KR20150062785A - Low heat wireless power receiving device - Google Patents

Abstract

The present invention relates to a low heat wireless power receiving device. The low heat wireless power receiving device according to an embodiment of the present invention comprises: a power receiving coil to receive a wireless power signal; an impedance matching unit to match impedance to resonate the power receiving coil by the wireless power signal; a rectification unit to rectify the wireless power signal to convert the wireless power signal into direct current power; a power conversion unit comprising a low heat transformer unit having a first resistance value and a high heat transformer unit having a second resistance value larger than the first resistance value, wherein the low heat transformer unit is connected in parallel with the high heat transformer unit to supply the output power of the rectification unit to charge a load; and a reception control unit to control the impedance matching unit to match impedance and supply charging power to the load by selectively turning the low heat transformer unit on and off while keeping the high heat transformer unit turned on constantly.

Description

[0001] LOW HEAT WIRELESS POWER RECEIVING DEVICE [0002]

The present invention relates to a wireless power receiving apparatus for receiving a wireless power signal, and more particularly, to a wireless wireless power receiving apparatus which has excellent charging efficiency and generates less heat during charging.

2. Description of the Related Art Generally, various portable terminals such as a mobile phone and a PDA (Personal Digital Assistant) are equipped with a water receiving device such as a battery pack for supplying electric power by charging electric power. The power receiving device charges electric power supplied from an external charging device, and supplies the charged electric power to the portable terminal to operate the portable terminal.

The power reception device may include a battery cell for charging electric power, and a charging / discharging circuit for charging the battery cell with electric power supplied from an external charging device and discharging the charged electric power to supply it to the portable terminal.

A power input terminal of a charging device for inputting commercial AC power and outputting power of a voltage and a current corresponding to the power receiving device and a power input terminal of a power input terminal of the power receiving device, Is directly connected through a cable.

However, since the terminals of the charging apparatus and the terminals of the power receiving apparatus have different potential differences, the terminal connecting method is not suitable for the moment when the terminals of the charging apparatus and the terminals of the power receiving apparatus are brought into contact with each other or separated from each other A discharge phenomenon occurs.

This instantaneous discharge phenomenon worsens the terminal of the charging device and the terminal of the water receiving device and generates heat from the foreign substance when foreign substances are accumulated on the terminal of the charging device and the terminal of the water receiving device, There is a possibility of occurrence.

In addition, due to moisture and the like, the electric power charged in the battery cells of the water receiving apparatus is naturally discharged to the outside through the terminals of the water receiving apparatus, thereby shortening the service life of the water receiving apparatus and deteriorating the use performance .

In recent years, in order to solve various problems of the above-mentioned terminal connection method, a wireless power transmission apparatus transmits a power signal wirelessly, and a wireless power transmission apparatus wirelessly receives a wireless power signal and charges the battery cell A wireless power receiving apparatus has been proposed (see Korean Patent Publication No. 10-2012-0128114).

For example, the wireless power receiving apparatus is coupled to the wireless power transmission apparatus through an electromagnetic induction method to receive a wireless power signal wirelessly transmitted from the wireless power transmission apparatus, and charges the battery cell with the received power.

[0003] The wireless power receiving apparatus has been stably and wirelessly received, and has been put to a great deal of effort in order to receive power and charge the battery cell.

Such a wireless power receiving apparatus rectifies a wireless power signal received from a wireless power transmission apparatus to a rectified rectified DC power, converts the converted DC power into a voltage level of a DC power corresponding to a battery cell corresponding to a battery cell And charges the battery cell.

However, when the DC / DC converter is used to convert the voltage level of the DC power, the DC / DC converter generates a lot of heat in the process of converting the voltage level of the DC power, / DC converter in order to dissipate the heat generated by the heat exchanger.

In addition, since the heat dissipating means must be installed on the circuit board, the size of the circuit board is increased.

An object of the present invention is to provide a low-power wireless power receiving apparatus capable of reducing heat generated in a process of charging a load using a power signal transmitted from a wireless power transmission apparatus.

According to an aspect of the present invention, there is provided a low-power wireless power receiving apparatus including: a power receiving coil for receiving a wireless power signal; An impedance matching unit matching the impedance so that the power receiving coil resonates with the wireless power signal; A rectifier for rectifying and converting the wireless power signal into DC power; A low heat generating transformer having a first resistance value and a high heat generating transformer having a second resistance value larger than the first resistance value, which are connected in parallel with each other and supply the output power of the rectifying section to the load as charging power, ; And a receiving control unit for controlling impedance matching of the impedance matching unit and supplying the charging power to the load while selectively turning on and off the low heat generating transformer in a state in which the high-temperature heat transformer is always on.

Here, the reception control unit may supply the charging power to the load in a state of light load, in a state in which the low heat generation transforming unit is turned off.

Here, in the heavy load state, the reception control section can supply the charging power to the load in a state in which the low heat generation transforming section is turned on.

The low-heating wireless power receiving apparatus may further include a current detector disposed downstream of the power converter to detect a current of the charge power.

Here, the reception control unit may control the impedance matching unit based on the current value detected by the current detection unit.

Here, the low-heating wireless power receiving apparatus may further include a communication unit that transmits an ASK signal through the receiving coil, and the reception control unit receives the status information from the load, controls the communication unit, And transmit the status information to the wireless power transmission apparatus through the coil.

Here, the low heat generating transformer may include a FET and a switching element connected to the gate driver of the FET, and the high heat generating transformer may be an LDO.

Here, the low-fever wireless power receiving apparatus may further include a controller power supply for supplying power to the reception controller.

Here, the power source of the controller may be an LDO.

Here, the low-heat wireless power receiving apparatus may include a virtual load positioned between the rectifying unit and the power converting unit.

Here, the voltage stabilizing circuit part may be disposed between the rectifying part and the power converting part.

According to an embodiment of the present invention, there is provided a low-heat generating wireless power receiving apparatus including a low heat generating transformer and a high heat-generating transformer, wherein the power charging load state of the power receiving device is determined according to the elapsed charging time and the current of the power receiving device, , The low-heat-generating transformer and the high-heat-temperature transformer are controlled to operate, thereby minimizing the heat generation during charging.

1 is a block diagram of a low-heating wireless power receiving apparatus according to an embodiment of the present invention;
2 is a circuit diagram of the low-heat-generating wireless power receiving apparatus shown in Fig.
3 is a flow chart for explaining an operation in a low-heating wireless power receiving apparatus which is an embodiment of the present invention.
4 is a chart showing an output voltage at a rectifying section and a charging current to a load in a charging operation in a low-heating wireless power receiving apparatus according to an embodiment of the present invention.
FIG. 5 is a graph for explaining an operation state of an example of an output voltage of a rectifying section and a charging current to a load of a low-heat-type wireless power receiving apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which like reference numerals refer to like elements throughout.

FIG. 1 is a block diagram of a low-heating wireless power receiving apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of the low-heat wireless power receiving apparatus shown in FIG.

1 and 2, a low-heating wireless power receiving apparatus 100 according to an embodiment of the present invention includes a receiving coil 110, an impedance matching circuit 120, a rectifying unit 130, an OVP (voltage stabilization) A virtual load 150, a power conversion unit 160, a current detection unit 170, a communication unit 180, a control unit power supply 190, a load 200 (e.g., a battery cell), and a reception control unit 210 have.

The reception coil 110 is coupled to a transmission coil of a wireless power transmission device, for example, by an electromagnetic induction method or a magnetic resonance type, and receives a wireless power signal transmitted by the power transmission coil.

The impedance matching circuit 120 may be composed of a plurality of capacitors as shown in FIG. 2 as an element for performing impedance matching between the receiving coil 110 and the transmission coil of the wireless power transmission apparatus.

The rectifying unit 130 is a device for converting DC power into AC power generated in the receiving coil 110 by a radio power signal.

The power converting unit 160 converts the DC power output from the rectifying unit 130 into a charging power according to the load and supplies the charging power to the load. The power conversion section 160 may be constituted by a low heat generation transforming section 162 and a high heat generation transforming section 164. 2, the low heat generation transformer 162 may include a switching element 162-2 connected to the gate driver of the FET 162-1 and the FET 162-1, The transformer 164 may be composed of an LDO.

