JPH0627251A - Information input device - Google Patents

Abstract

PURPOSE:To obtain an information input device which can input a plurality of pieces of information through one input terminal. CONSTITUTION:When a switch 4 is connected to a terminal 1 to be selected, a p-channel transistor 7 is turned off and the output of an inverter 9 becomes '1'. As a result, a noise removing function control circuit 10 outputs '0' by discriminating that no noise removing function exists and an analog switch 11 is turned off. When the switch 4 is connected to another terminal 2 to be selected, the transistor 7 is turned on and the output of the inverter 9 becomes '0'. As a result, the circuit 10 outputs '1' by discriminating that the noise removing function exists and the switch 11 is turned on. The current corresponding to the resistance of a resistor 3 is generated from a resistance-current conversion circuit 12 and outputted to a current switching circuit 13 as analog information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information input device.

[0002]

2. Description of the Related Art Conventionally, for example, in a detection circuit for detecting a human body by an IR (infrared) sensor, a noise component is generated due to the nature of the IR sensor, which causes a malfunction. Therefore, this noise component is removed. Therefore, if the IR sensor produces the first output and then the next output is produced within the observation period, it is determined that the detection target exists, and if the next output is not produced, the previous output is output. There is a device having a noise removal function that determines that is a noise component.

This detection circuit has an input terminal for turning on and off the noise removing function and an input terminal for setting the observation period within a certain range. The observation period is set by connecting a resistor having a desired resistance value to one input terminal in order to reduce the number of terminals and reading the resistance value.

[0004]

In order to reduce the number of terminals as much as possible, the detection circuit requires two input terminals for ON / OFF setting of the noise elimination function and for setting the observation period, so that it is attempted to be integrated. There is a problem that the chip area becomes large when doing.

An object of the present invention is to provide an information input device capable of inputting a plurality of information with one input terminal.

[0006]

According to the present invention, a plurality of selected terminals to be connected to a power source directly or via resistors and a selection for connecting one of the selected terminals to one input terminal are selected. By providing means, a discrimination circuit for discriminating binary input information from the potential of the input terminal, and a control means for taking in the resistance value as analog input information when a resistor is connected to the input terminal, the above object is achieved. Has achieved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on an embodiment shown in the drawings. In this embodiment, the present invention is applied to an observation period setting unit in a drive unit that removes a noise component generated from an IR (infrared) sensor and its operation control unit.

In FIG. 1, reference numerals 1 and 2 denote selected terminals, the selected terminal 1 is connected to the high potential side VDD of the power source, and the selected terminal 2 is connected to the low potential side Vss of the power source through the resistor 3.
The resistor 3 is used to set the observation period according to its resistance value. Reference numeral 4 denotes a switch that constitutes a selection means, and connects either one of the selected terminals 1 and 2 to one input terminal 5. Reference numeral 6 denotes a discriminating circuit, which includes a P-channel transistor 7, a constant current source 8, an inverter 9 and the like. A noise removal function control circuit 10 is composed of an inverter, a flip-flop circuit, etc., and controls the operation of the analog switch 11 according to the output of the inverter 9.

Reference numeral 12 is a resistance-current conversion circuit which constitutes a control means, and is composed of an operational amplifier, a resistance and the like, and outputs a current according to the resistance value of the resistance 3. 13 is a current switching circuit,
It is composed of an operational amplifier, an analog switch, etc., and charges and discharges the capacitor 14 based on the output of the resistance-current conversion circuit 12. A window comparator 15 compares the potential at the terminal a with the upper limit voltage generated by the upper limit voltage generation circuit 16 and the lower limit voltage generated by the lower limit voltage generation circuit 17.

Next, the operation will be described. When the switch 4 is connected to the selected terminal 1, the gate signal of the P-channel transistor 7 becomes "1" and the P-channel transistor 7 is turned off. Therefore, the drain of the P-channel transistor 7 is pulled to Vss by the constant current source 8, and the output of the inverter 9 becomes "1". The output "1" causes the noise elimination function control circuit 10 to judge that there is no noise elimination function. 0 "is output, which turns off the analog switch 9. That is, when the switch 4 contacts the selected terminal 1, the noise removing function does not operate.

When the switch 4 is connected to the selected terminal 2, P
The channel transistor 7 is turned on. At this time, by setting the current generated from the constant current source 8 to be smaller than the drain current of the P-channel transistor 7, the output of the inverter 9 becomes “0”, and the noise removal function control circuit 10 has the noise removal function. When it is judged to be present, "1" is output and the analog switch 11 is turned on. Therefore, a current corresponding to the resistance value of the resistor 3 is generated from the resistance-current conversion circuit 12, and is output to the current switching circuit 13 as analog information. The current switching circuit 13 includes the window comparator 1
When the output of 5 is "0", a current corresponding to the input current value is supplied to charge the capacitor 14, and when the output of the window comparator 15 is "1", the current corresponding to the input current value is absorbed, The electric charge is discharged from the capacitor 14.

The window comparator 15 outputs "1" when the voltage of the terminal a, that is, the voltage of the capacitor 14 becomes larger than the upper limit voltage generated by the upper limit voltage generation circuit 16.
When it is lower than the lower limit voltage generated by the lower limit voltage generation circuit 17, "0" is output. That is, when the voltage of the terminal a becomes smaller than the lower limit voltage, the capacitor 14 is charged to increase the voltage of the terminal a, and when the voltage of the terminal a becomes larger than the upper limit voltage, the charge is discharged from the capacitor 14 and the voltage of the terminal a is decreased. .

