KR20230000160A - Overcharge protection circuit, wireless power receiver and wireless charging device including the same - Google Patents

Abstract

Disclosed are an overcharge protection circuit, a wireless power receiver including the same and a wireless charging device thereof. The wireless power receiver comprises: an output terminal connected to a battery pack; a charge control circuit that controls charging of the battery pack by outputting a constant voltage to the output terminal; and an overcharge protection circuit that detects a voltage of the output terminal and protects the battery pack from overcharging by lowering the voltage of the output terminal when the voltage of the output terminal exceeds a first reference voltage.

Description

Overcharge protection circuit and wireless power receiver and wireless charging device including the same

The present invention relates to a wireless charging device, and more particularly, to an overcharge protection circuit capable of safely protecting a battery pack from overcharging, a wireless power receiver including the same, and a wireless charging device.

Recently, interest in electric kickboards as a means of short-distance movement is increasing. In addition, electric kickboards are easy to operate and do not require a separate license, so many people can use them conveniently.

Due to this convenience, electric kickboards are widely used not only for personal possession for hobbies, but also for commuting. Accordingly, the sales business of personal electric kickboards, the rental business of electric kickboards, and electric kickboard-related markets are rapidly growing.

However, as the use of electric kickboards with convenience increases, safety problems also occur. The electric kickboard includes a motor that supplies power and a battery pack that supplies power to the motor.

Battery packs applied to electric kickboards have more battery cells connected in series or parallel than existing electronic devices such as mobile phones or laptops.

In such a battery pack, a battery management system (BMS) monitors voltages of a plurality of battery cells. Monitoring information on a plurality of battery cells is transmitted to the charge control circuit of the electric kickboard and used to control the charging and discharging of the battery pack.

However, there is a problem in that the battery pack is overcharged when the BMS of the battery pack or some parts of the charge control circuit are broken. This may cause a fire or explosion accident during charging. Also, some low-priced electric kickboards do not have a BMS function.

Accordingly, there is a need for a technology capable of safely protecting a battery pack from overcharging even when a BMS of the battery pack or some components of a charging control circuit are out of order.

Document 1: Republic of Korea Patent No. 10-2218431 (2021.02.16) Document 2: Republic of Korea Patent No. 10-0777884 (November 13, 2007)

A technical problem to be solved by the present invention is to provide an overcharge protection circuit that can safely protect a battery pack from overcharge, and a wireless power receiver and a wireless charging device including the same.

In addition, a technical problem to be solved by the present invention is to provide an overcharge protection circuit that operates independently of a BMS or a charge control circuit of a battery pack, and a wireless power receiver and a wireless charging device including the same.

In addition, the technical problem to be solved by the present invention is an overcharge protection circuit that can safely protect the battery pack from overcharge even if a BMS of the battery pack or some parts of the charge control circuit fails, and a wireless power receiver and wireless charging including the same device is provided.

In addition, the technical problem to be solved by the present invention is to provide an overcharge protection circuit that can eliminate the possibility of malfunction due to a surge on the power supply side, a wireless power receiver and a wireless charging device including the same.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

An overcharge protection circuit according to an embodiment, a wireless power receiver and a wireless charging device including the same, drop the voltage of the output terminal when the voltage of the output terminal is detected as overvoltage.

Specifically, the overcharge protection circuit detects the voltage of the output terminal to which the battery pack is connected, and protects the battery pack from overcharging by dropping the voltage of the output terminal when the voltage of the output terminal exceeds the first reference voltage.

In addition, the overcharge protection circuit according to an embodiment and the wireless power receiver and wireless charging device including the same are enabled when the voltage of the output stage is detected as overvoltage.

Specifically, the overcharge protection circuit is enabled when the voltage of the output terminal to which the battery pack is connected exceeds the first reference voltage and operates independently of the BMS or charge control circuit of the battery pack.

In addition, the overcharge protection circuit according to an embodiment, and the wireless power receiver and wireless charging device including the same, drop the voltage of the output terminal when the voltage of the output terminal is detected as overvoltage regardless of the BMS or the charging control circuit of the battery pack. .

Specifically, the overcharge protection circuit safely protects the battery pack from overcharging because the voltage of the output terminal drops according to the voltage of the output terminal even if a BMS of the battery pack or some parts of the charge control circuit fails.

