Sanyo Semiconductor Co., Ltd.

Semiconductor Components Industries, LLC

On Semiconductor Trading, Ltd.

Sanyo Electric Co., Ltd.

Sanyo Semiconductor Manufacturing Co., Ltd.

Toshiyuki Imai

Joji Noie

Tetsuya Yoshitomi

Takahiro Iida

Masahiro Nakahata

Junko Kimura

Hiroyuki Kikukawa

A motor drive circuit comprising: a drive circuit configured to supply a drive current to a drive coil of a motor; a control circuit configured to control an operation of the drive circuit; a locking protection circuit configured to control an operation of the control circuit so that the drive circuit stops supplying the drive current to the drive coil, if a rotation signal, indicating rotation of the motor, is not generated during a predetermined time period although the drive circuit is supplying the drive current to the drive coil; and a prohibition circuit configured to prohibit the locking protection circuit from controlling the control circuit.

Motor drive circuit

The invention provides a motor with a low speed start function and a soft start function. The motor includes a first pulse generation circuit generating a first pulse signal of which a first duty ratio of one of logic levels is increased as a drive voltage corresponding the target rotation speed of the motor is increased, a second pulse generation circuit generating a second pulse signal of which a second duty ratio of one of logic levels is different from the first duty ratio, and a drive control circuit supplying a drive current to a motor coil at the second duty ratio in order to start the rotation of the motor that is stopping and supplying a drive current to the motor coil at the first duty ratio after a predetermined time passes from the start of the rotation of the motor in response to a rotation signal corresponding to the rotation of the motor.

A motor drive circuit is configured to drive a motor coil based on duty ratio of a PWM signal, and includes a first pulse signal generating circuit configured to generate a first pulse signal for each time period, the time period being equal to 1/n of a time period during which the PWM signal is at one logic level, a counter configured to change a count value based on the first pulse signal, a drive signal output circuit configured to output a drive signal of one logic level when the count value is not a predetermined value and output the drive signal of the other logic level when the count value reaches the predetermined value, a drive circuit configured to perform PWM driving for the motor coil based on the duty ratio of the drive signal, and a setting circuit.

A motor drive circuit configured to supply drive currents to drive coils with a plurality of phases of a motor to drive the motor, includes: a trapezoidal wave signal generation circuit configured to output a trapezoidal wave signal whose inclination is changed with a rotation speed of the motor or a target rotation speed of the motor; and a plurality of output transistors configured to output the drive current to the drive coils, respectively, in accordance with the trapezoidal wave signal.

A motor drive circuit is configured to drive a motor based on first and second position detection signals opposite in phase to each other, the signals having a frequency corresponding to a rotational speed of the motor and indicating a rotational position of the motor. The circuit includes a first level-shift circuit, a second level-shift circuit, a timing detecting circuit, and an output circuit. The first level-shift circuit is configured to shift a level of at least either one of the first and second position detection signals so that a first period, during which a first output signal corresponding to the first position detection signal is higher in level than a second output signal corresponding to the second position detection signal, becomes longer than a second period, during which the second output signal is higher in level than the first output signal.

A motor-driving circuit includes: a plurality of output transistors; a first-comparator circuit to compare a voltage of each phase of driving coils of a plurality of phases in a motor, with a neutral-point voltage; a position-detecting circuit to detect a rotor position of the motor based on a comparison result of the first-comparator circuit; a switching-control circuit to supply switching signals to the plurality of output transistors according to the rotor position; and a current-limiting circuit to limit the driving currents to a first-current value so that the motor rotates at a target-rotation speed when the current-limiting circuit determines that the motor is rotating at a speed higher than or equal to a predetermined-reference-rotation speed, and limit the driving currents to a second-current value smaller than the first-current value when the current-limiting circuit determines that the motor is not rotating at the speed higher than or equal to the predetermined-reference-rotation speed.

