Abstract: Embodiments of a method for amplifier calibration and an amplifier system are described. In one embodiment, a method for amplifier calibration involves amplifying an input signal using a first amplifier connected between an input terminal and an output terminal to generate an output signal and digitally performing offset calibration on a second amplifier coupled in parallel with the first amplifier between the input terminal and the output terminal while amplifying the input signal using the first amplifier. Other embodiments are also described.

Abstract: One example discloses a voltage reference, including: a bandgap circuit core having a first intermediate bandgap voltage output, a second intermediate bandgap voltage output, and a bandgap voltage reference output; an amplifier having a first input, a second input, an input offset, an output, and an input_offset_trim; a trim controller; a switch matrix coupled between the bandgap circuit, the amplifier and the trim controller; wherein the switch matrix has a functional configuration and a calibration configuration; wherein in the functional configuration of the switch matrix, the first intermediate bandgap voltage output is coupled to the first input of the amplifier and the second intermediate bandgap voltage output is coupled to the second input of the amplifier; and wherein in response to the calibration configuration of the switch matrix, the trim controller is coupled to adjust the input offset of the amplifier using the input_offset_trim.

Abstract: One example discloses an inductive power supply device, comprises: an inductive coupler including a resonant circuit having a first resonant state in response to an object at a first distance from the inductive power supply, and a second resonant state in response to the object at a second distance from the inductive power supply; a driver circuit coupled to send a first power-level to the inductive coupler when in a charge-object state and to send a second power-level to the inductive coupler when in a detect-object state, wherein the second power-level is less than the first power-level; and an object detector coupled to detect the first and second resonant states and place the driver circuit in the charge-object state in response to the first resonant state, and place the driver circuit in the detect-object state in response to the second resonant state.

Abstract: One example discloses an inductive power supply device, comprises: an inductive coupler including a resonant circuit having a first resonant state in response to an object at a first distance from the inductive power supply, and a second resonant state in response to the object at a second distance from the inductive power supply; a driver circuit coupled to send a first power-level to the inductive coupler when in a charge-object state and to send a second power-level to the inductive coupler when in a detect-object state, wherein the second power-level is less than the first power-level; and an object detector coupled to detect the first and second resonant states and place the driver circuit in the charge-object state in response to the first resonant state, and place the driver circuit in the detect-object state in response to the second resonant state.

Abstract: Systems and methodologies are described that facilitate calibration techniques for a station in a wireless communication system that can be utilized to provide joint estimates for distortion introduced by in-phase and quadrature (I/Q) imbalance and mixing-product modulated images.

Abstract: A current-mode direct conversion RF receiver is presented. In one set of embodiments the RF receiver comprises a simple transconductor input stage to create a current-mode modulated signal from a voltage-mode modulated signal. A downconversion mixer may be coupled to the transconductor input stage via a low impedance current cascode stage, and may operate to create a set of current-mode quadrature baseband signals from the current-mode modulated signal. The downconversion mixer may be implemented with a transistor-switching network, which may be driven by a phase locked loop (PLL) with quadrature outputs. The set of current-mode quadrature baseband signals may be converted back to the voltage domain by a transimpedance filter, which may perform channel selection for the receiver. The transimpedance filter may additionally include a low frequency zero to remove DC offsets.

Abstract: Systems and methodologies are described that facilitate calibration techniques for a station in a wireless communication system that can be utilized to provide joint estimates for distortion introduced by in-phase and quadrature (I/Q) imbalance and mixing-product modulated images.

Abstract: A system and method for maintaining communications with a radio frequency (RF) peripheral device such as an RF input device and an RF output device. A computer may search for an RF peripheral device by transmitting a signal request on available channels until a response is received from an RF peripheral device. If the RF channel becomes busy and/or jammed, the RF peripheral device may tune into a predetermined channel while the computer scans for another channel to use. Once the computer finds a better channel, the computer may go to the predetermined channel and broadcast the new channel location to the RF peripheral device. In addition, if an RF signal arrives incomplete or corrupt, the computer may transmit a negative acknowledgement to the RF peripheral device, which may retransmit the previous RF signal.

