Low-power high-accuracy clock harvesting in inductive coupling systems
First Claim
1. An apparatus, comprising:
- a front-end circuit, which comprises an antenna and a modulation switch; and
a digital processing circuit, which is configured to transmit data to a remote unit using inductive coupling of an Alternating Current (AC) magnetic field generated by the remote unit, by modulating a load impedance of the antenna using the modulation switch,wherein the front-end circuit is configured to supply to the digital processing circuit a voltage signal, which has a frequency of the AC magnetic field and which has a non-zero envelope both during intervals in which the modulation switch is closed and during intervals in which the modulation switch is open, and wherein the digital processing circuit is configured to derive a clock signal from the voltage signal.
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Abstract
An apparatus includes a front-end circuit and a digital processing circuit. The front-end circuit includes an antenna and a modulation switch. The digital processing circuit is configured to transmit data to a remote unit using inductive coupling of an Alternating Current (AC) magnetic field generated by the remote unit, by modulating a load impedance of the antenna using the modulation switch. The front-end circuit is configured to supply to the digital processing circuit a voltage signal, which has a frequency of the AC magnetic field and which has a non-zero envelope both during intervals in which the modulation switch is closed and during intervals in which the modulation switch is open, and wherein the digital processing circuit is configured to derive a clock signal from the voltage signal.
148 Citations
31 Claims
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1. An apparatus, comprising:
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a front-end circuit, which comprises an antenna and a modulation switch; and a digital processing circuit, which is configured to transmit data to a remote unit using inductive coupling of an Alternating Current (AC) magnetic field generated by the remote unit, by modulating a load impedance of the antenna using the modulation switch, wherein the front-end circuit is configured to supply to the digital processing circuit a voltage signal, which has a frequency of the AC magnetic field and which has a non-zero envelope both during intervals in which the modulation switch is closed and during intervals in which the modulation switch is open, and wherein the digital processing circuit is configured to derive a clock signal from the voltage signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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using a digital processing circuit, transmitting data to a remote unit using inductive coupling of an Alternating Current (AC) magnetic field generated by the remote unit, by modulating a load impedance of an antenna using a modulation switch; supplying to the digital processing circuit a voltage signal, which has a frequency of the AC magnetic field and which has a non-zero envelope both during intervals in which the modulation switch is closed and during intervals in which the modulation switch is open; and in the digital processing circuit, deriving a clock signal from the voltage signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method, comprising:
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applying an external unit to form a magnetic field, having a frequency and an accuracy, around a remote system comprising a modulation switch and a digital processing circuit; in the remote system, deriving from the magnetic field a clock signal having the frequency and the accuracy; applying the digital processing circuit to generate a digital signal carrying data synchronized with the clock signal; applying the digital processing circuit to manipulate the modulation switch in a series of alternations between an open state and a closed state in a pattern derived from the digital signal, thereby encoding the data by way of load modulation; and applying the external unit to decode the data by extracting the load modulation with the clock signal. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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Specification