Wireless charging device, a receiver device, and a method of operating the same
A wireless charging device includes a driver unit configured to generate one of a first AC voltage signal having a first frequency and a second AC voltage signal having a second frequency. Also, the wireless charging device includes a transmitting unit having a first coil and a first capacitor and configured to transmit the first AC voltage signal. Further, the transmitting unit includes a second coil and a second capacitor and configured to transmit the second AC voltage signal. Additionally, the wireless charging device includes a control unit configured to detect a first receiver device operating at the first frequency based on a change in a first voltage in the transmitting unit, and detect a second receiver device operating at the second frequency based on a change in a second voltage in the transmitting unit.
1. A wireless charging device comprising:
a driver unit to generate an alternating current (AC) voltage signal;
a transmitting unit including a first coil to transmit the AC voltage signal; and
a control unit configured to:
cause the driver unit to generate the AC voltage signal according to a selected one of a first frequency standard and a second frequency standard during a first time period;
detect a change, greater than a threshold value, in a voltage at the first coil during the first time period;
confirm a presence of a receiver device based on a duration of the change being a predefined time period; and
cause the driver unit and the transmitting unit to transmit the AC voltage signal according to the first frequency standard or the second frequency standard based on the change occurring while the driver unit is generating the AC voltage signal according to the first frequency standard or the second frequency standard, respectively.
2. The wireless charging device of claim 1 , wherein the transmitting unit includes a first capacitor and the first coil, and wherein the control unit is further configured to:
monitor the voltage at a junction between the first coil and the first capacitor during the first time period.
3. The wireless charging device of claim 1 , wherein the control unit includes:
a peak detecting unit to measure the voltage at a junction between the first coil and a first capacitor; and
a comparator coupled with first peak detecting unit and designed produce a first signal when the measured voltage is greater than the threshold value.
4. The wireless charging device of claim 1 , wherein the control unit is configured to:
determine that a foreign object is present based on the duration of the change being greater than the predefined time period; and
control the driver unit to stop transmitting the AC voltage signal based on a determination that the foreign object is present.
5. The wireless charging device of claim 1 , wherein the control unit is further configured to:
after confirming the presence of the receiver device, cause the driver unit to continuously transmit the AC voltage signal to the receiver device while the presence of the receiver device is confirmed.
6. The wireless charging device of claim 5 , wherein the control unit is further configured to:
repeatedly confirm the presence of the receiver device based on changes in the voltage being greater than the threshold value for the predefined time period within respective time intervals.
7. The wireless charging device of claim 6 , wherein the control unit is further configured to:
cause the driver unit to stop transmitting the AC voltage signal when the change becomes less than the threshold value in a time interval.
8. The wireless charging device of claim 1 , further comprising:
the driver unit to generate the AC voltage signal having a first frequency of the first frequency standard for the first time period and generate the AC voltage signal having a second frequency of the second frequency standard for a second time period; and
the transmitting unit including the first coil to transmit the AC voltage signal having the first frequency and a second coil to transmit the AC voltage signal having the second frequency.
9. A wireless charging device comprising:
a driver unit to generate an alternating current (AC) voltage signal;
a transmitting unit including a capacitor and a coil to transmit the AC voltage signal; and
a control unit configured to:
cause the driver unit to generate the AC voltage signal according to a selected one of a first frequency standard and a second frequency standard during a time period;
detect a change, greater than a threshold value, in a voltage at a junction between the capacitor and the coil during the time period;
determine that a receiver device or a foreign object is present based on the change;
distinguish between the receiver device and the foreign object based on a duration of the change; and
determine that the receiver device is configured for a particular one of the first frequency standard or the second frequency standard based on the change occurring while the driver unit is generating the AC voltage signal according to the first frequency standard or the second frequency standard, respectively.
10. The wireless charging device of claim 9 , wherein the control unit is configured to:
confirm a presence of the receiver device based on the duration of the change being a predefined time period; and
determine that the foreign object is present based on the duration of the change being more than the predefined time period.
11. The wireless charging device of claim 10 , wherein the control unit is configured to control the driver unit to stop transmitting the AC voltage signal based on a determination that the foreign object is present.
12. The wireless charging device of claim 10 , wherein the control unit is further configured to:
after confirming the presence of the receiver device, cause the driver unit to continuously transmit the AC voltage signal to the receiver device while the presence of the receiver device is confirmed.
13. The wireless charging device of claim 12 , wherein the control unit is further configured to:
repeatedly confirm the presence of the receiver device based on changes in the voltage being greater than the threshold value for the predefined time period within respective time intervals.
14. A method of a wireless charging device, the method comprising:
generating, by a driver unit, an alternating current (AC) voltage signal according to a selected one of a first frequency standard and a second frequency standard for a first time period;
transmitting, by a first coil and a first capacitor in a transmitting unit, the AC voltage signal;
detecting a change, greater than a threshold value, in a voltage at the first coil during the first time period;
confirming a presence of a receiver device based on a duration of the change being a predefined time period; and
transmitting the AC voltage signal according to the first frequency standard or the second frequency standard based on the change occurring while the driver unit is generating the AC voltage signal according to the first frequency standard or the second frequency standard, respectively.
15. The method of claim 14 , further comprising:
measuring the voltage at a junction between the first coil and the first capacitor during the first time period.
16. The method of claim 14 , further comprising:
determining that a foreign object is present based on the duration of the change being more than the predefined time period; and
causing the driver unit to stop transmitting the AC voltage signal based on a determination that the foreign object is present.
17. The method of claim 14 , further comprising:
after confirming the presence of the receiver device, causing the driver unit to continuously transmit the AC voltage signal to the receiver device while the presence of the receiver device is confirmed.
18. The method of claim 17 , further comprising:
repeatedly confirming the presence of the receiver device based on changes in the voltage being greater than the threshold value for the predefined time period within respective time intervals.
19. The method of claim 18 , further comprising:
causing the driver unit to stop transmitting the AC voltage signal when the change becomes less than the threshold value in a time interval.
20. The method of claim 14 , further comprising:
generating, by the driver unit, the AC voltage signal having a first frequency of the first frequency standard for the first time period and the AC voltage signal having a second frequency of the second frequency standard for a second time period;
transmitting the AC voltage signal having the first frequency using the first coil and the first capacitor during the first time period; and
transmitting the AC voltage signal having the second frequency using a second coil and a second capacitor during the second time period.