SU888297A1

SU888297A1 - Push-pull pulse power amplifier

Info

Publication number: SU888297A1
Application number: SU782675967A
Authority: SU
Inventors: Иван Семенович Голоскоков; Валерий Алексеевич Калуженский
Original assignee: Предприятие П/Я В-8835
Priority date: 1978-10-20
Filing date: 1978-10-20
Publication date: 1981-12-07

Description

Изобретение относится к области электротехники и может быть исполь- ⁴зовано в источниках вторичного электропитания.The invention relates to electrical engineering and can be in the Call ⁴ The use of secondary power sources.

Известен мощности, в временность состоящий из дополнительной обмотки выходного транцсформатора, вклю ченной через диод на вход транзисто-_:ра, с помощью которой до тех пор, пока не изменится полярность напряжения на выходе преобразователя, транзистор принудительно удерживается закрытым, несмотря на появление отпирающего сигнала управления, а после реверса полярности напряжения обмотка не участвует в работе схемы, так как ее напряжение блокируется диодом [1] .Power is known, in time it consists of an additional winding of the output transformer included through a diode to the input of the transistor _: with which, until the polarity of the voltage at the output of the converter changes, the transistor is forcibly kept closed, despite the appearance of an unlocked control signal , and after reversing the polarity of the voltage, the winding does not participate in the operation of the circuit, since its voltage is blocked by the diode [1].

Однако такому усилителю присущ ряд существенных недостатков: необходимы дополнительные обмотки трансформаторов , необходим избыточный дополнидинрмичессквознымиHowever, such an amplifier has a number of significant drawbacks: additional transformer windings are needed, excessive additional

1S ток базы, что приводит к тельным потерям мощности, кие потери, обусловленные токами, снижаются не более чем на •50%.1S base current, which leads to real power losses, which losses due to currents are reduced by no more than • 50%.

⁵ Наиболее близким к изобретению техническим решением является двухтактный импульсный усилитель мощности^ содержащий в каждом плече по транзистору, причем эмиттеры транзисторов соединены между собой и с одним из выводов для подключения источника питания, а коллекторы соединены между собой через первичную обмотку выходного трансформатора, сред. няя точка которого соединена с другим выводом для подключения источника питания, а.вторичная обмотка выходного трансформатора соединена с выводами для подключения нагрузки, при этом базы транзисторов через базовые резисторы и элементы задержки связаны с выводами для подключения (источников управляющих сигналов[2]. ¹ ³ 8£ ⁵ The technical solution closest to the invention is a push-pull switching power amplifier ^ containing a transistor in each arm, the emitters of the transistors connected to each other and to one of the terminals for connecting the power source, and the collectors connected to each other through the primary winding of the output transformer, media. the far point of which is connected to another terminal for connecting the power source, and the secondary winding of the output transformer is connected to the terminals for connecting the load, while the base of the transistors through the base resistors and delay elements are connected to the terminals for connection (sources of control signals [2]. ¹ ³ 8 £

Недостатками такого усилителя является то, что, диод, включенный параллельно переходу база-эмиттер, используется не как пороговый элемент, а как элемент задержки, которая определяется временем восстановления обратного сопротивления диода и носит экспоненциальный характер, причем частотные свойства диода должны быть ниже, чем у транзистора, то шунтирование диодом база-эмиттёрного перехода увеличивает длительность фронта импульса управления, что в свою очередь приводит к увеличению длительности фронта импульса тока, протекающего через коллекторный переход. Затягивание фронта импульса тока'управления ухудшает частотные свойства усилителя.The disadvantages of such an amplifier is that, a diode connected in parallel to the base-emitter junction is used not as a threshold element, but as a delay element, which is determined by the recovery time of the diode's inverse resistance and is exponential, and the frequency properties of the diode should be lower than transistor, then shunting the base-emitter junction with a diode increases the duration of the front of the control pulse, which in turn leads to an increase in the duration of the front of the current pulse flowing through collector junction. Tightening the edge of the current-control pulse impairs the frequency properties of the amplifier.

Кроме того, известный усилитель имеет малый КПД и большие габариты и массу, в связи с чем его надежность невысока, а для управления транзисторами требуется более мощный источник управляющих сигналов.In addition, the known amplifier has low efficiency and large dimensions and mass, in connection with which its reliability is low, and for controlling transistors, a more powerful source of control signals is required.

Целью изобретения является повышение надежности и КПД путем уменьшения сквозных токов в транзисторах.The aim of the invention is to increase reliability and efficiency by reducing through currents in transistors.

Поставленная цель достигается тем, что в двухтактном импульсном усилителе мощности элементы задержки выполнены на оптронах, светодиоды которых последовательно с ограничивающими резисторами подключены параллельно выводам для подключения источников управляющих сигналов, а фототиристоры включены в цепи баз транзисторов.This goal is achieved by the fact that in the push-pull pulsed power amplifier, the delay elements are made on optocouplers, the LEDs of which are connected in series with the limiting resistors in parallel with the terminals for connecting the sources of control signals, and the photothyristors are included in the base circuits of the transistors.

На чертеже приведена схема предлагаемого усилителя.The drawing shows a diagram of the proposed amplifier.

Положительный полюс источника 1)_Пиг, через первичные полуобмотки выходного трансформатора 1* , 1¹¹ приложен к коллекторам транзисторов 2¹ , 2 усилителя мощности. Отрицательный полюс ; источника питания U_n ^одключей непосредственно к эмиттерам транзисторов усилителя мощности. К входам, имеющим общую точку с эмиттерами транзисторов усилителя мощности, подключены параллельно через ограничивающие резисторы З¹, 3' светодиоды 4’, 4оптронов 5’, 5'¹, а их фототиристоры 6¹, 6^м последовательно с переходами база-эмиттер транзисторов усилителя мощности через базовые резисторы 7, 7The positive pole of the source 1) _Pig , through the primary half-windings of the output transformer 1 *, 1 ^{11 is} applied to the collectors of transistors 2 ¹ , 2 of the power amplifier. Negative pole; power supply U _n ^ of the keys directly to the emitters of the power amplifier transistors. The inputs that have a common point with the emitters of the power amplifier transistors are connected in parallel through the limiting resistors Z ¹ , 3 ', LEDs 4', 4 optrons 5 ', 5' ¹ , and their photo thyristors 6 ¹ , 6 ^{m in} series with the base-emitter junctions of the amplifier transistors power through base resistors 7, 7

629/ 4629/4

Усилитель работает·следующим образом.The amplifier works as follows.

Положим, что для данного момента времени транзистор 2^,( открыт сигна5 лом положительной полярности, поступившим на второй вход, а транзистор 2* закрыт через диод 8* сигналом отрицательной полярности, поступившим на первый вход,Let us assume that for a given moment of time, transistor 2 ^{, (} open signal5 is a positive-polarity scrap fed to the second input, and transistor 2 * is closed through diode 8 * with a negative polarity signal received at the first input,

Ю При поступлении на первый вход управляющего сигнала положительной полярности, а на второй вход - отрицательной полярности транзистор 2'< начинает закрываться, а транзистор 2¹и не открывается до·тех пор, пока не откроется фототиристор 6’ оптоэлектронной пары 5¹ · Но, как известно, у оптронов светодиод-фототиристор существует вполне определенный порог Ю срабатывания, который наступает в течение определенного времени, на величину которого осуществляется задержка сигнала, открывающего транзистор 2’.Yu When a control signal of positive polarity arrives at the first input and a negative polarity at the second input, transistor 2 '<starts to close, and transistor 2 ¹ does not open until the photo-thyristor 6' opens, 5 ¹ · But, As is known, for optocouplers, the LED-photo thyristor has a well-defined threshold of operation, which occurs within a certain time, the amount of which is the delay of the signal opening the transistor 2 '.

j$ При поступлении на первый вход сигнала отрицательной полярности, а на второй вход - положительной транзистор 2' через диод 8'запирается, а отпирание транзистора 2 происходит 30 с той же задержкой, что и в предыдущем такте.j $ Upon receipt of a negative polarity signal at the first input and a positive transistor 2 'through the diode 8', the transistor 2 is locked, and the transistor 2 is unlocked 30 with the same delay as in the previous clock cycle.