Generally, when charging is performed with a charging power of 5V, 1A, the FET of the low heat generation transformer 162 has a low resistance value of 30m? And the LOD of the high heat generating transformer 164 has a high resistance value of 0.2 ?. The low heat generating transformer 162 and the high heat generating transformer 164 are connected in parallel with each other.

In the present invention, the high heat generating transformer 164 always maintains the on state during the charging operation after the start of charging (i.e., in both the light load state and the heavy load state), and the low heat generation transformer 162 is turned on only in the heavy load state . When the low heat generating transformer 162 is turned on, the high heat generating transformer 164 connected in parallel has a high resistance value, so that most of the current is supplied to the low heat generating transformer 162. Accordingly, only a small amount of current flows through the high heat-generating transformer 164, so that the amount of heat generated is extremely small.

The OVP circuit 140 and the virtual load 150 may be positioned between the rectification unit 130 and the power conversion unit 160.

The OVP circuit 140 and the virtual load 150 are components for preventing the surge voltage from being supplied to the load at the initial stage of wireless charging. When the initial wireless power signal is received, the reception control unit 210 controls the virtual load 150 Is turned on and the normal current value is measured by the current detector 170, the virtual load 150 is turned off. The OVP circuit is a circuit for preventing a voltage higher than necessary from being supplied to the load. That is, between the rectification part 130 and the power conversion part 160 in order to prevent excessive voltage from being supplied to the load at the initial stage of charging. When the wireless power reception signal is received for the first time, the reception control unit 210 controls the OVP circuit so that an overvoltage is not supplied to the load.

The current detection unit 170 has a function of measuring the current value of the charging power supplied to the load. If the current value becomes smaller due to an abnormal emergency situation (such as a movement of the receiving apparatus 100) during normal charging, the receiving control unit 210 informs the wireless power transmitting apparatus through the communication unit 180, It is possible to change the signal. In addition, the reception controller 210 controls the impedance matching circuit 120 so that the reception coil 110 is impedance-matched with the transmission coil again, so that the wireless charging can be continued.

The communication unit 180 transmits charge status information from the current detection unit 170 and the load 200 to the wireless power transmission apparatus through the reception coil 110 as an ASK communication signal.

The reception control unit power supply 190 supplies power to the reception control unit 210. [ And may be made of LDO as shown in FIG.

The reception control unit 210 controls the impedance matching of the impedance matching circuit 120 and controls the impedance matching circuit 120 such that the low heat generating transformer 162 is selectively turned on and off while the high heat generating transformer 164 is always on. And supplies charging power to the load (200). Here, the reception control unit 210 supplies the charging power to the load 200 while the low heat generation transformer 162 is turned off in the light load state, and in the heavy load state, the low heat generation transformer 162 to the load 200 in the on state. The reception controller 210 changes the impedance of the impedance matching circuit 120 based on the current value detected by the current detector 170 so that an appropriate current flows to the load. The reception control unit 210 receives the state information from the load 200 and controls the communication unit 180 to transmit the ASK signal to the wireless power transmission apparatus via the reception coil 110. [ To be transmitted.

Hereinafter, the charging operation of the low-heating wireless power receiving apparatus having the above-described configuration will be described in more detail with reference to FIG. 3 through FIG.

FIG. 3 is a flow chart for explaining an operation of the low-fever wireless power receiving apparatus according to an embodiment of the present invention. FIG. 4 is a flowchart illustrating an operation of the low- 5 is a graph showing an output voltage of the rectifying unit and a charging current to the load of the low-heating wireless power receiving apparatus, which is an embodiment of the present invention, .

3, the reception control unit 210 controls the impedance matching circuit 120 so that the impedance between the transmission coil and the reception coil 110 is impedance (impedance) The matching operation is executed (S1, S3). Then, when impedance matching is performed, a wireless power signal from the wireless power receiving apparatus 100 is received (S5). In this case, it will be referred to as an initial state (see FIGS. 4 and 5). In this case, as shown in Fig. 5, the output voltage of the rectifying section 130 is about 7 to 10.5 V, but the current to the load is not supplied. At this time, the reception control unit 210 keeps the virtual load 150 in the ON state while checking the output voltage of the rectification unit 130 (S7). Next, in consideration of the output voltage and the elapsed time, it is checked whether the current state is the light load state (S9). Further, the OVP circuit 140 is operated to prevent an overvoltage from being supplied to the load. As shown in FIGS. 4 and 5, the light load state has an output voltage of 5.45 to 5.6 V and an output current of 200 to 1000 mA. If it is determined that the load is in the light load state, the charging voltage is supplied to the load 200 while turning on the high heat generating transformer 164 while turning off the virtual load 150 (S11). At this time, the current detector 170 measures the current of the charge power.