In addition, in the overcharge protection circuit and the wireless power receiver and wireless charging device including the same, the overcharge protection circuit is installed in the wireless power receiver that supplies power to the battery pack.

Specifically, the overcharge protection circuit is installed in a wireless power receiver that supplies power to the battery pack to eliminate the possibility of malfunction due to a surge or the like on the power supply side.

A wireless power receiver according to an embodiment includes an output terminal connected to a battery pack, a charging control circuit that outputs a constant voltage to the output terminal to control charging of the battery pack, and detects a voltage of the output terminal and controls the voltage of the output terminal. 1 Includes an overcharge protection circuit that protects the battery pack from overcharge by dropping the voltage of the output terminal when the standard voltage is exceeded.

A wireless charging device according to an embodiment includes a wireless power transmitter that converts commercial power into a power signal having a wireless power transmission frequency and transmits it, and a battery pack that receives a power signal from the wireless power transmitter and converts the power signal into an output voltage. It includes a wireless power receiver that supplies to. The wireless power receiver includes an output terminal connected to a battery pack, a charge control circuit that controls charging of the battery pack by outputting a constant voltage to the output terminal, and detecting a voltage of the output terminal so that the voltage of the output terminal exceeds a first reference voltage. In this case, an overcharge protection circuit that protects the battery pack from overcharge by dropping the voltage of the output terminal is included.

An overcharge protection circuit according to an embodiment detects a fuse provided between an output terminal to which a battery pack is connected and a charge control circuit that controls charging of the battery pack by outputting a constant voltage to the output terminal, and detects a voltage of the output terminal. and a protection circuit that protects the battery pack from overcharging by dropping the voltage of the output terminal when the voltage exceeds the first reference voltage.

As described above, the overcharge protection circuit according to an embodiment and the wireless power receiver and wireless charging device including the same reduce the voltage of the output terminal when the voltage of the output terminal to which the battery pack is connected is detected as overvoltage, thereby preventing the battery from overcharging. The pack can be protected.

In addition, the overcharge protection circuit according to an embodiment and the wireless power receiver and wireless charging device including the same are enabled when the voltage of the output terminal is detected as overvoltage, so they can operate independently of the BMS or charge control circuit of the battery pack. can

In addition, the overcharge protection circuit according to an embodiment, and the wireless power receiver and wireless charging device including the same, even if a failure occurs in some parts of the BMS or charging control circuit of the battery pack, the voltage of the output terminal is adjusted according to the voltage of the output terminal. As it descends, it can safely protect the battery pack from overcharging.

In addition, the overcharge protection circuit according to an embodiment, and the wireless power receiver and wireless charging device including the same, since the overcharge protection circuit is installed in the wireless power receiver that supplies power to the battery pack, malfunction due to surge on the power supply side possibility can be eliminated.

In addition, the overcharge protection circuit according to an embodiment and the wireless power receiver and wireless charging device including the same block overcharging of the battery pack even when some parts of the BMS or charging control circuit of the battery pack fail, thereby preventing fire that may occur during charging. You can prevent explosions, etc.

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is a block diagram of a wireless charging device according to an embodiment.
2 is a circuit diagram of an overcharge protection circuit and a wireless power receiver including the same according to an embodiment.
3 is a circuit diagram of an overcharge protection circuit and a wireless power receiver including the same according to another embodiment.
FIG. 4 is a diagram showing a semiconductor structure of the switching circuit shown in FIG. 3 .
5 illustrates a wireless charging system to which a wireless charging device according to an embodiment is applied.

The above objects, means and effects will be described in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Hereinafter, an overcharge protection circuit that can safely protect a battery pack from overcharge, and a wireless power receiver and a wireless charging device including the same are disclosed.

1 is a block diagram of a wireless charging device 10 according to an embodiment.

Referring to FIG. 1 , a wireless charging device 10 includes a wireless power transmitter 100 and a wireless power receiver 200 .

The wireless charging device 10 charges the battery pack 300 including at least one battery cell. For example, the wireless charging device 10 may be installed in a charging station for charging an electric kickboard.

Of course, the charging target is not limited to the electric kickboard. For example, powertrains equipped with a battery pack 300 including a plurality of battery cells may be subject to wireless charging.

The wireless power transmitter 100 converts commercial power into a power signal having a wireless power transmission frequency and transmits it to the wireless power receiver 200 through a transmission antenna.

