AM data recovery circuit
First Claim
1. An AM data recovery circuit, comprising:
- a demodulator for converting an incoming RF signal at an input node to a voltage signal at an output node;
a current-mode data detector for converting said voltage signal into a current signal responsive to the power at said output node of said demodulator and providing a feedback signal responsive to said current signal; and
a power-limiting device coupled in parallel to said demodulator to control the power at said output node of said demodulator responsive to said feedback signal.
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Abstract
The present invention provides a passive RFID chip with on-chip charge pumps for generating electrical power for the chip from radio frequencies. The passive RFID chip comprises an analog portion and a digital portion. The analog portion primarily comprises a voltage sensor and an AM data detector. The digital portion comprises a state machine digital logic controller. Incoming RF signals enter the chip via external antennas. The RF signals are converted into regulated DC signals by RF-DC converters with the voltage sensor. The RF-DC converters provide power for all the on-chip components and hence the chip does not require external power supply. The incoming RF signals are demodulated by demodulators and enter the AM data detector where the envelope transitions are detected. A voltage alarm is provided to ensure the voltage level does not drop below an operational level of the chip. The logic signals and programming data are controlled by the state machine digital logic controller and the timing signals are provided by an on-chip oscillator.
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Citations
25 Claims
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1. An AM data recovery circuit, comprising:
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a demodulator for converting an incoming RF signal at an input node to a voltage signal at an output node; a current-mode data detector for converting said voltage signal into a current signal responsive to the power at said output node of said demodulator and providing a feedback signal responsive to said current signal; and a power-limiting device coupled in parallel to said demodulator to control the power at said output node of said demodulator responsive to said feedback signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An AM data recovery circuit, comprising:
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a demodulator for converting an incoming RF signal at an input node to a voltage signal at an output node; a voltage to current converter for converting said voltage signal into a current signal responsive to the power at said output node of said demodulator; a baseband data recovery circuit for converting said current signal to a digital data signal; and a power control circuit responsive to said current signal; wherein said power at said output node of said demodulator is responsive to the envelope of said incoming RF signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification