Abstract: A data bus and message handling method provide a definitive means of indicating a client-aborted message for data bus systems which employ a message protocol that requires each message conveyed between a client device and an originating device to automatically and atomically include a frame check sequence (FCS). When a message is not to be client-aborted, a ‘good’ FCS is generated by a first method, typically based on the message's data content. However, when a message is to be client-aborted, the FCS is generated by a second method which requires modifying the good FCS value to create a ‘bad’ FCS, preferably using a mathematical means that preserves the uniqueness of the bad FCS to a high degree.

Abstract: A system and method for portable computer battery management using host processing relocates analog and digital components needed to implement the SBDS standard from the battery pack to the computer, which processes the acquired battery data using the host processor. The battery pack requires only battery temperature and voltage sensing circuits, and an interface circuit for conveying the sensed data out of the battery pack. The portable computer includes a circuit which senses current provided to or drawn from the battery. Battery temperature, voltage and current data is provided to the computer's host system, which executes a battery management application program to determine battery status in accordance with the SBDS standard.

Abstract: A plug-in device discrimination circuit is connected to the contacts of a jack. When a plug-in device is plugged into the jack, the circuit discerns the type of device it is, thereby enabling proper interface circuitry to be connected to the plug-in device. The discrimination circuit includes a comparison circuit, a switching network, and a controller. The controller operates the switching network to connect the comparison circuit to the jack contacts. When so connected, the comparison circuit compares the electrical characteristics of at least two of the circuits contained within the plug-in device, and produces an output which varies with the results of the comparison. The controller receives the output of the comparison circuit and may configure additional circuitry to present an appropriate interface to the plug-in device.

Abstract: A rechargeable battery measurement and calibration system for use with a removable battery pack suitably used to power a mobile computer locates current measurement and battery status intelligence outside of the battery pack, thereby reducing the cost, complexity, and power consumption of the battery pack when compared with prior art systems. A system host controls the measurement and calibration of the battery system; the host requests current measurements under both zero-current and non-zero calibration current conditions, with the resulting calibration values enabling linearity errors that might otherwise be present in the current measurements to be totally and easily identified and accounted for in a fuel gauge measurement. The present system complies with the SBS-IF specification for Smart Battery systems.

Abstract: A novel battery monitoring device is described. The monitoring device determines amount of battery self-discharge, determines amount of battery discharge from a monitoring circuit, determines amount of battery discharge from a host device when the host device is in a first power consumption mode, and determines amount of battery discharge from the host device when the host device is in a second power consumption mode. The first mode causes greater discharge of the battery during a given period of time than the second mode.

Abstract: An open-loop speaker amplifier and a dynamic range reduction circuit are disclosed. The speaker amplifier includes a bridge driver and a bridge circuit. The bridge circuit includes a first set of switches and a second set of switches. When the first set of switches are activated, a positive current flows through a speaker load. When the second set of switches are activated, a negative current flows through the speaker load. The bridge driver generates a pulse width modulated signal and a delayed pulse width modulated signal to drive the first and second set of switches of the bridge circuit responsive to a modulation signal. The modulation signal maybe for example, a plurality of pulse code modulated samples representing sound. The dynamic range reduction circuit modifies a selected signal to reduce the dynamic range of the sound reproduced based on the modulation signal. The selected signal is either the modulation signal or a reference signal.

Abstract: A low power consumption oscillator circuit. The oscillator circuit comprises a capacitor coupled to a first resistor that is capable of delaying discharge of the capacitor. The oscillator circuit further comprises a first inverter coupled to the capacitor and having a first input. The first inverter is capable of applying charge to the capacitor when a first voltage potential on the first input is above a first threshold voltage of the first inverter. The first inverter is capable of removing charge from the capacitor when a second voltage potential on the first input is below a second threshold voltage of the first inverter. The oscillator circuit further comprises threshold detection circuitry having a second circuitry is coupled to the first input of the first inverter, and the second input is coupled to the capacitor.

Abstract: A technique is provided for substantially reducing clicks and pops caused by power cycling, in particular, the power cycling conservation strategy used in a portable computer. More specifically, an audio amplifier arrangement for a computer, in accordance with one embodiment of the present invention, includes a differential amplifier having a first input terminal, a second input terminal and an output terminal. A sound output connector may be connected to the output terminal through a signal path. First switching circuitry is responsive to a first mute signal for connecting together the first input terminal and the second input terminal through a low-impedance path. As a result, an output signal produced by the differential amplifier is essentially forced to zero. When power is removed from or applied to the differential amplifier, however, its behavior is not entirely predictable, and the output signal produced cannot be guaranteed to remain zero throughout the power-down transition.

Abstract: An open-loop speaker amplifier and a dynamic range reduction circuit are disclosed. The speaker amplifier includes a bridge driver and a bridge circuit. The bridge circuit includes a first set of switches and a second set of switches. When the first set of switches are activated, a positive current flows through a speaker load. When the second set of switches are activated, a negative current flows through the speaker load. The bridge driver generates a pulse width modulated signal and a delayed pulse width modulated signal to drive the first and second set of switches of the bridge circuit responsive to a modulation signal. The modulation signal may be, for example, a plurality of pulse code modulated samples representing sound. The dynamic range reduction circuit modifies a selected signal to reduce the dynamic range of the sound reproduced based on the modulation signal. The selected signal is either the modulation signal or a reference signal.