Novel method of exciting a piezoelectric crystal

• US 20050275308A1
• Filed: 05/16/2005
• Published: 12/15/2005
• Est. Priority Date: 05/17/2004
• Status: Active Grant

• Current Assignee: Schmitt Measurement Systems, Inc. (Schmitt Industries, Inc.)
• Original Assignee: Xtero Datacom, Inc. (Schmitt Industries, Inc.)
• Inventors: Kazemir, Steven Scott, Lagergren, Peter John
• Granted Patent: US 7,245,059 B2
• Time in Patent Office: Days
• US Class Current: 310/317
• CPC Class Codes: G01F 23/2968 Transducers specially adapted for acoustic level indicators
• CPC Class Codes: H10N 30/802 Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits

Abstract

The invention describes the use of an electrical pulse that is a single square wave to excite a piezoelectric crystal. This pulse is applied alternately to either side of the crystal at twice the nominal resonant frequency of the crystal. This method provides a significant increase in net drive power to the crystal without the need to provide a sine wave excitation of plus and minus voltage to the crystal.

Claims

1. What is claimed in this invention is a method of exciting a piezoelectric crystal in an ultrasonic ranging device that includes a drive circuit for generating a drive voltage, and;

a switch system that applies the drive voltage alternately to the opposite sides of the piezoelectric crystal at twice the nominal resonant frequency.