WO1990012442A1

WO1990012442A1 - A rechargeable battery system for maintaining volatile memory data in a computer

Info

Publication number: WO1990012442A1
Application number: PCT/US1990/001624
Authority: WO
Original assignee: Accumation, Inc.
Priority date: 1989-03-27
Filing date: 1990-03-27
Publication date: 1990-10-18
Also published as: CA2013116A1

Abstract

A rechargeable battery system (28) designed to provide current to one or more volatile memory devices in a computer while the computer is not otherwise energized. When the computer is energized and power is available to the volatile memory device directly from the computer's power supply, the subject system recharges the battery (25'') of the system (28) from the now energized computer power supply (19''). The system (28) includes a transistor (29) which directs the power from the computer's power supply (19''), when energized, through a voltage regulator (31) and resistor assembly (37, 38) to the battery (25'') from the batteries from flowing back to the computer's power supply (19'') when the computer is not energized.

Description

5 A RECHARGEABLE BATTERY SYSTEM FOR MAINTAINING

VOLATILE MEMORY DATA IN A COMPUTER

Field of the Invention 10 A rechargeable battery system for maintaining the data in a volatile memory device of a computer which is recharged and/or refreshed automatically by the computer's normal power supply. 15

Background of the Invention

In existing personal computers, especially that known commercially as the IBM PC/AT, it is conventional

²⁰ to have a mother board with a power supply on which there is a computer chip which serves as a volatile memory device, such as a clock. Conventionally, when the computer is energized, the volatile memory device ⁵ cause the entries in the computer to automatically include the correct time, that is the date or the hour if desired. The problem has been that when the computer is not energized, there must be some way to

30 cause the clock to continue to operate and represent the continuity of time. To this end, there has been provided a battery means connected to the clock or volatile memory device so that it remains energized _≠r^{' 35} when the computer is not energized. Such batteries hopefully have a life of an extended period; however, because of various factors, the batteries lose their energy. This results in a problem of inaccurate information being entered in the computer or the loss of accurate information.

This invention is the provision in the computer of a rechargeable battery system and includes batteries and a circuit associated therewith so the same are recharged while the computer is powered. When the computer is not energized, the battery will take over and drive the clock or volatile memory device, without fear of the battery energy being exhausted.

Objects of the Device

It is an object of this invention to provide a battery recharging circuit and battery means which is simple and effective to provide for recharging of batteries to drive a volatile memory device of such a computer during those periods when the computer is not energized.

Description of the Drawings

Figure 1 is a schematic diagram of the relevant prior art;

Figure 2 is a schematic view illustrating the instant invention; i Figure 3 is a schematic diagram describing more in detail the circuit of the instant invention.

5

Description of the Preferred Embodiment

Referring to the drawings wherein like reference characters designate like or corresponding parts

10 throughout the several views, there is shown in schematic a mother board 15 of a computer represented by the outline 17 on which there is a conventional power supply 19 which through the mother board 5 energizes a volatile memory device or clock 21 when the computer is energized as through the conductor 23 which connects to a source. The volatile memory device or clock senses when power to the computer power supply is

²⁰ interrupted and while this condition prevails, the clock is driven by the battery means 25 through the conductor means 27. This is the state of the prior art.

²⁵ As shown in Figure 2, this invention also provides a mother board 15' of a computer represented schematically as at 17' having a power supply 19' and a volatile memory device or clock 21' which is energized

³⁰ from the power supply 19' when the computer is energized from a wall outlet representing a conventional source as indicated by the numeral 23.

" There is, however, the additional feature of the ' ³⁵ battery means 25' and a circuit means 28* for _^*' accomplishing recharging of the battery means 25'. First, generally, the battery means 25 in the prior art represented in Figure 1 and that of the invention 25*, shown in Figure 2, are for delivering current at about 6 volts DC and at 500 to 600 milli-amp hours. This is for the purpose of supplying the volatile memory device at the rate of about 80 micro amps when the computer is off. It has also been found that about 10 micro amps are utilized in the prior art device when the computer is qη. Referring now to Figure 3, a circuit of the system is generally indicated as 28 and corresponds to 28' of Figure 2 wherein the output of the power supply is represented at 19" and includes 12 volts delivered to a transistor 28 and outputted to a voltage regulator 31 to energize the battery means indicated by the numeral 25". The voltage regulator 31 is also connector to a resistor, preferably 1/2 watt fixed carbon resistor, indicated by the numeral 37 to cause the output to the battery to be constant. Also, in certain applications, a variable potentiometer generally indicated as 39 is provided as shown in Figure 3. A connector as at 39 is provided to provide suitable connector means to supply voltage to the volatile memory device, such as a clock, as discussed with regard to Figure 2. The transistor 29 prevents the circuit 28 from operating if input terminals leading from the 12 volt supply 19" are connected to an a.c. source and improperly to a d.c. source. This transistor also keeps the battery means 25" from discharging through the 12 volt input 19" when no voltage is available at these input terminals. The voltage regulator 31 is adjustable for output voltage and current. It can be so adjusted as to charge the battery means 19" in a stand-by charged state thus affording long-life and the ability to be configured for many applications.

In use, when the power to the computer is interrupted, as in the prior art device of Figure 1, as well as the device shown in Figure 2, the clock or volatile memory device senses that this has occurred and then causes energy to flow from the battery to the volatile memory device. The difference in the operation of the device shown in Figures 2 and 3 from the prior art device of Figure 1 is that when the power to the computer is initiated, the circuit shown in Figure 3 is energized which causes current to flow through the transistor 29, voltage regulator 31 and resistor delivering a recharging current flow to the battery means 25".

Thus, irrespective of the original life of the battery means, there need not be a fear that the battery will wear out and cause defects in the data of the volatile memory device. In the preferred embodiment, the battery means comprises a plurality of rechargeable type nickel-cadmium batteries of proper voltage which are interconnected in series with one another as indicated generally in Figure 3.

Thus, it is seen that the battery is continually recharged when the computer is energized so that when it is not energized it will have sufficient energy to supply the needed current for the volatile memory device. It will be appreciated that the recharging operation takes place automatically upon utilization of this device. While the instant invention has been shown and described in what is considered to be a practical and preferred embodiment, it is recognized that departures may be made within the spirit and scope of this invention which is therefore not to be limited except as set forth in the claims which follow and within the doctrine of equivalents.

Claims

⁵ 1. A rechargeable battery system for use with a computer including a volatile memory device to be energized when the power supply of the computer is not energized and further including:

¹⁰ a rechargeable battery means including, a) at least one rechargeable battery, b) conductor means and connector means to electrically connect the battery to the power supply of

¹⁵ the computer to recharge the battery while the computer is energized, and c) means to sense when the power supply of the computer is not energized and to interrupt current

20 flow from the battery to the power supply and to direct current flow from the battery to the volatile memory device.

2. The product as set forth in claim 1 wherein

25 said battery means comprises a plurality of batteries electrically interconnected in series.

3. The product as set forth in claim 2 wherein said battery means are effective to deliver a voltage

30 of about 6 to 7 volts DC and about 500 to 600 milli-amp hours.

s 35