Charging device, power receiving device, and method
Attenuation of transmission power transmitted from a power transmission coil according to distance causes a problem that a power receiving device such as a smartphone with an accessory cover may increase a difference from reception power received by a power reception coil and prevent normal charging. Therefore, provided is a charging device including, for example, a transmission unit that periodically transmits a response request, a reception unit that receives a response to the response request from a power receiving device, a determination unit that determines whether a power intensity of the response request received by the power receiving device, indicated by the response, is equal to or less than a predetermined threshold, and a power control unit that increases output power of the response request when it is determined that the power intensity is equal to or less than the predetermined threshold.
1 . A charging device comprising:
circuitry configured to
periodically transmit a response request;
receive a response to the response request from a power receiving device;
under a condition the response is not received, periodically increase output power until the response is received;
under another condition in which the output power has been increased to a first threshold, periodically reduce the output power until the response is received;
under a further condition in which the output power is reduced to a second threshold, periodically increase the output power until the response is received;
determine whether power intensity of the response request received by the power receiving device, indicated by the response, is equal to or less than a predetermined threshold; and
periodically increase or decrease the output power until the response is received that indicates the power intensity higher than the predetermined threshold.
2 . The charging device according to claim 1 , wherein the response is a signal strength packet (SSP).
3 . The charging device according to claim 1 , wherein the circuitry is configured to extract a signal strength value from the response.
4 . A wireless charging system comprising:
a power receiving device; and
a charging device, wherein
the power receiving device includes circuitry configured to detect application of an accessory cover,
under a condition the application of the accessory cover is detected, adjust a foreign object detection (FOD) parameter,
calculate reception power based on the FOD parameter, and
convey the reception power to the charging device; and
the charging device includes circuitry configured to
receive the reception power from the power receiving device,
determine whether a power intensity indicated by the reception power is equal to or less than a predetermined threshold, and
periodically increase or decrease an output power until the received reception power indicates the power intensity higher than the predetermined threshold.
5 . The wireless charging system of claim 4 , wherein the circuitry of the power receiving device is configured to adjust the FOD parameter so as not to erroneously detect a state where the accessory cover is applied but recognized as a foreign object.
6 . The wireless charging system according to claim 4 , wherein the reception power is conveyed in a signal strength packet (SSP).
7 . The wireless charging system according to claim 4 , wherein the circuitry of the charging device is configured to extract a signal strength value from the reception power.
8 . The wireless charging system according to claim 4 , wherein the circuitry of the power receiving device is configured to calculate the reception power by adding an offset value to a measured power value, the offset value being determined based on the FOD parameter.
9 . The wireless charging system according to claim 4 , wherein the circuitry of the power receiving device is configured to convey the reception power to the charging device at a periodic interval during a power transfer phase.
10 . A wireless charging system comprising:
a power receiving device; and
a charging device, wherein:
the power receiving device includes
a display configured to display a user interface (UI) that is configured to receive as input an application/non-application of an accessory cover;
an input interface configured to receive an input of the application/non-application of the accessory cover input via the UI;
a sensor configured to detect the application of the accessory cover, under a condition the input indicates the accessory cover is applied; and
circuitry configured to
adjust, under a condition the accessory cover is detected as being applied, a foreign object detection (FOD) parameter,
calculate reception power based on the FOD parameter, and
convey the reception power to the charging device; and
the charging device includes circuitry configured to
receive the reception power from the power receiving device,
determine whether a power intensity indicated by the reception power is equal to or less than a predetermined threshold, and
periodically increase or decrease an output power until the received reception power indicates the power intensity higher than the predetermined threshold.
11 . The wireless charging system of claim 10 , wherein the circuitry of the power receiving device is configured to adjust the FOD parameter so as not to erroneously detect a state where the accessory cover is applied but recognized as a foreign object.
12 . The wireless charging system according to claim 10 , wherein the reception power is conveyed in a signal strength packet (SSP).
13 . The wireless charging system according to claim 10 , wherein the circuitry of the charging device is configured to extract a signal strength value from the reception power.
14 . The wireless charging system according to claim 10 , wherein the circuitry of the power receiving device is configured to calculate the reception power by adding an offset value to a measured power value, the offset value being determined based on the FOD parameter.
15 . The wireless charging system according to claim 10 , wherein the sensor is a Hall effect sensor.
16 . The wireless charging system according to claim 10 , wherein the circuitry of the power receiving device is configured to convey the reception power to the charging device at a periodic interval during a power transfer phase.