Abstract: Detecting a radio frequency (RF) environment around a computer and using a power management scheme for an RF user input device being used by the computer system. If the computer system is in a single user environment, a power management scheme may be used to conserve power on the RF user input device. If the computer system is in a multi-user environment, a power management scheme may be used to minimize interference between neighboring computer systems by minimizing the signal strength of the RF signal from the RF user input device and the RF signal from the computer system.

Abstract: A radio transmitter system designed using an FSK modulator with IQ up-mixers and sinewave coded digital-to-analog converters (DACs). The radio transmitter system may include a frequency shift keying (FSK) coding logic circuit coupled to the inputs of an IQ modulation and image reject up-mixer through a respective DAC and a respective low pass filter (LPF) for each the I and the Q channels. The FSK modulation scheme may employ sine and cosine signals for the I and Q channels, respectively, where the sine and cosine waves are directly coded into the DACs. The coded levels required by the DACs may be generated using current sources and may be Gray-coded. The output of the IQ modulation and image reject up-mixer may be connected to a power amplifier, which may be used to transmit the modulated RF signal via a loop antenna.

Abstract: A single-wire bus protocol named Budget Sensor Bus (BBUS) for simplified system management. The BBUS may transmit information packets in NRZ format from a monitored device/circuit to a host. In one embodiment, each packet comprises a start sequence, a data type, a device or register number, device data, and a stop sequence. The BBUS may directly transmit raw data bits from the monitored device/circuit to the host and may use the start sequence to communicate to the host the bit frequency that is used by the monitored device/circuit. Following the start sequence the host may get in sync with the monitored device/circuit and may be enabled to directly read the data bits that follow. The BBUS may provide a means for the monitored device/circuit to immediately transfer device information to the host. All functions and operations required to interpret the device information may reside within the host.

Abstract: An integrated demodulator tuning circuit (10, 60) receives differential currents at input terminals (12, 46) and provides an AFC signal at an output terminal (48). The AFC current characteristic has a dead band (72) in the output current generated when the integrated demodulator tuning circuit (10, 60) operates under the condition where the difference between the currents supplied at the input terminals (12 and 46) is at or below a set threshold value. The set threshold value is determined by the relative sizes of the transistors (14, 16 and 20, 36, 38 and 40) that form the current mirrors connected to the input terminals (12, 46).

Abstract: A current-mode direct conversion RF receiver is presented. In one set of embodiments the RF receiver comprises a simple transconductor input stage to create a current-mode modulated signal from a voltage-mode modulated signal. A downconversion mixer may be coupled to the transconductor input stage via a low impedance current cascode stage, and may operate to create a set of current-mode quadrature baseband signals from the current-mode modulated signal. The downconversion mixer may be implemented with a transistor-switching network, which may be driven by a phase locked loop (PLL) with quadrature outputs. The set of current-mode quadrature baseband signals may be converted back to the voltage domain by a transimpedance filter, which may perform channel selection for the receiver. The transimpedance filter may additionally include a low frequency zero to remove DC offsets.

Abstract: In one embodiment, a plurality of pn-junctions are grouped into n(n-1)/2 pairs (where n is an integer greater than 1) and each pn-junction pair includes a first pn-junction coupled antiparallel to a second pn-junction. In addition, n access points are coupled to the plurality of pn-junctions, and through the n access points n-1 pn-junctions are simultaneously accessible. In another embodiment, an integrated circuit is coupled to the plurality of pn-junctions via the n access points. In one embodiment, the integrated circuit may be configured as a temperature measurement IC and the plurality of pn-junctions may be used as temperature sensors. In this embodiment, the temperature measurement IC may be configured to access the first pn-junction independently from the second pn-junction and may be configured to access n-1 pn-junctions simultaneously to perform temperature measurements.

