JPH07162292A - Non-volatile counter circuit - Google Patents

Abstract

PURPOSE:To obtain a non-volatile counter circuit capable of storing a counter value even when a power supply is turned off. CONSTITUTION:The non-volatile counter circuit is constituted of a counter 3, a non-volatile memory 7, a delay part 4, a 5V detection part 2, and mono- stable multivibrators 5, 6. When the power supply 1 is off, output voltage from the power supply 1 is detected and counter data are written in the memory 7 by the multivibrator 6. When the power supply 1 is on, its output voltage is detected and the stored counter data are loaded from the memory 7 to the counter 3 by the multivibrator 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a counter circuit,
In particular, it relates to a nonvolatile counter circuit.

[0002]

2. Description of the Related Art Conventionally, a non-volatile counter has been implemented by a battery backup system using a battery.

FIG. 2 is a block diagram of a conventional nonvolatile counter circuit.

In the figure, a power source 1 is supplied to a counter 3, and a battery 2 is connected to the power source line. When the power supply 1 is off, the battery 2 supplies the power to the counter 3 and the normal counting operation can be maintained.

[0005]

Since the conventional method shown in FIG. 2 is a battery backup method using a battery, it has a drawback that the battery needs maintenance and cannot be maintenance-free.

The present invention proposes one method to solve this drawback.

[0007]

A nonvolatile counter according to the present invention comprises a counter IC1, a nonvolatile memory 2, a delay unit 3,
A 5V detector 4, a one-shot multi 1 and a one-shot multi 2 are provided.

[0008]

1 is a block diagram of a counter circuit according to the present invention.

In the figure, the power source 1 is turned on from the ON state to the OF state.
When in the F state, the 5V detection unit 2 that inputs the output voltage 100 of the power supply 1 outputs a voltage that drops from + 5V to the monostable multivibrator 6. The monostable multivibrator 6 has the characteristic of detecting the falling edge of the input voltage and outputting a predetermined pulse. The pulse signal 104 output from the monostable multivibrator 6 is stored in the nonvolatile memory 7
Input to the WRITE terminal. As a result, the non-volatile memory 7 writes the output data 103-1 to N of the counter 3.

On the contrary, when the power source 1 is changed from the OFF state to the ON state, the output voltage 100 of the power source 1 is input 5
The V detection unit 2 outputs a voltage rising from a low voltage to + 5V to the monostable multivibrator 5. The monostable multivibrator 5 has the characteristic of detecting the rising of the input voltage and outputting a predetermined pulse. The pulse signal 105 output from the monostable multivibrator 5 is the LOA of the counter 3.
The count data 107-1 to N input to the D terminal and stored in the nonvolatile memory 7 when the power is turned off are stored in the counter 3.
Will be LOADed.

The delay unit 4 has an output voltage 100 of the power supply voltage 1.
To produce an output voltage 106 delayed by. The delayed output voltage 106 is input to the 5V detection unit 2, the monostable multivibrators 5 and 6, the counter 3, and the power supply voltage terminal of the nonvolatile memory 7.

As a result, even when the power is off, the count data when the power is normal is stored in the non-volatile memory, and when the power is turned on again, the data in the non-volatile memory is used to make the non-volatile A counter circuit can be realized.

[0013]

As described above, according to the present invention, which is composed of a simple circuit centering on an IC and does not use a battery or the like, there is an effect that it can be maintenance-free.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a counter circuit of the present invention.

FIG. 2 is a block diagram of a conventional embodiment.

[Explanation of symbols]

 1 Power Supply 2 5V Detection Unit 3 Counter Circuit 4 Delay Unit 5, 6 Monostable Multivibrator 7 Nonvolatile Memory 100 Power Supply Output Voltage 101 Counter Pulse Input Signal 102 UP / DOWN Control Input Signal 103 Count Output Signal 104 Monostable Multivibrator 6 Output pulse 105 Output pulse of monostable multivibrator 5 Output voltage of delay unit 4

Claims (2)

[Claims] 1. A counter circuit that counts pulses input from the outside, and means for detecting disconnection of a power supply voltage,
Means for writing the count data of the counter to the non-volatile memory based on the detection output, means for detecting the turn-on of the power supply voltage, and means for reading the data written in the non-volatile memory on the basis of the detection output into the counter. A non-volatile counter circuit having. 2. The non-volatile counter circuit according to claim 1, wherein a voltage obtained by delaying a power supply input voltage for a predetermined time is used as an operating voltage.