JP3004475U - Electrical limit circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to an electric limit circuit, and particularly, an object thereof is to obtain a stable output voltage without temperature drift by digitization. [Structure] The electrical limit circuit according to the present invention compares each voltage limit value (± V _LIMIT ) with the input voltage (V _IN ), and outputs the comparison output through each gate circuit (12, 13) to each switch circuit. By applying the voltage to (14, 15) and outputting the output voltage (15A) from the switch circuit (15), an output without temperature drift due to digital processing is obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electric limit circuit, and more particularly to a new improvement for obtaining a stable output voltage without temperature drift by digitization.

[0002]

[Prior art]

As this type of electrical limit circuit that has been conventionally used, for example, as shown in FIG. 3, first and second operational amplifiers 1 and 2 are used, and first and second operational amplifiers 1 and 2 input to each operational amplifier 1 and 2 are used. 2 Input voltages V _in 1 and V _in 2 are output as output voltages V _OUT 1 and V _OUT 2.

[0003]

[Problems to be solved by the device]

 Since the conventional electric limit circuit is configured as described above, there are the following problems. That is, since a zener diode is connected to each operational amplifier, the temperature drift is large and the limit value fluctuates. Since it was decided, fine adjustment of the limit value was impossible.

The present invention has been made to solve the above problems, and in particular, an object thereof is to provide an electric limit circuit capable of obtaining a stable output voltage without temperature drift by digitization. And

[0005]

[Means for Solving the Problems]

 The electrical limit circuit according to the present invention comprises a positive side voltage limit value connected to a first comparator, a negative side voltage limit value connected to a second comparator, an input voltage input to each of the comparators, A first gate circuit connected to a first comparator, a second gate circuit connected to the second comparator, first and second switch circuits connected to each of the gate circuits, and a second switch circuit. And an output unit connected to the output unit, and the input voltage is output from the output unit within the range of each voltage limit value.

[0006]

[Action]

 In the electrical limit circuit according to the present invention, the input voltage is compared with each voltage limit value in each gate circuit, and each switch circuit is turned on / off based on the output level (H or L) from each gate circuit, Is output within the range of each voltage limit value. Further, each of these voltage limit values can be arbitrarily set externally.

[0007]

【Example】

Hereinafter, preferred embodiments of an electric limit circuit according to the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numerals 10 and 11 denote first and second comparators, and each of the comparators 10 and 11 has a positive side voltage limit value + V _LIMIT , a negative side voltage limit value −V _LIMIT, and an input voltage V. _IN is input.

The first and second comparison outputs 10a and 11a of the comparators 10 and 11 are input to a first gate circuit 12 formed of an OR circuit and a second gate circuit 13 formed of an AND circuit, and the gate circuits 12 and The input voltage V _IN is input to each of 13.

The first and second gate outputs 12 a and 13 a of the gate circuits 12 and 13 are input to the L-active type first and second switch circuits 14 and 15, respectively, and the switch circuits 14 and 15 are input. It is configured to perform 15 switchings (on / off).

The first switch 14a of the first switch circuit 14 is connected to the positive side voltage limit value + V _LIMIT , and the second switch 14b is connected to the negative side voltage limit value −V _LIMIT of the first switch circuit. The output side 14A of 14 is input to the first switch 15a of the second switch circuit 15, and the input voltage V _IN is input to the second switch 15b. The output side 15A of the second switch circuit 15 is connected to the output section 20.

Next, the operation will be described. First, the output voltage V _{OUT with} respect to the input voltage V _IN is controlled so as to be limited by the positive side voltage limit value + V _LIMIT and the negative side voltage limit value −V _LIMIT , as shown in the characteristic diagram of FIG. Then, when each voltage limit value ± V _{LIM IT} is arbitrarily set from the outside and the input voltage V _IN (value in Table 1) is input, each comparison output 10a, 11a of each comparator 12, 13 becomes The levels are like A and B in the table.

[0012]

[Table 1]

The respective comparison outputs 10a and 11a are inputted to the respective gates 12 and 13, and the respective switches 14 and 15 are switched by the level L or H of the gate outputs 12a and 13a from the respective gates 12 and 13 to change the respective voltages. output voltage 15A in a range that does not exceed the limit value ± V _lIMIT input voltage V _iN, is output from the output unit 2 0 as either the voltage limit value ± V _lIMIT.

[0014]

[Effect of device]

 Since the electric limit circuit according to the present invention is configured as described above, the following effects can be obtained. That is, since the input voltage is compared with each voltage limit value and the output voltage is obtained by switching the switch circuit with each gate output obtained based on the comparison output, all the processing can be digital processing. And, the limit value can be set externally, small signals can be supported, temperature drift is small, and stable operation can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an electric limit circuit according to the present invention.

FIG. 2 is a characteristic diagram.

FIG. 3 is a circuit diagram showing a conventional electric limit circuit.

[Explanation of symbols]

10 First Comparator 11 Second Comparator + V _LIMIT Positive Side Voltage Limit Value −V _LIMIT Negative Side Voltage Limit Value V _IN Input Voltage 12 First Gate Circuit 13 Second Gate Circuit 14 First Switch Circuit 15 Second Switch Circuit 20 Output Section

Claims (1)

[Scope of utility model registration request] 1. A positive side voltage limit value (+ V _LIMIT ) connected to a first comparator (10) and a second comparator (1
Negative voltage limit value (-V _{LIM IT} ) connected to 1),
Input voltage (V input to each of the comparators (10, 11)
_IN ), a first gate circuit (12) connected to the first comparator (10), a second gate circuit (13) connected to the second comparator (11), and the gate circuits (12) , 13) connected to the first and second switch circuits (14, 15) and the second switch circuit (15) connected to the output section (20),
An electric limit circuit characterized in that the input voltage (V _IN ) is output from the output section (20) within a range of each of the voltage limit values (± V _LIMIT ).