SU1259473A1 - Differential voltage-to-current converter - Google Patents

Abstract

The invention relates to radio engineering and can be used in differential measurement amplifiers, data acquisition systems and analog-digital converters. Conversion accuracy is increased and the dynamic range of input common-mode signals is expanded. The device contains a power source 1, scaled 1 st resistor 2, two voltage converters - current 3, each of which contains a current generator 4, an amplifier stage (CC) 5 ,. voltage follower 6, complementary voltage follower (CTN) 7. The device also contains two additional voltage repeater (DPN) 8 with normalized output resistance. The input common-mode voltage through the DPN 8 is transmitted to the inputs of the respective CIT 7. The voltage on the inputs of the CC 5 is not required for voltage changes on the CIT 7, i.e. voltage to current generator 4 remains unchanged. The transfer ratio of the CBS 8 and the gain of the CC 5 with respect to the input of the PCT 7 are determined by the ratio of the normalized output impedance of the CAM 8 and the output resistance of the CC 5. By appropriately selecting these resistances, you can expand the dynamic range of the input common-mode signals. 1 hp f-ly, 2 ill. (L ts9 JV F 00

Description

The invention relates to the field of audio engineering and can be used in differential measurement amplifiers of data acquisition systems and analog-digital converters.

The aim of the invention is to improve the accuracy of conversion and the expansion of the dynamic range of input common-mode signals.

Fig. 1 shows a circuit diagram of a differential voltage-current converter; FIG. 2 is a circuit diagram of one arm of a differential converter; the voltage is current.

The proposed differential voltage converter — the current contains a power source 1, a scaling resistor 2, two identical voltage converters — a current 3, each of which contains a current generator A, an amplifier stage 5, a voltage follower 6, a complementary voltage follower 7. Differential voltage converter - the current also contains two additional voltage follower 8 with normalized output impedance.

The proposed differential voltage converter - the current works as follows.

At equal voltages at the inputs of the differential voltage converter - the current at the outputs of the repeaters 6 and the voltage are also equal, and the current through the scaling resistor 2 does not flow. current. If a voltage difference appears at the inputs of the differential voltage converter, then this difference will be applied to the scaling resistor 2 through the voltage followers 6 and the current determined by the formula

t - Eac D. - - -.

 michsht

Voltage repeaters 6 are covered by deep negative feedback through amplification stage 5 and. complementary repeater 7 voltage. The action of this feedback is aimed at maintaining at the output of the repeater 6 the voltage of the potential ensuring the passage through

It is the current set by the generator 4 current. The state of the current through the voltage follower 6 ensures the constancy of the voltage between its input and output, i.e. The voltage follower 6 accurately transmits the input voltage to its output. As a result, the input voltages i. the differential input voltage is accurately converted to

the difference of the output currents, while the slope of the S transformation is inversely proportional to the resistance of its resistor. In the proposed differential voltage converter - current, the effect of changing the differential input voltage on the current generator 4 is reduced by the negative feedback circuit's action by a factor of 1, which is the product of the gain of the amplifier stage 5 and the slope (complementary voltage) repeater voltage 7 and the resistance of the scaling resistor 2. Additional

voltage follower 8 allows i to expand the dynamic range of input common mode signals. Under the influence of the input common-mode voltage, it is through additional repeaters

8 voltages are transmitted to the inputs.

corresponding complementary followers of voltage 7. Therefore, changes in voltage at the inputs of the amplifier stages 5 for changes in the voltage at the inputs of the complementary voltage followers 7 are not required, i.e. the voltage on the current generators 5 remains unchanged when exposed to a common mode signal. The transfer coefficient of the additional repeaters 8 and the gain ratio of the amplifying stage 5 in relation to the input of the complementary follower 7 are determined

the ratio of the normalized output impedance of the additional repeater 8 voltage and the output impedance of the amplifier stage 5. By appropriately selecting these resistances, the dynamic range of the input common-mode signals of the differential voltage-current converter can be expanded.

Claims (2)

1. Differential voltage converter - a current containing a power source, a scaling resistor and two voltage converters - a current, each of which is connected to a current generator, an amplifier stage and a voltage transformer, whose input is one of the inputs of a differential voltage converter - current, the output is connected to one of the terminals of the scaling resistor, and the common electrode is connected directly to the input of the amplifier cascade and through the current generator from one of the power supply buses, differing from m, that, in order to make it more accurate, to convert, to each voltage converter - the current is introduced by the complementar Compiler V.Serov Editor L.Gratillo Tehred A.Kravchuk .Corrector S.Shekmar Order 5138/57 Circulation 816 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 voltage repeater, the output of which is connected to the output of the corresponding repeater voltage, input - with inverting, output respectively. The downstream amplifier stage, the common electrode, is one of the outputs of the differential voltage-current converter. 2. The converter according to claim 1, characterized in that, in order to broaden the dynamic range of input common-mode signals, an additional voltage repeater with a normalized output resistance is input to each converter, the input of which is connected to the input of the corresponding repeater voltage, and output - with the input of the corresponding complementary voltage follower.