Span, Inc.

Malcolm S McClure

Phong B Chau

A unit that can be a tiny module within a battery pack includes a microprocessor operating through onboard sensors and read circuitry to monitor battery current, voltage and temperature and to develop fast charge termination control data. Various termination schemes are available including negative delta V, dT/dt, dV/dt, absolute temperature, absolute voltage, and override timer. The microprocessor also operates to develop state of charge, percentage of capacity charge and other status data, to store such data along with setup and calibration data, in an EEPROM, to report data to a host periodically or when polled to and to operate automatically or at a user's request to initially perform and update a calibration as to actual battery capacity. During times when the pack is idle, the unit automatically reverts to a low-power mode in which measuring circuitry is deenergized but during such times, it operates periodically to compensate for self-discharge as a function of temperature. In the read circuitry, a ramp generator generates a linear ramp voltage that is compared with voltages proportional to battery voltage, supply voltage, battery current and temperature, using comparators connected to pins of a common port of the microprocessor and using a mask to obtain all readings from a single generation of the ramp. Voltage dividers of the read circuitry are so arranged as to permit accurate readings of current in either direction and to operate in a bridge configuration to obtain normalized measurements independent of ramp slope. Dynamic correction of readings and other features are also provided.

Battery monitoring and charging control unit

This invention relates to the use of rechargeable batteries for supply of electrical power. Devices are provided which are highly efficient and which provide accurate and reliable control and indications, while using a small number of component parts and being otherwise readily and economically manufacturable. Devices of the invention are compact and such that they can be readily included, if desired, as integral parts of battery packs such as those used for supplying power to lap-computers and other types of portable equipment.

Battery charging and monitoring system

A battery charger has battery terminals connected to a conventional wall outlet through a switching power supply to provide a direct conductive non-isolated path from the supply for direct transformer-less supply of charging current to a battery. Pulse width modulated signals are applied to a MOSFET of the power supply from an output port of a microprocessor which is operates a ramp generator and responds to a comparator circuit coupled to a battery voltage sense circuit and the ramp generator. The microprocessor is programmed to accurately control generation of the pulse width modulated signals, to shut off current when a true voltage peak is reached at a full charge condition, to avoid response to false peaks, to cut off current for short time intervals during voltage measurements, to perform an exponential averaging function and to shut down at excessive battery temperatures or time rates of change of battery temperature.

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Indianapolis, IN, United States of America

Malcolm S McClure