Abstract: A bandgap reference circuit includes a ?Vbe/R circuit portion and an amplification circuit portion. The ?Vbe/R circuit portion has a first and second current path from first and second terminals through first and second bipolar transistors, respectively. The first and second bipolar transistors have different emitter areas and the second path has a resistor. The amplification circuit portion provides a current to each of the first and second terminals of the ?Vbe/R circuit portion and changes the current in response to a voltage difference between the first and second terminals of the ?Vbe/R circuit portion. The ?Vbe/R circuit portion also has first and second base resistors connected to bases of the first and second bipolar transistors, respectively.

Abstract: An active pixel sensor imaging system is disclosed. In one aspect, the system includes a plurality of active pixel sensor circuits arranged into an array of rows and columns. Each active pixel sensor is connected to a supply line and a column line, and operable to generate a voltage output through the column line corresponding to a detected light intensity. The system includes a current sensing circuit, located external to the plurality of active pixel sensor circuits and connected to the supply line. The current sensing circuit is implemented as a current mirror for sensing a current through an active pixel sensor circuit readout transistor. The system includes a feedback circuit, located external to the plurality of active pixel sensor circuits and connected to the column line, to a current generator and to the current sensing circuit. The feedback circuit is implemented as a classAB current mirror configured for controlled quiescent current.

Abstract: An active pixel sensor imaging system is disclosed. In one aspect, the system includes a plurality of active pixel sensor circuits arranged into an array of rows and columns. Each active pixel sensor is connected to a supply line and a column line, and operable to generate a voltage output through the column line corresponding to a detected light intensity. The system includes a current sensing circuit, located external to the plurality of active pixel sensor circuits and connected to the supply line. The current sensing circuit is implemented as a current minor for sensing a current through an active pixel sensor circuit readout transistor. The system includes a feedback circuit, located external to the plurality of active pixel sensor circuits and connected to the column line, to a current generator and to the current sensing circuit. The feedback circuit is implemented as a classAB current minor configured for controlled quiescent current.

Abstract: A process for performing Near Field Communication (NFC) between a first NFC device and a second NFC device is provided. The first NFC device includes an NFC transceiver and an FM receiver which are both integrated into the same chip. The provided process involves initializing the first NFC device to perform a device detection polling loop for detecting a second NFC device. The device detection polling loop has activity detection periods, which occur periodically. The first NFC transceiver may then perform a slicing procedure, which slices the activity detection periods into small time slots. Each time slot has a duration smaller than a predetermined value so as to reduce the noise generated by harmonics of the NFC operation frequency which might be audible to the user.

Abstract: A process for performing Near Field Communication (NFC) between a first NFC device and a second NFC device is provided. The first NFC device includes an NFC transceiver and an FM receiver which are both integrated into the same chip. The provided process involves initializing the first NFC device to perform a device detection polling loop for detecting a second NFC device. The device detection polling loop has activity detection periods, which occur periodically. The first NFC transceiver may then perform a slicing procedure, which slices the activity detection periods into small time slots. Each time slot has a duration smaller than a predetermined value so as to reduce the noise generated by harmonics of the NFC operation frequency which might be audible to the user.

Abstract: A mixer is described having a Gilbert cell structure including a first input and a second input for inputting an RF signal, a third input and a fourth input for inputting a local oscillator signal, a first output and a second output for outputting an IF signal, a plurality of switches for converting the RF signal to an IF signal, and a dynamic bleed circuit for dynamically reducing the dc-current of the switches at the switching-point. As the dc-current of the switches is reduced at the point of commutation, the 1/f-noise is also strongly reduced without degrading the linearity. The switching happens at twice the local oscillator frequency. The mixer also includes a common mode feedback circuit that feeds the common mode signal, optionally amplified, to a common mode feedback control device that is in series between the dynamic bleed circuit and the supply voltage.

Abstract: A receiver is described including circuitry for deriving at least a first stream of first digitized samples from a received analog signal at a first sampling rate, circuitry for selecting a first sampling point and at least a second sampling point, a demodulator for demodulating first and second symbols from the at least first stream of samples based on the first and the at least second sampling points, and circuitry for determining a value related to a demodulation accuracy for the first and second symbols and for outputting a signal, the circuitry for selecting being adapted to alter the sampling point based on the signal. By assessing a demodulation accuracy in real time clock drift can be compensated. The demodulation accuracy can be a value related to a phase error or an error energy such as EVM or DEVM for each demodulated symbol.

