Rohm Co., Ltd.

Yuki Gohara

Tomofumi Mishima

Toshiya Suzuki

Kenji Asai

Joji Noie

Masateru Moroizumi

Hikaru Sasaki

A control circuit includes: a cycle counter configured to measure a cycle of revolutions per minute (RPM) signal indicating an RPM of a motor to be driven to generate a digital measurement value; and a controller configured to generate a control command based on a digital target value corresponding to a target cycle of the RPM signal and the measurement value, wherein the controller switches between a first mode in which the control command is monotonously changed and a second mode in which the control command is generated based on proportional-integral (PI) control.

Motor control circuit, control method, motor drive system, electronic device

The present invention relates to a fan motor driving circuit, a driving method, and a cooling device and an electronic machine using the same. The present invention provides a motor driving circuit capable of suppressing strain on coil current and/or reducing noise. A control circuit a control circuit switches an output phase of an H-bridge circuit based on a Hall signal, and in a soft switching duration (Tss) that starts before and ends after the output-phase switching, slowly varies a duty ratio (DUTY) of an output voltage (V) of one leg of the H-bridge circuit over time, and meanwhile, varies a duty ratio (DUTY) of an output voltage (V) of another leg of the H-bridge circuit in an opposite direction with respect to the duty ratio (DUTY) of the output voltage (V) of the one leg.

Fan motor driving circuit, driving method, and cooling device and electronic machine using the same

A driving circuit of an electric motor includes: a PWM input pin for externally receiving an input pulse modulation signal with an input duty cycle; a duty cycle to digital converter for receiving and converting the input pulse modulation signal into a first digital value; a slope setting pin for receiving information indicative of a slope of an output duty cycle corresponding to the input duty cycle; a slope acquisition unit for acquiring a second digital value corresponding to the information indicative of the slope; a duty cycle computation unit for generating a linearly increased duty cycle instruction value corresponding to the first digital value by referring to the slope; a digital pulse width modulator for generating a controlling pulse having the output duty cycle corresponding to the duty cycle instruction value; and an output circuit for driving the electric fan motor in accordance with the controlling pulse.

Motor driving circuit, cooling apparatus and electronic device using the same

A control circuit for a motor, includes: a plurality of m number of analog ports to each of which a detection signal indicating an electrical state of the motor is input, m being an integer of 2 or more; an A/D converter including a multiplexer to receive detection signals of the m number of analog ports and being configured to convert a detection signal selected by the multiplexer into digital data; a processor to generate a drive command of the motor based on the digital data; a pulse width modulator to perform pulse width modulation to generate a PWM signal based on the drive command; and an interface circuit to be triggered by at least one internal signal generated in the control circuit to control an operation of the A/D converter according to a control command from the processor and deliver the digital data to the processor.

Motor control circuit and fan including the same

A circuit for driving a fan motor includes: a control input interface circuit configured to generate a first digital value indicating an input duty ratio; a duty calculation unit configured to generate a duty command value linearly increasing with a slope with respect to the first digital value; a digital pulse width modulator configured to generate a control pulse having an output duty ratio corresponding to the duty command value; an output circuit configured to drive a fan motor based on the control pulse; a lock protection circuit configured to switch between an enable state and a disable state and to stop supply of power to the fan motor when lock of the fan motor is detected in the enable state; and a torque-off determination unit configured to switch the lock protection circuit to the disable state in a torque-off state.

Motor driving circuit, cooling device and electronic apparatus including the same

The present invention inhibits the voltage jump of a source voltage or an output voltage by an approach which is different from a conventional one. A logic circuit allows an H bridge circuit to be shifted among a plurality of states in a specific sequence. A compulsory regenerating circuit is configured to be switched between an enabled state and a disabled state; while being in the enabled state, the current that flows in from a ground line via the H bridge circuit and a motor coil to a power line back-flows to the ground line.

Fan motor driving means, driving method, and cooling device and electronic equipment using the same

A motor driving apparatus comprises an H bridge circuit having outputs coupled with a motor coil of a single-phase motor, a hall comparator configured to generate a hall detection signal indicating a position of a rotor of the motor, an electric angle generator configured to generate a pulse signal indicating that the motor rotates by a predetermined electric angle, a current monitoring circuit configured to asserts a zero current detection signal upon detecting a reversed direction of a coil current; a transition trigger circuit configured to assert a transition pulse when a count value of the first counter matches an lead angle set value; a logic circuit configured to transition the H bridge circuit according to a predetermined sequence of states; and a lead angle controller configured to adjust the lead angle set value based on a timing of assertion of the zero current detection signal.

Fan motor driving apparatus and method, cooling system including the same, and electronic equipment

According to the voltage Vthat occurs at one end of at least one of multiple coils of a fan motor, a back electromotive force detection circuit generates a detection signal BEMFasserted in a cyclic manner when a fan motor is stably rotating. A lock protection circuit detects a lock state of the fan motor rotor. A period detection unit measures the detection signal BEMFperiod. A synchronization pulse generating circuit generates a synchronization pulse having a period that is 1/N (N represents an integer of 2 or more) of that of the detection signal BEMFmeasured in a previous cycle. A lock judgment unit counts the synchronization pulse in increments of cycles of the detection signal BEMF. When the count value exceeds a predetermined threshold value M (M represents an integer of 2 or more) which is greater than N, the lock mode judgment signal is asserted.

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Kyoto, Japan

Yuki Gohara