SU1608587A1 - Peak detector - Google Patents

Abstract

The invention relates to electrical engineering, more specifically to devices designed to obtain peak values of a variable input voltage made on semiconductor devices. The aim of the invention is to improve the accuracy of the peak detector. The use of two opposite diodes 2.3 of key element 1 in the detector virtually eliminates the temperature instability and shift of the input voltage of the detector, which increases the stability and accuracy of the detector, and the use of a special current generator 4 retains this positive effect for voltage inputs having a rather wide spectrum bandwidth. 1 il.

Description

The invention relates to electrical engineering, and more specifically to devices designed to obtain peak values of AC input voltage, performed on semiconductor devices.

The purpose of the invention is improving the accuracy of the detector.

The drawing shows a diagram of the detector.

The device contains a key element 1 on diodes 2 and 3, a current generator 4, consisting of a DC generator 5, an amplifying element 6 on a transistor, a current-charging element 7 on a resistor and a separation element 8 on a capacitor, a storage element 9 on a capacitor.

The device operates as follows.

The input voltage is supplied to the emitter through element 8 and is converted into an alternating component of the collector current of the transistor of element 6 in accordance with the ratio where i _to is the alternating component of the collector current of transistor 4;

SD - the value of the capacity of the element 8;

U is the input voltage; t is time.

The value of the constant current component of the collector of the transistor of element 6 is determined by the values of the element 7 and the source of constant negative voltage E. These values are selected from the condition of mutual compensation of the constant current component of the collector of the transistor of element 6 and the current of the current generator 5. Then the output current (i ^) of the current generator 5 will be CURRENT

The output current of the current generator 4, up to a constant proportionality coefficient, coincides with the result of differentiation of the input voltage. This output current controls the conductivity state of cell 1.

The value of the capacitance of the element 8 is chosen exactly two times the value of the capacitance of the capacitor 9. At the time when the increasing input voltage reaches the voltage value on the element 9, the diodes and 3 elements 1 open by the current i ^. At the same time, the same current flows through each of the diodes of the element 1 at the same time as the input voltage rises, equal to the value of i _BMX / 2, which is integrated on the element 9, being converted into the output voltage. The voltage increment on element 9 is determined from the expression

I t _ „1 [4 BblX j.

^B6IX Cj J 2 ^at 'where C <j is the value of the capacitance of element 9. Then, taking into account (1), we can write since by condition - = 2, then for the case under consideration, the increment of the output voltage exactly repeats the increment of the input until the latter has a growing character. When the input voltage reaches a positive value 1 ^ = 0 and, therefore, the increase in voltage at the output of the circuit stops. Further, the input voltage decreases and the polarity i _{B [X} changes, which leads to the opening of element 1, and therefore the output voltage remains equal to the new positive extreme value of the input voltage. The output voltage of the core. It remains unchanged until the value of the input voltage, changing and rising again, is again equal to the output voltage, after which the process of generating another positive extreme value at the circuit output is repeated. Parameters characterizing the speed and accuracy of the detector can be achieved by using the appropriate type of high-frequency transistor and Schottky diodes with consistent characteristics. The use of a 2T371A type transistor and 2D922AR, AG type Schottky diodes in the circuit allows it to work with input voltage signals with an amplitude of up to 1 V, the spectrum of which occupies a frequency band of up to

100 MHz The accuracy of the resulting peak values of the input voltage can be estimated with an error within 1 Z.

Claims (1)

SUMMARY OF THE INVENTION A peak detector comprising a storage element on a capacitor, 1608587 'key element on the first diode, the cathode of which is connected to the first output of the storage element capacitor and is the information output of the detector, the second output of the storage element capacitor is connected to the zero potential bus of the detector, characterized in that, in order to improve accuracy, a second key element diode is introduced into it , a current generator, consisting of a direct current generator, an amplifying element on a transistor, a current-setting element on a resistor, a separation element on a capacitor, the first in the water of which is connected to the cathode of the second diode of the key element and is the information input of the detector, the anodes of the diodes of the key element are connected to the output of the DC generator and the collector of the transistor of the amplifier element, the base of which is connected to the bus of the detector’s zero potential, and the emitter is connected to the second output of the capacitor of the separation element and the first terminal of the resistor of the current-sensing element, the second terminal of which is connected to the bus of constant negative voltage.