As an example, the wireless power transmitter 100 may include an AC/DC converter, a constant voltage unit, an oscillation unit, an amplification unit, a transmission antenna matching unit, and a transmission antenna.

An AC/DC converter converts commercial power into direct current. The constant voltage section generates a constant voltage from the output of the AC/DC converter. The oscillation unit uses the constant voltage of the constant voltage unit as a power source to generate a wireless power transmission frequency signal.

The amplification unit amplifies the transmission frequency signal generated by the oscillation unit using the constant voltage of the constant voltage unit as a power source.

The transmit antenna outputs the transmit frequency signal as a wireless power signal. The transmitting antenna may use an antenna having directivity in the direction of the receiving antenna, and if necessary, a shield may be installed in the opposite direction of the receiving antenna.

The wireless power receiver 200 includes a receiving antenna, a rectifier, a charge control circuit 210 and an overcharge protection circuit 220.

The receiving antenna receives a power signal wirelessly transmitted from the wireless power transmitter 100 . The rectifier rectifies the power signal received through the receiving antenna into a DC voltage.

The charge control circuit 210 stabilizes the DC voltage rectified by the rectifier into a constant voltage and outputs the stabilized voltage. For example, the charge control circuit 210 may include a boost converter, boost the DC voltage of the rectifier through the boost converter, and regulate the output voltage to a constant voltage.

The charge control circuit 210 charges the battery cells in the battery pack 300 using the output voltage regulated as a constant voltage.

The overcharge protection circuit 220 detects the output voltage provided to the battery pack 300 and protects the battery pack 300 from overcharging by dropping the output voltage when the output voltage exceeds a first reference voltage.

Here, the first reference voltage is set to a higher level than the second reference voltage set to regulate the output voltage to a constant voltage in the charge control circuit 210 . For example, when the second reference voltage set in the charge control circuit 210 is 42V, the first reference voltage may be set to 44.5V higher than the second reference voltage.

The overcharge protection circuit 220 is enabled regardless of the operation of the charge control circuit 210 or the BMS operation of the battery pack 300 when the charging of the battery pack 300 is completed and the output voltage exceeds the first reference voltage. do.

The overcharge protection circuit 220 controls the operation of the charge control circuit 210 when the output voltage exceeds the first reference voltage due to a failure of some parts of the charge control circuit 210 or an abnormal operation of the BMS of the battery pack 300. It is enabled regardless of the BMS operation of the battery pack 300 .

The battery pack 300 includes a plurality of battery cells and a BMS 310 that manages the battery cells. For example, the BMS 310 may include a cell detection unit 312 that detects voltage or current of a battery cell, and a cell balance unit 314 that balances a plurality of battery cells according to a detection signal.

The battery pack 300 may be installed in an electric device such as an electric kickboard.

The wireless charging device 10 may be installed in an electric charging station for charging an electric device such as an electric kickboard.

2 is a circuit diagram of an overcharge protection circuit 220 and a wireless power receiver 200 including the same according to an embodiment.

Referring to FIG. 2, the wireless power receiver 200 includes a receiving antenna 202, a rectifier 204, a charge control circuit 210, an overcharge protection circuit 220, an output capacitor 230, and output terminals 240a and 240b ).

[Charging Control Circuit]

The charge control circuit 210 includes a converter 211, a voltage detection circuit 212, a current detection circuit 214, an amplifier 215, a first diode D1, a second diode D2, a controller 217 and A regulating switch 218 is included.

The converter 211 receives the input voltage VIN from the rectifier 204. The rectifier 204 receives a power signal wirelessly transmitted from the wireless power transmitter 100 through the receiving antenna 202, and provides an input voltage VIN obtained by rectifying the power signal to a DC voltage to the converter 211. .

The converter 211 converts the input voltage VIN provided through the rectifier 204 into an output voltage VOUT. For example, the converter 211 may be configured as a boost converter that converts DC/DC by boosting the input voltage VIN.

The voltage sensing circuit 212 senses the output voltage VOUT. For example, the voltage sensing circuit 212 may include resistor elements that voltage-divide the output voltage VOUT. Here, the resistance values of the resistance elements may be set to a value for outputting the output voltage VOUT as a preset constant voltage.

The signal detected through the voltage sensing circuit 212 is fed back to the converter 211 through the first diode D1 and is provided to the controller 217.

Current sensing circuit 214 senses the output current, and amplifier 215 amplifies a signal corresponding to the output current. The signal amplified by the amplifier 215 is fed back to the converter 211 through the second diode D2.

