RECEIVER REMOVAL DETECTION IN WIRELESS CHARGING SYSTEMS
First Claim
1. A method for detecting removal of a receiver (RX) from a wireless charging system comprising a transmitter (TX) having a TX coil, the method comprising:
- (a) determining TX input power applied to the transmitter;
(b) determining TX power loss within the transmitter; and
(c) detecting the removal of the receiver based on a comparison of the determined TX input power and the determined TX power loss.
3 Assignments
0 Petitions
Accused Products
Abstract
A wireless charging system has a transmitter and a receiver. The transmitter has (i) a TX coil that wirelessly transfers power to the receiver and (ii) TX circuitry that powers the TX coil and detects receiver removal by comparing TX input power and TX power loss. The TX circuitry can determine (1) TX input power as the product of sampled TX input current and voltage and (2) TX power loss using a mapping based on sampled TX coil current. When the receiver is present, the difference between TX input power and TX power loss has a first value and when the receiver is removed, the difference has a second, lesser value. The transmitter detects removal of the receiver by determining when the difference decreases below a specified threshold level. By frequently generating and analyzing the difference, the transmitter can quickly detect receiver removal and safely power down the TX coil.
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Citations
20 Claims
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1. A method for detecting removal of a receiver (RX) from a wireless charging system comprising a transmitter (TX) having a TX coil, the method comprising:
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(a) determining TX input power applied to the transmitter; (b) determining TX power loss within the transmitter; and (c) detecting the removal of the receiver based on a comparison of the determined TX input power and the determined TX power loss. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A transmitter (TX) for a wireless charging system, wherein the transmitter comprises:
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a TX coil that wirelessly transfers power to a receiver of the wireless charging system; and TX circuitry that powers the TX coil, wherein the TX circuitry detects removal of the receiver by; (a) determining TX input power to the transmitter; (b) determining TX power loss within the transmitter; and (c) detecting the removal of the receiver based on a comparison of the determined TX input power and the determined TX power loss. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A wireless charging system comprising a transmitter (TX) and a receiver (TX) that is configured to receive power wirelessly from the transmitter, wherein the transmitter detects removal of the receiver by:
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(a) determining TX input power applied to the transmitter; (b) determining TX power loss within the transmitter; and (c) detecting the removal of the receiver based on a comparison of the determined TX input power and the determined TX power loss. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification