Wireless power transfer in-band communication system
First Claim
1. A wireless charging in-band communication system comprising:
- a load device including a first coil and a switched impedance coupled in parallel with the first coil, the load device being configured to transmit a message packet at least in part by;
generating a preamble comprising a synchronization sequence that has no more than three consecutive “
1”
states,encoding a payload according to a channel encoding scheme to generate an encoded payload,applying a modulation scheme that ensures no more than three consecutive “
1”
states are transmitted to the encoded payload to generate a modulated payload without applying the modulation scheme to the preamble,inverting the preamble to generate an inverted preamble, andtransmitting the inverted preamble and the modulated payload by controlling the switched impedance to change a reflected impedance seen by another device electromagnetically coupled to the first coil; and
a source device including a second coil configured to electromagnetically couple to the first coil, the source device being configured to receive the message packet from the load device at least in part by detecting changes in the reflected impedance of the load device and decode the encoded payload.
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Accused Products
Abstract
A wireless charging in-band communication system includes a channel encoding for message error correction and detection. A modulation module performs biphase modulation for DC balanced signals and impedance switching to change reflected impedance seen by the source. A synchronization module prepends the message with a synchronization sequence having Golay complementary codes. A receiver module receives the message from the transmitter module. A preamble detection block has a Golay complementary code correlator used for message detection, synchronization, and equalization coefficient estimation and selection. A decoding module that performs biphase demodulation with error correction with a DC offset being estimated as the average value of the signal over the length of the message before channel decoding. The decoding module performs equalization, error correction and detection channel decoding.
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Citations
46 Claims
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1. A wireless charging in-band communication system comprising:
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a load device including a first coil and a switched impedance coupled in parallel with the first coil, the load device being configured to transmit a message packet at least in part by; generating a preamble comprising a synchronization sequence that has no more than three consecutive “
1”
states,encoding a payload according to a channel encoding scheme to generate an encoded payload, applying a modulation scheme that ensures no more than three consecutive “
1”
states are transmitted to the encoded payload to generate a modulated payload without applying the modulation scheme to the preamble,inverting the preamble to generate an inverted preamble, and transmitting the inverted preamble and the modulated payload by controlling the switched impedance to change a reflected impedance seen by another device electromagnetically coupled to the first coil; and a source device including a second coil configured to electromagnetically couple to the first coil, the source device being configured to receive the message packet from the load device at least in part by detecting changes in the reflected impedance of the load device and decode the encoded payload. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of performing the operations of a wireless charging in-band communication system, the method comprising:
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generating, by a load device, a preamble comprising a synchronization sequence that has no more than three consecutive “
1”
states;encoding, by the load device, a payload according to a channel encoding scheme; applying, by the load device, a modulation scheme that ensures no more than three consecutive “
1”
states are transmitted to the encoded payload to generate a modulated payload without applying the modulation scheme to the preamble;inverting, by the load device, the preamble to generate an inverted preamble; transmitting, by the load device, the inverted preamble and the modulated payload at least in part by controlling a switched impedance coupled in parallel with a first coil to change a reflected impedance seen by a source device electromagnetically coupled to the first coil; receiving, by the source device, the inverted preamble and the modulated payload from the load device using a second coil electromagnetically coupled to the first coil at least in part by detecting changes in a reflected impedance of the load device; and decoding, by the source device, the modulated payload. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A load device supporting wireless charging in-band communication with a source device comprising:
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a first coil configured to electromagnetically couple to a second coil of the source device; a transmitter module configured to generate a message packet for transmission at least in part by; generating a preamble comprising a synchronization code that has no more than three consecutive “
1”
states,encoding a payload according to a channel coding scheme, applying a modulation scheme to the encoded payload that ensures no more than three consecutive “
1”
states are to be transmitted without applying the modulation scheme to the preamble,inverting the preamble to generate an inverted preamble, and transmitting the inverted preamble and the modulated payload to the source device, wherein the load device transmits the message packet to the source device at least in part by changing a reflected impedance seen by the source device without interrupting electromagnetic coupling between the first coil and the second coil. - View Dependent Claims (31, 32, 33, 34, 35, 43)
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30. A source device supporting wireless charging in-band communication with a load device comprising:
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a first coil for electromagnetically coupling to a second coil of the load device; a sensing circuit for detecting a message packet sent by the load device at least in part by detecting characteristics changes of the load device; a front end filter for pulse shaping and noise rejection; a preamble detection block for detecting a preamble in the message packet, the preamble comprising a synchronization sequence having no more than three consecutive “
1”
states, and wherein the preamble is inverted to generate an inverted preamble, wherein the preamble detection block comprises a correlator used for message detection, synchronization, and equalization coefficient estimation and selection; anda decoding module for detecting a payload in the message packet modulated by the load device using a modulation scheme that ensures no more than three consecutive “
1”
states, wherein the modulation scheme is not applied to the inverted preamble by the load device, and performing demodulation with error correction, equalization, and channel decoding on the payload,wherein changing of the characteristics of the load device to transmit the message packet does not interrupt electromagnetic coupling between the first coil and the second coil and wherein the preamble is not modulated using the modulation scheme. - View Dependent Claims (36, 37, 38, 39, 40, 44)
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41. A load device supporting wireless charging in-band communication with a source device comprising:
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a passive component for electromagnetically coupling with a passive component of the source device and receiving power from the source device; and a switch coupled to the passive component, wherein a load impedance of the load device is varied by controlling the switch, such that a message packet is transmitted to the source device, the message packet having no more than three consecutive “
1”
states and comprising;a payload modulated in accordance with a modulation scheme that ensures no more than three consecutive “
1”
states are transmitted; anda preamble including a synchronization sequence that has no more than three consecutive “
1”
states, wherein the preamble is not modulated in accordance with the modulation scheme, and wherein the preamble is inverted to generate an inverted preamble,wherein the message packet is transmitted to the source device without interrupting the electromagnetic coupling between the passive component of the load device and the passive component of the source device. - View Dependent Claims (45)
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42. A source device supporting wireless charging in-band communication with a load device comprising:
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a passive component for electromagnetically coupling with a passive component of the load device and providing power to the load device; a sensing circuit for receiving a message packet transmitted from the load device by detecting characteristics changes of the load device, the message packet comprising; a payload modulated in accordance with a modulation scheme that ensures no more than three consecutive “
1”
states are transmitted; anda preamble including a synchronization sequence that has no more than three consecutive “
1”
states, wherein the preamble is not modulated in accordance with the modulation scheme, and wherein the preamble is inverted to generate an inverted preamble; anda decoding module for performing demodulation on the payload, wherein changing of the characteristics of the load device to transmit the message packet does not interrupt the electromagnetic coupling between the passive component of the load device and the passive component of the source device. - View Dependent Claims (46)
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Specification