For example, the current sensing circuit 214 senses the current flowing across both ends of the resistive element, the amplifier 215 amplifies the signal difference between both ends of the resistive element, and converts the amplified signal through the second diode D2. (211).

The controller 217 controls the regulating switch 218 in response to a signal sensed through the voltage sensing circuit 212 . In one example, the controller 217 turns off the regulating switch 218 when a sensed signal indicating that the output voltage VOUT is higher than the second reference voltage is received.

The controller 217 controls the regulating switch 218 so that the converter 211 outputs the output voltage VOUT as a constant voltage. For example, the controller 217 turns on the regulating switch 218 when the output voltage VOUT is detected as 35V or less, and turns off the regulating switch 218 when detected as 42V or more.

The regulating switch 218 is turned on or off so that the output voltage VOUT is output as a constant voltage under the control of the controller 217 .

A second reference voltage for regulating the output voltage to a constant voltage may be set in the charge control circuit 210 . For example, the second reference voltage may be set to 42V, and the charge control circuit 210 may regulate the output voltage VOUT to be output in the range of 35V to 42V.

[Overcharge Protection Circuit]

The overcharge protection circuit 220 includes a protection circuit including a fuse 221 and a monitoring circuit 222 , a generating circuit 223 and a switching circuit 224 .

A fuse 221 is connected between the charge control circuit 210 and the output terminals 240a and 240b.

For example, the fuse 221 has one end connected to the charging control circuit 210 and the other end connected to the first output terminals 240a of the output terminals 240a and 240b. The fuse 221 protects the battery pack 300 from overcurrent, and a short circuit can be maintained by turning on the switching circuit 224 in case of overvoltage.

Here, the output terminals 240a and 240b include a first output terminal 240a and a second output terminal 240b, and the battery pack 300 of the electric kickboard is connected to the output terminals 240a and 240b.

The battery pack 300 includes a BMS 310 and a battery cell 320 . Here, the battery cell 320 may include a plurality of battery cells, and the BMS 310 detects the state of the plurality of battery cells, performs balancing of the battery cells according to the detection signal, and manages the state of the battery cells do.

The monitoring circuit 222 detects the output voltage VOUT of the output terminals 240a and 240b and outputs a monitoring signal to the generating circuit 223 when the output voltage VOUT exceeds a first reference voltage.

This monitoring circuit 222 includes a sensing circuit, a shunt regulator (SR) and a first output circuit.

The sensing circuit includes a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series between the first output terminal 240a and the second output terminal 240b to divide the voltage between the output terminals 240a and 240b.

Here, the resistance values of the first resistor R1 and the second resistor R2 are set to a value at which the overcharge protection circuit 220 is enabled when an overvoltage is detected.

For example, the first reference voltage set to detect the overvoltage of the output terminals 240a and 240b may be set to a higher level than the second reference voltage set to regulate the output voltage to a constant voltage in the charge control circuit 210. can

For example, when the second reference voltage is set to 42V in the charge control circuit 210, the first reference voltage may be set to 44.5V higher than the second reference voltage in the overcharge protection circuit 220.

The sensing circuit senses the voltages of the output terminals 240a and 240b through the first resistor R1 and the second resistor R2 and provides the sensing signal to the shunt regulator SR.

The shunt regulator SR receives a voltage-divided signal by the first resistor R1 and the second resistor R2 as a detection signal, and is turned on or off according to the detection signal. For example, when the output voltage VOUT exceeds the first reference voltage, the shunt regulator SR is turned on in response to a detection signal corresponding thereto.

The first output circuit includes a third resistor R3 and a fourth resistor R4. The third resistor R3 and the fourth resistor R4 are connected in series between the first output terminal 240a and the cathode terminal of the shunt regulator SR. The first output circuit outputs a signal voltage-divided by the third resistor R3 and the fourth resistor R4 as a monitoring signal to the generator circuit 223 when the shunt regulator SR is turned on.

As such, the monitoring signal is generated as the shunt regulator SR is turned on when the voltage of the output terminals 240a and 240b exceeds the first reference voltage and is provided to the generation circuit 223 .

Also, the monitoring circuit 222 may further include a Zener diode ZD between the shunt regulator SR and the fourth resistor R4 of the first output circuit. The zener diode ZD may be used when the output voltage VOUT supplied to the battery pack 300 is higher than the breakdown voltage of the shunt regulator SR.