Therefore, the temporal change of the voltage of the terminal a becomes a triangular wave having a slope according to the resistance value of the resistor 3 as shown in FIG. 2a, and the temporal change of the voltage of the terminal b is also shown in FIG. 2b.
As described above, the output signal has a frequency corresponding to the resistance value of the resistor 3.

According to the frequency of the output signal of the window comparator 15, for example, when the frequency becomes high, the observation period is shortened to set the observation period for removing noise.

As described above, by switching the switch 4, it is possible to turn on / off the noise removing function and set the observation period in the noise removing function (by changing the resistance value of the resistor 3) with only one input terminal.

In the above, the present invention is used in the observation period setting unit and the operation control unit in the driving unit for removing the noise component. Next, the human body detection judgment for noise removal is output by the IR sensor within the observation period. And a switching unit that switches between two times and three times
An example in which the present invention is used in the observation time setting unit that sets the observation time by analog information according to the number of outputs of the sensor will be described with reference to FIG.

In the figure, reference numerals 18 and 19 denote selected terminals. The selected terminal 18 is connected to the high potential side VDD of the power source through the resistor 20 and the selected terminal 19 is connected to the low potential side Vss of the power source through the resistor 21. Connect to each. Reference numeral 22 denotes a count number switching circuit, which is composed of an inverter, a resistor, and the like, and switches the count value of the output number of the IR sensor (not shown) which is used for human body detection determination during the observation period. In the present embodiment, when the output of the count number switching circuit 22 is "0", the determination of the human body detection is made when the output of the IR sensor is two or more times within the observation period. When the output is "1", the IR sensor outputs It is assumed that the output is three times or more. Reference numeral 23 is a resistor forming a control means
The current conversion circuit includes an operational amplifier, a resistor, a switch, and the like, and outputs a current according to the resistance values of the resistors 20 and 21. Reference numeral 24 is a first reference voltage generating circuit, which is a resistor 20.
A reference voltage is generated when the resistance value of is converted into a current. Two
Reference numeral 5 is a second reference voltage generating circuit, which generates a reference voltage when converting the resistance value of the resistor 21 into a current. A noise removal function control circuit 26 controls ON / OFF of the analog switch 27 by setting the terminal c to "1" or "0" by another switch (not shown). The same numbers as in FIG. 1 are the same.

Next, the operation will be described. Now, it is assumed that the noise removal function control circuit 26 determines that there is a noise removal function by the input signal of the terminal c and turns on the analog switch 27.

When the switch 4 is connected to the selected terminal 18, the output of the discrimination circuit 6 becomes "1", and the count number switching circuit 22 outputs "0" as a control output. That is, the detection of the human body is performed when the output of the IR sensor is twice or more. Since the control output is "0", the resistance-current conversion circuit 23 outputs a current corresponding to the resistance value of the resistor 20 with the voltage generated from the first reference voltage generation circuit 24 as a reference. The following observation period setting operation is the same as above.

When the switch 4 is connected to the selected terminal 19, the output of the discrimination circuit 6 becomes "0", and the control output generated from the count number switching circuit 22 becomes "1". That is,
The presence of the human body is detected when the output of the IR sensor is three times or more within the observation period. Since the control output is "1", the resistance-current conversion circuit 23 outputs a current corresponding to the resistance value of the resistor 21 with the voltage generated from the second reference voltage generation circuit 25 as a reference. The subsequent operation is the same as above.

Thus, according to this embodiment, the switch 4
It is possible to switch the number of outputs generated from the IR sensor within the observation period, which is the reference for human body detection, and the observation period, by switching the input information from one input terminal. For example, when the switch 4 is connected to the selected terminal 18, the number of outputs of the IR sensor is 2 and the observation period is 2
By setting the second, the switch 4 is switched and connected to the selected terminal 19, the output number of the IR sensor can be changed to 3 times and the observation period can be changed to 3 seconds.

Although the present invention is used in the detection circuit having the noise removing function of the IR sensor in the above embodiments, the present invention is not limited to the above, and binary input information and analog information are input. Any circuit used as information has the same effect as described above.

[0023]

According to the present invention, a plurality of selected terminals connected to the power source directly or via resistors, and a selection means for selecting one of the selected terminals and connecting it to one input terminal are provided. By providing a discriminating circuit for discriminating binary input information from the potential of the input terminal and a control means for taking in the resistance value as analog input information when a resistor is connected to the input terminal, a plurality of input terminals are provided. Information can be input, and the circuit can be downsized.

[Brief description of drawings]

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

FIG. 2 is a diagram showing voltage changes at terminals a and b in FIG.

FIG. 3 is a block circuit diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1, 2, 18, 19 Selected terminals 3, 20, 21 Resistance 4 Selection means 5 One input terminal 6 Discrimination circuit 12, 23 Control means

Claims (1)

[Claims] 1. A plurality of selected terminals connected to a power source directly or via resistors, a selection means for selecting one of the selected terminals and connecting it to one input terminal, and a potential of the input terminal. 2. An information input device comprising: a discrimination circuit for discriminating binary input information from the above, and control means for taking in the resistance value as analog input information when a resistance is connected to the input terminal.