Motor driving circuit

A motor drive circuit comprising: a triangle wave generation circuit configured to charge/discharge a capacitor with a charging/discharging current having a current amount corresponding to an amplitude control voltage for controlling an amplitude of an oscillation voltage that varies in a triangle wave shape, and to output a charging voltage of the capacitor as the oscillation voltage; a pulse signal generation circuit configured to generate a pulse signal having a duty ratio corresponding to a level of a speed control voltage for controlling a rotational speed of a motor, based on a comparison result between the speed control voltage and the oscillation voltage output from the triangle wave generation circuit; and a drive circuit configured to intermittently drive a motor coil based on the pulse signal.

A motor drive circuit includes a first amplifier circuit to amplify a difference between first and second position detection signals with a gain becoming smaller according to drop in power supply voltage, to output a first amplification signal, the first and second position detection signals being signals indicating a rotational position of a rotor in a motor, having a frequency corresponding to a rotation speed of the motor, and being opposite in phase to each other; a second amplifier circuit to amplify the difference between the first and second position detection signals with the gain, to output a second amplification signal opposite in phase to the first amplification signal; and a drive circuit to amplify the difference between the first amplification signal and the second amplification signal with a predetermined gain to be saturated at the power supply voltage, to output a driving voltage for driving the motor.

A motor drive circuit comprising: first and second transistors connected in series, a voltage of a connection-point therebetween being a drive-voltage applied to one end of a motor coil; an operational amplifier for controlling the transistors such that the drive-voltage is a voltage according to a difference between first and second control voltages; a switch circuit for driving the transistors such that the motor coil is in an undriven state regardless of control by the operational amplifier when a pulse-signal is at one logic level, and driving the transistors based on the control when the pulse-signal is at the other logic level; and an auxiliary drive circuit for driving the transistors to increase the drive-voltage for a predetermined time period shorter than a time period of the pulse signal being at the other level regardless of the control, when the pulse-signal changes from the one level to the other.

Motor drive circuit, fan motor, electronic device, and notebook personal computer

A motor drive circuit includes: a pulse generation circuit configured to generate a pulse signal whose duty ratio of one logic level is increased as a drive voltage is increased in accordance with a target rotation speed of a motor; and a drive control circuit that configured to drive the motor with the drive voltage using a duty ratio higher than the duty ratio of the pulse signal when the motor starts rotating from the stopped state, and configured to drive the motor with the drive voltage during a period when the pulse signal is at the one logic level after the motor starts rotating, based on a rotation signal corresponding to the rotation of the motor.

A motor control circuit comprising: a rotation control circuit configured to control rotation of a motor based on a rotation control signal for controlling rotation of the motor and a rotational position detection signal from a Hall element for detecting a rotational position of the motor; a determining circuit configured to determine whether the rotation control signal has been generated for a predetermined time period; and a Hall element control circuit configured to apply a Hall element source voltage to the Hall element when the determining circuit determines that the rotation control signal has been generated for the predetermined time period, and to stop applying the Hall element source voltage to the Hall element when the determining circuit determines that the rotation control signal has not necessarily been generated for the predetermined time period.

Motor control circuit, fan motor, electronic device, and notebook personal computer

A first switch circuit includes first and second N-type MOSFETs. A second switch circuit includes third and fourth N-type MOSFETs. A control signal is input to a first inverter and a third inverter, the output of the first inverter input to a second inverter and the gate of the fourth MOSFET, the output of the second inverter input to the gate of the first MOSFET, the output of the third inverter input to a fourth inverter and the gate of the third MOSFET, the output of the fourth inverter input to the gate of the second MOSFET. A first input voltage is connected to the source of the second MOSFET and the sources of N-type MOSFETS in the third and fourth inverters. A second input voltage is connected the source of the fourth MOSFET and the sources of N-type MOSFETS in the first and second inverters.

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Oizumi-machi, Japan

Toshiyuki Imai