For example, when the withstand voltage of the shunt regulator (SR) is 36V and the output voltage (VOUT) is 42V and is supplied to the battery pack 300, the zener diode (ZD) is connected to the shunt regulator (SR) and the fourth resistor of the first output circuit. (R4) may be connected between them.

Also, the monitoring circuit 222 may further include a first capacitor C1 and a second capacitor C2 for noise filtering.

The first capacitor C1 has one end connected between the gate terminal of the shunt regulator SR and the sensing circuit and the other end connected to the second output terminal 240b. The second capacitor C2 has one end connected between the base terminal of the first switch TR1 and the first output circuit and the other end connected to the first output terminal 240a.

And, the generating circuit 223 generates a control signal in response to the monitoring signal provided from the monitoring circuit 222 . This generation circuit 223 includes a first switch TR1 and a second output circuit.

The first switch TR is turned on in response to the monitoring signal. For example, the first switch TR1 may include a PNP transistor.

The second output circuit provides a control signal to the switching circuit 224 when the first switch TR1 is turned on. For example, the second output circuit may include a fifth resistor R5 and a sixth resistor R6 connected in series between the collector terminal of the first switch TR1 and the second output terminal 240b.

The generating circuit 223 may further include a third capacitor C3 for noise filtering. The third capacitor C3 has one end connected between the gate terminal of the thyristor THR and the second output circuit and the other end connected to the second output terminal 240b.

Also, the switching circuit 224 drops the output voltage VOUT of the output terminals 240a and 240b in response to the control signal provided from the generating circuit 223 . For example, the switching circuit 224 may include a thyristor THR that is turned on in response to a control signal and drops the output voltage VOUT.

The thyristor THR maintains a turn-on state in response to a control signal. For example, the thyristor THR may be turned on in response to a control signal generated when the voltage of the output terminals 240a and 240b is detected as an overvoltage higher than the first reference voltage, and turns on until the fuse 221 is blown. - Can stay on.

And, the overcharge protection circuit 220 may further include an output capacitor 230 connected in parallel with the output terminals 240a and 240b. A wired charging terminal 250 may be connected to the output terminals 240a and 240b.

The output capacitor 230 may be configured as a high-capacity capacitor so that the fuse 211 is not damaged by the wired charger when the wired charger is connected to the wired charging terminal 250 .

The overcharge protection circuit 220 protects the battery pack 300 in an overcurrent state through the fuse 211 . The overcharge protection circuit 220 is configured such that the fuse 211 is shorted in an overvoltage state of the output terminals 240a and 240b through the thyristor THR.

In addition, the overcharge protection circuit 220 precisely detects the voltage of the output terminals 240a and 240b through the shunt regulator SR, and when the voltage of the output terminals 240a and 240b exceeds the first reference voltage, the thyristor ( THR) can be turned on.

In addition, the overcharge protection circuit 220 can prevent the fuse 221 from being damaged due to a sudden inflow of current when a wired charger is connected through the output capacitor 230 .

As such, when the wireless power receiver 200 including the overcharge protection circuit 220 detects that the voltage of the output terminals 240a and 240b to which the battery pack 300 of the electric kickboard is connected is overvoltage, the output terminals 240a and 240b Since the voltage of the battery pack 300 is dropped, it is possible to protect the battery pack 300 from overcharging.

In addition, since the overcharge protection circuit 220 is enabled when the voltage of the output terminals 240a and 240b to which the battery pack 300 is connected is detected as overvoltage, the BMS 310 of the battery pack 300 or the charge control circuit 210 ) and can operate independently.

In addition, the overcharge protection circuit 220 drops the voltage of the output terminals 240a and 240b when an overvoltage occurs even if a failure occurs in the BMS 310 of the battery pack 300 or some parts of the charge control circuit 210 to prevent overcharging. The battery pack 300 can be safely protected from

In addition, since the overcharge protection circuit 220 is installed in the wireless power receiver 200 that supplies power to the battery pack 300, it is possible to eliminate the possibility of malfunction due to a surge or the like on the power supply side.

In addition, the overcharge protection circuit 220 blocks overcharging of the battery pack 300 even when the BMS 310 of the battery pack 300 or some parts of the charge control circuit 210 fail, thereby preventing fire or explosion that may occur during charging. Accidents can be prevented.

