JPH02140815A - Memory card - Google Patents

Abstract

PURPOSE:To easily exchange batteries without mistakes by providing a main battery which can be exchanged as the battery for holding storage data and an auxiliary battery which is connected to the main battery in parallel. CONSTITUTION:An auxiliary battery part 23 is added in parallel to a main primary battery part 22. The auxiliary primary battery part 23 is constituted in such a way that a protection diode 18, a protection resistance 19, the auxiliary primary battery 20 and a switch 21 which is turned on and off in connection with the exchange action of the main primary battery 13 are connected in serial. When the main primary battery 13 is exchanged, the switch 21 is turned on in connection with an action fetching a battery holder in which the main primary battery 13 is stored from a memory card mainbody, and the auxiliary primary battery 20 supplies power for holding storage data to an internal power source 11. Thus, the batteries can easily be exchanged without eliminating storage data and without mistakes in a memory card unit because the internal power source is automatically switched at the time of exchanging the main battery.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a memory card that is equipped with a volatile semiconductor memory such as a static RAM and is used by being attached to an external device such as a terminal, especially a memory card that is carried or carried by a battery. The present invention relates to a memory card that can retain stored data even when there is no external power source, such as when there is no external power source.

[Prior Art] FIG. 5 is a block diagram showing the configuration of a conventional memory card. In the figure, reference numeral 1 denotes a memory circuit section, which is composed of a plurality of static RAMs 2 and an address decoder 3 for selecting them, and each static RAM 2 is connected to an address bus 4. Data bus 5 is connected, and write enable (WE) signal 6. Output enable (O
E) The signal 7 and the chip enable signal from the address decoder 3 are input, and the address decoder 3 also receives the upper few bits of the address bus 4 and the chip select (CS) signal.
signals are input, and based on these, any static RA
A chip enable signal is output to M2. Reference numeral 9 denotes a power supply control circuit unit, which detects the voltage of an external power input 10 from a terminal device etc. into which the memory card is installed, and when the voltage exceeds a specified value, the external power input 10 is used as an internal power supply 11 to control the memory circuit. At the same time, a control signal 12 of logic level "HII" is output to the memory circuit section 1 to make the memory circuit section 1 active, that is, ready for operation, and when the voltage is below a specified value, the external power source 10 is cut off. and control signal 1
2 is set to logic level "'L" (ground level), and the memory circuit section 1 is placed in a power-down state, that is, a standby state. On the other hand, 13 is a primary battery for retaining stored data.

Reference numerals 14 and 15 denote a protection diode and a protection resistor that are connected in series to the secondary battery 13 and limit the current flowing into the primary battery 13, and the secondary battery 13 is connected to the internal power supply 1 through these.
Connected to 1. Note that 16 is a capacitor connected in parallel to the primary battery 13, and 17 is a battery voltage monitor terminal for monitoring the voltage of the primary battery 13 with an external device to which the memory card is attached.

Next, the operation will be explained.

When the memory card is attached to an external device and the voltage of the external power input 10 reaches a specified value or more, the power supply control circuit section 9 supplies the external power supply 10 to the internal power supply 11 and at the same time inputs the control signal 12 to the internal power supply 11. The logic level ``H'' is output. As a result, the memory circuit section 1 becomes active, and each static RAM 2 can be read and written. This operation is similar to the operation of the static RAM 2 alone, and is well-known. Since this is a technology, the details thereof will be omitted.

On the other hand, if the voltage of the external power supply 10 becomes lower than the specified value due to the memory card being removed from the external device, etc., the power supply control circuit section 9 cuts off the external power supply 10 and at the same time outputs the control signal 12. The logic level is set to "L", and the memory circuit section 1 is placed in a power-down state. At this time, -th battery 1
3 is supplied to the internal power supply 11 via the protection resistor 15 and the protection diode 14, so the data stored in each static RAM 2 is retained.

Here, the battery life of the secondary battery 13 will be considered. In general, the standby current of static RAM2 is 1 μA at 25°C and 5 μA at 50°C, even if a low current type is used.
It becomes about μA. In the case of a memory card that uses 16 static RAM2.

At 25°C, 1μAX16 = 16μA At 50°C, 5μAX16 = 80μA. Now, when calculating the battery life when the battery capacity of the secondary battery 13 is 70 mAH, it is as follows. Note that the battery capacity is 2.5V when the voltage of the primary battery 13 is the final voltage.
It is defined by the capacity up to . Further, this voltage can be detected by an external device using the battery voltage monitor terminal 17.

