unit 380.

Hereinafter, an operation of measuring the guaranteed power of the wireless power transmitter will be described in detail. The guarantee power may determine the guarantee power of the wireless power transmitter by sequentially connecting the load resistors having the high power consumption.

Measuring the guaranteed power may be performed at an initial stage when power is supplied and the inverter may not be powered.

Referring to FIG. 6, a step S301 of connecting the first load resistor 390a having the first power consumption may be performed. To this end, the first switch 391a may be turned on. The first load resistor 390a may be electrically connected to the DC-DC converter 310.

In operation S302, a sudden drop of the DC voltage, which is an input voltage connected to the first load resistor 391a, may be performed. For example, when a DC voltage having a power of 15W or more is connected to the first load resistor 391a having a power consumption of 15W, voltage drop does not occur.

As described above, when the voltage drop does not occur, the guaranteed power can be determined for the power consumption of the first load resistor 390a. The determined guaranteed power may be sent to the wireless power receiver at the negotiation stage. At this time, the power of the delivery coil may not be cut off.

On the other hand, if a DC voltage having a power of less than 15W is connected to the first load resistor 390a having a power consumption of 15W, a voltage drop may occur. If a voltage dip occurs, it may be determined that charging of the wireless power receiver is impossible with 15 W of power.

When the voltage drop occurs, the step S303 of connecting the second load resistor 390b having the second power consumption may be performed. In this case, the first switch 391a may be turned off and the second switch 391b may be turned on.

Subsequently, a step S304 of checking whether a sudden drop of the DC voltage connected to the second load resistor 390b occurs may be performed. For example, when a DC voltage having a power of 7.5W or more is connected to the second load resistor 390b having a power consumption of 7.5W, the voltage drop does not occur.

As described above, when the voltage drop does not occur, the guaranteed power can be determined for the power consumption of the second load resistor 390b. The determined guaranteed power may be sent to the wireless power receiver at the negotiation stage.

On the other hand, when an input voltage having a power of less than 7.5W is connected to the second load resistor 390b having a power consumption of 7.5W, a sudden drop in the input voltage may occur. If a voltage dip occurs, it may be determined that the wireless power receiver cannot be charged with a power of 7W.

When the voltage drop occurs, the step S306 of connecting the third load resistor 390c having the third power consumption may be performed. In this case, the second switch 391b may be turned off and the third switch 391c may be turned on.

Subsequently, it may be determined whether a sudden drop of the DC voltage connected to the third load resistor 390c occurs (S307). For example, when a DC voltage having a power of 5W or more is connected to the third load resistor 390c having a power consumption of 5W, voltage drop does not occur.

As described above, when the voltage drop does not occur, the guaranteed power can be determined for the power consumption of the third load resistor 390c. The determined guaranteed power may be sent to the wireless power receiver at the negotiation stage.

On the other hand, when a DC voltage having a power of less than 5W is connected to the third load resistor 390c having a power consumption of 5W, a voltage drop may occur. If a voltage dip occurs, it may be determined that charging of the wireless power receiver is impossible.

In the above, the guarantee power was measured by connecting three load resistors in parallel, but the present invention is not limited thereto and may be configured as follows.

As shown in FIG. 7, a plurality of load resistors may be connected in series. A plurality of switches may be included between the plurality of load resistors. Multiple load resistors may have the same power consumption. Power consumption of the first to fourth load resistors 390a, 390b, 390c, and 390d may include 4W, respectively.

The first to fourth load resistors 390a, 390b, 390c, and 390d may be connected in series. The first switch 391a may be disposed between the DC-DC converter 310 and the first load resistor 390a. The second switch 391b may be disposed between the first load resistor 390a and the second load resistor 390b. The third switch 391c may be disposed between the second load resistor 390b and the third load resistor 390c. The fourth switch 391d may be disposed between the third load resistor 390c and the fourth load resistor 390d.

The controller 380 may control the first to fourth switches 391a, 391b, 391c, and 391d on / off sequentially to measure the guaranteed power.

The controller 380 may measure whether the voltage drops sharply while the first to fourth load resistors 390a, 390b, 390c, and 390d are connected. In this case, all of the first to fourth switches 391a, 391b, 391c, and 391d may be turned on. When the sudden drop of the DC voltage does not occur, the sum of the power consumption of the first to fourth load resistors 390a, 390b, 390c, and 390d may be determined as the guaranteed power. For example, the guaranteed power may be determined to be 16W.

On the other hand, if a sudden drop in DC voltage occurs while the first to fourth load resistors 390a, 390b, 390c, and 390d are connected, the first to third load resistors 390a, 390b, and 390c are connected. It is possible to measure whether the voltage dips at. In this case, the first to third switches 391a, 391b, and 391c may be turned on, and the fourth switch 391d may be turned off. If the voltage drop does not occur, the sum of the power consumption of the first to third load resistors 390a, 390b, and 390c may be determined as the guaranteed power. For example, the guaranteed power may be determined to be 12W.

On the other hand, when a voltage drop occurs in a state where the first to third load resistors 390a, 390b, and 390c are connected, the voltage drops in the state where the first load resistor 390a and the second load resistor 390b are connected. It can be measured. In this case, the first switch 391a and the second switch 391b may be turned on, and the third switch 391c and the fourth switch 391d may be turned off. If the voltage drop does not occur, the sum of the power consumption of the first load resistor 390a and the second load resistor 390b may be determined as the guaranteed power. For example, the guaranteed power may be determined to be 8W.

On the other hand, if a voltage drop occurs in a state where the first load resistor 390a and the second load resistor 390b are connected, the voltage drop may be measured in the state where the first load resistor 390a is connected. In this case, the first switch 391a may be turned on and the second to fourth switches 391b, 391c and 391d may be turned off. If the voltage drop does not occur, the power consumption of the first load resistor 390a may be determined as the guaranteed power.

In the above, the guaranteed power is measured using the output voltage of the DC-DC converter, but the guaranteed power can be measured using the input voltage input from the power supply unit.

In the above, the guaranteed power is measured using a load resistor having a fixed resistance value, but the present invention is not limited thereto and may be configured as follows.

As shown in FIG. 8, the load resistor 390 may include a variable resistor. A switch 391 may be further included between the load resistor 390 and the DC-DC converter.

The load resistor 390 may change the resistance value so that the power consumption may vary from 1W to 15W. For example, when the Vrail value is supplied at 5V, the load resistor 390 may be fixed at 5 ohms and have a power consumption of 5W. On the other hand, when the Vrail value is supplied at 5V, the load resistor 390 may be fixed at about 17 ohms to have a power consumption of 15W.

The controller 380 may detect a voltage drop while fixing the load resistor 390 to 17 ohms. If the voltage drop does not occur, the controller 380 may determine the power consumption of the load resistor 390 as the guaranteed power.

On the other hand, when a voltage drop occurs, the controller 380 may control to lower the resistance value of the load resistor 390. The controller 380 may select power consumption of the load resistor 390 as the guaranteed power at the previous measurement time point when no voltage dip occurs.

The embodiment has the effect of reducing the resistance and the switch component by using a variable resistor as the load resistance, and has the effect of more easily measuring the time point of the voltage drop.

9 is a block diagram illustrating a structure of a wireless power transmitter according to a second embodiment.

As shown in FIG. 9, the wireless power device includes a power supply unit 360, an inverter 320, a resonant circuit 330, a sensing unit 350, a communication unit 340, an alarm unit 370, and a control unit 380. ), Including a load resistance. Here, description of the same structure as FIG. 3 is omitted.

The load resistor 390 may be connected to the power supply 360. The load resistor 390 may include one resistor or a plurality of resistors. The load resistor 390 may adopt the structures of FIGS. 3, 5, and 7.

Input power may be supplied to the load resistor 390. The input power may include a voltage of 12V. The load resistor 390 may be supplied with a specific value, for example, 5V. The controller 380 may change the frequency to lower the voltage of the input voltage of 12V. The controller 380 may lower the input voltage value by controlling the PWM signal of the input voltage. The controller 380 may vary the frequency from 110Khz to 150KHz. If the frequency is the resonance point of 100KHz, the input voltage may be 12V, but as the frequency increases, the voltage decreases. This results in a voltage lower than 12V when the frequency is varied from 110KHz to 150KHz. Therefore, the controller 380 may control the frequency such that the input power is about 5V.

