CN202034957U - Adjustable hysteresis comparator - Google Patents

Abstract

The utility model provides an adjustable hysteresis comparator, comprising an existing hysteresis comparator. The adjustable hysteresis comparator is characterized in that the hysteresis comparator module comprises two paths, wherein the first path is connected with a first digit/analogue converter and is used as the arrangement of the target threshold of the hysteresis comparator; the second path is connected with a second digit/analogue converter, a compared target voltage input signal and an analogue multiplier; the second digit/analogue converter and the compared target voltage input signal are together input to the analogue multiplier; and the output of the analogue multiplier is input to the input terminal of the hysteresis value and is used as the arrangement of the hysteresis value. By combining the digit/analogue converter and the analogue multiplier, the arrangement on the target threshold and the arrangement on the hysteresis value of the hysteresis comparator can be achieved; and simultaneously the arrangement precision of the hysteresis value can be ensured.

Description

A kind of adjustable hysteresis loop comparator

Technical field

The utility model relates to a kind of circuit, relates in particular to a kind of high-precision voltage hysteresis loop comparator circuit.

Background technology

The size of the hysteresis value of the hysteresis loop comparator circuit of current hardware voltage is provided with generally and is realized by digital regulation resistance, and because the restriction of the switch number of digital regulation resistance, cause the precision of hysteresis value not increase, improving precision can only could realize by the connection in series-parallel of a plurality of digital regulation resistances, make that so again the structure of this circuit is very complicated, and circuit that should complexity needs complicated software algorithm to cooperate could to realize.

The circuit of prior art hysteresis loop comparator is as shown in Figure 1a: hysteresis loop comparator 1 comprises: resistance R 1, resistance R 2 and operational amplifier C1, wherein, resistance R 1 and resistance R 2 are connected in series in the output of operational amplifier C1, the tie point of resistance R 1 and resistance R 2 is connected with the positive input terminal of operational amplifier C1, during this hysteresis loop comparator 1 work, the other end input reference voltage V of resistance R 1 _Vef, the negative input end applied signal voltage V of operational amplifier C1 _In, output signal voltage V like this _InWith reference voltage V _VefCurve shown in Fig. 1 b: the width D between this rectangular curve is certain, and rectangle is at V _InThe position also be certain.

As Fig. 1 a, the hysteresis loop comparator 1 of 1b does not have flexible adjustable type, can not regulate the width D of output rectangular curve, can not regulate the position L of rectangle, there is certain limitation in such hysteresis loop comparator 1 in warning system, temperature-controlling system or the like application.

Summary of the invention

In order to address the above problem, the utility model provides and the utility model proposes a kind of circuit arrangement, utilize digital to analog converter and analog multiplier, just can reach the targets threshold setting of hysteresis loop comparator and the size setting of hysteresis value, guarantee the precision that is provided with of hysteresis value simultaneously.

The utility model for the technical scheme that solves its technical problem and adopt is: a kind of adjustable hysteresis loop comparator comprises existing hysteresis loop comparator module, it is characterized in that: the hysteresis loop comparator module comprises two-way, wherein the first via is connected with first digital to analog converter, as the setting of the target threshold values of hysteresis loop comparator, the second tunnel with second digital to analog converter, be connected with target voltage input signal and analog multiplier relatively; Described second digital to analog converter, the target voltage input signal that is compared input to analog multiplier jointly, and the output of analog multiplier is input to the input of hysteresis value again, as the setting of hysteresis value size.

Wherein, preferred version is: the hysteresis loop comparator module comprises resistance R 1, resistance R 2 and operational amplifier C1, resistance R 1 and resistance R 2 are connected in series in the output of operational amplifier C1, and the tie point of resistance R 1 and resistance R 2 and the positive input terminal of operational amplifier C1 are connected.

Advantage of the present utility model is: the utility model proposes a kind of circuit arrangement, cooperate digital to analog converter and analog multiplier, just can reach the targets threshold setting of hysteresis loop comparator and the size setting of hysteresis value, guarantee the precision that is provided with of hysteresis value simultaneously.