3 is a circuit diagram of an overcharge protection circuit 420 and a wireless power receiver 200 including the same according to another embodiment.

The wireless power receiver 200 includes a charge control circuit 210, an overcharge protection circuit 420, and output terminals 240a and 240b. A description of the charge control circuit 210 and the same configuration is replaced with the description of FIG. 2 .

The overcharge protection circuit 420 includes a fuse 421 and a protection circuit including a monitoring circuit 422 and a switching circuit 424 .

A fuse 421 is connected between the charge control circuit 210 and the output terminals 240a and 240b. For example, the fuse 421 has one end connected to the charging control circuit 210 and the other end connected to the first output terminals 240a of the output terminals 240a and 240b.

The monitoring circuit 422 detects voltages of the output terminals 240a and 240b and provides a monitoring signal to the switching circuit 424 when the voltages of the output terminals 240a and 240b exceed a first reference voltage.

The monitoring circuit 422 includes a sensing circuit, a shunt regulator (SR) and a first output circuit. The sensing circuit includes a first resistor R1 and a second resistor R2 connected in series between the first output terminal 240a and the second output terminal 240b.

The sensing circuit generates a sensing signal by dividing the voltage of the output terminals 240a and 240b and provides the sensing signal to the shunt regulator SR. The shunt regulator SR is turned on in response to a detection signal corresponding to the output voltage VOUT exceeding the first reference voltage.

The switching circuit 424 drops the voltage of the output terminals 240a and 240b in response to the monitoring signal provided from the monitoring circuit 422 .

The switching circuit 424 is turned on by the second switch TR2 which is turned on in response to the monitoring signal and the second switch TR2 is turned on to drop the voltage of the output terminals 240a and 240b. and a third switch TR3 for

For example, the second switch TR2 may include an NMOS transistor, and the third switch TR3 may include a PMOS transistor.

FIG. 4 is a diagram showing a semiconductor structure of the switching circuit 424 shown in FIG. 3 .

3 and 4, the switching circuit 424 includes a second switch TR2 and a third switch TR3, the second switch TR2 is composed of an NMOS transistor, and the third switch TR3 ) is composed of PMOS transistors.

The NMOS transistor of the second switch TR2 has a source terminal connected to the first output terminal 240a, a gate terminal connected to the monitoring circuit 422, and a drain terminal connected to the third switch TR3.

The PMOS transistor of the third switch TR3 has a source terminal connected to the gate terminal of the NMOS transistor, a gate terminal connected to the drain terminal of the NMOS transistor, and a source terminal connected to the second output terminal 240b.

In the switching circuit 424, when the monitoring signal is provided from the monitoring circuit 422, the NMOS transistor is turned on, and the PMOS transistor is turned on when the NMOS transistor is turned on, thereby dropping the voltage of the output terminals 240a and 240b. can

As such, the switching circuit 424 may have a simplified structure through an NMOS transistor and a PMOS transistor that are turned on in response to a monitoring signal.

As described above, the overcharge protection circuit 420 drops the voltage of the output terminals 240a and 240b when the voltage of the output terminals 240a and 240b is detected as an overvoltage exceeding the first reference voltage, thereby reducing the voltage of the output terminals 240a and 240b. 240b) can prevent overcharging of the battery pack 300 of the electric kickboard.

Meanwhile, although not shown in FIG. 3 , the overcharge protection circuit 420 may further include output capacitors having a large capacity at the output terminals 240a and 240b. The output capacitor prevents the fuse, the overcharge protection circuit 220, or the charge control circuit 210 from being damaged by a surge when the battery pack 300 is connected to the output terminals 240a and 240b.

5 illustrates a wireless charging system to which the wireless charging device 10 according to an embodiment is applied.

Referring to FIG. 5 , the wireless charging device 10 may be applied to a charging station for charging an electric kickboard.

For example, the wireless charging device 10 may include one wireless power transmitter 100 and a plurality of wireless power receivers 200-1, 200-2, and 200-n. A plurality of battery packs 300-1, 300-2, and 300-n corresponding to a plurality of electric kickboards may be connected to the plurality of wireless power receivers 200-1, 200-2, and 200-n. .

Also, the plurality of wireless power receivers 200-1, 200-2, and 200-n may include the overcharge protection circuits 220 and 420 described in FIGS. 2 and 3.

The wireless power transmitter 100 may wirelessly transmit power to each of the wireless power receivers 200-1, 200-2, and 200-n. The wireless power transmitter 100 may wirelessly transmit power to an authenticated wireless power receiver through a preset authentication procedure. For example, the wireless power transmitter 100 may transmit power to a plurality of wireless power receivers 200-1, 200-2, and 200-n through a resonance method.

The wireless power transmitter 100 and the wireless power receivers 200-1, 200-2, and 200-n may form a wireless communication connection for bi-directional communication. For example, the wireless power transmitter 100 and the wireless power receivers 200-1, 200-2, and 200-n may process or transmit/receive packet data including data and control data.

The wireless power receivers 200-1, 200-2, and 200-n transmit data including a signal requesting wireless power transmission, information necessary for wireless power reception, status information of wireless power receivers, etc. to the wireless power transmitter ( 100) can be sent.

Each of the wireless power receivers 200-1, 200-2, and 200-n may transmit data indicating a charging state to the wireless power transmitter 100.

The wireless power transmitter 100 may include a display unit, and based on data received from the wireless power receivers 200-1, 200-2, and 200-n, respectively, the wireless power receivers 200-1 and 200-n. 2, 200-n) Each state can be displayed. In addition, the wireless power transmitter 100 may display an estimated time until charging of the respective wireless power receivers 200-1, 200-2, and 200-n is completed.

The wireless power transmitter 100 may transmit a control signal to disable the wireless charging function to each of the wireless power receivers 200-1, 200-2, and 200-n. The wireless power receivers 200-1, 200-2, and 200-n may receive a control signal to disable the wireless charging function from the wireless power transmitter 100 to disable the wireless charging function.

On the other hand, the embodiments exemplify charging the electric kickboard, but are not limited thereto. It can be applied to a powertrain in which a battery pack including a plurality of battery cells is mounted.

As an example, the embodiments may be applied to wired and wireless charging devices of charging stations for charging electric vehicles or portable power devices. The embodiments may be applied to preventing a fire or explosion by preventing an abnormal increase in voltage of an output stage when overcharging, a failure of some parts of a charging control circuit, or a failure of a BMS.

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operational effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be recognized.

10: wireless charging device 100: wireless power transmitter
200: wireless power receiver 202: receiving antenna
204: rectifier
210: charge control circuit 211: converter
212: voltage sensing circuit D1: first diode
214 current sensing circuit 215 amplifier
D2: second diode 217: controller
218: regulating switch
220 overcharge protection circuit 221 fuse
222: monitoring circuit R1: first resistor
R2: second resistor C1: first capacitor
SR: shunt regulator ZD: zener diode
R3: 3rd resistor R4: 4th resistor
C2: second capacitor
223 generating circuit TR1 first switch
R5: fifth resistor R6: sixth resistor
C3: third capacitor
224: switching circuit THR: thyristor
230: output capacitor
240: output stage
250: wired charging terminal
300: battery pack 310: battery management system
312: cell detection unit 314: cell balance unit
320: battery cell
420: overcharge protection circuit TR2: second switch
TR3: third switch

Claims (20)

