SU926720A1 - Analogue storage - Google Patents

Description

(54) ANALOG MEMORIZATION

The invention relates to computing, is intended to store instantaneous voltage values, and can be used in analog-digital converters.

Known precision analog storage devices containing operational amplifiers, switches and memory capacitors. The use of common feedback allows one to significantly reduce the errors introduced by amplifiers t1 and 2.

However, such devices have insufficient speed due to significant transients occurring at the output of the device during the transition to the storage mode.

The closest to the proposed technical entity is an analog storage device that contains the first amplifier, the non-inverting input of which is connected to the input and output of the device through the first and second keys, and the output through the third switch to the inverter input tee friend

The lining of which is connected to the bus of zero potential, the second amplifier, the output of which is connected to the output of the device, is inverting; the input is through resistors to the output of the device and to the output of the first amplifier, and the non-inverting input is connected to the inverting input of the first amplifier (2. In the discharge mode, the first n and third keys are closed, the second key is open. The first amplifier is closed loop through the third key. and the memory capacitor is charged to the voltage corresponding to the input voltage. When switching to the storage mode, the state of the keys is reversed. At the output of the device, a constant voltage equal to the instantaneous value of the device at the time of switching the device. The known device is otlnchaetsya high accuracy. The overall accuracy of the device does not have a significant

the influence of the bias voltage, common-mode errors, the finiteness of the amplification factors of amplifiers. Since the third key is in storage mode is under voltage, close to zero, the error due to leakage of capacitors by the storage mode has been reduced. However, the dynamic properties of the device require improvement. If, in Sample mode, the first amplifier is covered by feedback, then when switching to the storage mode, the feedback is switched on, covering both the first and second amplifier. The inclusion of a second amplifier in the circuit means that the order of the system is increasing. This leads to significant transitions at the device output and to an increase in the voltage setting time at the output upon transition to the storage mode. Since the output signal can not. to undergo further processing (for example, an analog-to-digital converter) until its steady-state value is within the permissible error, an increase in the settling time means a deterioration in the device performance.

The purpose of the invention is to increase the speed of the device.

 The goal is achieved by the fact that in an analog storage yct device, containing the first storage element, for example, the first capacitor, one of the plates connected to the zero potential bus, an amplifier whose output is connected to the output of the device and connected to the inputs of the first and second keys with the other lining of the first capacitor and with the first inverting input of the amplifier, the second 1a converting input of which is connected to the outputs of the second and third keys, the input of the third key is connected with the input of the device triplets, a voltage follower, a fourth key and a second storage element, for example, a second capacitor, one of the plates of which is connected to the zero potential bus, are introduced, the other cover of the second capacitor is connected to the non-inverting inputs of the amplifier, and the output of the fourth key, whose input is connected to the output of the repeater voltage, the input of which is connected to the output of the third key ..

The drawing shows the functional diagram of the device.

It contains amplifier 1, voltage follower 2, switches 3-6, accumulative elements, for example, capacitors 7 and 8, inverting inputs 9 and 10 of amplifier 1, non-inverting inputs of And and 12 of amplifier 1, output 13 of amplifier 1, and potential-free terminal 14 .

The device operates as follows,

In sampling mode, keys 3, 5, 6 are closed and key 4 is open. Input voltage

through the closed key 3 arrives on inver. The tampering input 9 of amplifier 1 is swept over input 10 via a closed key 5 with negative feedback. The input voltage also flows through the closed switches 3 and 6 and the repeater 2 to the non-inverting inputs 11 and 12 of the amplifier 1. The voltage on the memory capacitor 7 is determined by the formula

and, OvhKp, (f)

where UBX is the input voltage;

Kn is the transfer coefficient of repeater 2.,

The voltage on the capacitor 8 of the memory is

c / () A- / and „, -. and„, ..-

i

4th

cvl + kt

H

where Uoi / Uoj is the zero bias voltage, taking into account common-mode errors at inputs 9, 11 and 12, 10, respectively;

KI is the voltage gain from the inputs 9. And the open amplifier L; K-2 is the voltage gain from the inputs 12 and 10 of the open amplifier 1. When switching to storage mode, the keys 3, 5 and 6 open and the switch 4 is closed. The output voltage is determined from the formula

shh-v

-about . h,

+ and

(B1

. 01 1 + K-, oai4K,

After appropriate transformations, it can be shown that the bias voltage UQI and DO 2 in the device are effectively suppressed by Kz and Kj times, respectively, and the muly error at.

(four)

D K - Unbix V .V U

Jbx

Thus, the proposed device is practically not inferior to the known device in accuracy, but surpasses it in speed. The use of a differential differential amplifier allows the use of a second amplifier to be abandoned. Thus, the feedback covers only one amplifier in both the sample mode and the store mode. Excluding the second amplifier reduces the order of the system and shortens the voltage setting time at the output of the device during the transition to the storage mode. This allows subsequent processing to begin much earlier (for example, analog-to-digital conversion). Possessing high accuracy, the device does not require the use of precision amplifiers. This fact can also be used by zuiH to further enhance fast action. In particular, amplifiers with relatively small amounts of co-amplification may be used, however, with a high bandwidth. The proposed device allows higher gains. speed performance without compromising accuracy. Formula of the invention An analog storage device comprising a first storage element, for example, a first capacitor, one of the plates of which is connected to a wider zero potential, an amplifier whose output is connected to the output of the device and to the inputs of the first and second keys, the output of the first key is connected to another the lining of the first conductor and with the first inverting input of the amplifier, the second inverting input of which is connected to the outputs of the second and third keys, the input of the third key is connected to the input of the device, exc Considering that, in order to increase the device speed, a repeater, a fourth switch and a second switchgear element, for example, a second capacitor, one of the plates of which is connected to the zero potential bus, are inserted into it, the second cover of the second capacitor is connected to the non-inlet amplifier and with the output of the fourth key, the input of which is connected to the output of the voltage follower, the input of which is. connected to the output of the third key. Sources of information taken into account in the examination 1. USSR author's certificate number 586500 cl. G 11 C 27/00, 1976. 2. USSR author's certificate No. 482815, cl. G 11 C 27/00, 1973 (prototype).

Claims (1)

Claim An analog storage device containing a first storage element, for example, a first capacitor, one of the plates of which is connected to a zero 926720 .6 of the first and second keys, the output of the first key is connected to another lining of the first capacitor and to the first inverting input of the amplifier, the second inverting input of which is connected to the outputs of the second and third keys, the input of the third key is connected to the input of the device, characterized in that, with In order to improve the performance of the device, a voltage follower, a fourth switch and a second storage element, for example, a second capacitor, one of the plates of which is connected to the zero potential bus, the other lining in orogo capacitor connected to the non-inverting, input of amplifier 5 conductive with N output fourth. the key whose input is connected to the output of the voltage follower, whose input ·. connected to the output of the third key.