US 12,261,563 B2
Motor driver circuit for linear motor, positioning device using the same, and hard disk device
Hisashi Sugie, Kyoto (JP)
Assigned to ROHM Co., LTD., Kyoto (JP)
Filed by ROHM Co., LTD., Kyoto (JP)
Filed on Oct. 10, 2022, as Appl. No. 18/045,216.
Claims priority of application No. 2021-167664 (JP), filed on Oct. 12, 2021.
Prior Publication US 2023/0113909 A1, Apr. 13, 2023
Int. Cl. H02P 7/025 (2016.01); G11B 5/55 (2006.01); H02P 7/292 (2016.01)
CPC H02P 7/025 (2016.02) [H02P 7/292 (2013.01); G11B 5/55 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A motor driver circuit comprising:
a logic circuit that generates a second code that changes linearly with a slope “a” with respect to a first code based on a position command for a linear motor to be driven, the logic circuit being configured to switch the slope “a”;
a digital-to-analog converter that converts the second code into an analog control signal; and
a driver that drives the linear motor such that a current detection signal VCS indicating a drive current of the linear motor approaches a target value VREF that changes linearly with a slope “g” with respect to the control signal, the driver being configured to switch the slope “g,”
wherein the motor driver circuit is switchable between a first state and a second state,
in the first state, g=g1 and a=a1, and
in the second state, g=g2 (where |g2|>|g1|) and a=a2=a1×(g1/g2).