Таким образом, в предлагаемом усилителе обеспечивается практически полное устранение сквозных токов (динамических потерь) при переключении транзисторов, повышается КПД примерно на 10-15%, уменьшаются габариты и вес на 5Ю%, увеличивается надежность.Thus, the proposed amplifier provides almost complete elimination of through currents (dynamic losses) when switching transistors, increases efficiency by about 10-15%, reduces overall dimensions and weight by 5%, and increases reliability.

Claims

The invention relates to the field of electrical engineering and can be used in secondary electric power sources. A push-pull power amplifier is known, in which the one-time opening of the transistors, consisting of the additional winding of the output transformer connected through the diode to the input of the transistor, is excluded, until until the polarity of the voltage at the output of the converter changes: the transistor forcibly holds with the closed, despite the appearance of the unlocking control signal, and after reversing the polarity of the voltage, the winding does not participate in the operation of the circuit, since its voltage is blocked by the TI diode. However, this amplifier has a number of significant drawbacks: additional transformer windings are needed, excessive base current is required, which leads to additional power losses, and the minimum losses due to through currents are reduced by no more than 50%. The closest technical solution to the invention is a push-pull switching power amplifier containing in each arm through a transistor, the emitters of the transistors are connected to the source and one of the terminals for connecting the power source, and the collectors are interconnected through the primary winding of the output transformer, the midpoint of which connected to another terminal for connecting the power source, and the secondary winding of the output transformer is connected to terminals for connecting the load, while the base The resistors through the base resistors and the delay elements are connected to the leads for connecting the control signal sources G23. The disadvantages of such an amplifier is that the diode connected in parallel with the base-emitter junction is not used as a threshold element, but as a delay element which is determined by the recovery time of the reverse resistance of the diode and is exponential, and the frequency properties of the diode must be lower than a transistor, the shunting of a base-emitter junction diode increases the duration of the front of the control pulse, which in turn leads to an increase in the duration of the front of the current pulse flowing through rez collector transition. Closing the front of the current control pulse impairs the frequency properties of the amplifier. In addition, a well-known amplifier has low efficiency and large size and weight, and therefore its reliability is low, and a more powerful source of control signals is required to control transistors. The aim of the invention is to increase the reliability and efficiency by reducing the through currents in the transistors. This goal is achieved by the fact that in a push-pull power amplifier, delay elements are made on optocouplers whose LEDs are connected in series with limiting resistors in parallel to the terminals for connecting control signal sources, and the photo thyristors are included in the transistor base circuits. The drawing shows the circuit of the proposed amplifier. The positive pole of the source, through the primary half windings of the output transformer 1, 1 is applied to the collectors of transistors 2, 2 power amplifier. The negative pole of the power supply is connected directly to the emitters of the transistors of the power amplifier. To the inputs having a common point with the emitters of the transistors of the power amplifier, are connected in parallel via limiting resistors 3, LEDs, A of the optocouplers 5, 5, and their phototristors 6, 6 in series with the base-emitter transitions of the power amplifier transistors through the basic pe -1 - .11 Zistors 7, 7 7 The amplifier works as follows. Let us assume that for a given moment in time transistor 2 is open by a positive polarity signal received at the second input, and transistor 2 is closed through a diode 8 by a negative polarity signal that arrives at the first input. at the second input, the negative polarity, the transistor 2 starts to close, and the transistor 2 does not open until the photo thyristor 6 of the optoelectronic pair 5 opens. But The wavelength of a certain threshold, which occurs within a certain time, the value of which delays the signal opening transistor 2. When a negative signal is received at the first input, and the second input is positive transistor 2 through the diode 8 is locked, and the unlocking of the transistor 2 occurs with the same delay, as in the previous tact. Thus, the proposed amplifier provides almost complete elimination of through currents (dynamic losses) when switching transistors, increases efficiency by about 10-15%, reduces size and weight by 5-10%, and increases reliability. A push-pull power amplifier containing a transistor in each arm, the emitters of the transistors being connected to each other and to one of the terminals for connecting the power supply, and the collectors being connected to each other through the primary winding of the output transformer, the middle point of which is connected to the other. the output for connecting the power source, and the secondary winding of the output transformer is connected to the terminals for connecting the load, while the bases of the transistors through the base resistors and elements The delays are related to you.