Motor drive device and electronic device using the same
AssigneeRohm Co., Ltd.
InventorDaiki Yanagishima
Life of this patent
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Abstract
A motor drive device includes: chopping signal generation means for generating a chopping signal Sa when drive current of a driver has reached a first threshold value; chopping signal cut-off means for cutting off the chopping signal Sa when the drive current has reached a second threshold value which is greater than the first threshold value; and overcurrent protection means for generating an overcurrent protection signal Se when the drive current has reached a third threshold value which is greater than the first threshold value and its continuation time has reached a predetermined threshold value time. Thus it is possible to simultaneously obtain the constant current chopping function and the overcurrent protection function and to improve its reliability and safety.
Claims6
A motor drive device for turning on and off an output stage switching device to control driving of a motor, the motor drive device comprising:
- a chopping signal generator to generate, when a current flowing through the switching device reaches a first threshold value, a chopping signal for chopping an on-period of the switching device;
- a chopping signal interrupter to interrupt the chopping signal when the current flowing through the switching device reaches a second threshold value greater than the first threshold value;
- and
- an overcurrent protector to generate, when the current flowing through the switching device reaches a third threshold value greater than the first threshold value and thereafter remains equal to the third threshold value for a duration equal to a predetermined threshold period, an overcurrent protection signal for latching the switching device in an off state.
A motor drive device for turning on and off an output stage switching device to control driving of a motor, the motor drive device comprising:
- a chopping signal generator to generate, when a current flowing through the switching device reaches a first threshold value, a chopping signal for chopping an on-period of the switching device;
- an overcurrent protector to generate, when the current flowing through the switching device reaches a second threshold value greater than the first threshold value and thereafter remains equal to the second threshold value for a duration equal to a predetermined threshold period, an overcurrent protection signal for latching the switching device in an off state;
- and
- a chopping signal interrupter to interrupt the chopping signal when the overcurrent protector detects the current flowing through the switching device to have reached a second threshold value greater than the first threshold value.
Dependencies are inferred from the claim text.