Texas Instruments Corporation

National Semiconductor Corporation

Mikko Topi Loikkanen

Wei Ma

Zhenyong Zhang

Mark Kuhns

Juha Olavi Hauru

Tuomas Tapani Tuikkanen

Angelo William Pereira

Ari Kalevi Väänänen

Juha Tapani Pennanen

Kae Ann Wong

Siang Tong Tan

Luis Ariel Malave-Perez

Mitsuyori Saito

Antti Veli Johannes Piila

Jacobus Adrianus Van Oevelen

Jeremy K Yaeger

Tomi Juhani Koskela

Ari Kalevi Vããnãnen

A transistor diagnostic circuit includes a protection transistor output terminal, a fault terminal, and circuitry coupled to the protection transistor output terminal and the fault terminal. The protection transistor output terminal is adapted to be coupled to a current terminal of a protection transistor. The transistor diagnostic circuit is configured to, at start-up, load the protection transistor output terminal to test the protection transistor, and to generate a fault signal at the fault terminal responsive to a voltage on the protection transistor output terminal exceeding a threshold.

Transistor diagnostic circuit

A system includes a power supply source and a power control circuit coupled to the power supply source, in which the power control circuit includes a pass field-effect transistor (FET). The system also includes a short-to-ground protection circuit coupled to an output of the pass FET. The short-to-ground protection circuit includes a sense circuit configured to detect when a magnitude and a change rate of a voltage drop at the output of the pass FET is greater than respective thresholds. The short-to-ground protection circuit also includes a control node at the output of the sense circuit. The sense circuit is configured to induce a control current at the control node in response to the magnitude and the change rate of a voltage drop at the output of the pass FET being greater than respective thresholds. The control current is used to turn off the pass FET.

High-speed short-to-ground protection circuit for pass field-effect transistor (FET)

A duty-cycled acoustic sensor saves power, for example, by operating for relatively short periods of time in a repetitive manner. A sensor bias current provides operating power to the sensor. An output analog signal from the sensor carries the information induced by the sensor upon the bias signal. Capacitive coupling is employed to remove direct DC voltage from the output analog signal to generate an analog input signal for acoustic analysis. A capacitor for capacitive coupling is pre-charged to reduce the charging time of the capacitor as the sensor is being powered up. After the capacitor is sufficiently precharged, acoustic analysis is performed on the analog input signal. The sensor is powered down by substantially blocking current flow through the sensor, which saves power. Results of the acoustic analysis can be used, for example, to control parameters of the duty-cycling of the acoustic sensor.

Duty-cycling microphone/sensor for acoustic analysis

The line banding image artifact that results from the interaction of LCD ripple and LED flicker in an LCD device that utilizes LED backlighting strings is substantially reduced by selecting a number of LED strings, individually driving the number of LED strings with a corresponding number of identical clock signals that are equally phase delayed, and selecting the frequency of the clock signals so that the product of the frequency of the clock signal multiplied by the number of LED strings is equal to the line clock frequency.

LED backlight controller

A control circuit for controlling a DC-DC converter, with the converter including an inductor and associated switching circuitry, with the switching circuitry including a first transistor switch connected intermediate an input voltage terminal and a first terminal of the inductor, a second transistor switch connected intermediate the first terminal of the inductor and a circuit reference, a third transistor switch connected intermediate a second terminal of the inductor and an output voltage terminal and a fourth transistor switch connected intermediate the second terminal of the inductor and the circuit reference. Mode control circuitry responsive to separate buck and boost comparators and configured to cause the switching circuitry to switch among a pass phase where the first and second transistor switches are ON, a boost phase where the first and third transistors are ON and a buck phase where the second and third transistors are ON, with first selected switching periods beginning operation in the pass phase followed, in response to an output of the buck comparator, with operation in the buck phase and with second selected switching periods beginning operation in the pass phase followed, in response to an output of the boost comparator, to operation in the boost phase.

Buck or boost DC-DC converter

A converter controller for discharge of a coil used in a DC/DC converter including a voltage detector connected to monitor a state of a diode connected between the coil and ground and an offset comparator, having an adjustable offset, for causing a coil discharge path to be interrupted. The comparator is provided with an initial high offset so that for at least a first converter switching period, the coil will have sufficient charge when the coil discharge path is interrupted to cause the diode to become forward biased as determined by the voltage detector. The offset is periodically reduced until the coil is sufficiently discharged so that the diode is not forward biased, with that value of offset being optimum and thus used in subsequent switching periods.

Control circuitry in a DC/DC converter for zero inductor current detection

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Oulu, Finland

Mikko Topi Loikkanen