Abstract: A circuit for minimizing the current spikes in through the stator coils in a brushless dc motor is disclosed. The circuit includes a voltage amplifier for receiving an input signal voltage and a feedback voltage, a compensation circuit for compensating the output of the voltage amplifier, a second voltage amplifier for amplifying the compensated output, a switch for selectively connecting compensated output to the stator coils, and a conductive path for discharging the compensation circuit when the switch is not conducting. The conductive path can be a transistor or a transistor in series with a voltage reference device. The invention reduces the commutation noise and the dynamic power requirement in a brushless direct current motor.
Abstract: In a computer system, a processing unit generates a read request and sends it to a cache. If data for the read request is not in the cache, the cache forwards the request to a bus interface unit. If the forwarded request does not fall within the address range of any bus read transaction stored in the bus interface unit, the bus interface unit stores a new bus read transaction corresponding to the forwarded request and sends an identifier for the new transaction to the processing unit. In one preferred embodiment, if the forwarded request falls within the address range of one of the bus read transactions stored in the bus interface unit, the bus interface unit discards the forwarded request and sends an identifier for the one transaction to the processing unit. Additionally, a method of processing read requests is provided. A read request is stored in a buffer and sent to a cache.
Type:
Grant
Filed:
August 25, 1998
Date of Patent:
June 19, 2001
Assignee:
STMicroelectronics, Inc.
Inventors:
Nicholas J. Richardson, Charles A. Stack, Ut T. Nguyen