Semiconductor Components Industries, LLC

Sanyo Semiconductor Co., Ltd.

Sanyo Electric Co., Ltd.

Kosaku Hioki

Kazumasa Takai

Yoshihiro Niwa

Takeshi Naganuma

Tsutomu Murata

An amount of a motor drive current is controlled to an appropriate value. Two coils are provided, and a rotor is rotated by the coils by setting different phases for the supplied currents to the two coils. During a phase where one of the coils is in a high-impedance state, an induced voltage generated in the coil is detected. According to the state of the induced voltage, an output control circuit controls the amounts of the motor drive currents supplied to the two coils.

Driver circuit and method

A stepping motor includes two coils. A driver circuit drives the stepping motor by setting dissimilar phases of supply currents to these two coils. One terminal of one coil is connected to ground and another terminal is set to a high impedance state, and an induced voltage generated at that coil is detected as a voltage with respect to ground. Then, in accordance with the state of the detected induced voltage, the magnitude of motor drive current supplied to the two coils is controlled.

Drive circuit and method

When a driver unit is in a high impedance state as viewed from a first coil or a second coil, an induced voltage detector detects the voltage across the first coil or that across the second coil so as to detect an induced voltage occurring in the first coil or the second coil. The induced voltage detector includes a differential amplifier circuit for differentially amplifying an electric potential across the first coil or that across the second coil, and an analog-to-digital converter circuit for converting an analog value outputted from the differential amplifier circuit into a digital value and outputting the converted digital value to a control unit. The control unit generates a drive signal based on an input signal set externally and adjusts the drive signal in accordance with the induced voltage detected by the induced voltage detector so as to set the adjusted drive signal in the driver unit.

Motor drive circuit for rotating a rotor by supplying the currents to two coils

Driver circuit

Driver circuit for driving a stepping motor

A serial-parallel conversion circuit in which power consumption is reduced is provided by using a latch clock generation circuit including multiple latch signal generation circuits which outputs a latch signal with a period of an integer multiple of that of a system clock signal. Here, the latch signal generation circuit includes a gate circuit which receives a control signal and a feedback signal, and outputs, according to a combination of the received control signal and feedback signal, a latch signal obtained by inverting a pulse corresponding to one clock of the system clock signal, and an output synchronization circuit which holds the latch signal output from the gate circuit and at the same time outputs the latch signal as a control signal supplied to a gate circuit of a latch signal generation circuit of the succeeding stage and a feedback signal supplied to the gate circuit of the self stage.

Growing community of inventors

Ogaki, Japan

Kosaku Hioki