Wireless Charging System With Metallic Object Detection
First Claim
1. A wireless power transmitting device with a charging surface configured to receive a wireless power receiving device that has a wireless power receiving coil, the wireless power transmitting device comprising:
- a coil;
wireless power transmitting circuitry coupled to the coil and configured to transmit wireless power signals with the coil;
impulse response measurement circuitry coupled to the coil; and
control circuitry configured to;
control the wireless power transmitting circuitry to supply a first impulse signal at a first maximum power level to the coil;
measure an impulse response of the coil with the impulse response measurement circuitry;
detect whether a metal foreign object is present on the charging surface based on the measured impulse response; and
control the wireless power transmitting circuitry to supply a second impulse signal at a second maximum power level to the coil in response to detecting that the metal foreign object is present on the charging surface, wherein the second maximum power level is different from the first maximum power level.
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Accused Products
Abstract
A wireless power transmission system has a wireless power receiving device that is located on a charging surface of a wireless power transmitting device. The receiving device has a wireless power receiving coil and the transmitting device has a wireless power transmitting coil array. Control circuitry in the transmitting device uses inverter circuitry to supply alternating-current signals the coil array, thereby transmitting wireless power signals. Measurement circuitry coupled to the coil array makes impulse response measurements while the control circuitry uses the inverter circuitry to apply impulse signals to each of the coils. The control circuitry analyzes output from the measurement circuitry to detect the presence of a metal foreign object on the charging surface. In response to such a detection, the control circuitry reduces the power of subsequent impulse signals to minimize physical vibration and audible noise generated in the system by the metal foreign object.
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Citations
20 Claims
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1. A wireless power transmitting device with a charging surface configured to receive a wireless power receiving device that has a wireless power receiving coil, the wireless power transmitting device comprising:
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a coil; wireless power transmitting circuitry coupled to the coil and configured to transmit wireless power signals with the coil; impulse response measurement circuitry coupled to the coil; and control circuitry configured to; control the wireless power transmitting circuitry to supply a first impulse signal at a first maximum power level to the coil; measure an impulse response of the coil with the impulse response measurement circuitry; detect whether a metal foreign object is present on the charging surface based on the measured impulse response; and control the wireless power transmitting circuitry to supply a second impulse signal at a second maximum power level to the coil in response to detecting that the metal foreign object is present on the charging surface, wherein the second maximum power level is different from the first maximum power level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A wireless power transmitting device with a charging surface configured to receive a wireless power receiving device that has a wireless power receiving coil, the wireless power transmitting device comprising:
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a coil; wireless power transmitting circuitry coupled to the coil and configured to transmit wireless power signals with the coil; impulse response measurement circuitry coupled to the coil; and control circuitry configured to; control the wireless power transmitting circuitry to supply impulse signals at a first maximum power level to the coil, wherein the impulse signals generate impulse responses on the coil; gather measurements of the impulse responses on the coil with the impulse response measurement circuitry; determine whether the gathered measurements have changed over time; and control the wireless power transmitting circuitry to supply an additional impulse signal at a second maximum power level to the coil in response to determining that the gathered measurements have changed over time, wherein the second maximum power level is greater than the first maximum power level. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A wireless power transmitting device configured to transmit wireless power signals to a wireless power receiving device, the wireless power transmitting device comprising:
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a coil; inverter circuitry coupled to the coil and configured to transmit the wireless power signals with the coil; impulse response measurement circuitry coupled to the coil; and control circuitry configured to; provide a first control signal to the inverter circuitry using a first duty cycle, wherein the first control signal controls the inverter circuitry to supply a first impulse signal to the coil; measure a response of the coil to the first impulse signal with the impulse response measurement circuitry; and provide a second control signal to the inverter circuitry using a second duty cycle that is different than the first duty cycle based on the measured response of the coil to the first impulse signal, wherein the second control signal controls the inverter circuitry to supply a second impulse signal to the coil. - View Dependent Claims (20)
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Specification