Description of drawings

Fig. 1 a is the structure principle chart of prior art hysteresis loop comparator;

Fig. 1 b is the signal input voltage of prior art hysteresis loop comparator and the curve chart of output voltage;

Fig. 2 a is the schematic diagram of first embodiment of a kind of high accuracy of the utility model hysteresis loop comparator that hysteresis value and desired value are set arbitrarily;

Fig. 2 b is the curve chart of the first embodiment signal input voltage and output voltage;

Fig. 3 a is the schematic diagram of second embodiment of a kind of high accuracy of the utility model hysteresis loop comparator that hysteresis value and desired value are set arbitrarily;

Fig. 3 b is the curve chart of the second embodiment signal input voltage and output voltage.

Embodiment

The utility model is described in further detail below in conjunction with drawings and the specific embodiments.

Shown in Fig. 2 a, Fig. 2 b, the hysteresis loop comparator that the utility model high accuracy can be provided with back stagnate value and desired value arbitrarily comprises hysteresis comparison module 11, described hysteresis comparison module 11 comprises resistance R 1, resistance R 2 and operational amplifier C1, wherein, resistance R 1 and resistance R 2 are connected in series in the output of operational amplifier C1, and the tie point of resistance R 1 and resistance R 2 and the positive input terminal of operational amplifier C1 are connected; First digital to analog converter 12 is connected with resistance R 1; The second digital-to-analogue converter 13 is connected an analog multiplier 15 jointly with input signal end 14, and the negative input end of back analog multiplier 15 and operational amplifier C1 is connected.

The signal input voltage Vin of present embodiment hysteresis loop comparator and the curve of output between the Vo are shown in Fig. 2 b: curve of output is the rectangle of a closure, along with the variation of the voltage U of signal input voltage Vin, the voltage U of the output of the output of operational amplifier _oBecome a rectangular curve.

The operation principle of present embodiment is: wherein, the input terminal voltage of the first digital-to-analogue converter 12 with V1 represent, the input terminal voltage of the second digital-to-analogue converter 13 with V2 represent, the input voltage of input signal represents with Vin, output voltage is represented with Vo, the inverting input voltage of operational amplifier C1 is represented with V-, in-phase input end voltage is represented with V+, the product U of Vin and V2 _THExpression, when Vin from little during to big variation, U _THAlso from little to big variation (∞=＞U _TH2=＞U _TH1), can get following calculating formula:

V-＝Vin*V2---------------------1

V+＝V- ---------------------2

$\frac{U_{\mathrm{TH}1}-V1}{R1}=\frac{\mathrm{Vo}-U_{\mathrm{TH}1}}{R2}---3$

When Vin from greatly to little variation the time, U _THAlso from greatly to little variation (+∞=＞U _TH1-＞U _TH2), can get following equation

$\frac{U_{\mathrm{TH}2}-V1}{R1}=\frac{-\mathrm{Vo}-U_{\mathrm{TH}2}}{R2}---4$

Can get by 3,4

$U_{\mathrm{TH}1}-U_{\mathrm{TH}2}=\frac{2\mathrm{Vo}}{1+R2/R1}--5$

Can get by 1,5,

$U_{\mathrm{TH}1}-U_{\mathrm{TH}2}=\mathrm{Vin}1*V2-\mathrm{Vin}2*V2=\frac{2\mathrm{Vo}}{1+R2/R1}---6$

$\mathrm{Vin}1-\mathrm{Vin}2=\frac{2\mathrm{Vo}}{(1+R2/R1)*V2}---7$

Can get by 7, the size of the hysteresis value of signal input voltage Vin is only relevant with the voltage V2 of the second digital-to-analogue converter 13, thereby the setting of the hysteresis value size of hysteresis loop comparator is finished in the setting of voltage V2 that can be by the second digital-to-analogue converter.