Abstract: Method and apparatus for a wireless receiver are described which derive at least a first stream of first digitized samples from a received analog signal at a first sampling rate and identify a first frequency offset based on a plurality of parallel correlations using complex reference signals which differ from each other by phase offsets. A second frequency offset is identified based on tracking a demodulation accuracy for each symbol which is demodulated from the first stream of digitized samples. These frequency offsets can be used to rotate decision areas in the demodulator. The methods and apparatus may be used in a Bluetooth receiver.

Abstract: A buffer circuit buffers incoming signals, from a local oscillator generator to a mixing circuit and has a push-pull circuit having two inputs, a first being coupled to a first incoming signal, and a second of the inputs being coupled to one of the buffered versions of the incoming signals, having a phase related to that of the first incoming signal. By coupling a second input to a buffered version rather than to the incoming signal, the load presented to the preceding circuit can be halved, while maintaining reduced power consumption. By using as a second input, a signal which is phase related to the first incoming signal, the normal operation of the push-pull circuit can be maintained. The incoming signals from the LO generator can be differential IQ signals and the buffered version of the further incoming signal be in phase with the first incoming signal.

Abstract: An active RC filter has an op-amp and a biasing circuit arranged to bias the op-amp to set a gain bandwidth product of the op-amp according to a desired pole frequency of the filter. The biasing circuit is operable according to an output of an RC calibration circuit. The op-amp can be an OTA transconductance amplifier, and the biasing circuit can be arranged to maintain a constant product of R and transconductance at an input of the transconductance amplifier. This biasing can help to set the pole frequency more accurately and can thus reduce the need for bandwidth margin to be provided to allow for manufacturing process variations.

Abstract: A mixer is described having a Gilbert cell structure including a first input and a second input for inputting an RF signal, a third input and a fourth input for inputting a local oscillator signal, a first output and a second output for outputting an IF signal, a plurality of switches for converting the RF signal to an IF signal, and a dynamic bleed circuit for dynamically reducing the dc-current of the switches at the switching-point. As the dc-current of the switches is reduced at the point of commutation, the 1/f-noise is also strongly reduced without degrading the linearity. The switching happens at twice the local oscillator frequency. The mixer also includes a common mode feedback circuit that feeds the common mode signal, optionally amplified, to a common mode feedback control device that is in series between the dynamic bleed circuit and the supply voltage.

Abstract: A buffer circuit buffers incoming signals, from a local oscillator generator to a mixing circuit and has a push-pull circuit having two inputs, a first being coupled to a first incoming signal, and a second of the inputs being coupled to one of the buffered versions of the incoming signals, having a phase related to that of the first incoming signal. By coupling a second input to a buffered version rather than to the incoming signal, the load presented to the preceding circuit can be halved, while maintaining reduced power consumption. By using as a second input, a signal which is phase related to the first incoming signal, the normal operation of the push-pull circuit can be maintained. The incoming signals from the LO generator can be differential IQ signals and the buffered version of the further incoming signal be in phase with the first incoming signal.

Abstract: An active RC filter has an op-amp and a biasing circuit arranged to bias the op-amp to set a gain bandwidth product of the op-amp according to a desired pole frequency of the filter. The biasing circuit is operable according to an output of an RC calibration circuit. The op-amp can be an OTA transconductance amplifier, and the biasing circuit can be arranged to maintain a constant product of R and transconductance at an input of the transconductance amplifier. This biasing can help to set the pole frequency more accurately and can thus reduce the need for bandwidth margin to be provided to allow for manufacturing process variations.

Abstract: A receiver is described including circuitry for deriving at least a first stream of first digitized samples from a received analog signal at a first sampling rate, circuitry for selecting a first sampling point and at least a second sampling point, a demodulator for demodulating first and second symbols from the at least first stream of samples based on the first and the at least second sampling points, and circuitry for determining a value related to a demodulation accuracy for the first and second symbols and for outputting a signal, the circuitry for selecting being adapted to alter the sampling point based on the signal. By assessing a demodulation accuracy in real time clock drift can be compensated. The demodulation accuracy can be a value related to a phase error or an error energy such as EVM or DEVM for each demodulated symbol.

Abstract: Method and apparatus for a wireless receiver are described which derive at least a first stream of first digitized samples from a received analog signal at a first sampling rate and identify a first frequency offset based on a plurality of parallel correlations using complex reference signals which differ from each other by phase offsets. A second frequency offset is identified based on tracking a demodulation accuracy for each symbol which is demodulated from the first stream of digitized samples. These frequency offsets can be used to rotate decision areas in the demodulator. The methods and apparatus may be used in a Bluetooth receiver.