JPH01266695A - Power source control circuit for memory card - Google Patents

Abstract

PURPOSE:To simplify the delivery case of a RAM card and to extend the service life of a battery by providing a switch in a power source control circuit for the RAM card, and turning ON/OFF connection to the battery for backup arbitrarily. CONSTITUTION:An ON/OFF switch 16 is the switch, for example, of sliding type, and the switch is closed by sliding to a right side, and the voltage of the battery 10 for backup is impressed on a memory chip 1. Adversely, when the switch is slided to a left side, the switch is opened, and no voltage of the battery 10 is introduced to the chip 1 entirely. The switch 16 is opened while being transported in a long distance from the delivery of the RAM card from a manufacturer to a user. Therefore, the battery 10 is delivered from the manufacturer at a state where it is set at a normal position and by a normal method even when it is exchangeable. No consumption of the battery 10 occurs since the circuit is opened, and it remains as a new product with normal capacity just before the user uses it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a memory card, and in particular to an R A 1.4 card incorporating a backup battery.

[Conventional technology]

Figure 2 is a basic configuration diagram of a memory card described on page 10 of the "IC Memory Card Guidelines" by the Personal Computer Business Committee of the Japan Electronics Industry Promotion Association. ,(
2) is an interface connector, (8) is a control line such as a read/write signal, (4) is an upper address line, and (5) is a control line such as a read/write signal.
) is the lower address line, (6) is the data line, L7) #
(a3 is the power supply and ground, (9), αQ is the RAM
Power control circuit and backup battery for cards (
11) is a control and chip select circuit, and Q3 is a write protect switch. Also, Figure 3 shows the power supply control circuit (9) and backup battery α in the case of a RAM card.
O) is shown in detail, and in the figure,
03 are both backflow prevention diodes, and ns+ is a current control resistor. The former backflow prevention diode U allows the current of the backup battery α0 to pass through the interface connector (
2), and the latter backflow prevention diode C14) prevents the current from the power supply (7) from the reader/writer from flowing through the interface connector (2) for backup purposes. Prevent charging of battery aQ. The resistor α9 is provided to prevent the maximum charging current from exceeding the allowable charging current when the reverse current prevention diode (3) is damaged.

By these two diodes t13) and (14), the higher voltage of the voltage of the external power supply (γ) and the voltage of the backup battery αQ will be applied to the memory chip (1). Backup battery aQ
The voltage for boat fishing is approximately 3V due to the primary voltage of lithium. First of all, when the voltage of the power supply (γ) is around 5V, diode Q3 is in a conductive state and diode I is in a non-conductive state, and normally data is not read or written to the memory chip (1). will be carried out. Next, RAM
When the voltage of the power supply (7) is 0, such as when carrying a card, etc.
At 10 o'clock, diode U is non-conducting and diode I
is in a conductive state, and the voltage of the backup battery αQ is applied to the memory chip (1).
) is in standby state and the data stored in the memory chip is retained. At this time, the battery is exhausted.

In this way, in a RAM card, a backup battery (10) is used to hold data in the memory chip (1) when there is no voltage from an external power source. Depending on the capacity ffi (mAh) of the battery αO) and the number of memory chips (1), there are two implementations: one in which they are completely built into the RAM card, and another in which they can be easily replaced from the outside.

For example, when there is only one memory chip (1), the standby current of the memory chip (1) is small, so the battery life is several years or more, and there is no need to replace the battery. RA 14 cards are common. Next, if there are only a few memory chips (1), the battery life may be less than one year, so 3-5 year RA h4 cards are used, so battery-replaceable RAM cards are common. .

In the case of this large-capacity battery-replaceable RAM card, as mentioned above, the battery life is less than one year, and if the battery is installed when the RAM card is shipped from the manufacturer, it will be stored at a business office for a long time and the user will not be able to use it. By the time the battery reaches your hands, the battery life may be significantly shortened.

