SU902222A1

SU902222A1 - Square-wave generator

Info

Publication number: SU902222A1
Application number: SU802937752A
Authority: SU
Inventors: Леонид Алексеевич Брякин; Николай Петрович Вашкевич; Владимир Федорович Говоров; Станислав Борисович Демин
Original assignee: Пензенский Политехнический Институт
Priority date: 1980-06-11
Filing date: 1980-06-11
Publication date: 1982-01-30

Description

(54) ГЕНЕРАТОР ПРЯМОУГОЛЬНЫХ ИМПУЛЬСОВ(54) GENERATOR OF RECTANGULAR PULSES

1one

Изобретение относитс к вычислительной и измерительной технике.The invention relates to computing and measuring technology.

Известен импульсный генератор, содержащий первый, второй и третий инверторы. Каждый инвертор представл ет собой последовательно включенные полевые транзисторы одинакового типа проводимости. Цепочки из последовательно включенных транзисторов , соединенных каскадно, образуют замкнутую петлю. Выходной зажим ТО подключен к третьему инвертору. Ко входу второго инвертора подключен первый конденсатор , а второй конденсатор включен между входом третьего инвертора и шиной опорного потенциала (IJ.Known pulse generator containing the first, second and third inverters. Each inverter is a series-connected field-effect transistors of the same conductivity type. Chains of series-connected transistors connected in cascade form a closed loop. The output terminal is connected to the third inverter. The first capacitor is connected to the input of the second inverter, and the second capacitor is connected between the input of the third inverter and the reference potential bus (IJ.

Недостаток данного устройства заключаетс в том, что действие внешних возмущающих воздействий нарушает заданный режим генерации, что приводит к настабильной работе устройства.The disadvantage of this device lies in the fact that the action of external disturbing influences violates the specified generation mode, which leads to instable operation of the device.

Наибслее близким к предлагаемому в- л етс генератор, который содержит три соединенные в кольцо инвертора 2.The closest to the proposed is a generator that contains three ring-connected inverters 2.

В генераторах, построенных по кольцевой схеме, существенным недостатком вл етс сильна зависимость стабильностиIn generators, built on a ring circuit, a significant drawback is the strong dependence of stability

работы от внешних возмущающих воздействий . В таких генераторах период колебаний определ етс суммарным временем задержки переключени логических элементов. Врем задержки переключени логическогоwork from external disturbing influences. In such generators, the oscillation period is determined by the total switching delay time of the logic elements. Time delay switching logical

элемента в свою очередь зависит от величины порогового напр жени . Вли ние внешних возмущающих воздействий приводит к изменению вхрдного порогового напр жени логических элементов, что ведет к изменению element in turn depends on the magnitude of the threshold voltage. The influence of external disturbing influences leads to a change in the ambient threshold voltage of logic elements, which leads to a change in

,0 частоты генерации данных устройств., 0 the frequency of generation of data devices.

Цель изобретени - повышение стабильности частоты.The purpose of the invention is to increase the frequency stability.

Поставленна цель достигаетс тем, что в генератор пр моугольных импульсов, содержащий кольцевую схему последовательноThe goal is achieved by the fact that in a generator of rectangular pulses containing an annular circuit in series

Claims

15 connected logic elements, a current source of negative polarity, a current source of positive polarity with a current-supplying transistor and an inverter, the output of which is connected to the base; which is connected to the second. inputs of logical elements. The current source of negative polarity is made multi-channel and the channel outputs are connected to the corresponding second inputs of logical elements. FIG. 1 is a schematic diagram of the device; in fig. 2 shows an embodiment of the device. The device contains logic elements 1-3, current sources of negative 4 and positive 5 polarities, an inverter 6, and the second inputs of logic elements 1-3 are connected to the output of current source 4 of negative polarity, the input of which is connected to the output of current source 5 of positive polarity , the output of the inverter b is connected to the base of the current-setting transistor of the current source 5 of positive polarity, and the output is connected to the emitter of the same transistor. The device operates as follows: The initial generation time of the device is adjusted by the trimming element of the positive current source 5. Inverter 6 sets the threshold voltage level of the logic elements 1-3, which determines the set frequency of the device generation. A change in external disturbances, such as causing an increase in the threshold voltage at the inputs of the logic elements 1-3 of the inverter 6, causes an increase in the delay time of switching the logic elements 1-3. An increase in the threshold voltage at the input of the inverter b causes an increase in the current Ig of the current supply transistor of the positive current source 5, included in the inverter 6 feedback. As a result, the current 1, 3, I, H-Ij + Ij increases, and the switching time of logic elements 1–3 decreases. To ensure the same thermal mode, the logic elements 1-3 and the inverter 6 are made in the same package. Constructing the current source 4 of negative polarity according to the "current mirror" scheme makes it possible to achieve the equality 1 1, which ensures that the generation frequency of the device is maintained in a given mode. However, this device has the disadvantage that, due to the possible technical variation of the parameters of logic elements 1-3, the equality I, Ij Ij is not observed, which is necessary for stable operation of the device. A distinctive feature of the circuit, which takes into account the above mentioned disadvantage (Fig. 2), is that it uses a source 4 of negative current, the number of outputs of which corresponds to the number of logic elements 1-3 of the generator of rectangular pulses and which are connected to their second entrances. This allows you to perform the equality 1, la C necessary for stable operation of the device. Constructing a negative current source 4 with independent outputs allows a less powerful transistor to be used as the current transfer transistor of the positive current source 5. The introduction of negative and positive polarity current sources and an inverter, the combination of these elements with logic elements in accordance with the foregoing, allows stabilizing the generator frequency. Claim 1. A square-wave pulse generator comprising an annular circuit of series-connected logic elements, characterized in that, in order to increase frequency stability, a negative-current current source, a positive-polarity current source and an inverter are introduced into it; connected to the base, and the input to the emitter of the current-carrying transistor, the collector of which is connected to the output of the current source of negative polarity, the output of which is connected to the second inputs l cal elements. 2. The generator according to claim 1, wherein the negative polarity current source is made multi-channel, and the channel outputs are connected to the corresponding second inputs of logic elements. Sources of information taken into account in the examination 1. UK Patent No. 1475724, cl. H 3 P, 1977.

2. Meleshko E. A. Integrated circuits in nanosecond nuclear electronics. M., Atomizdat, 1978, p. 184 (prototype).