JPH0358111A - Semiconductor disk device - Google Patents

Abstract

PURPOSE:To extend the backup time of a semiconductor memory to be brought to backup by providing a power source switching control part for selecting one DC power source from among a main power source part, a primary battery and a secondary battery and supplying it to the semiconductor memory. CONSTITUTION:In the case a main power source permitting signal is inputted to a power source switching control part, a DC power source from a main power source part 3 is selected and supplied to a semiconductor memory 1. In the case a main power source disconnecting signal is inputted to the power source switching control part 8, a DC power source from a secondary battery 6 is selected and supplied to the semiconductor memory 1. Also, in the case the DC power source from the secondary battery 6 is supplied to the semiconductor memory 1, when this DC power source drops, a DC power source from a primary battery 7 is selected and supplied to the semiconductor memory 1. In such a way, the backup time when a prescribed DC power source can be supplied to the semiconductor memory 1 becomes a total of the backup time of the secondary battery 6 and the primary battery 7, therefore, the backup time can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor disk device backed up by a battery, and more particularly to a semiconductor disk device having a primary battery and a secondary battery as backup batteries.

[Prior Art] Conventionally, one of the following two types of batteries has been used as a backup battery in a semiconductor disk device.

■Primary batteries, that is, batteries that cannot be returned to their original state by charging once discharged, such as water-based batteries and lithium batteries.

■Secondary batteries, such as lead-acid batteries and nickel-cadmium batteries, which can be used repeatedly by being discharged and then charged using an external power source.

[Problems to be Solved by the Invention] In recent years, the capacity of semiconductor disk devices has increased, so the power consumed by backup has also increased.

Therefore, when a primary battery is used as a backup battery, the life of the primary battery is extremely shortened because it cannot be charged, and the period during which backup can be performed is also significantly shortened. In order to avoid this, the only way to avoid this is to increase the number of primary batteries, so there is a problem in that a large number of primary batteries are required to back up a large capacity semiconductor disk device.

Further, when a secondary battery is used as a backup battery, it is possible to charge and replenish the power consumed by the backup, so that it is possible to cope with an increase in the capacity of the semiconductor disk device to some extent. However, for example, when the amount of discharge is large compared to the amount of charge, the backup time that can be backed up is less than the maximum backup time when the secondary battery is fully charged. Therefore, there is a risk that the semiconductor disk device will not be able to be backed up and the memory contents of the semiconductor disk device will be erased.
Further, there is a problem in that the life of the secondary battery is significantly shortened due to repeated over-discharging.

[Means for Solving the Problems] The semiconductor disk device of the present invention has the following means.

(a) Main power supply section that converts AC power into DC power and supplies it; (b) Primary battery that supplies DC power; (c) Secondary battery that supplies DC power; (e) Monitors the status of the DC power supply supplied from the main power supply unit, and outputs a main power enable signal when the DC power supply is in a normal state, indicating that the DC power supply is abnormal. (f) selects one DC power source from among the DC power sources of the main power source section, primary battery, and secondary battery and supplies it to the semiconductor memory; Power supply switching control unit.

[Operation] When the main power supply permission signal is input to the power supply switching control section, the DC power from the main power supply section is selected and supplied to the semiconductor memory. When the main power supply cutoff signal is input to the power supply switching control section, DC power from the secondary battery is selected and supplied to the semiconductor memory. In addition, DC from the secondary battery
When power is being supplied to the semiconductor memory and this DC power drops, the DC power from the primary battery is selected and supplied to the semiconductor memory.

Therefore, if the DC power of the secondary battery is being supplied to the semiconductor memory because the AC power is cut off and normal DC power is not supplied from the main power supply to the semiconductor memory, the voltage of the DC power of this secondary battery will be When the voltage drops, DC power from the primary battery is supplied to the semiconductor memory instead of the secondary battery.

[Example] Next, the present invention will be explained with reference to the drawings.

The figure is a block diagram showing an embodiment of the semiconductor disk device of the present invention.

1 is a semiconductor memory backed up by a battery;
2 is an access made to this semiconductor disk device 10 from a host device. That is, it is an access control section that controls reading and writing to the semiconductor memory. 3 is a main power supply unit that inputs AC power and supplies DC power; 4 is a power supply monitoring unit that monitors whether the main power supply unit 3 is powered off; and 5 is a control unit that controls charging of a backup secondary battery 6. The charging control unit 7 is a backup primary power source. 8 is a main power supply section 3.8 for the semiconductor memory 1. This is a power supply switching unit that switches and supplies the primary power source 7 or the secondary power source 6.

Next, the operation will be explained.

(1) When the AC power is normal If the AC power is being supplied to the main power supply section 3 as usual,
The main power supply section 3 includes a power supply switching control section 8 and a charging control section 5.
supply normal DC voltage to the

The power supply monitoring section 4 is connected to the D that is supplied to each section from the main power supply section 3.
When detecting that the C power supply is normal, it sends an access permission signal to the access control unit 2 to permit execution of access, and also sends the DC power supply from the main lightning source unit 3 to the power supply switching control unit 8 to the semiconductor memory. Sends a main power permission signal instructing power supply to ↓.

