US 12,003,204 B2
Driver device for a stepping motor
Ryota Miyagi, Kyoto (JP); and Hiroki Hashimoto, Kyoto (JP)
Assigned to Rohm Co., Ltd., Kyoto (JP)
Appl. No. 17/913,361
Filed by ROHM CO., LTD., Kyoto (JP)
PCT Filed Mar. 18, 2021, PCT No. PCT/JP2021/011140
§ 371(c)(1), (2) Date Sep. 21, 2022,
PCT Pub. No. WO2021/193364, PCT Pub. Date Sep. 30, 2021.
Claims priority of application No. 2020-058203 (JP), filed on Mar. 27, 2020.
Prior Publication US 2023/0144831 A1, May 11, 2023
Int. Cl. H02P 8/12 (2006.01); H02P 8/34 (2006.01)
CPC H02P 8/12 (2013.01) [H02P 8/34 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A driver device for a stepping motor having a rotor and a coil, comprising:
an output stage circuit configured to supply an output current to the coil by applying a voltage to the coil;
a control circuit configured to control the output stage circuit based on
a current setting signal for setting a target of the output current to be supplied to the coil and
a current sense signal indicating a result of sensing of the output current; and
a particular current waveform detector configured to detect occurrence of a particular current waveform in a waveform of the output current,
wherein
the rotor rotates according to change of the output current based on change of the current setting signal,
when the current setting signal is changed to require that, according to the current setting signal changed, a polarity of the output current be set to a target polarity and a magnitude of the output current be set to a target magnitude, the control circuit changes the output current to a current having the target polarity and the target magnitude according to the current setting signal changed and then, to approximate the magnitude of the output current to the target magnitude, the control circuit repeatedly performs a unit operation which is a sequence of a power supply mode operation and a decay mode operation,
in the power supply mode operation, the output stage circuit is in a power supply state in which the output stage circuit supplies electric power to the coil to increase the magnitude of the output current and, in the decay mode operation, the output stage circuit is in a decay state in which the output stage circuit suspends supplying the electric power to decrease the magnitude of the output current,
after a start of repetition of the unit operation, the particular current waveform detector detects, as the particular current waveform, a waveform with which the magnitude of the output current increases above the target magnitude and, on detecting occurrence of the particular current waveform, the particular current waveform detector transmits a predetermined detection signal to a device external to the driver device.