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1.发明授权公开(公告)号：US11245347B2
公开(公告)日：2022-02-08
申请号：US16798641
申请日：2020-02-24
申请人： ROHM CO., LTD.
摘要： The present invention relates to a driving circuit and a driving method for a stepping motor, and an electronic machine using the same. A current value setting circuit generates a current setting value. A constant current chopper circuit generates a pulse modulation signal, which pulse-width modulates by having a detection value of a coil current flowing through a coil approach close to the current setting value. A logic circuit controls a bridge circuit connected to the coil of the stepping motor according to the pulse modulation signal. The current value setting circuit sets the current setting value to a predetermined full-torque setting value in a first period after rotation starts, reduces the current setting value to a predetermined second setting value less than the first setting value in the following second period, and switches to a high-efficiency mode and adjusts the current setting value by means of feedback control.
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2.发明授权公开(公告)号：US11251728B2
公开(公告)日：2022-02-15
申请号：US16815645
申请日：2020-03-11
申请人： ROHM CO., LTD.
发明人： Masanori Tsuchihashi , Mitsuo Okada
摘要： A back electromagnetic force detection circuit detects a counter EMF generated in a coil of a stepping motor. A revolution count detection circuit generates a revolution count detection signal. A determining circuit generates a determination signal that is asserted if the revolution count detection signal is stable across multiple consecutive cycles. A current value setting circuit generates a current setting value indicating a target value of a coil current. The current value setting circuit sets the current setting value to a predetermined value in a period in which the determination signal is negated, and adjusts the current setting value according to the counter EMF in a period in which the determination signal is asserted. A constant current chopper circuit generates a pulse modulation signal that modulates by way of having a detection value of a coil current approach close to a target value of the current setting value.
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公开(公告)号：US12088155B2
公开(公告)日：2024-09-10
申请号：US17831803
申请日：2022-06-03
申请人： ROHM CO., LTD.
摘要： A driving circuit drives a stepping motor in synchronization with an input clock using a 2-phase excitation method. A constant current chopper circuit generates a pulse modulation signal such that the detection value of the coil current approaches a current setting value. A detection window generation circuit generates a detection window. The detection window becomes an open state at a timing at which the coil current IOUT becomes smaller than a predetermined threshold value. A logic circuit sets a full-bridge circuit to a high-impedance state when the detection window is in the open state and controls the full-bridge circuit according to the pulse modulation signal when the detection window is in the closed state. In the open state of the detection window, a back electromotive force (BEMF) detection circuit detects the BEMF of the coil. A current value setting circuit controls a current setting value based on the BEMF.
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公开(公告)号：US11381184B2
公开(公告)日：2022-07-05
申请号：US16788692
申请日：2020-02-12
申请人： ROHM CO., LTD.
IPC分类号： H02P8/12
摘要： There is provided a driving circuit for a stepping motor, including: a counter electromotive force detection circuit configured to detect a counter electromotive force generated in a coil; a current value setting circuit configured to generate a current set value based on the counter electromotive force; a constant current chopper circuit configured to generate a pulse-modulated signal which is pulse-modulated so that a detected value of a coil current flowing through the coil approaches a target amount based on the current set value; and a logic circuit configured to control a bridge circuit connected to the coil according to the pulse-modulated signal, wherein the driving circuit is configured to output the current set value to outside or to access the current set value from the outside.
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5.发明授权公开(公告)号：US11418138B2
公开(公告)日：2022-08-16
申请号：US16798812
申请日：2020-02-24
申请人： ROHM CO., LTD.
摘要： The task of the present invention is to provide a driving circuit capable of outputting information useful to design or control of a system to outside. The present invention relates to a driving circuit and a driving method of a stepping motor, and an electronic machine using the driving circuit of a stepping motor. A counter electromotive force detection circuit detects a counter EMF generated in a coil. A revolution count detection circuit acquires the revolution count of the stepping motor. A load angle estimating portion calculates a load angle according to the counter EMF and the revolution count. An interface circuit is configured to be capable of outputting angle information associated with the load angle to outside, or accessing the angle information from the outside.
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