Abstract: Methodology and circuitry for determining if a device, such as a cellular phone or personal digital assistant has been tapped is disclosed. The device includes an accelerometer and in response to an acceleration, the accelerometer outputs an acceleration signal. The accelerometer may continuously output an acceleration signal even if no acceleration occurs. A tap detection device receives the temporally sampled acceleration signal and takes the first derivative of the temporally sampled acceleration signal producing one or more derivative values. The tap detection system compares each derivative value to a threshold value and if the derivative value exceeds the threshold a tap is detected. By taking the derivative of the acceleration signal, the noise floor for the acceleration signal is reduced leading to more accurate results with less false positives and less positive negatives.

Abstract: A hearing instrument has a plurality of electronic components within a body, and an inertial sensor mechanically coupled with the body. The inertial sensor is configured to monitor the motion of the body and generate a movement signal representative of the body motion. A controller operatively coupled with the inertial sensor controls power usage by at least one or more of the electronic components as a function of the movement signal.

Abstract: A system and method for implementing a differential signaling driver with a common-mode voltage not equal to one half the power supply voltage using voltage-mode techniques. Embodiments of the present invention maintain balanced impedance at the signal output. In an embodiment, a driver may have multiple operating modes for each potential supply voltage or common-mode voltage. In an embodiment, each potential mode may involve configuring the driver by activating or deactivating switches or resistors in the driver and each potential mode may have different resistor values.

Abstract: A switch can be implemented by a switch circuit, which can include a pair of NMOS transistors connected in series as pass-through transistors to transmit an input signal at an input terminal to produce an output signal at output terminal in response to an active state of a switching signal, and a pair of PMOS transistors connected in series as pass-through transistors to transmit the input signal at the input terminal to produce the output signal at output terminal in response to the active state of the switching signal. The switch circuit can also include a switch network connecting, in response to the active state of the switching signal, sources to bodies of the pairs of NMOS and PMOS transistors, and connecting, in response to an inactive state of the switching signal, the bodies of the pair of NMOS transistors to a first reference voltage, the bodies of the pair of PMOS transistors to a second reference voltage, and the sources of the pairs of NMOS and PMOS transistors to a third reference voltage.

Abstract: Apparatus and methods for biasing amplifiers are provided. In certain implementations, a bias circuit is provided for controlling the drain-source voltage of input transistors electrically connected to the inputs of a transconductance amplification circuit. For example, the bias circuit can maintain a relatively constant drain-source voltage in the input transistors by using a feedback loop that includes a feedback amplifier for adjusting the bias current of the input transistors based upon a difference between the drain and source voltages of the input transistors. In certain implementations, the feedback amplifier has an offset voltage equal to about the desired value of the drain-source voltage, and the feedback amplifier is configured to adjust the bias current until the difference between the inputs of the feedback amplifier is equal to about the offset voltage.

Abstract: An instruction-based parallel median filtering processor and method sorts in parallel each combination of pairs of inputs into greater and lesser values; determines from that sorting the minimum, maximum and median filter values of the inputs; processes one of those values and provides the processed value as an input; and applies an instruction for providing one of the values to the processing step, and at least one other instruction for enabling indication of at least one of the maximum, minimum, median filter values.

Abstract: An oscillator synchronization system employs two oscillators, each of which includes an integrator which provides a ramping signal at its output, a comparator which receives the ramping signal and a reference signal at respective inputs and toggles an output when the ramping voltage crosses the reference signal, and a one-shot circuit that generates the integrator's reset signal when triggered. The system is preferably arranged such that the oscillators can be operated independently, in which case each oscillator's one-shot is triggered by its own comparator output, or synchronously, in which case each oscillator's one-shot is triggered by the other oscillator's comparator output—with the ramp signal of each oscillator operating to reset the integrator of the other oscillator. The oscillators are typically out-of-phase when synchronized, with the phase difference varying with the magnitude of the reference signals applied to the comparators.

Abstract: Apparatus and methods for electronic circuit protection are disclosed. In one embodiment, an actively-controlled protection circuit includes a detector, a timer, a current source and a latch. The detector is configured to generate a detection signal when the detector determines that a transient signal satisfies a first signaling condition. The timer is configured to receive the detection signal, and to generate a current control signal. The current control signal is provided to a current source, which produces a trigger current at least partly in response to the control signal. The trigger current is provided to a node of the latch, thereby enhancing the conductivity modulation of the latch and selectively controlling the activation voltage of the latch.

Abstract: A channel adaptive iterative turbo decoder for computing with MAP decoders a set of branch metrics for a window of received data, computing the forward and reverse recursive path state metrics and computing from the forward and reverse recursive path state metrics the log likelihood ratio for 1 and 0 and interleaving the decision bits; and identifying those MAP decoder decision bits which are non-convergent, computing a set of branch metrics for the received data, computing from the forward and reverse recursive path state metrics the log likelihood ratio (LLR) for 1 and 0 for each non-converged decision bit and interleaving the non-convergent decision bits.

Abstract: An error correction method corrects and replaces erroneous digital signal samples (having N companded bits) in a receiver after ascertaining by parity check that a sample is erroneous. The method chooses M MSBs where M is less than or equal to N, and produces M test samples, each of the M test samples being obtained by inverting a single bit from the M bits, keeping other bits unaltered. Each test sample is expanded and passed through a selected low pass filter (e.g., 15 kHz) to obtain a filtered output and a differential value between the test sample and its filtered output. The test sample producing the least differential value is chosen to replace the erroneous signal sample. The technique is especially applicable in NICAM demodulators receiving 14 bit sample signals (at 32 kHz) companded to (N) 10 bits from which (M) 6 MSB parity encoded bits are chosen for producing test samples.

