Patent ID: 8305035
Filing Date: 2012-11-06
Classification: G01R,H02J

Abstract:
1. An energy storage device comprising: an energy storage section; a charging circuit electrically coupled to the energy storage section; a first comparator electrically coupled to the energy storage section, an output of the first comparator being inverted when a voltage (Vc) of the energy storage section reaches a first predetermined voltage (Vc a second comparator electrically coupled to the energy storage section, an output of the second comparator being inverted when the voltage (Vc) of the energy storage section reaches a second predetermined voltage (Vc a control circuit electrically coupled to the charging circuit, the first comparator, and the second comparator; wherein the control circuit obtains a period (tm) from inversion of the output of the first comparator to inversion of the output of the second comparator at charging the energy storage section with a constant current (Ics), and calculates a capacitance C of the energy storage section based on the period (tm) and a voltage change width (ΔVc) between the first predetermined voltage (Vc