Shown in Fig. 3 a, Fig. 3 b, the adjustable hysteresis loop comparator of the utility model comprises hysteresis loop comparator module 21, described hysteresis loop comparator module 21 comprises resistance R 1, resistance R 2 and operational amplifier C1, wherein, resistance R 1 and resistance R 2 are connected in series in the output of operational amplifier C1, and the tie point of resistance R 1 and resistance R 2 and the positive input terminal of operational amplifier C1 are connected; The negative input end of first digital to analog converter 22 and operational amplifier C1 is connected; The second digital-to-analogue converter 23 is connected an analog multiplier 25 jointly with input signal end 24, and back analog multiplier 25 is connected with resistance R 1.

The signal input voltage Vin of the hysteresis loop comparator of present embodiment and the curve of output between the Vo are shown in Fig. 3 b: curve of output is the rectangle of a closure, along with the variation of the voltage U of signal input voltage Vin, the voltage U of the output of the output of operational amplifier _oBecome a rectangular curve.

The operation principle of present embodiment is: wherein, the input terminal voltage of the first digital-to-analogue converter 22 with V1 represent, the input terminal voltage of the second digital-to-analogue converter 23 with V2 represent, the input voltage of input signal represents with Vin, output voltage is represented with Vo, the inverting input voltage of operational amplifier C1 is represented with V-, in-phase input end voltage is represented with V+, the output U of analog multiplier _THExpression, when Vin from little during to big variation, U _THAlso from greatly to little variation (+∞=＞U _TH1=＞U _TH2), can get following calculating formula:

V+＝V2 ----------------------1

U _TH＝Vin*V1----------------------2

$\frac{V2-U_{\mathrm{TH}1}}{R1}=\frac{-\mathrm{Vo}-V2}{R2}---3$

When Vin from greatly to little variation the time (+∞=＞U _TH1=＞U _TH2), can get following equation

$\frac{V2-U_{\mathrm{TH}2}}{R1}=\frac{\mathrm{Vo}-V2}{R2}---4$

Can get by 3,4

$U_{\mathrm{TH}1}-U_{\mathrm{TH}2}=\frac{2\mathrm{Vo}}{R2/R1}---5$

Can get by 2,5,

$U_{\mathrm{TH}1}-U_{\mathrm{TH}2}=\mathrm{Vin}1*V1-\mathrm{Vin}2*V1=\frac{2\mathrm{Vo}}{R2/R1}---6$

$\mathrm{Vin}1-\mathrm{Vin}2=\frac{2\mathrm{Vo}}{R2/R1*V1}---7$

Can get by 7, the size of the hysteresis value of Vin is only relevant with the voltage V1 of the first digital-to-analogue converter 23, thereby the setting of the hysteresis value size of hysteresis loop comparator is finished in the setting of voltage V1 that can be by the first digital-to-analogue converter.

Advantage of the present utility model is: utilize digital to analog converter and analog multiplier, thereby reach the targets threshold setting of hysteresis loop comparator and the size setting of hysteresis value, guarantee the precision that is provided with of hysteresis value simultaneously.

The above is the utility model most preferred embodiment only, is not to be used to limit scope of the present utility model, and all equivalences of being done according to the utility model claim change or modify, and are all the utility model and contain.

Claims (2)

1. an adjustable hysteresis loop comparator comprises existing hysteresis loop comparator module, it is characterized in that: the hysteresis loop comparator module comprises two-way, wherein the first via is connected with first digital to analog converter, as the setting of the target threshold values of hysteresis loop comparator, the second tunnel is connected with second digital to analog converter, the target voltage input signal and the analog multiplier that are compared; Described second digital to analog converter, the target voltage input signal that is compared input to analog multiplier jointly, and the output of analog multiplier is input to the input of hysteresis value again, as the setting of hysteresis value size.

2. hysteresis loop comparator according to claim 1, it is characterized in that: the hysteresis loop comparator module comprises resistance R 1, resistance R 2 and operational amplifier C1, resistance R 1 and resistance R 2 are connected in series in the output of operational amplifier C1, and the tie point of resistance R 1 and resistance R 2 and the positive input terminal of operational amplifier C1 are connected.

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