ApplicationNo. 05/936725 filed on 08/25/1978
US Classes:324/428, Including an integrating device341/158Analog input compared with static reference
ExaminersPrimary: Tokar, M.
Attorney, Agent or Firm
International ClassesG01R 31/36 (20060101)
G01R 31/00 (20060101)
AbstractA method and apparatus are disclosed for measuring the state of charge of a battery. The apparatus comprises threshold means for sensing reductions below a threshold level in the output terminal voltage of the battery and for producing a signal in response thereto and means for integrating said signal over a plurality of such reductions. The output of the integrating means is indicative of the state of charge of the battery. In a preferred embodiment the signal comprises a series of pulses whose number is proportional to the time that the terminal voltage is below the threshold value and the integrating means counts such pulses. Alternatively, a single pulse may be produced and counted for each time the output terminal voltage is reduced below the threshold level. In another embodiment, the signal from the threshold means is integrated directly to develop a representation of the state of charge of the battery. Circuits are also disclosed using a plurality of threshold means connected in series or in parallel.