JPH04225184A - Device for multiple-step detection of battery voltage - Google Patents

Abstract

PURPOSE:To notify a degree of consumption of a battery at several stages without increasing the number of parts by switching the load current of the battery to a multistage and detecting the degree of a voltage drop by the magnitude of the load current with a voltage detector. CONSTITUTION:A control element 2 makes a fixed process by the indication of a key input element 3 and the program of a ROM 4, and displays (6) the result. The control element 2 is driven by one of among a clock H to make the output frequency of a oscillator 8 basic and clocks M, L divided (9), through a change-over switch 7. H is set at the maximum value and L the minimum on clock frequency. A power source is made on and the change-over switch 7 specifies the clock L to the control element 2. If terminal voltage VDD in operation in this clock is 2. 7 V or more by a voltage detector 1, the clock L is switched (7) to the clock M; and if less than 2.7V, for example 'No battery' is displayed (6), and power is automatically made off. If the VDD is 2.7V or more in the clock M, the clock M is switched to the clock H (7) ; and if less than 2.7V, 'Battery exchange' is displayed (6). If the VDD is less than 2. 7V in the clock H, 'Battery a little consumed' is displayed (6).

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-step detection device for detecting a voltage drop at a battery terminal for the purpose of notifying a user of battery exhaustion in electronic equipment using a battery as a power source.

0002

2. Description of the Related Art Conventionally, in electronic equipment that uses a battery as a power source, a method of detecting a decrease in the terminal voltage of the battery is known as a method for detecting battery consumption. As a specific example, two or more reference voltage regulators with different voltages set in advance are used, and the reference voltage of these reference voltage regulators is compared with the battery terminal voltage step by step to determine the degree of battery consumption. There is something to detect.

0003

However, this method requires two or more reference voltage generators and an equal number of voltage comparators, which increases the number of parts and causes problems in terms of cost and implementation.

[0004] The present invention was made to solve this problem, and as a method for detecting the degree of battery consumption, the battery load current is switched in multiple stages and the degree of voltage drop depending on the magnitude of the load current is determined. Multi-step detection of battery terminal voltage drop that uses a single voltage comparator to detect battery terminal voltage drop without increasing the number of parts, and that can notify the user of the battery consumption level at each stage. The purpose is to provide equipment.

[0005]

[Means for Solving the Problems] A multi-stage detection device for battery terminal voltage drop according to the present invention includes a switching means for switching the current consumption of an equipment circuit in multiple stages, and a terminal voltage of the battery at each stage that is set to a reference voltage. Voltage monitoring means for comparing and monitoring with
and means for notifying a user of the degree of battery consumption in accordance with each stage when the voltage monitoring means detects that the terminal voltage of the battery at each stage has decreased below the reference voltage. It is characterized by

[0006]

[Operation] This invention utilizes the property that the current consumption increases as the operating frequency of the circuit increases, and the current consumption of the circuit is switched in multiple stages, and the terminal voltage of the battery is monitored at each stage. When the terminal voltage of the battery drops below the reference voltage, the user is notified of appropriate details according to each stage. Automatic power off as needed
It is also possible to perform processing such as F.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block circuit diagram showing a schematic hardware configuration of an electronic device according to this embodiment. In the same figure, 1
1 is a voltage detector for detecting the terminal voltage VDD of a battery (not shown) that serves as a power source for operating the electronic equipment of this embodiment. This voltage detector 1 is connected between VDD and GND, and has a built-in A reference voltage generator (not shown) is configured to send a detection signal to the control unit 2 when the terminal voltage VDD becomes 2.7V or less.

The control unit 2 controls the operation of the electronic device of this embodiment, and the control unit 2 exchanges data with the RAM 5 based on instructions from the key input unit 3 and programs stored in the ROM 4. It executes predetermined processing and displays the processing results etc. on the display section 6. Further, this control unit 2 is driven by a clock sent via a switch 7, that is, either a clock H based on the output frequency of an oscillator 8 or a clock M or L divided by a frequency divider 9. It looks like this.