Conventionally, for example, the card and battery were shipped in separate cases, and the user inserted the battery into the card just before purchasing and actually using it, or placed a thin insulating sheet between the battery and the electrodes. They are shipped sandwiched together, and the user removes the insulating sheet immediately before purchasing and actually using the product.

[Problem to be solved by the invention]

Since the connection between the power control circuit and the backup battery of conventional RAM cards is configured as described above, in the case of a large-capacity, battery-replaceable type, two shipping cases are required, one for the card and one for the battery. There were other problems, such as the insulating sheet being large and difficult to handle, and the insulating sheet unnecessarily weakening the springiness of the electrode for contacting the battery.

If the user is long (if no RAM card is used),
In order to prevent wasted battery life, it was troublesome to take out the battery, and there was no easy way to stop using the battery.

This invention was made to solve the above-mentioned problems.When shipped from the manufacturer, there is no need for special cases, sheets, or work, and the battery can be delivered to the user's hands. In addition to preventing unnecessary consumption of
To obtain a power supply control circuit for an RA 1,4 card that can easily disable battery use when not used for a long time.

[Means to solve the problem]

The power supply control circuit for a RAM card according to the present invention has a switch between it and the backup battery that can be turned on and off at any time from the outside, so that the voltage of the backup battery can be applied to or cut off from the memory chip. .

[Effect]

The switch in this invention is turned on when the user purchases it and starts using it, or when it is necessary to retain data in the RAM card, so that the backup battery voltage can be applied to the memory chip. be.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (6) is an ON/OFF switch, and may be of a sliding type, for example.

It can be operated from the outside with a finger or the tip of a mechanical pencil, and by moving it to the right, the switch closes, closing the circuit and allowing the voltage of the backup battery αQ to be applied to the memory chip (1). Conversely, by moving to the left, the switch opens 1, the circuit opens, and the voltage of the backup battery α@ is no longer introduced to the memory chip.

This switch σe is left open for a long time after the RAM card is shipped from the manufacturer until it reaches the user.Therefore, even if the backup battery α0) is a replaceable type, it must not be stored in the correct location. It is shipped from the manufacturer after being set using a regular method.

The backup battery α@ does not wear out because the circuit is "open" and remains close to the new capacity (tytAh) until just before the user uses it.Similarly,
When the user does not use the RAM card for a long time, the user can easily open the switch (161) to prevent unnecessary battery consumption.

Next, when the user purchases a RAM card and starts using it, by closing the switch (161), the data retention function of the memory chip (1) is activated and the RAM card can be used for its intended purpose. From this moment on, the backup battery αQ will begin to be depleted for the first time, and the battery will not be depleted from the time of shipment from the manufacturer, and will be used only for actual use by the user.

〔Effect of the invention〕

As described above, according to the present invention, a switch is provided in the power control circuit of the RA 14 card, and the connection with the backup battery can be turned on and off at will.
The shipping case for RAM cards has become simpler and smaller in size, and from the time users start using them,
The user can easily use a backup battery only for data retention, and the overall effect is that an inexpensive RAM card can be provided and the battery life can be extended.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of a power control circuit of a RAM card according to an embodiment of the present invention, FIG. 2 is a basic configuration diagram of a memory card, and FIG. 3 is a basic configuration diagram of a power control circuit of a conventional RA h4 card. It is. (1) is a memory chip, (7) (8) is a power supply, ground, (9) is a power supply control circuit, (10) is a backup battery, (131C14) is a diode, (151 is a resistor, and 16) is a switch. be.

Claims (1)

[Claims] In a memory card having a backup battery for data retention, a power supply control circuit that switches between the power supply voltage supplied from the outside and the battery of the backup battery and applies it to the memory chip is provided with a switch that can be turned on and off from the outside. A power supply control circuit for a memory card, characterized in that supply of backup battery voltage to the memory chip can be arbitrarily controlled.