The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 22, 1988
Filed:
May. 15, 1987
Miran Milkovic, Schenectady, NY (US);
General Electric Co., , US;
Abstract
A switched-capacitor integrator is employed in an electronic watthour measurement device for integrating the average component of a product signal formed by pulse-width modulating an analog signal proportional to one of a load current and voltage at a pulse duty ratio proportional to the other of the load current and voltage. A hysteresis comparator forces the direction of integration to alternate between positive and negative limits for balancing out offset voltages in the integrator and comparator. A triangular-wave generator employed as part of the pulse-width-modulation technique is also implemented using a switched-capacitor integrator. The switched-capacitor integrators permit fabrication of the circuit with the required accuracy without needing external, discrete time-constant-determining resistances and capacitances. Measurement accuracy is determined by the ratio of capacitances of two on-chip capacitors, the accuracy to a clock signal and two reference voltages. These parameters are closely controllable on a single MOS or CMOS chip using normal process control whereby the entire electronic watthour measurement device may be realized on a single chip without requiring off-chip components.