The switch 7 is designed to initially supply the clock L to the control section 2 when the power switch is turned on, and after a predetermined period of time, it is sequentially switched from the clock M to the clock H according to an instruction from the control section 2. It has become. The clock frequency of these clocks H, M, and L is that clock H is the highest and clock L is the lowest, for example, H=500KHZ,
M=100KHZ, L=10KHZ are set.

It is a well-known fact that the current consumption of the electronic device of this embodiment including the control section 2 driven by these clocks is the largest when the clock is H, and the smallest when the clock is L.

In the embodiment configured as described above, when the power switch is turned on, the terminal voltage VDD of the battery is detected in three stages according to the voltage drop detection processing flow shown in FIG. 2, and necessary messages are displayed on the display section 6. This is what is displayed on the page.

In the flowchart of FIG. 2, when the power is turned on, the switch 7 specifies the clock L as the clock for the control unit 2 in step P1, and the voltage detector 1 detects the terminal voltage VDD in operation using this clock. P2
monitor and judge. At this step, the terminal voltage is 2.7V
If it is determined that there is more than one, the switch 7 is switched after a predetermined time, for example, 2 seconds, and the clock is switched to the clock M in step P3.

If, in this step P2, the terminal voltage VD
If it is determined that D is less than 2.7V, for example, "no battery" is displayed on the display section 6 in step P4, and after a predetermined time, the power is automatically turned off in step P5. In other words, in the operating state using clock L, which consumes the least current,
If the voltage is already less than 2.7V, the battery is at its final stage, and use beyond this point may lead to malfunctions, so the user is prohibited from using the battery.

[0014] The terminal voltage VDD in the operating state according to the clock M is monitored in step P6. If the terminal voltage is 2.7 V or more in this operating state, the clock is switched to clock H in step P7 after a predetermined time.

If the terminal voltage is 2 in this step P6,
．． If it is determined that the voltage is less than 7V, for example, "Please replace the battery" is displayed on the display section 6 in step P8. In other words, if the load is lower than 2.7V under the operating state of clock M, which is an intermediate load, the battery is in the replacement stage, so the above message will be displayed, but it is not an emergency situation that will stop the system. , the power will not turn off automatically.

Furthermore, the terminal voltage VDD in the operating state based on the clock H is monitored in step P9. If it is determined that the voltage is less than 2.7V in this operating state, step P10
For example, "Battery is running low" is displayed on the display unit 6. In other words, when operating under clock H, which has the maximum load, a voltage of less than 2.7V is within the usable range for the battery, so the above message is displayed, but of course it is not enough to stop the system. So,
Do not turn off the power automatically.

In this way, by sequentially switching the clock frequency from a low frequency to a high frequency, the load on the battery is made heavier, and the terminal voltage VDD of the battery is increased in each load state.
By monitoring the information, appropriate instructions can be given to the user.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with modifications without changing the gist.

[0019]

[Effects of the Invention] According to the present invention, appropriate message display and OFF processing are performed according to the degree of battery consumption without increasing the number of parts, so the user can know the degree of battery consumption from an early stage. Since the battery can be replaced at an appropriate time, the electronic device can be used with peace of mind.

Since the present invention is a system for monitoring battery voltage in detail over multiple stages, it can be particularly effective when applied to battery-powered electronic equipment where memory protection is important.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the hardware configuration of an embodiment of the present invention.

FIG. 2 is a flowchart for monitoring battery terminal voltage in the same embodiment.

[Explanation of symbols]

1...Voltage detector 2...Control unit
3...Key input section 4...ROM 5...RAM
6... Display section 7... Switcher 8... Oscillator
9...Frequency divider

Claims (1)

[Claims] 1. An electronic device using a battery as a power source, comprising: switching means for switching the current consumption of a device circuit in multiple stages; and voltage monitoring means for comparing and monitoring the terminal voltage of the battery at each stage with a reference voltage. and means for notifying a user of the degree of battery consumption in accordance with each stage when the voltage monitoring means detects that the terminal voltage of the battery at each stage has decreased below the reference voltage. A multi-step detection device for battery terminal voltage drop, characterized by: