SU1599975A1 - Pulse shaper - Google Patents

Abstract

The invention relates to a pulse technique and can be used in devices for testing integrated circuits and electronic components. The aim of the invention is to extend the functionality of the formation of pulses. This is achieved by providing independent adjustment of the upper and lower levels of the input signal over the entire range of variation of these levels and increasing the temperature stability of the lower level. In this case, a third transistor is additionally introduced into the shaper, the base of which is connected to the input of the operating amplifier, and the collector is connected to the source voltage bus of the upper output level and the collector of the first transistor. The voltage-controlled current source contains a second operational amplifier and a fourth transistor. 1 hp f-ly, 1 ill.

Description

The invention relates to devices of pulsed technology and can be used in devices for testing integrated circuits and electronic components.

The aim of the invention is to enhance the functionality of the pulse former by providing independent adjustment of the upper and lower levels of the output signal over the entire range of variation of these levels and increasing the temperature stability of the lower level.

The drawing shows a diagram of the device.

pulse generator contains bus 1- voltage sources of the upper (1), lower output level (2), reference (3) and negative power (k), differential transistor current switch 5, the left arm of which is connected to the output of the imaging unit 6, direct input with the input of the imager 7 and the inverse input with bus 3, the first, second and third transistors 8-10, the bases of transistors 8 and 10 are connected to the output of operational amplifier 11, their collectors are connected to bus 1, the emitter of transistor 8 is connected to output 6, and transistor 10 - with the collector of transistor 3 and an inverted input of the operational amplifier 11, a voltage-controlled current source 12 connected between bus 1 and the emitter of transistor E, which in turn is connected via a resistor 13 to bus D, the control input of the controlled current source 12 is connected to the direct input of the operating amplifier 11 and bus 2, and the base of the transistor 9 - with bus 3.

In turn, the voltage controlled current source 12 comprises, for example, a second operational amplifier I, a fourth transistor 15 and a second resistor 16.

(f

WITH

ate her X

.

U1

The pulse shaper operates as follows.

The input 7 is supplied with control pulses that switch the current switch 5. And as a result, the output pulses are generated on the load of the left arm 17 and on the output 6 of the driver, the upper level of which is determined by the voltage on the bus 1, and the lower emitter potential of the transistor 8. In this case, in the mode of forming the lower level of the output signal (U,), the emitter of the transistor 8 flows through E.- UH

current I, g I, - R

17

Where

1 current

the switch defined by the current-carrying element 18. The transistor 10 together with the operational amplifier 11 forms a voltage follower, so the potential on the emitter-THIS transistor is E. If the emitter current of the transistor 10 is equal to the emitter current of transistor 8 , then for the output signal Uu Eo. those. magnitude

2

living

Bh

and if you take re

the voltage of the lower level of the output signal will be equal to the voltage on the bus 2.

If the resistors are 13 and. 18 is chosen equal, the emitter current of the transistor 10 will be determined by the expression

about o 12 fl 1 of the source of Current 12. The latter is determined by expression. 2

Since the resistors 1b and 17 are equal, regardless of the magnitude of the voltages on buses 1 and 2, the lower voltage level of the output signal will always be equal to the voltage Eg.

If you select the same type of pairs of transistors 8 and 10, as well as the transistors of switch 5 with transistor 9, compensation for changes in their parameters from temperature will occur, which will lead to an increase in temperature stability of the lower level of the output signal.

Claims (2)

Invention Formula T. Pulse Formering Containing Transistor Differential. a current switch connected between the top voltage source bus about S 0 five five 0 the output level and bus of the negative voltage power supply source, one of the arms of which is connected to the output of the driver, the direct input is connected to the input of the driver, and the inverse is connected to the bus of the reference voltage source, operational amplifier, the output of which is connected to the base of the first transistor, emitter of which is connected the output of the driver, the second transistor, the collector of which is connected to the inverse input of the operational amplifier, and the emitter - to the first output of the resistor, characterized in that, in order to extend the functional possibilities By providing independent adjustment of the upper and lower levels of the output signal over the entire range of variation of these levels and increasing the temperature stability of the lower level, a third transistor is inserted into the driver, the base of which is connected to the output of the operational amplifier, the emitter - with the inverse input of the operational amplifier, and the collector - with the bus voltage source of the upper output level and the collector of the first transistor Q, and the voltage controlled current source connected between the collector of the third and e the second transistor miter, the control input of which is connected to the forward input of the operational amplifier and the voltage source bus of the lower output level, the base of the second transistor connected to the source bus the reference stress and the second exit eg a resistor - with a negative voltage power supply bus. 2. A pulse shaper according to claim 1, characterized in that the voltage controlled current source contains a second operational amplifier and a fourth transistor, the base of which is connected to the output of the second operational amplifier, the emitter to its inverse input and through the second resistor to the collector of the third the transistor, the collector with the emitter of the second transistor, and the direct input of the second operational amplifier is the source control input current. ABOUT / J M