an output terminal connected to the battery pack;
a charge control circuit for controlling charging of the battery pack by outputting a constant voltage to the output terminal; and
A wireless power receiver comprising an overcharge protection circuit that detects the voltage of the output terminal and protects the battery pack from overcharging by lowering the voltage of the output terminal when the voltage of the output terminal exceeds a first reference voltage. According to claim 1,
The first reference voltage is set to a level higher than the second reference voltage set to regulate the voltage of the output terminal to a constant voltage in the charging control circuit. According to claim 2,
The overcharge protection circuit is enabled when the voltage of the output terminal exceeds the first reference voltage regardless of the operation of the charge control circuit and a battery management system (BMS) of the battery pack Wireless power receiver . According to claim 1,
The overcharge protection circuit,
a fuse connected between the charge control circuit and the output terminal;
a monitoring circuit that detects a voltage of the output terminal and outputs a monitoring signal when the voltage of the output terminal exceeds the first reference voltage;
a generating circuit for generating a control signal in response to the monitoring signal; and
A wireless power receiver comprising a switching circuit for stepping down the voltage of the output terminal in response to the control signal. According to claim 4,
The monitoring circuit,
a sensing circuit dividing and sensing the voltage of the output terminal;
a shunt regulator turned on when the voltage of the output terminal is detected to exceed the first reference voltage through the detection circuit; and
A wireless power receiver comprising a first output circuit outputting the monitoring signal to the generating circuit by shorting the shunt regulator. According to claim 5,
The wireless power receiver further comprising a zener diode between the shunt regulator and the first output circuit. According to claim 4,
The generating circuit,
a first switch turned on in response to the monitoring signal; and
A wireless power receiver comprising a second output circuit outputting the control signal to the switching circuit by turning on the first switch. According to claim 4,
The switching circuit is a wireless power receiver including a thyristor that is turned on in response to the control signal to drop the voltage of the output terminal. According to claim 1,
Wireless power receiver further comprising an output capacitor connected in parallel with the output terminal. According to claim 1,
The overcharge protection circuit,
a fuse connected between the charge control circuit and the output terminal;
a monitoring circuit that detects a voltage of the output terminal and outputs a monitoring signal when the voltage of the output terminal exceeds the first reference voltage; and
A wireless power receiver comprising a switching circuit for stepping down the voltage of the output terminal in response to the monitoring signal. According to claim 10,
The switching circuit,
a second switch turned on in response to the monitoring signal; and
A wireless power receiver comprising a third switch that is turned on by the turn-on of the second switch and drops the voltage of the output terminal. A wireless power transmitter that converts commercial power into a power signal having a wireless power transmission frequency and transmits the converted power signal; and
A wireless power receiver receiving the power signal from the wireless power transmitter, converting the power signal into an output voltage, and supplying it to a battery pack;
The wireless power receiver,
an output terminal connected to the battery pack;
a charge control circuit for controlling charging of the battery pack by outputting a constant voltage to the output terminal; and
A wireless charging device comprising an overcharge protection circuit that detects the voltage of the output terminal and protects the battery pack from overcharging by lowering the voltage of the output terminal when the voltage of the output terminal exceeds a first reference voltage. According to claim 12,
The first reference voltage is set to a level higher than the second reference voltage set to regulate the voltage of the output terminal to a constant voltage in the charge control circuit wireless charging device. According to claim 13,
The overcharge protection circuit is enabled when the voltage of the output terminal exceeds the first reference voltage regardless of the operation of the charge control circuit and the BMS of the battery pack. According to claim 12,
The overcharge protection circuit,
a fuse connected between the charge control circuit and the output terminal;
a monitoring circuit that detects a voltage of the output terminal and outputs a monitoring signal when the voltage of the output terminal exceeds the first reference voltage;
a generating circuit for generating a control signal in response to the monitoring signal; and
A wireless charging device comprising a switching circuit for stepping down the voltage of the output terminal in response to the control signal. According to claim 15,
The monitoring circuit,
a sensing circuit dividing and sensing the voltage of the output terminal;
a shunt regulator turned on when the voltage of the output terminal exceeds the first reference voltage; and
and a first output circuit outputting the monitoring signal to the generating circuit by shorting the shunt regulator. a fuse provided between an output terminal and a charge control circuit, to which a battery pack is connected to the output terminal, and wherein the charge control circuit controls charging of the battery pack by outputting a constant voltage to the output terminal; and
Overcharge protection of a wireless power receiver including a protection circuit that detects the voltage of the output terminal and protects the battery pack from overcharging by lowering the voltage of the output terminal when the voltage of the output terminal exceeds a first reference voltage Circuit. 18. The method of claim 17,
The first reference voltage is set to a level higher than the second reference voltage set to regulate the voltage of the output terminal to a constant voltage in the charge control circuit;
The protection circuit is enabled when the voltage of the output terminal exceeds the first reference voltage regardless of the operation of the charge control circuit and the BMS of the battery pack. 18. The method of claim 17,
The protection circuit,
a monitoring circuit that detects a voltage of the output terminal and outputs a monitoring signal when the voltage of the output terminal exceeds the first reference voltage;
a generating circuit for generating a control signal in response to the monitoring signal; and
An overcharge protection circuit of a wireless power receiver comprising a switching circuit that drops the voltage of the output terminal in response to the control signal. 18. The method of claim 17,
The protection circuit,
a monitoring circuit that detects a voltage of the output terminal and outputs a monitoring signal when the voltage of the output terminal exceeds the first reference voltage; and
An overcharge protection circuit of a wireless power receiver comprising a switching circuit that drops the voltage of the output terminal in response to the monitoring signal.

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