Then, the reception control section 210 confirms whether it is a heavy load state (S13). As shown in FIGS. 4 and 5, in the heavy load state, the charge current is 350 to 1000 mA, and the output voltage of the rectifier 130 is 5.15 to 5.3 V. If it is determined that the engine is in a heavy load state, the low heat generating transformer 162 connected in parallel with the high heat generating transformer 164 is turned on (S15). That is, when the low heat generating transformer 162 is turned on while the high heat generating transformer 164 remains in the on state, most of the current is supplied to the low heat generating transformer 162 because the low heat generating transformer 162 has a low resistance value. (162). Thus, the heat generation in the high heat-generating transformer 164 is minimized. In this heavy load state, the reception control section 210 again checks whether the vehicle is in the light load state (S17). In FIGS. 4 and 5, the light load state is approximately 5.45 to 6.0 V, and the charge current may have a value of 200 to 500 mA. When receiving the light load again, the reception control unit 210 turns on only the high heat-heat transforming unit 164 by turning off the low heat-generating transforming unit 162 (S19). Then, when the fully charged state is established, the high-heat-generating transformer 164 is also turned off to prevent the current from being supplied to the load (S21).

According to the low heat generating radio power receiving apparatus of the present invention having the above-described configuration, the low heat generating transformer and the high heat generating transformer are provided, and the power charging load state of the power receiving apparatus And by controlling the operation of the low heat generating transformer and the high heat generating transformer, the heat generation during charging can be minimized.

The low-calorie wireless power receiving apparatus and method described above can be applied to all or some of the embodiments so that various modifications of the embodiments can be made without limiting the configuration and method of the embodiments described above. Or may be selectively combined.

100: Wireless power receiving device
110: Receive coil
120: Impedance matching circuit
130: rectification part
140: OVP circuit (voltage stabilization circuit)
150: Virtual load
160: Power conversion section
162: Low heat generating transformer
162-1: FET
162-2: Switching element
164:
170:
180:
190:
200: Load
210:

Claims (11)

A power receiving coil for receiving a wireless power signal;
An impedance matching unit matching the impedance so that the power receiving coil resonates with the wireless power signal;
A rectifier for rectifying and converting the wireless power signal into DC power;
A low heat generating transformer having a first resistance value and a high heat generating transformer having a second resistance value larger than the first resistance value, which are connected in parallel with each other and supply the output power of the rectifying section to the load as charging power, ; And
And a reception control section for controlling impedance matching of the impedance matching section and for supplying charging power to the load while selectively turning on and off the low heat generation transforming section in a state in which the high- Device.
The method according to claim 1,
The reception control unit,
And supplies the charging power to the load in a light load state in a state in which the low heat generating transformer is turned off.
3. The method of claim 2,
The reception control unit,
And supplies the charging power to the load in a state in which the low heat generating transformer is turned on in a heavy load state.
The method according to claim 1,
Further comprising a current detection unit provided at a rear stage of the power conversion unit to detect a current of the charging power.
5. The method of claim 4,
The reception control unit,
And controls the impedance matching unit based on the current value detected by the current detecting unit.
The method according to claim 1,
A communication unit for transmitting an ASK signal through the reception coil;
The reception control unit,
Receives the state information from the load, and controls the communication unit to transmit the state information to the wireless power transmission apparatus through the reception coil.
The method according to claim 1,
Wherein the low heat generating transformer includes a FET and a switching element connected to a gate driver of the FET,
Wherein the high heat-generating transformer is an LDO.
The method according to claim 1,
And a control unit power supply for supplying power to the reception control unit.
9. The method of claim 8,
Wherein the power source of the controller is an LDO.
The method according to claim 1,
And a virtual load placed between the rectification section and the power conversion section.
The method according to claim 1,
And a voltage stabilizing circuit portion located between the rectifying portion and the power converting portion.

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