Abstract: An amplifier circuit. In one embodiment, the amplifier includes a first pair of transistors and a second pair of transistors. Each transistor in the amplifier includes a control terminal (e.g. a gate) as well as a first and second terminals. In one embodiment, the transistors are field effect transistors (FETs) and thus the first and second terminals may be either source or drain terminals. First terminals of each of the first pair of transistors may be coupled to a voltage source. The first terminal of each of the second pair of transistors is coupled to the second terminal of one of the first pair of transistors. A current source may be coupled between each of the second terminals and a voltage reference (e.g. ground plane).

Abstract: A radio transmitter system designed using an FSK modulator with IQ up-mixers and sinewave coded digital-to-analog converters (DACs). The radio transmitter system may include a frequency shift keying (FSK) coding logic circuit coupled to the inputs of an IQ modulation and image reject up-mixer through a respective DAC and a respective low pass filter (LPF) for each the I and the Q channels. The FSK modulation scheme may employ sine and cosine signals for the I and Q channels, respectively, where the sine and cosine waves are directly coded into the DACs. The coded levels required by the DACs may be generated using current sources and may be Gray-coded. The output of the IQ modulation and image reject up-mixer may be connected to a power amplifier, which may be used to transmit the modulated RF signal via a loop antenna.

Abstract: Various embodiments of methods and apparatus for an amplifier with wide output voltage swing are disclosed. The amplifier may include multiple output stages, each associated with a distinct supply voltage. Each output stage may contribute current to the output of the amplifier over a range of amplifier output voltages and these ranges may overlap. Each output stage may contribute current until the amplifier output voltage reaches the supply voltage associated with that output stage. The amplifier output may be as great as the largest supply voltage minus a drop equal to Rdson for an output transistor multiplied by the output current. In a CMOS implementation, this voltage drop may be approximately 0.15V. When the amplifier output voltage is close to the supply voltage associated with an output stage, both that output stage and the output stage associated with the next highest supply voltage may contribute to the amplifier output.

Abstract: Various embodiments of methods and apparatus for an amplifier with wide output voltage swing are disclosed. The amplifier may include multiple output stages, each associated with a distinct supply voltage. Each output stage may contribute current to the output of the amplifier over a range of amplifier output voltages and these ranges may overlap. Each output stage may contribute current until the amplifier output voltage reaches the supply voltage associated with that output stage. The amplifier output may be as great as the largest supply voltage minus a drop equal to Rdson for an output transistor multiplied by the output current. In a CMOS implementation, this voltage drop may be approximately 0.15V. When the amplifier output voltage is close to the supply voltage associated with an output stage, both that output stage and the output stage associated with the next highest supply voltage may contribute to the amplifier output.

Abstract: An oscillator circuit. In one embodiment, the oscillator includes a gain circuit, an envelope detector, and an amplitude comparison circuit. The trans-conductance circuit is configured to amplify a periodic signal produced by a crystal. Amplitude peaks of the periodic signal may be detected in the envelope detector, which may determine an average amplitude value based on the detected peaks. The average amplitude value may be compared to a DC voltage value in an amplitude comparison circuit. The DC voltage value may include both a DC average of the periodic signal as well as a predetermined DC offset value. The gain circuit may adjust the level of amplification of the periodic signal based on a feedback signal in order to ensure that the oscillator produces a periodic output signal at a desired level so as to insure oscillation and the minimum use of current to achieve oscillations.

Abstract: A low-power phase detector with differential output may comprise a control signal generator. In one embodiment, two cyclic waveforms whose phase relationship is to be measured may be input to a control signal generator. The control signal generator may output a first control signal corresponding to the first cyclic waveform such that the control signal is de-asserted at a specific point with respect to the first cyclic waveform. For example, the control signal may be de-asserted corresponding to the rising edge of the first cyclic waveform. The control signal generator may also output a second control signal corresponding to the second cyclic waveform such that the control signal is asserted at a specific point with respect to the second cyclic waveform. For example, the control signal may be asserted corresponding to the falling edge of the second cyclic waveform.