Abstract: A transceiver for use in induction-based communication protocols, such as radio-frequency identification (RFID) and near field communication (NFC), is described. The transceiver may be arranged such that the transmitter and the receiver share a common input/output (I/O) terminal. The transceiver may be configured to interrogate a transponder to which it is inductively coupled, and to wait for the transponder's response. Data transmitted back by the transponder may be detected by sensing an impedance modulation at the I/O terminal or at a node whose impedance varies with the I/O terminal. The impedance modulation may be sensed by allowing a current to be modulated by the impedance variation and by converting the current into a voltage. The corresponding voltage modulation may be sensed by a receiver.

Abstract: A proximity sensing method employed by a wireless communications device includes the steps of: performing a first predetermined operation to detect a presence of at least a transponder in the proximity of the wireless communications device; when the presence of a transponder in the proximity of the wireless communications device is not detected by the first predetermined operation, performing a second predetermined operation to obtain a first characteristic value and after a period of time, performing the second predetermined operation to obtain a second characteristic value sequentially; checking if the first characteristic value and the second characteristic value satisfy a predetermined criteria; and when the predetermined criterion is satisfied, performing the first predetermined operation again to check the presence of the transponder in the proximity of the wireless communications device.

Abstract: An integrated circuit is disclosed. The integrated circuit includes an amplifier and a capacitor array coupled to the amplifier. The capacitor array is configured to be coupled in parallel to an inductor that is external to the integrated circuit, and the capacitor array and the external inductor comprise a tank circuit. The integrated circuit includes a resistor array coupled in parallel with the capacitor array. The resistor array is utilized to provide an overall frequency response of the capacitor array and resistor array that is opposite of a frequency response of the external inductor over a predetermined frequency range.

Abstract: A method for controlling a modulation index of a near field communication (NFC) device includes: in a calibration mode of the NFC device, coupling a receiver of the NFC device to a transmitter of the NFC device to form a probing path between the receiver and the transmitter; and in the calibration mode of the NFC device, adjusting at least one portion of a plurality of modulation parameters corresponding to the modulation index according to probed results of outputs of the transmitter, in order to calibrate the modulation index, for use of transmitting through the transmitter in a normal mode of the NFC device. An associated apparatus is also provided.

Abstract: A method for controlling a modulation index of a near field communication (NFC) device includes: in a calibration mode of the NFC device, coupling a receiver of the NFC device to a transmitter of the NFC device to form a probing path between the receiver and the transmitter; and in the calibration mode of the NFC device, adjusting at least one portion of a plurality of modulation parameters corresponding to the modulation index according to probed results of outputs of the transmitter, in order to calibrate the modulation index, for use of transmitting through the transmitter in a normal mode of the NFC device. An associated apparatus is also provided.

Abstract: A method for controlling a modulation index of a near field communication (NFC) device includes: in a calibration mode of the NFC device, temporarily coupling a receiver of the NFC device to a transmitter of the NFC device to form a probing path between the receiver and the transmitter; and in the calibration mode of the NFC device, dynamically adjusting at least one portion of a plurality of modulation parameters corresponding to the modulation index according to probed results of outputs of the transmitter, in order to calibrate the modulation index, for use of transmitting through the transmitter in a normal mode of the NFC device. An associated apparatus is also provided.

Abstract: A method for controlling a modulation index of a near field communication (NFC) device includes: in a calibration mode of the NFC device, temporarily coupling a receiver of the NFC device to a transmitter of the NFC device to form a probing path between the receiver and the transmitter; and in the calibration mode of the NFC device, dynamically adjusting at least one portion of a plurality of modulation parameters corresponding to the modulation index according to probed results of outputs of the transmitter, in order to calibrate the modulation index, for use of transmitting through the transmitter in a normal mode of the NFC device. An associated apparatus is also provided.

Abstract: An integrated circuit is disclosed. The integrated circuit includes an amplifier and a capacitor array coupled to the amplifier. The capacitor array is configured to be coupled in parallel to an inductor that is external to the integrated circuit, and the capacitor array and the external inductor comprise a tank circuit. The integrated circuit includes a resistor array coupled in parallel with the capacitor array. The resistor array is utilized to provide an overall frequency response of the capacitor array and resistor array that is opposite of a frequency response of the external inductor over a predetermined frequency range.

Abstract: A proximity sensing method employed by a wireless communications device includes the steps of: performing a first predetermined operation to detect a presence of at least a transponder in the proximity of the wireless communications device; when the presence of a transponder in the proximity of the wireless communications device is not detected by the first predetermined operation, performing a second predetermined operation to obtain a first characteristic value and after a period of time, performing the second predetermined operation to obtain a second characteristic value sequentially; checking if the first characteristic value and the second characteristic value satisfy a predetermined criteria; and when the predetermined criterion is satisfied, performing the first predetermined operation again to check the presence of the transponder in the proximity of the wireless communications device.

Abstract: A transconductor. The transconductor comprises first and second active device networks. The first active device network has a first node and a second node and comprises a first MOS transistor having a gate, a source coupled to the first node, and a drain coupled to the second node. The second active device network has a first node and a second node respectively connected to the first and second nodes of the first active device network and comprises a second MOS transistor and a voltage drop generator. The second MOS transistor has a gate and a source respectively connected to the gate and the source of the first MOS transistor. The voltage drop generator is coupled between a drain of the second MOS transistor and the second nodes of the first and second active device networks and generates a voltage drop across the same.

Abstract: A dual gain amplification low noise amplifier that includes an amplification circuit to a provide dual gain amplification—high gain amplification for a weak data signal and low gain amplification for a strong data signal. Also included is a control circuit to maintain approximately the same P1dB point for the weak signal during high gain amplification as for the strong signal during low gain amplification.

Abstract: Tuning of a filter circuit is accomplished by determining a real RC time constant value for the filter circuit, then comparing the real RC vale to a predetermined RC value. If the real RC value does not match the predetermined RC value, the real RC value is varied (e.g.

Abstract: A dual gain amplification low noise amplifier that includes an amplification circuit to a provide dual gain amplification—high gain amplification for a weak data signal and low gain amplification for a strong data signal. Also included is a control circuit to maintain approximately the same P1dB point for the weak signal during high gain amplification as for the strong signal during low gain amplification.

Abstract: Tuning of a filter circuit is accomplished by determining a real RC time constant value for the filter circuit, then comparing the real RC vale to a predetermined RC value. If the real RC value does not match the predetermined RC value, the real RC value is varied (e.g.