Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitachi Haramachi Electronics Co., Ltd.

Yoshiaki Ajima

Tsunehiro Endo

Kiyoshi Sakamoto

Shigeo Kuboki

Hidefumi Shirahama

Hiroshi Ichige

Takamasa Fujinaga

Isao Saitoh

Yoshinori Atsuwata

Yoshiaki Homitsu

Satoko Iwama

A driving apparatus of a synchronous motor fixes all the switching devices of an inverter at OFF in accordance with a value of an all-OFF control pulse signal outputted by a pulse generator. A motor current keeps flowing through free wheel diodes for a predetermined period even after all the switching devices shift to the OFF state. Therefore, pulse generator changes an induced voltage detection signal to an H (high) level after the passage of the time in which a motor current drops down to zero. A terminal voltage of the motor is taken in to acquire an induced voltage and a rotor position is estimated.

System and method for driving synchronous motor

The communication control device allows a plurality of data items to be transferred to and from external devices, such as a CPU and a memory, via an external bus having a different data bus width in DMA (direct memory access) transfer mode. DMA transfer is controlled by the DMA controller provided in the communication control device. The DMA controller produces a signal indicating that a plurality of data items are continual.

Communication control device and a communication system using the same

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Hitachi, Japan

Yoshiaki Ajima