Resources Contact Us Home
Battery charge monitor and fuel gauge

Image Number 11 for United States Patent #5315228.

A battery charge controller and fuel gauge which accurately monitors the voltage, temperature, and charge and discharge current of a rechargeable battery, and calculates the battery's charge capacity and charge level. Each time the battery is fully discharged, any calculated charge level remaining is divided by two and subtracted from the previously calculated charge capacity. When the battery is fully charged, the charge level is set equal to the charge capacity. During subsequent charge and discharge, the current is converted to a coulomb count and added or subtracted from the charge level to maintain an accurate charge level. Fast charge inefficiency due to temperature is considered by subtracting a temperature proportional factor before the charge level of the battery is updated. The charge level, voltage and temperature are used to determine the optimal fast charge termination point to achieve full charge and prevent temperature abuse and overcharge. A fast charge is applied only if the battery is within proper voltage and temperature ranges. The charge controller includes a microcontroller circuit within the same battery pack as the battery, which is powered by the battery when AC power is unavailable. The microcontroller circuit consumes very little power, measures circuit errors to assure data accuracy, times periods of self-discharge and updates the charge level accordingly. The microcontroller circuit also includes memory to store the battery charge information and a communication port to provide the charge information to a computer system connected to the battery pack.

  Recently Added Patents
Image processing apparatus, image display apparatus, and image processing method
Supply voltage generating circuit and semiconductor device having the same
Method for producing organo-oligo silsesquioxanes
Copolymer for positive type lithography, polymerization initiator used in production of said copolymer, and composition for semiconductor lithography
Crystalline solvates of 6-(piperidin-4-yloxy)-2H-isoquinolin-1-one hydrochloride
Architectural panel with bamboo rings light density embossed surface
  Randomly Featured Patents
Apparatus to facilitate jam recovery and hot roll reversal in a fusing assembly
Transition metal tris-dithiolene and related complexes as precursors to active catalysts
Self-alignment magnetic connector reduced in size
Portable pulmonary respirator, intermittent positive pressure breathing machine and emergency oxygen equipment
Reducing floating gate to floating gate coupling effect
Electron emission device and display device using the same
Data signal transmission system using decision feedback equalization
Yoghurt based douche kit and assembly therefor
Laying of underwater pipelines
Active matrix liquid crystal display having first and second display electrodes capacitively couple to second and first data buses, respectively