As a result, when the access control unit 2 receives the access permission signal and accepts an access request from the host device,
Executes read and write access to semiconductor memory 1. On the other hand, the power supply switching control section 8 that has received the main power supply permission signal supplies the DC power supplied from the main power supply section 3 to the semiconductor memory l.

Furthermore, the charging control section 5 charges the primary battery 6 using the DC power supplied from the main power supply section 3 .

When the f21Ac power supply stops When the AC power that has been normally supplied to the main power supply unit 3 stops, the voltage of the DC power output from the main power supply unit 3 gradually decreases. The power supply monitoring unit 4 that has detected this drop in the DC power supply voltage sends an access stop signal to the access control unit 2 and outputs a main power cutoff signal to the power supply switching control unit 8.

As a result, the access control unit 2 that has received the access stop signal immediately stops reading and writing accesses from the host device to protect the contents of the semiconductor memory 1. On the other hand, the power supply switching control unit 8 that has received the main power supply disconnection signal switches the DC power supply to the semiconductor memory 1 from the DC power supply of the main power supply unit 3 to the DC power supply of the secondary battery 6 .

Thereafter, the power supply switching control unit 8 monitors the voltage state of the DC power supply of the secondary battery 6. When the power supply switching control unit 8 detects that the voltage output of the secondary battery 6 has decreased below a predetermined value, the power supply switching control unit 8 switches the DC power supply to the semiconductor memory from the DC power supply of the secondary battery 6 to the DC power supply of the primary battery 7. Switch to In this manner, by switching the supply source of DC power to the semiconductor memory 1 from the secondary battery 6 to the primary battery 7, over-discharge of the secondary battery 6 can be prevented.

(31 When the AC power returns to normal state When normal AC power is supplied to the main power supply section 3, the voltage of the DC power output from the main power supply section 3 gradually increases.Power supply monitoring section 4 When detecting that the DC power supply has reached a usable voltage, it outputs an access permission signal to the access control section 8 and outputs a main power permission signal to the power supply switching control section 8 .

As a result, the access control unit 2 that has received the access permission signal allows read and write access to the semiconductor memory 1 from the host device. On the other hand, the power supply switching control unit 8 that has received the main power supply permission signal switches the DC power supply to the semiconductor memory device to the secondary battery 6 or the primary battery 7.
Switch from the DC power source to the DC power source of the main power supply section 3.

The secondary battery 6 is charged by the charging control unit 5 and enters a charging state. At this time, the primary battery 7 enters a discharging stopped state.

[Effects of the Invention] As explained above, according to the semiconductor disk device of the present invention, when the main power supply permission signal is input to the power supply switching control section, the DC power supply from the main power supply section is selected and the semiconductor memory is Supplied. When the main power supply cutoff signal is input to the power supply switching control section, DC power from the secondary battery is selected and supplied to the semiconductor memory. Furthermore, when DC power from the secondary battery is being supplied to the semiconductor memory and this DC power drops, the DC power from the primary battery is selected and supplied to the semiconductor memory.

As a result, if the DC power of the secondary battery is being supplied to the semiconductor memory because the AC power is cut off and normal DC power is not supplied from the main power supply to the semiconductor memory, the DC power of the secondary battery will be When the voltage drops, DC power from the primary battery is supplied to the semiconductor memory instead of the secondary battery.

Therefore, the backup time during which a predetermined DC power can be supplied to the semiconductor memory is the sum of the backup times of the secondary battery and the primary battery, so the backup time can be extended. In addition, when the output voltage of the secondary battery that supplies DC power to the semiconductor memory drops, the supply of DC power from the secondary battery to the semiconductor memory is stopped. It has the effect of extending the life of the next battery.

[Brief explanation of drawings]

The figure is a block diagram showing an embodiment of the semiconductor disk device of the present invention. ■... Semiconductor memory, 3... Main power supply unit, 4... Power supply monitoring unit, 6... Secondary battery, 7... Primary battery, 8...
. . . Power supply switching control unit, 10 . . . Semiconductor disk device.

Claims (1)

[Scope of Claims] A main power supply section that converts and supplies AC power to DC power; a primary battery that supplies DC power; a secondary battery that supplies DC power; and a main power supply that converts and supplies DC power. It monitors the status of the semiconductor memory held and the DC power supplied from the main power supply unit, and outputs a main power permission signal when the DC power is in a normal state, and outputs a main power permission signal when the DC power is in an abnormal state. a power supply monitoring section that outputs a main power cutoff signal to the main power supply section, and a power supply switching control section that selects one DC power source from among the DC power supplies of the main power supply section, the primary battery, and the secondary battery and supplies it to the semiconductor memory. However, the power supply switching control unit selects the DC power from the main power supply unit and supplies it to the semiconductor memory when the main power supply enable signal is input, and selects the DC power from the secondary battery when the main power supply disconnection signal is input. If DC power is selected and supplied to the semiconductor memory and DC power from the secondary battery is supplied to the semiconductor memory, and this DC power drops, the DC power from the primary battery is selected and supplied to the semiconductor memory. A semiconductor disk device characterized by supplying.