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US 8,274,249 B2Granted
Motor drive device with lock protection function
AssigneeRohm Co., Ltd.
InventorTomofumi Mishima
Life of this patent
Estimating the term…
Abstract
A cooling system is provided with a motor drive device, a fan motor, and a Hall element. The motor drive device includes a lock protection circuit and a lock controller. When a control signal instructing rotation of the fan motor that is to be driven instructs stoppage of the motor for a predetermined time-period or longer, the lock controller has the lock protection circuit inactive. At an occasion when the control signal has continued to instruct stoppage of the fan motor for a first time-period or longer, a standby controller starts time measurement, and after a further predetermined second time-period has elapsed, makes at least a part of the motor drive device transition to a standby mode.
Claims16
A motor drive device comprising:
- a control input terminal which receives a control signal instructing rotation of a fan motor that is to be driven;
- an oscillator which has a predetermined oscillating frequency and generates a periodical signal of triangular form or sawtooth form;
- a comparator which compares the periodical signal with the control signal so as to generate a pulse width modulation signal subjected to pulse width modulation according to a target rotational frequency of the fan motor;
- a drive unit which controls energization of the fan motor, based on the pulse width modulation signal;
- a lock protection circuit which stops energization of the fan motor, when rotation of the fan motor is stopped;
- a lock controller which has the lock protection circuit inactive, in cases in which the pulse width modulation signal continues to instruct stoppage of the fan motor for at least a predetermined first time-period;
- and
- a standby controller which starts time measurement at an occasion when the control signal has continued to instruct stoppage of the motor for at least the first time-period, and after a further predetermined second time-period has elapsed, stops at least part of the motor drive device, and makes the motor drive device transit to a standby mode,
- wherein the first time-period is longer than the period of the pulse width modulation signal occurring when the pulse width modulation signal has a lower-limit frequency and shorter than a verification time-period necessary for the lock protection circuit to confirm that the fan motor has stopped.
6 more elements
A motor drive device comprising:
- a drive unit which controls energization of a motor that is to be driven, based on a duty ratio of a control signal instructing rotation of the fan motor and subjected to pulse width modulation according to a target rotational frequency;
- a lock protection circuit which stops energization of the fan motor, when rotation of the fan motor is stopped;
- a lock controller which has the lock protection circuit inactive, in cases in which the control signal continues to be placed at a level instructing stoppage of the fan motor for at least a predetermined first time-period, and
- a standby controller which starts time measurement at an occasion when the control signal continues to be placed at a level instructing stoppage of the fan motor for at least a predetermined first time-period, and after a further predetermined second time-period has elapsed, stops at least part of the motor drive device, and makes the motor drive device transit to a standby mode,
- wherein the first time-period is longer than the period of the control signal occurring when the control has a lower-limit frequency and shorter than a verification time-period necessary for the lock protection circuit to confirm that the fan motor has stopped.
2 more elements
A lock protection method of stopping energization of a fan motor to be driven, when rotation of the fan motor is stopped, comprising:
- comparing a control signal instructing stoppage of the fan motor with a period signal of triangular form or sawtooth form of a predetermined oscillating frequency so as to generate a pulse width modulation signal subjected to pulse width modulation according to a target rotational frequency of the fan motor;
- measuring a time-period for which the pulse width modulation signal continues to be placed at a level instructing stoppage of the fan motor;
- releasing lock protection when the measured time-period exceeds a predetermined first time-period;
- and
- starting time measurement at an occasion when the predetermined first time-period has elapsed, and after a further predetermined second time-period has elapsed, making at least part of the motor drive device transit to a standby mode,
- wherein the first time-period is longer than the period of the pulse width modulation signal occurring when the pulse width modulation signal has a lower-limit frequency and shorter than a verification time-period necessary to confirm that the fan motor has stopped for lock protection.
3 more elements
A lock protection method of stopping energization of a fan motor to be driven, when rotation of the fan motor is stopped, comprising:
- measuring a time-period for which a control signal instructing rotation of the fan motor and subjected to pulse width modulation according to a target rotational frequency continues to be placed at a level instructing stoppage of the fan motor;
- releasing lock protection when the measured time-period exceeds a predetermined first time-period;
- and
- starting time measurement at an occasion when the predetermined first time-period has elapsed, and after a further predetermined second time-period has elapsed,
- making at least part of the motor drive device transit to a standby mode,
- wherein the first time-period is longer than the period of the control signal occurring when the control signal has a lower-limit frequency and shorter than a verification time-period necessary to confirm that the fan motor has stopped for lock protection.
3 more elements
Dependencies are inferred from the claim text.