# US 2017/0288458 A1 · Wireless power transmitter and method of controlling the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288458 A1 - Document ID: US20170288458A1 - Status: Published application - Kind: A1 - Application number: 15/298,881 - Filed: 2016-10-20 - Published: 2017-10-05 - Earliest claimed: 2016-03-31 - Assignees: Samsung Electro-Mechanics Co., Ltd. - Applicants: Samsung Electro-Mechanics Co., Ltd. - Inventors: Tae Won LEE; Young Hyok JI; Seung Hee LEE - Web page: https://patentgrep.com/patent/US20170288458A1 ## CPC - H02J 50/12: of the resonant type - H02J 50/10: using inductive coupling - H02J 50/90: involving detection or optimisation of position, e.g. alignment - H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries - H02J 7/42: with electronic devices having internal batteries, e.g. mobile phones - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A wireless power transmitter includes a resonator configured to transmit a detection signal; a period detector configured to detect a period of oscillation of an oscillation signal caused by remnants of the detection signal; and a controller configured to determine whether an external charging object is approaching in response to a change in the period of the oscillation signal. ## Claims ### Claim 1 A wireless power transmitter, comprising: a resonator configured to transmit a detection signal; a period detector configured to detect a period of oscillation of an oscillation signal caused by remnants of the detection signal; and a controller configured to determine whether an external charging object is approaching in response to a change in the period of the oscillation signal. ### Claim 2 (depends on 1) The wireless power transmitter of claim 1, wherein the resonator is further configured to transmit the detection signal as a substantially sine shaped wave, at a substantially constant frequency, and the period detector is further configured to detect the period of the self-induced oscillation signal caused in the resonator by the detection signal after transmitting the detection signal. ### Claim 3 (depends on 1) The wireless power transmitter of claim 1, wherein the controller is further configured to determine that the external charging object is approaching in response to another period of a self-induced oscillation signal caused by remnants of another detection signal, transmitted after the detection signal, being longer than the period of the oscillation signal caused by the detection signal. ### Claim 4 (depends on 1) The wireless power transmitter of claim 1, wherein the period detector is further configured to detect a period of a first waveform of the oscillation signal, and determine that the external charging object is approaching in response to the period of the first waveform changing. ### Claim 5 (depends on 1) The wireless power transmitter of claim 1, wherein the period detector is further configured to compare the oscillation signal caused by the detection signal with a reference value to generate a pulse signal substantially corresponding to the oscillation signal. ### Claim 6 (depends on 5) The wireless power transmitter of claim 5, wherein the controller is further configured to receive the pulse signal corresponding to the oscillation signal from the period detector, and determine that the external charging object is approaching in response to a detected change in a pulse width of the pulse signal. ### Claim 7 (depends on 5) The wireless power transmitter of claim 5, wherein the period detector comprises: a voltage divider connected to the resonator and configured to divide a voltage level of an output signal of the resonator at a constant ratio; and a comparator configured to compare an output of the voltage divider with the reference value to generate the pulse signal. ### Claim 8 A method of controlling a wireless power transmitter, the method comprising: generating a detection signal; detecting a period of oscillation of an oscillation signal caused by remnants of the detection signal; and determining whether an external charging object is approaching in response to a change in the period of the oscillation signal. ### Claim 9 (depends on 8) The method of claim 8, wherein the detection signal is generated to be a resonance signal which is transmitted at a constant frequency through a resonator, and the detecting of the period of the oscillation signal comprises detecting the oscillation signal caused in the resonator by the detection signal, after transmitting the detection signal. ### Claim 10 (depends on 8) The method of claim 8, wherein the determining of whether the external charging object is approaching comprises: detecting the period of the oscillation signal caused by the detection signal; detecting another period of another oscillation signal caused by another detection signal transmitted after the detection signal; and determining that the external charging object is approaching in response to the other period being longer than the period. ### Claim 11 (depends on 8) The method of claim 8, wherein the detecting of the period of the oscillation signal comprises: detecting a period of a first waveform of the oscillation signal. ### Claim 12 (depends on 11) The method of claim 11, wherein the determining of whether the external charging object is approaching comprises: determining that the external charging object is approaching in response to the period of the first waveform of the oscillation signal changing. ### Claim 13 (depends on 8) The method of claim 8, wherein the detecting of the period of the oscillation signal comprises: comparing the oscillation signal with a preset reference value; outputting a voltage having a first level in response to the oscillation signal being greater than the reference value; outputting a voltage having a second level in response to the oscillation signal being equal to the reference value or less; and time-continuously outputting the voltage having the first level or the voltage having the second level to generate a pulse signal corresponding to the oscillation signal. ### Claim 14 (depends on 13) The method of claim 13, wherein the determining of whether the external charging object is approaching comprises: determining that the external charging object is approaching in response to a detected change in a pulse width of the pulse signal. ### Claim 15 A wireless power transmitter, comprising: a resonator configured to transmit a detection signal; and, a detector coupled to the resonator, the detector being configured to detect a change in an oscillation of the resonator after conclusion of provision of the detection signal to the resonator. ### Claim 16 (depends on 15) The wireless power transmitter of claim 15, wherein the oscillation of the resonator is a self-induced oscillation. ### Claim 17 (depends on 15) The wireless power transmitter of claim 15, further comprising: a power supply coupled to the resonator, and wherein the detector is further configured to detect substantially concurrent inactivity between the power supply and the resonator, and changing period of the oscillation of the resonator. ### Claim 18 (depends on 15) The wireless power transmitter of claim 15, further comprising: a controller configured to provide the detection signal to the resonator, to initiate wireless power transfer to an external wireless power receiver via actuation of the resonator in response to the detected change in the oscillation of the resonator after conclusion of provision of the detection signal from the controller. ### Claim 19 (depends on 18) The wireless power transmitter of claim 18, wherein the controller is further configured to indicate to the detector that provision of the detection signal to the resonator has concluded, and the detector is further configured to detect the change in period of the oscillation in the resonator after receiving the indication from the controller that the provision of the detection signal has concluded.