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(11) | EP 1 441 372 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Actuator driving apparatus and method |
(57) An actuator driving apparatus (10) comprising at least one processing circuit (12)
including: a first switching device (32) placed between an exciting coil (14) of an
actuator and a dc power source (16,18) and operated by a pulse-width modulated signal
(S4) generated so as to correspond to an overexciting period (T2) and a holding period
(T3) subsequent to the overexciting period (T2) in a drive period (T1); a reflux circuit
(36) connected in parallel to the exciting coil (14) and including a fly-wheel diode
(44) and a second switching device (42) connected in series to the fly-wheel diode
(44); and a disconnection signal generator (38) sending a disconnection signal (S5)
to the second switching device (42) for a predetermined period after the termination
of the drive period (T1). The fly-wheel diode (44) is provided so that a current generated
from one end of the exciting coil (14) toward the other end when turning off the first
switching device (32) can be recirculated. The second switching device (42) is turned
off by the disconnection signal (S5) to be generated with the termination of the drive
period (T1) to interrupt the flow of current to the exciting coil (14).
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