JPH05143805A - Memory card - Google Patents

Abstract

PURPOSE:To reduce the power consumption of an external power source by controlling a pull-up resistor by setting high potential connected to the pull-up resistor of a memory card as the output of a semiconductor element provided with an output off state. CONSTITUTION:When a signal is added on a card control signal line 7 from the outside, the potential of the card control signal line 7 is fixed, and it is not required to fix the potential of the card control signal line 7 by the pull-up resistor 8. At this time, the output of a tri-state element 9 is set in the output off state by an output control line 10. Thereby, the power consumption of the external power source can be reduced. Also, when the signal is added on the card control signal line 7 from the outside, it is required to fix the potential level of the card control signal line 7 by the pull-up resistor 8. At this time, the output of the tri-state element 9 is set as the one with high voltage level by the output control line 10. Thereby, it is possible to prevent malfunction from occurring without opening the input line of a memory control element 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pull-up resistor connecting method for connecting a control signal line in a memory card to a high potential.

[0002]

2. Description of the Related Art At least a conventional RAM, a battery, an element for switching a battery voltage and a power source supplied from the outside of a memory card, an element for controlling the memory, and a pull-up resistor for connecting a control signal line of the memory to a high voltage. FIG. 2 is a block diagram of a memory card configured by.

In a conventional memory card, as shown in FIG. 2, a power source 21 (hereinafter,
An external power supply 21 was connected to a pull-up resistor 28 that connects a control signal line of the memory card (hereinafter abbreviated as memory card control signal line 27) to a high voltage.

In the conventional memory card, since the card control signal line 27 is directly pulled up to the external power source 21,
When an L level signal is applied to the card control signal line 27, a current flows through the pull-up resistor 28 and the current consumption of the external power supply increases.

[0005]

In the above prior art, since the card control signal line 27 is directly pulled up to the external power source 21, when the L level signal is applied to the card control signal line 27. However, there is a problem in that a current flows through the pull-up resistor 28 and the current consumption of the external power supply increases.

The present invention has been made to solve the above problems, and an object thereof is to make a high potential grounded to a pull-up resistor of a memory card an output of a semiconductor element having an output off state. As a result, the pull-up resistor can be invalidated. Therefore, the purpose is to control the pull-up resistor and reduce the external power supply tail current consumption.

[0007]

In the memory card according to the present invention, a high potential connected to a control signal line of the memory card through a pull-up resistor is used as an output of a semiconductor element having an output off state. Thus, the pull-up resistor can be invalidated.

Accordingly, it is intended to control the pull-up resistor to reduce the current consumption of the external power supply.

[0009]

FIG. 1 is a block diagram of a memory card showing an embodiment of the present invention.

In FIG. 1, a power source 1 (hereinafter abbreviated as external power source 1) supplied from the outside of the memory card and a battery 2 are an element 3 (hereinafter, referred to as a battery voltage and a voltage supplied from the outside of the memory card). Power switching element 3
Is abbreviated).

The internal power source 6 is an element 4 for controlling the memory.
(Hereinafter, abbreviated as memory control element 6) and a power source for the RAM 5. The power supply switching element 3 outputs an external power supply voltage when the external power supply 1 is applied, and outputs a battery voltage when the external power supply 1 is not applied.

A control signal line 7 of the memory card (hereinafter abbreviated as a card control signal line 7) is connected to a semiconductor element 9 (hereinafter abbreviated as a tri-state element 9) having an output off state via a pull-up resistor 8. It is connected. Output control line
Reference numeral 10 is for controlling the tri-state element 9, and depending on the state of the output control line 10, the tri-state element 9 can be in two states of a high voltage level output and an output off state.

Generally, an input line of a semiconductor element cannot be opened, and it is necessary to apply a high voltage level potential or a low voltage level potential to the input line without fail.

When a signal is externally applied to the card control signal line 7, the potential level of the card control signal line 7 is fixed, and the potential level of the memory card control signal line 7 is not fixed by the pull-up resistor 8. , Is unnecessary. At this time, the output control line 10 turns off the output of the tri-state element 9. As a result, the current consumption of the external power supply can be reduced. When no signal is externally applied to the card control signal line 7, it is necessary to fix the potential level of the card control signal line 7 by the pull-up resistor 8. At this time, the output control line 10 causes the output of the tri-state element 9 to be a high voltage level output.

As a result, even when no signal is externally applied to the card control signal line 7, the input line of the memory control element 6 will not be opened, and malfunction of the memory control element 6 can be prevented. ..

[0016]

As is apparent from the above description, according to the present invention, at least the RAM, the battery, the element for switching the battery voltage and the power supplied from the outside of the memory card, the element for controlling the memory, and the memory card. In a memory card composed of a pull-up resistor connecting a control signal line to a high potential, the pull-up resistor is effective by setting the high potential connected to the pull-up resistor to the output of a semiconductor element having an output off state. It is possible to create a simple state and an invalid state.

Therefore, there is an effect that the pull-up resistor can be controlled to reduce the current consumption of the memory card external power source.

[Brief description of drawings]

FIG. 1 is a block diagram of a memory card showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional memory card.

[Explanation of symbols]

1 Power supply supplied from outside the memory card 2 Battery 3 Device that switches between battery voltage and voltage supplied from outside the memory card 4 Device that controls memory 5 RAM 6 Internal power supply 7 Memory card control signal line 8 Pull-up resistor 9 Output Semiconductor device in the off state 10 Output control line 21 Power supply supplied from outside the memory card 22 Battery 23 Device that switches between battery voltage and voltage supplied from outside the memory card 24 Memory control device 25 RAM 26 Internal power supply 27 Memory card Control signal line of 28 Pull-up resistor

Claims (1)

[Claims] 1. At least a RAM and a battery, an element for switching the battery voltage and a power source supplied from the outside of the memory card, an element for controlling the memory, and a pull-up resistor for connecting a control signal line of the memory card to a high potential. In the constituted memory card, a high potential connected to the pull-up resistor is used as an output of a semiconductor element having an output off state.