SU855985A1 - Two-threshold comparator - Google Patents

Description

(54) TWO-THRESHOLD COMPARATOR

I

The invention relates to instrumentation technology and can. be used as a control sensor of the type-out-out-out and discriminator with an adjustable window. .

A comparator with two thresholds is known that contains different polarity inputs connected to the bases of successively connected transistors of the same conductivity, the collector of one of them is connected to the base of the output transistor of another conductivity, the collector of which is connected to one of the different polarity inputs via a resistor

Disadvantage. For this device, the setting of the upper and lower thresholds for the operation of the comparator is made by changing the values of the two resistors, which makes it difficult to precisely adjust the comparator.

A two-threshold comparator is also known, which contains a dual comparator, setting thresholds and a source of reference voltage 12J.

However, the rearrangement of the lower and upper thresholds of operation of such a comparator is achieved by changing the values of two or more resistors, which makes it difficult to accurately and symmetrically position the window relative to some average reference voltage.

ten

The purpose of the invention is to improve the accuracy and simplify the symmetrical setting of the upper and lower trigger thresholds.

The goal is achieved

Claims (2)

ts that two differential amplifiers and an inverter voltage repeater are introduced into a two-threshold comparator containing a dual comparator, a threshold setting unit and a voltage source, the dual comparator non-inverting input is connected to the output of the first differential amplifier, the non-inverting input of which is connected to the source the reference voltage, and the inverting input is connected to the output of the inverting voltage follower j; the inverting input of the dual comparator is connected to the output of the second a differential amplifier, the non-inverting input of which is connected to a source of reference voltage, and the inverting input is connected to the input of an inverting voltage follower. The drawing shows a two-threshold comparator circuit. The comparator contains a dual comparator 1, differential amplifiers 2 and 3, an adjustable divider 4, an inverting inverter repeater 5 and a voltage and a source 6 of the reference voltage. The voltage from the source 6 of the reference voltage goes to the non-inverting inputs of the differential amplifiers 2 and 3, assembled on operational amplifiers in a differential circuit, with a transfer coefficient equal to; Nom unit. The adjustable divider 4 sets the voltage UU equal to half the window span and is transmitted to the input of the inverting voltage repeater, which is assembled on the operational amplifier in the inverting switch. Adjustable divider 4 allows the value of Di to be changed. The inverting input of the differential amplifier 2 receives a voltage equal to plus & U, and to the inverting input of the differential force. bodies 3 - minus L U ". Thus, at the outputs of differential amplifiers 2 and 3, the lower threshold of the operation is formed, equal, and the upper threshold of operation is not LI + AU, respectively. In the case when the input voltage Y, which lies within the .aU window, arrives at the combined input of the dual comparator 1, the logic level, one, otherwise appears at the MIDA output, appears at the output of the dual comparator 1. In the case of a case, there is a logical zero level at the output. 85 Therefore, using the adjustable divider 4, the upper and lower thresholds can be set symmetrically and accurately. The use of the proposed two-threshold comparator with an adjustable window distinguishes it favorably from the known one, since it greatly simplifies the achievement of the accuracy and symmetry of the installation of an RC with respect to a certain average reference voltage. The application of the proposed device, for example, to control the gain of a DC amplifier, allows you to automate this process and simplify the setup and maintenance of the control circuit. Claims of the invention A double-threshold comparator comprising a dual comparator, a threshold setting block and a voltage source, characterized in that, in order to improve the accuracy and simplify the symmetrical setting of the upper and lower trigger thresholds, two differential amplifiers and an inverting voltage follower the non-inverting input of the dual comparator is connected to the output of the first differential amplifier, the non-inverting input of which is connected to the source of the reference voltage, and ertiruyuschy input connected to the output of the inverting repeater voltage, the inverting input of a dual comparator coupled to an output vtotrogo differential amplifier, whose input is einvertiruyuschy Cpd a source of reference voltage, an inverting input connected to the inverting swing voltage repeater April. Sources of information, rinty 30 attention in the examination 1. The author's certificate of the USSR 224586, cl. H 03 K 5/20, 1967. 2. Analog integrated circuits. /. Analog integrated circuits., World, 1977, a. 152, fig, 4.12 (And 1 l -, - 1 - - - prototype). You} (about