By controlling the voltage using a variable frequency, the embodiment can effectively measure the guarantee power that can be transmitted even without a DC-DC converter.

In the above, the fixed voltage is supplied through the DC-DC converter, but the present invention is not limited thereto, and the guaranteed power may be measured by supplying a variable voltage.

10 is a block diagram illustrating a structure of a wireless power transmitter according to a third embodiment.

As shown in FIG. 10, the wireless power device includes a power supply unit 360, a DC-DC converter 310, an inverter 320, a resonant circuit 330, a sensing unit 350, and a communication unit. 340, an alarm unit 370, a controller 380, a load resistor, and a switch may be configured. Here, description of the same structure as FIG. 3 is omitted.

The load resistor 390 may include a fixed resistance value. For example, the resistance value of the load resistor 390 may be 1.6 ohms. A switch 391 may be further disposed between the load resistor 390 and the DC-DC converter 310. The switch 391 may be connected such that a DC voltage, which is an input voltage, flows to the ground through the load resistor 390.

The DC-DC converter 310 may output the first voltage V1 or the second voltage V2. The controller 380 may control a plurality of voltages to be output from the DC-DC converter 310. For example, since the power P is V ² / R, when the resistance of the load resistor 390 is 1.6 ohms, the first voltage V1 may be about 5V so that the load resistor 390 has power consumption of 15W. . The second voltage V2 may be about 3V so that the load resistor 390 has a power consumption of 5W. The DC-DC converter 310 may sequentially supply voltages of 3V to 5V to measure guaranteed power. Here, the values of the load resistor 390, the first voltage V1, and the second voltage V2 are not limited thereto. In addition, the load resistance 390, the first voltage (V1), the second voltage (V2) values may be changed to correspond to each value. In addition, the power value may further include a separate resistance value in the circuit.

Since the power consumption is proportional to the voltage, the controller 380 may select the guaranteed power corresponding to the high output voltage among the output voltages in which the drop does not occur among the output voltages in which the voltage drop does not occur.

For example, when the DC-DC converter 310 supplies the first voltage V1, for example, 5V, the guaranteed power may be measured as 15W when no voltage drop occurs. On the other hand, a sudden drop in voltage is generated to supply the second voltage V2. At this time, if no drop in voltage occurs, the guaranteed power may be measured as 5W. On the other hand, if a voltage dip occurs, it may be determined that charging is impossible.

In the above, the variable voltage is generated using the DC-DC converter. However, the present invention is not limited thereto, and the guaranteed power may be measured by generating the variable voltage by controlling the frequency of the input voltage in the state in which the DC-DC converter is removed.

Hereinafter, the operation of the controller will be described. 11 is a diagram for describing an operation of a controller of a wireless charging apparatus, according to an exemplary embodiment.

Referring to FIG. 11, the controller 380 may perform an operation S401 of transmitting the magnitude of the first power stored in the storage 381, for example, the guaranteed power, to the wireless power receiver 400. The guaranteed power may be the maximum transmittable power value that can be transmitted to the wireless power receiver 400.

The wireless power receiver 400 may transmit required power to the wireless power transmitter 300 within the guaranteed power range.

In the prior art, since there was no configuration capable of detecting the power that can be transmitted from the wireless power transmitter, a power larger than the guaranteed power that can be transmitted by the wireless power transmitter could be negotiated with the required power. Could occur. In embodiments, by transmitting transmittable power to the wireless power receiver, the wireless power receiver may request power within the range of transmittable power.

Subsequently, the controller 380 may perform a step S402 of receiving the required power from the wireless power receiver 400. The required power may be the requested power within the range of transmittable guarantee power.

Subsequently, the controller 380 may perform an operation 403 of transmitting an ACK packet in response to the required power. In addition, after completing the negotiation step, the controller 380 may perform a step of transmitting power corresponding to the required power (S404). In addition, when the required power is changed from the wireless power receiver 400, the controller 380 may transmit power corresponding to the changed required power.

Hereinafter, the operation in the negotiation stage between the wireless power transmitter and the wireless power receiver will be described. 12 is a diagram for explaining a negotiation step between a wireless power transmitter and a wireless power receiver.

As shown in FIG. 12, the wireless power receiver 400 may transmit a FOD status packet for FO detection (S501). The wireless power receiver 400 may transmit a general request packet requesting a capability packet of a power transmitter for a power transmission contract (S502).

The wireless power transmitter 300 may transmit the power transmitter capability packet in response to the general request packet (S503).

The wireless power transmitter 300 may provide a guaranteed power value. The measurement of the guaranteed power may be performed at an early stage of powering up, and more specifically, before the pinging stage.

The wireless power receiver 400 may transmit a special request packet including the new power value within the guaranteed power range in order to establish a new power transmission contract based on the wireless power transmitter 300 guaranteed power value (S504). For example, the wireless power receiver may request a power value that is less than or equal to the wireless power transmitter guaranteed power value.

The wireless power transmitter 300 may transmit an ACK packet or a NACK packet in response to the special request packet (S505). That is, the wireless power transmitter 300 may transmit an ACK when the wireless power receiver 400 accepts the corrected power value requested by the wireless power receiver 400.

Thereafter, when the power transmission contract is completed, the wireless power receiver 400 may transmit a special request packet for terminating the negotiation step (S506). The wireless power transmitter 300 may transmit an ACK packet in response to the special request packet for ending the negotiation step (S507). That is, the wireless power transmitter 300 may transmit an ACK packet with the acceptance of the end of the summation phase.

Although not shown, in the subsequent renegotiation step, the wireless power receiver 400 may transmit required power within power that can transmit power of the wireless power transmitter 300. Therefore, even if the power required for charging is changed, it is possible to prevent the charging from being cut off.

Conventionally, since there is no configuration for checking the input power, when the wireless power receiver cannot supply the power requested by the wireless power receiver, the charging is cut off.

The wireless power device according to the embodiment configures the input power check unit to check the transmittable power of the input power, the wireless power receiver may request power in accordance with the transmission capability of the wireless power transmitter, the charge is cut off There is an effect that can prevent.

It is apparent to those skilled in the art that the present invention can 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 aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

300: wireless power transmitter
310: DC-DC converter
380: control unit
381: storage unit
390: load resistance

Claims (13)

inverter;
A switch for connecting the DC power input to the inverter to flow to ground through a first load resistor or a second load resistor; And
It is determined whether the voltage of the DC power is higher than the reference voltage when the first load resistor or the second load resistor is connected, and the guarantee power corresponding to the load resistance having a lower resistance value is selected among the load resistors in which the voltage is higher than the reference voltage. It includes a control unit for storing,
And the first load resistor has a lower resistance value than the second load resistor. The method of claim 1,
And the guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver is determined within the guaranteed power. The method of claim 2,
And a power supply unit configured to receive power from an external power supply terminal, wherein the DC power is output from the power supply unit. The method of claim 3,
The controller controls the magnitude of the DC power by varying the frequency of the input voltage. The method of claim 4, wherein
The control unit is a wireless charging device for reducing the magnitude of the DC power by varying the frequency from 110KHz to 150Hz. The method of claim 5,
And the converter supplies 5V or 10V to the load resistance. The method according to any one of claims 1 to 6,
And a transmitting coil for transmitting the guaranteed power. A converter for outputting DC power;
An inverter that receives the DC power and converts the AC power into AC power;
A switch for connecting the DC power to ground through a load resistance; And
The converter is controlled such that an output voltage of the DC power becomes a first voltage or a second voltage,
And a controller for determining whether an output voltage of the DC power is higher than a reference voltage while the load resistance is connected, and selecting and storing a guaranteed power corresponding to an output voltage having a higher voltage value among the output voltages higher than the reference voltage. Charging device. The method of claim 8,
And the guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver is determined within the guaranteed power. Measuring a DC voltage input to a first or second load resistor connected to an input terminal of the inverter;
Comparing whether the DC voltage is higher than a reference voltage; And
And selecting a guaranteed power corresponding to a load resistance having a lower resistance value among load resistances having a DC voltage higher than a reference voltage. The method of claim 10,
And the guaranteed power is delivered to a wireless power receiver, and the required guaranteed power of the wireless power receiver is determined within the guaranteed power. The method of claim 11,
The DC power is a wireless charging method for outputting the power to receive input power from an external power supply terminal. The method of claim 12,
Wireless charging method of controlling the magnitude of the DC power by varying the frequency of the input power.

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