Abstract: An amplifier having an imbalance between pull-up and pull-down sections may include a counterpart section to balance the output sections and/or enable them to be driven by balanced drive signals. In one embodiment, a rail-to-rail output stage may include a current minor to drive one side of the circuit. The other side may be driven by a transistor having a counterpart transistor to balance the circuit. A drive section may include a balance point to facilitate balancing the drive signals.

Abstract: Apparatus and methods for integrated circuit protection are provided. In one embodiment, an integrated circuit (IC) includes a first pad, a second pad, a third pad, a first protection subcircuit coupled between the first pad and a common node, a second protection subcircuit coupled between the second pad and the common node, and a third protection subcircuit coupled between the third pad and the common node. The first, second, and third protection subcircuits each include one or more building blocks for maintaining the voltage of each of the pads within a predefined safe range, as well as to maintain the voltage between each of the pads within acceptable limits. A portion of the building blocks used to provide transient signal protection can be shared between pads, thereby reducing the area of the pad protection circuit relative to a scheme using a separate stack of building blocks for each pad.

Abstract: Methods and devices for calculating the position of a movable device are disclosed. The device may include multiple optical detectors (ODs) and the movable device may include light sources. Optics may be above the ODs. A controller may calculate the position of the light source based on data from the ODs and properties of the optics. The device may be a game console, and the light source may be a game controller. The roles of the OD and light sources may be interchanged. The rotation of the movable device may be determined using multiple light sources and/or multiple ODs on the movable device. The movable device may calculate its position and transmit it to a console. The light sources may be modulated by time or frequency to distinguish between the light sources. There may be two or more movable devices. There may be two or more consoles.

Abstract: An overvoltage protection device in combination with a filter, the overvoltage protection device having a first node for connection to a node to be protected, a second node for connection to a discharge node; and a control node; and wherein the filter comprises at least one of: (a) a capacitor connected between the first node and the discharge node; (b) a capacitor connected between the control node and the discharge node; or (c) an inductor in series connection with the first node.

Abstract: An apparatus includes an electrostatic discharge (ESD) protection device. In one embodiment, the protection device electrically coupled between a first node and a second node of an internal circuit to be protected from transient electrical events. The protection device includes a bipolar device or a silicon-controlled rectifier (SCR). The bipolar device or SCR can have a modified structure or additional circuitry to have a selected holding voltage and/or trigger voltage to provide protection over the internal circuit. The additional circuitry can include one or more resistors, one or more diodes, and/or a timer circuit to adjust the trigger and/or holding voltages of the bipolar device or SCR to a desired level. The protection device can provide protection over a transient voltage that ranges, for example, from about 100 V to 330V.

Abstract: A battery monitoring system and method are disclosed. A battery monitor compares data in parallel register files. If voltage deviation above a certain threshold is detected in one register file, the system generates an alert that a fault exists upstream in the system. In order to better detect errors, the system may intentionally alter the voltages on the batteries to be monitored.

Abstract: An apparatus includes an electrostatic discharge (ESD) protection device. In one embodiment, the protection device electrically coupled between a first node and a second node of an internal circuit to be protected from transient electrical events. The protection device includes a bipolar device or a silicon-controlled rectifier (SCR). The bipolar device or SCR can have a modified structure or additional circuitry to have a selected holding voltage and/or trigger voltage to provide protection over the internal circuit. The additional circuitry can include one or more resistors, one or more diodes, and/or a timer circuit to adjust the trigger and/or holding voltages of the bipolar device or SCR to a desired level. The protection device can provide protection over a transient voltage that ranges, for example, from about 100 V to 330V.

Abstract: A voltage level shifter for a direct coupling of an external voltage source to a common mode of a circuit may include an amplifier, a voltage-controlled current source, a first and second resistors. A first input of the amplifier may be connected to the common mode. A second input of the amplifier may, via the first and second resistors, receive a voltage indicative of the external voltage source. The output of the amplifier may indicate a voltage difference between the first and second inputs. The voltage-controlled current source may be controlled by the voltage difference to supply a current to a common node of the first and second resistors so that the voltage difference between the first and second inputs may be minimized.

Abstract: Apparatus and methods for providing multi-mode clock signals are disclosed. In some embodiments, a multi-mode driver configured to receive a first clock signal, and to selectively output a different clock signal in response to one or more signals from a controller is provided. The driver can include an H-bridge circuit without substantial increases in the size of the design area. Advantageously, lower jitter and improved impedance matching can be accomplished.

Abstract: A method of forming a microphone forms a backplate, and a flexible diaphragm on at least a portion of a wet etch removable sacrificial layer. The method adds a wet etch resistant material, where a portion of the wet etch resistant material is positioned between the diaphragm and the backplate to support the diaphragm. Some of the wet etch resistant material is not positioned between the diaphragm and backplate. The method then removes the sacrificial material before removing any of the wet etch resistant material added during the prior noted act of adding. The wet etch resistant material then is removed substantially in its entirety after removing at least part of the sacrificial material.