JPH01216271A - Voltage detecting circuit - Google Patents

Abstract

PURPOSE:To accurately execute a dropping voltage display of an electric source and an initialization of an electronic equipment by detecting every constant time whether an input voltage exceeds a specified voltage or not and comparing the number of times exceeding the specified voltage with a standard value. CONSTITUTION:On detecting the input voltage every constant time by an input voltage detecting means 2, the number of times exceeding the specified voltage and the number of times under the specified voltage are added by first, second addition means 3a, 3b and stored in first, second storage means 4a, 4b for number of times respectively. By using a deciding means 5 for the detecting number of times, a detection and counting-storage are repeated until the sum of the stored number of times which are over and under the specified voltage come up to the detecting number of times set previously. And, when coming up to the detecting number of times, the stored number of times are brought into the initialization by an initialization means 8 and an action is continued repeatedly. Whenever the set detecting number of times have been worked out, the number of times which are under or over the specified voltage are compared with a value set in first and second deciding means 7a, 7b and decided. And, based on its result, outputs A, B for the initialization of the electronic equipment or the dropping voltage display are outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a voltage detection circuit that can detect input voltages of electronic typewriters, word processors, and printers and perform multiple controls.

(Prior Art) In recent years, a wide variety of portable devices have been sold, but in order to prevent malfunctions due to consumption of the built-in battery, many devices are incorporating display and control circuits to notify of a drop in power supply voltage. There is.

FIG. 6 is a configuration diagram of a conventional voltage detection circuit (hereinafter referred to as a reduced voltage detection circuit) that indicates a drop in power supply voltage. In FIG. 6, 41a and 41b are semi-fixed resistors, 42a
, 42b, 42c, 42d are resistors, 43a, 43b are transistors, 44a, 44b are light emitting diodes, 45
is a Zener diode.

Next, the operation of the conventional example will be explained. When the power supply voltage becomes lower than the specified voltage, the voltage between the base and emitter of the transistor 43a decreases and the current between the collector and emitter decreases, and the voltage between the base and emitter of the transistor 43b increases and the voltage between the collector and emitter decreases. By increasing the current, the light emitting diode 44b was lit.

(Problems to be Solved by the Invention) However, with the above-mentioned conventional configuration, there is a problem in that the judgment of the voltage reduction detection circuit for preventing malfunctions becomes ambiguous in devices where the consumption current changes rapidly and the power supply voltage changes rapidly.

The present invention solves these conventional problems, and aims to provide a voltage reduction detection circuit with high determination accuracy.

(Means for Solving the Problems) In order to achieve the above objects, the present invention includes an input voltage detection means for detecting that the input voltage is equal to or higher than a specified voltage, and operates the input voltage detection means at regular intervals. means for adding and storing the number of times the input voltage is equal to or higher than a specified voltage; means for adding and storing the number of times the input voltage is less than the specified voltage; and setting the number of times the input voltage is detected. a means for comparing and determining the value, and first and second means for setting the number of times the voltage is higher than the specified voltage or the number of times the voltage is lower than the specified voltage.
The apparatus includes first and second determining means for comparing and determining the number of times with different set values, and means for setting the means for storing the number of times to an initial value.

(Function) With the above configuration, the present invention has the following effects.

(1) Detect the input voltage at regular intervals, and add and store the number of times the input voltage is above the specified voltage and the number of times it is less than the specified voltage.

(2) Detection, counting, and storage are repeated until the total number of times the voltage is more than or equal to the specified voltage and the number of times it is less than the specified value reaches a preset number of detections. Furthermore, when the number of detections is reached, the number of times memory is initialized and the operation is repeated and continued.

(3) Every time the set number of detections is completed, the number of times the voltage is less than the specified voltage or more than the specified voltage is compared with the value set in the first and second judgment means, and based on the result, the voltage drop is displayed ( display) or initialize electronic equipment. Note that when a reduced voltage display is performed, the memory for the number of times the voltage is above and below the specified voltage is initialized and the operation is continued.

(Example) An example of the present invention will be described based on FIGS. 1 to 5.

FIG. 1 is a diagram showing the configuration and operation flow of the voltage detection circuit of the present invention. In Figure 1, 1 is the starting position, 2
The input voltage detection means detects and determines the relationship between the input voltage and the specified voltage. 3a and 3b are first and second addition means for adding the output of the input voltage detection means and the contents of the first and second number storage means; 4a and 4b are first and second number storage means; 5 Reference numeral numeral 6 indicates a detection number determination means, and 6 a timer which takes timing for a certain period of time. Reference numerals 7a and 7b represent first and second number determination means, and reference numeral 8 represents initialization means for the storage means.

FIG. 2 is a configuration diagram including input/output circuits of the voltage detection circuit. In Figure 2, lla, llb, lie, li
d.

11e, llf, l1g, llb are resistors, 12a, L
2b and 12c are transistors, 13 is a light emitting diode,
14 is a black box excluding the input/output portion of the voltage detection circuit.

FIG. 3 is a flowchart of the operation of the voltage detection circuit of the present invention, and FIG. 4 is a diagram showing an example in which three types of input signals and the number of detections are 10 times. FIG. 5 is a diagram showing the control contents of the voltage detection circuit based on the number of times determination result in the example of FIG. 4.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 to 5. In the above embodiment, the number of detections is 10. The first number judgment value is 10. An example will be described in which the second number determination value is set to 1 and the input voltage signal changes from A to C in FIG. 4.

Activation 1 starts the input voltage detection circuit 2 (S, in FIG. 3), and the signal A (FIG. 4) enters the input shown in FIG. The input voltage detection means 2 first checks whether the voltage at 81 points (FIG. 4) is equal to or higher than the specified voltage (FIG. 3, 82).

Since the voltage is higher than the specified voltage, the first adding means 3a adds 1 to the contents of the first number storage means 4a and stores it in the first number storage means 4a again (FIG. 3 83) (first and second number storage means 4a). 2
(The number storage means stores "o" at the time of start).Next, the detection number determination means 5 calculates the total number of times stored in the first and second number storage means 4a and 4b as the number of detections. It is determined whether the value is greater than or equal to the set value (FIG. 3, 84). If it is less than the set value, the timer 6 takes a certain period of time (FIG. 3 si), and the input voltage detection means 2 checks the input voltage again.

Since the voltages at a2 to a1° (Fig. 4) are all above the specified voltage, the above operation (Fig. 3 SL-S2-53-84-S
s) is executed repeatedly. a engineering. (Fig. 4) and the detection number judgment means 5 judges whether the number of detections is equal to or greater than the set value (84 in Fig. 3), since it is equal to the set value of the number of detections (10 in this embodiment) 6, the first number determination means 7a compares the value of the second number storage means 4b with the first number determination means 7a.
is compared with the number judgment value (10 in this embodiment) (FIG. 3 SG). Since the value in the second number storage means 4b is zero, the value in the second number storage means 4b is compared in the second number judgment means 7b. When compared with the second count judgment value (1 in this embodiment) (FIG. 3 87), the value in the second count storage means 4b is zero, so the initialization means 8 of the storage means 2. Initialize (reset) the number storage means 4a and 4b (Fig. 3S)
S) and returns to the input voltage detection operation. Fourth
In the case of signal A in the figure, since all voltages are above the specified voltage, no control is performed as shown above and in the case of signal A in FIG.

Next, the case of signal B in FIG. 4 will be explained.

b 1lb21b3tb in Fig. 4 with input voltage detection means 2
When the voltages of fftb, ,b, are detected, since they are above the specified voltage, the first adding means 3
a and stored in the first number storage means 4a.

On the other hand, Fig. 4 b4. b,, b,,b engineering. When the voltage is detected, it is less than the specified voltage, so it is added by the second addition means 3b and stored in the second number storage means 4b.

In the case of signal B, when the input voltage is detected 10 times, 6 is stored in the first number storage means and 4 is stored in the second number storage means. After 10 input voltage detections are completed, the first number determination means 7a compares the contents of the second number storage means 4b with the first number determination value (10 in this embodiment) (FIG. 3 SS ) The value of the second number of times storage means 4b is 4, which is smaller than the first number of times determination value, so the operation of the second number of times determination means 7b is started. When the second number of times determination means 7b compares the contents of the second number of times storage means 4b with the second number of times determination value (1 in this embodiment) (S, in FIG. 3), it is found that the second number of times storage means 4b is larger, so output B (reduced voltage display) is output, the transistor 12b in FIG. 2 is operated, and the light emitting diode 13 is lit (S in FIG. 1 and second number storage means 4
A, 4b are initialized (Fig. 3'S) and the process returns to input voltage detection. The summarized results of the operation of signal B in FIG. 4 are shown in the column for signal B in FIG.

Finally, the case of signal C in FIG. 4 will be explained. Fourth
In the case of the signal C in the figure, all voltages are less than the specified voltage, so when the input voltage detection means 2 detects Cyu~c1° in Figure 4,
The second addition means 3b adds the counted number of times, and the counted number of times is stored in the second number of times storage means 4b. After 10 times of detection is completed, the first number of times determination means 7a compares the value of the second number of times storage means 4b with the first number of times setting value (10 times in this embodiment).
) (FIG. 3 86), the second number storage means 4
Since the value of b is 10, which is equal to the first number of times setting value, output A (initialization of the electronic device) is output, and the electronic device is initialized (81° in FIG. 3). A summary of the operation of C is shown in the column for signal C in FIG.

Note that the above description is based on the first and second addition means and the first addition means.
Although the above description assumes that the and second number storage means are separated, the same function can be achieved by using a counter that integrates the addition means and the storage means.

(Effects of the Invention) As is clear from the above embodiments, the present invention detects that the input voltage is equal to or higher than the specified voltage at regular intervals, and performs multiple voltage controls with high accuracy based on the determined value. It has the effect of

[Brief explanation of the drawing]

FIG. 1 shows the configuration of a voltage detection circuit according to an embodiment of the present invention (second embodiment).
Figure 2 is a block diagram of the entire voltage detection circuit, Figure 3 is a flowchart of operation, Figure 4 is a diagram showing the input signals of this embodiment, and Figure 5 is a diagram showing the flow of operation. The figure shows the control contents based on the determination conditions and results of this embodiment, and FIG. 6 is a configuration diagram of a conventional voltage detection circuit. 1...Startup, 2...Input voltage detection means. 3a, 3b... Adding means, 4a, 4b... Number of times storage means, 5... Number of detections determining means, 6... Timer,
7a, 7b... Number of times determination means, 8... Storage means initialization means, lla, llb, llc, 11d, lie,
llf, l1g, 1lh - resistors, 12a, 12b. 12c... Transistor, 13... Light emitting diode, 14... Black box, 41a, 41b.
...Semi-fixed resistor, 42a, 42b, 42c, 42d-
Resistor, 43a, 43b - Transistor, 44a,
44b...Light emitting diode, 45...Zener diode. Figure 1 Figure 2 Figure 2 11a, 11b, 11c, Ild, 11e, 11f, 1
1g, 11h ,, tkJL Mt. 12a, 12b, 12
c-, Tora) Busta 13,..., Detection diode Fig. 4 111 Detection eye & (su) Work No. A Normal level Pe S No. B-X Electric, & Ship Ho 1 Nude level

Claims (1)

[Claims] input voltage detection means for detecting that the input voltage is equal to or higher than a specified voltage; a timer for operating the detection means at regular intervals; 1 addition means and a first storage means for storing the number of times the input voltage is detected at or above a specified voltage; a second addition means for adding the value of the second storage means when the input voltage is less than the specified voltage; a second storage means for storing the number of detections; a detection number determination means for comparing and determining the sum of the values of the first and second storage means with a set value of the number of detections; and the first or second storage means. a first number determination means that compares and determines the value and a set first number of times; a second number determination means that compares and determines the value of the first or second storage means and the set second number of times; initializing means for the first and second storage means, the first number of times setting value and the second number of times are initialized;
A voltage detection circuit characterized in that the set value of the number of times is different.