L 1 = 70 rn A / 16 p A = 437
From this calculation, the primary battery 13 needs to be replaced frequently.

It goes without saying that when replacing the primary battery 13, it is necessary to replace it while retaining the data stored in the static RAM 2.At this time, if the voltage supplied from the external power source 10 is below the specified value, the internal The power supplied to the power supply 11 is only the energy stored in the capacitor 1.6.

Generally, the thickness of a memory card is 2 to 4 mm, and the capacitance value and number of capacitors 16 are limited because components are mounted in a high density. Here, the eight conditions for determining the power supply maintenance time of the static RAM 2 at an ambient temperature of 25° C. when the capacitance C of the capacitor 16 is 0.1 μF x 20 pieces = 2 μF are as follows. 2.6V, and the power supply voltage at which the data stored in static RAM 2 is guaranteed is 2.6V. O
Let it be V.

FIG. 6 shows the power supply current from the capacitor 16.
In this figure, i standby current ■: forward voltage V* at current i: current i when the resistance value of the protective resistor 15 is R
If R = 1.5 and Ω, then 1 = 16μA, so V++ = 16X10-"Xl, 5X10' = 0.02
It becomes 4V. Vr”Fo, 3V, VF:>V
I'll do it. The relationship between the discharge time and discharge energy of the standby current i of the capacitor 16 is Δq=C×Δv=i )-2,0=0.3V. Therefore, t=CXΔv/1 =2xlO-'xo, 3/16xlO-'-37.6m
s, which is a very small value. If capacitor 16 is 20μ
Even if it is set to
becomes.

Generally, even if the battery is replaced quickly, it takes about 10 seconds. The capacity of the capacitor 16 required at that time is as follows.

Δq=cxΔv=iXt C=iXt/ΔV =16X10-'Xl010.3 Misaki 533μF Therefore, a large capacity capacitor is required.

When the ambient temperature is 50℃, 533μF x 5 = 2665
A capacitance of μF or more is required. Due to its structure, it is impossible to mount a capacitor of the above value inside a thin, business card-sized memory card.

[Problems to be Solved by the Invention] Since the conventional memory card is configured as described above, in order to replace the primary battery 13 without losing the data stored in the static RAM 2, a capacitor 16 of a very large capacity is required. It is impossible to implement such a capacitor in a thin, business card-sized memory card. Therefore, when replacing the secondary battery 13, it is necessary to attach the memory card to an external device and supply the external power source 10, and sometimes data in the memory card is transferred to an external storage device such as a magnetic disk. Evacuation (memory)
There was a problem that I had to let them do it.

This invention was made in order to solve the above-mentioned problems, and the purpose is to provide a memory card that allows batteries to be easily replaced without making mistakes while the card is alone, without losing stored data when replacing batteries. shall be.

[Means for Solving the Problems] A memory card according to the present invention includes a replaceable main battery and an auxiliary battery connected in parallel to the main battery as a battery for retaining stored data. A switch is provided in series with the auxiliary battery, which opens and closes in conjunction with the replacement operation and closes when the battery is replaced.

[Function] In this invention, the auxiliary battery retains the data stored in the memory when the main battery is replaced, and the switching between the main battery and the auxiliary battery is performed by a switch provided inside the card in conjunction with the main battery replacement operation. This is done automatically by opening and closing.

[,Example] An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are circuit diagrams and structural diagrams mainly showing the battery power supply portion of the memory card in this embodiment, and the other circuit configurations in the memory card are the same as those shown in FIG. 5 above. 1 In this embodiment, as shown in FIG.
An auxiliary secondary battery section 23 is added in parallel to the secondary battery section 22. This auxiliary secondary battery section 23 has a protection diode 18.
The protective resistor 19 is connected in series with an auxiliary secondary battery 20 for retaining stored data when the primary secondary battery 13 is replaced, and a switch 21 that opens and closes in conjunction with the replacement operation of the primary secondary battery 13. ing. The switch 21 is a limit switch consisting of contact terminals 24 and 25 and a contact piece 26, and the contact piece 26 is biased toward the contact terminals 24 and 25.

Note that 27 and 28 are a ten-electrode terminal and one-electrode terminal to which the main battery 13 is connected by contact, 29 is a memory card body, 30 is a battery holder that holds the main battery 13, and 3
1 is a printed circuit board on which the electric circuit shown in FIG.
The switch 21 is connected to the battery holder 3 as shown in FIG.
0 is stored in the storage section 32, and the protrusion of the contact piece 26 is pressed open by the tip of the battery holder 30 during normal use, and is released and closed when replacing the printed circuit board 31.
It is positioned and provided.

Next, the operation will be explained. In addition, FIG. 3(a).

(1)) is a circuit diagram showing the state during each operation, and Figure 4 (al.
, (bl is a state diagram showing the operation.

Detect the voltage of the battery voltage monitor terminal 17 with an external device, and
．． When the voltage reaches 6V, replace the main battery 13. At this time, the switch 21 is turned on in conjunction with the operation of removing the battery holder 30 containing the primary battery 13 from the memory card body 29, and the auxiliary battery 20 receives internal power for retaining the stored data. Power supply 11 is supplied.

Conversely, when the main battery 13 supplies the internal power 11, the switch 21 is turned off because the battery holder 30 containing the main battery 13 is set inside the memory card body (storage section 32). Therefore, the power supply from the auxiliary secondary battery 20 to the internal power supply 11 is cut off, thereby preventing the auxiliary secondary battery 20 from being exhausted.

The capacity of the auxiliary secondary battery 20 that is consumed during battery replacement is 16 μA when the ambient temperature is 25°C and 80 μA when the ambient temperature is 50°C, so the standby current of the static RAM 2 is 16 μA when the ambient temperature is 50°C. Ba.

Capacity at 25°C = 16x10-'xlO/3600 ≠0.04μAH Capacity at 50°C = 80x10-'xlO/3600 Misaki 0.2μAH So, let's take a margin and set the replacement time to 30 seconds. Auxiliary battery 2 required when replacing 100 times
0 capacity is battery capacity at 25℃ = 16x10-'x30/3600xlOO≠0.01
3mAH Battery capacity at 50℃ = 80x10-'x30/3600x100'' = 0.0
It becomes 67mAH, which is a very small value. Generally, the auxiliary secondary battery 20 with this capacity has a very small size and can be mounted on a thin memory card.

In the above embodiment, the main secondary battery section 22 and the auxiliary secondary battery section 23, each equipped with a protection diode and a protection resistor, are connected in parallel. A series circuit of an auxiliary battery 20 and a switch 21 may be connected in parallel to the secondary battery 13, and the same effect as in the above embodiment can be obtained. can also be monitored.

[Effects of the Invention] As described above, according to the present invention, a replaceable main battery and an auxiliary battery connected in parallel to the main battery are provided as batteries for storing stored data, and the main battery can be replaced. By placing a switch in series with the auxiliary battery that opens and closes in conjunction with operation and closes when replacing the main battery, internal power is automatically switched to the auxiliary battery when the main battery is replaced, so you can use the memory card as a standalone battery. The battery can be replaced easily and without error without losing stored data, and the effect is that a small and inexpensive memory card can be obtained.

[Brief explanation of the drawing]

1 and 2 are a circuit diagram and a structural diagram showing a battery power supply portion of a memory card according to an embodiment of the present invention, and FIG. 3 (al.
, (bl and FIG. 4(al), (bl is a circuit diagram and a structural diagram for explaining the operation of the embodiment, FIG. 5 is a block diagram showing the configuration of a conventional memory card, and FIG. 6 is a diagram showing the structure of a conventional memory card. 1 is a diagram for explaining power supply from a capacitor. 1 is a memory circuit section, 2 is a static RAM (volatile semiconductor memory), 3 is an address decoder, 9 is a power control circuit section, 10 is an external power input, 11 is an internal power supply, 13 is a main battery, 20 is an auxiliary battery, 21 is a switch, 22
23 is a main battery section, 23 is an auxiliary battery section, 29 is a memory card body, 30 is a battery holder, 31 is a printed circuit board, and 32 is a storage section. In addition, in one figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A main battery that is replaceable as the battery in a memory card to which a battery for retaining data stored in the semiconductor memory is connected when there is no external power input to a volatile semiconductor memory that becomes operational when an external power input is input. A memory card comprising an auxiliary battery connected in parallel to the main battery, and a switch connected in series with the auxiliary battery that opens and closes in conjunction with the replacement operation of the main battery and closes when replacing the main battery. .