Memory device in which electrical power consumption of power circuit thereof is reduced during an idle state

• US 5,799,199 A
• Filed: 07/31/1996
• Issued: 08/25/1998
• Est. Priority Date: 08/07/1995
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited, Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Fujitsu Limited
• Inventors: Ito, Masahiro, Isato, Nobuhiko
• Primary Examiner(s): Sheikh, Ayaz R.
• Assistant Examiner(s): PHAN, RAYMOND NGAN
• Application Number:
  US08/688,905
• Time in Patent Office: 755 Days
• Field of Search: 395/750, 395/750.01, 395/750.03, 395/750.04, 395/750.05, 395/750.06, 395/750.08, 395/735, 395/740, 364/707
• US Class Current: 713/324
• CPC Class Codes: G06F 1/3221 of disk drive devices
• CPC Class Codes: G06F 1/3256 Power saving in optical drive
• CPC Class Codes: G06F 1/3268 Power saving in hard disk drive
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A memory device connected to a host computer is disclosed wherein when a power consumption reducing function is performed, the power consumption can be further reduced. The memory device includes a memory medium, a data read/write circuit, a power circuit, an electric power processing IC, an interface circuit, and an MPU. The interface circuit is connected to the portion of the power circuit on the upstream side of the electric power processing IC. The circuits including the MPU are connected to the portion of the power circuit on the downstream side of the electric power processing IC. The interface circuit is provided with a sleep signal generating circuit which generates a sleep signal which is sent to the power processing IC to stop the power supply to the downstream side of the power processing IC when a specific instruction signal is supplied from the host computer. Thus, the power consumption of the memory device can be remarkably reduced. The supply of the sleep signal is stopped immediately after an optical disc or the like is inserted in the drive.

Claims

1. A memory device connected to a host computer and comprising a memory medium, a data read/write circuit including a data read/write mechanism to read and write data from and onto a recording medium, a power circuit, an electric power processing IC provided in the power circuit, an interface circuit provided at a connection to the host computer, and a micro-processor unit which controls the operation of the memory device, wherein;

said interface circuit is connected to a first portion of the power circuit on an upstream side of the electric power processing IC and has an output terminal connected to the electric power processing IC,

said micro-processor unit is connected to a second portion of the power circuit on a downstream side of the electric power processing IC,

said interface circuit is provided with a sleep signal generating circuit which generates a sleep signal to stop a power supply to the downstream side of the electric power processing IC when a specific instruction signal is supplied from the host computer,

whereby the, power supply to the portion of the power circuit on the downstream side of the electric power processing IC including the micro-processor unit is interrupted in accordance with the specific instruction signal.

2. A memory device according to claim 1, wherein said sleep signal generating circuit stops an issuance of the sleep signal when the memory medium is inserted in the data read/write circuit to thereby re-open the power supply to the portion of the power circuit on the downstream side of the electric power processing IC.

3. A memory device according to claim 1, further comprising a pull-down resistor connected to an input/output terminal of the interface circuit to protect an internal circuit of the interface circuit when the power supply to the portion of the power circuit on the downstream side of the electric power processing IC is stopped in response to the sleep signal.

4. A memory device according to claim 1, further comprising a logic circuit connected to an input/output terminal of the interface circuit to prevent a wrong signal from being input by mistake to an internal circuit of the interface circuit when the power voltage applied to the portions of the power circuit on the upstream and downstream sides of the electric power processing IC varies.

5. A memory device according to claim 2, further comprising a pull-down resistor connected to an input/output terminal of the interface circuit to protect an internal circuit of the interface circuit when the power supply to the portion of the power circuit on the downstream side of the electric power processing IC is stopped in response to the sleep signal.

6. A memory device according to claim 2, further comprising a logic circuit connected to an input/output terminal of the interface circuit to prevent a wrong signal from being input by mistake to an internal circuit of the interface circuit when the power voltage applied to the portions of the power circuit on the upstream and downstream sides of the electric power processing IC varies.

7. A memory device according to claim 3, further comprising a logic circuit connected to an input/output terminal of the interface circuit to prevent a wrong signal from being input by mistake to an internal circuit of the interface circuit when the power voltage applied to the portions of the power circuit on the upstream and downstream sides of the electric power processing IC varies.