Cushman, Darby & Cushman
Control circuit for electric motor
 A control circuit can drive an electric motor such as a stepping motor and a DC torque motor within a wide supply voltage range so that its rotor follows a selected speed pattern without error. The control circuit includes a monitoring circuit for monitoring a level of the supply voltage to output a detection signal. The control circuit also includes a memory storing a plurality of speed patterns, the plurality of speed patterns corresponding respectively to different levels of the supply voltage. One of the plurality of speed patterns is selectively read in response to the detection signal. The electric motor is then driven in accordance with the read speed pattern. 
Tokico Ltd.
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inventional inventional inventional
Mamoru Makoto
Kobayashi Nishimura