US 6,981,645 B2
Drive circuit for controlling a resonant motor
Robert J. Leach, Coram, N.Y. (US)
Assigned to Symbol Technologies, Inc., Holtsville, N.Y. (US)
Filed on Sep. 08, 2003, as Appl. No. 10/657,690.
Prior Publication US 2005/0051632 A1, Mar. 10, 2005
Int. Cl. G02B 26/10 (2006.01)
U.S. Cl. 235—462.25 19 Claims
OG exemplary drawing
 
1. A drive circuit for operating a resonant motor having associated motor circuitry, including a first winding and a second winding, the drive circuit comprising:
a coil drive circuit configured to operatively couple to the first winding of the motor circuitry for supplying a drive signal thereto;
a feedback circuit including at least a switch operable in a first and a second state and configured to operatively couple to the second winding; and
a control circuit operatively coupled to the switch and the coil drive circuit for providing a switching signal to said switch for switching between said first and second states, said control circuit providing a control signal to said coil drive circuit in response to a feedback signal received from said resonant motor, wherein a voltage value of said feedback signal varies when said switch is in the first state, and said voltage value of said feedback signal is held substantially constant when said switch is in the second state.