Apparatus and method of protecting power receiver of wireless power transmission system

1. A wireless power receiver comprising:

a rectifier comprising an input and an output, and configured to receive a power through the input, to rectify the power to produce a rectified power, and to output the rectified power through the output;

a capacitor connected to the output of the rectifier and to ground;

a direct current-to-direct current (DC/DC) converter connected to the output of the rectifier and to a load, and configured to convert the rectified power to a converted power, and to provide the converted power to the load;

a switch unit connected to the input of the rectifier;

a protection unit configured to control the switch unit to open or close based on a voltage of the rectified power;

wherein the converted power changes the load, and

wherein the protection unit is further configured to generate a switch control signal to comprise a first value when the load is being charged, and a second value when the load is fully charged; and

a communication/control unit configured to

receive, from the protection unit, the switch control signal, and

transmit, to a wireless power transmitter that transmits the power to the rectifier, a power transmission suspension signal when the switch control signal changes between the first value and the second value, an N number of times, N being an integer greater than or equal to 2.

2. The wireless power receiver of claim 1 , wherein the protection unit comprises:

a voltage adjustor configured to adjust a voltage of the converted power to generate a first comparator input signal;

a first voltage divider configured to divide the voltage of the rectified power to generate a second comparator input signal;

a comparator configured to compare the first comparator input signal and the second comparator input signal, and to output a comparator output signal based on a result the comparison; and

a second voltage divider configured to divide a voltage of the comparator output signal to generate the switch control signal to control the switch unit to open or close.

3. The wireless power receiver of claim 2 , wherein:

the comparator comprises

a positive input connected to the first voltage divider to receive the second comparator input signal,

a negative input connected to the voltage adjustor to receive the first comparator input signal, and

an output to output the comparator output signal;

the first voltage divider comprises

a first resistor connected to the positive input of the comparator and to the output of the rectifier, and

a second resistor connected to the positive input of the comparator and to the ground; and

the second voltage divider comprises

a third resistor connected to the switch unit and to the output of the comparator, and

a fourth resistor connected to the output of the comparator and to the ground.

4. The wireless power receiver of claim 1 , wherein:

the protection unit is further configured to control the switch unit to close when the voltage of the rectified power is less than a threshold, to enable the rectifier to receive the power through the switch unit and the input; and

the protection unit is further configured to control the switch unit to open when the voltage of the rectified power is greater than the threshold, to block the rectifier from receiving the power through the switch unit and the input.

5. The wireless power receiver of claim 1 , wherein the switch unit comprises a p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET) switch.

6. The wireless power receiver of claim 1 , wherein:

the converted power charges the load;

the protection unit is further configured to output the switch control signal to control the switch unit to close while the load is being charged; and

the protection unit is further configured to output the switch control signal to control the switch unit to open when the load is fully charged.

7. A method of receiving a wireless power, comprising:

rectifying a power received from a resonator;

converting the rectified power to a converted power;

providing the converted power to a load;

providing or blocking the rectifying of the power, by a switch control signal, based on a voltage of the rectified power,

wherein the converted power charges the load, and

wherein the switch control signal comprises a first value when the load is being charged, and a second value when the load is fully charged; and

transmitting, to a wireless power transmitter that transmits the power to the resonator, a power transmission suspension signal when the number of times the switch control signal changes is greater than or equal to N, N being an integer greater than or equal to 2.

8. The method of claim 7 , wherein the providing or blocking of the rectifying of the power comprises:

adjusting a voltage of the converted power to generate a first comparator input signal;

dividing a voltage of the rectified power to generate a second comparator input signal;

comparing the first comparator input signal and the second comparator input signal to output a comparator output signal based on a result the comparison; and

dividing a voltage of the comparator output signal to generate the switch control signal to provide or block the rectifying of the power.

9. A non-transitory computer-readable storage medium storing a program comprising instructions to cause a computer to perform the method of claim 7 .