Abstract: A capacitive transducer circuit comprises a capacitive transducer having first and second electrodes. The first and second electrodes are biased by respective first and second bias voltages. An amplifier is connected to receive a first analog signal on an input terminal, the first analog signal being generated by the capacitive transducer, and to generate a second analog signal on an output terminal. A digital feedback circuit is connected between the output terminal of the amplifier and the input terminal of the amplifier. The digital feedback circuit is configured to provide one of said first or second bias voltages. The output of a voltage source which provides the other bias voltage for the capacitive transducer may be filtered by a low pass filter. The low pass filter may comprise a switched capacitor filter circuit.

Abstract: There is provided a noise cancellation system, comprising: an input for a digital signal, the digital signal having a first sample rate; a digital filter, connected to the input to receive the digital signal; a decimator, connected to the input to receive the digital signal and to generate a decimated signal at a second sample rate lower than the first sample rate; and a processor. The processor comprises: an emulation of the digital filter, connected to receive the decimated signal and to generate an emulated filter output; and a control circuit, for generating a control signal on the basis of the emulated filter output. The control signal is applied to the digital filter to control a filter characteristic thereof.

Abstract: A bipolar output charge pump circuit 100 having a network of switching paths 110 for selectively connecting an input node (VV) and a reference node (VG) for connection to an input voltage, a first pair of output nodes (VP, VN) and a second pair of output nodes (VQ, VM), and two pairs of flying capacitor nodes (CF1A, CF1 B; CF2A, CF2B), and a controller for controlling the switching of the network of switching paths. The controller is operable to control the network of switching paths when in use with two flying capacitors (CF1, CF2) connected to the two pairs of flying capacitor nodes, to provide a first bipolar output voltage at the first pair of output nodes (VP, VN) and a second bipolar output voltage at the second pair of bipolar output nodes (VQ, VM).

Abstract: A transconductance difference amplifier (300) is described, for providing an output current dependent upon a difference between a first input voltage (302) and a second input voltage (304). The difference amplifier comprises an input sampling capacitor (306) having two conductors; a transconductance amplifier (312) having an input (318) coupled to a first conductor of said input sampling capacitor and a current output (314) for generating said output current; and an input switch (308, 310) for selectively coupling a second conductor of said input sampling capacitor to a first input of said difference amplifier for receiving said first input voltage and to a second input of said difference amplifier for receiving said second input voltage.

Abstract: Circuits and methods for generating a temperature dependent signal are described involving: generating a thermal voltage referenced positive temperature coefficient signal using a pair of transistors operating at different current densities; generating a transistor voltage referenced negative temperature coefficient signal using a transistor voltage of one of said pair of transistors; and subtracting one of said positive and negative temperature coefficient signals from the other of said signals to generate said temperature dependent signal, whereby the temperature dependence of said temperature dependent signal is greater than either of said subtracted signals.