SU1539941A1 - Push-pull transistor inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and automation systems. The purpose of the invention is to increase reliability by limiting the voltage on the elements. Transistors 11 and 12 are controlled from a master oscillator, made in the form of a current source 1, through a transformer 2. In the secondary windings 4 and 6 of transformer 2, zener diodes 8 and 10 are connected in series, respectively. When the transistor 11 (12) is locked during the dissipation of excess carriers, the voltage on the secondary winding 4 (6) is equal to the voltage drop at the input of the transistor 11 (12) and the zener diode 8 (10) in the forward direction. This voltage, when transformed into the secondary winding 6 (4), is less than the stabilization of the Zener diode 10 (8) and therefore the transistor 12 (11) cannot open at this stage. The damping circuit from capacitor 15 and double-sided voltage limiter 14 limits the voltage across the windings of the transformer 2. 2 Il.

Description

FIG. one

The invention relates to electrical engineering and can be used in secondary power supply and automation systems.

The purpose of the invention is to increase reliability by limiting the voltage on the elements.

FIG. 1 is a schematic diagram of a push-pull transistor inverter; in fig. 2 - time diagrams of his work.

The inverter contains a master oscillator 1, made in the form of a current source and having a transformer 2, on the core of which the secondary windings 3-6 are located. The winding 3 is connected to the anode of the first diode 7, winding 4 - with the cathode of the first Zener diode 8, winding 5 - with the anode of the second diode 9, winding 6 - with the cathode of the second Zener diode 10. The anode of the Zener diode 8 is connected to the base of the first transistor 11, to the collector of which is connected the cathode of the diode 7, and the second output of the winding 3, and the anode of the Zener diode 10 is connected to the base of the transistor 12-, to the collector of which the cathode of the diode 9 is connected, the second end of the third winding 4 and the emitter of the first transistor I, the second output winding 6 and the second conclusion about The coil 5. The damping circuit 13, consisting of a voltage suppressor (zener diode) 14 and a capacitor 15 connected in series, is connected in parallel with the primary winding of the transformer. The inverter operates as follows.

Until moment C (FIG. 2), the second transistor 12 is in the conducting state. At time C, the polarity of the current of the source generator 1 changes. The resorption process of minority carriers in the base region begins. Secondary windings 3 and 5, together with diodes 7 and 9, forming non-linear feedback, make it impossible to deeply saturate transistors 11 and 12. When transistors are closed, first the absorption of charge carriers occurs in the base-collector junction region, after which it is shifted in the opposite direction, and then in the transition region, the base – emitter base (stage t – h - ti. Fig. 2). At time t, the transition base-emitter transistor 12

P

0

, ° 5

closes, the base current of the transistor 12 starts to decrease and it goes into the dynamic cut-off region. In this case, in the interval r1 -t, the base-chemitter resistance of the second transistor 12 is small and the voltage U6 is also small and consists of the voltage drop across the Zener diode 10 V the direct direction and the voltage drop at the junction of the base - emitter of transistor 12. This ensures the absence of unlocking current I. in winding 4 and, respectively, in the base circuit of transistor 11, since the breakdown voltage of the Zener diode 8 is much higher than the voltage At the zener diode 10 in the forward direction. Thus, until the dissolution of minority carriers in the base area of transistor 12 is completed, the unlocking of transistor 11 is blocked. During the dynamic cutoff between time t and t, the current of master oscillator 1 must remain constant. Therefore, the voltage Uu at its output rises sharply ( t), a double-sided zener diode 14 is punched. The damping circuit 13 - and a part of the current 1y goes to the recharge of the capacitor 15.

At time t, there is also a sharp jump in voltages U4 and U6 on the third 4th and fourth 6 windings.

Thus, after a voltage jump Uy at the output of master oscillator 1 at time t, voltage jumps U4 and Ug occur, and then these voltages increase in accordance with the charge of capacitor 15. At the same time, the current Ifi of the fourth winding 6 decreases. At time tj, current 16 decreases to zero and the second transistor 12 closes. After the minimum protective pause, determined by the capacitor 15 capacitance, the voltage ui at the output of the master oscillator 1 and, respectively, at the output of the winding 4, reaches the voltage of the breakdown of the zener diode 8 and the current of the master oscillator 1y switches to the base of transistor 11 through the winding 4 (current 14, time t3), which leads to its unlocking "

At time t, the direction of the current of the master oscillator 1 is changed, which leads to a repetition of the process of locking and unlocking at time ts, t 6, similar to time tt tj.

Claims (1)

Invention Formula The bilitron is connected to the control input of the corresponding transistor, characterized in that, in order to increase the reliability of the voltage limitation on the elements, the input damping chain is inserted parallel to the primary winding of the transformer, made in the form of A push-pull transistor inverter containing a power amplifier on two transistors and a master oscillator, made in the form of a source of series-connected condensate and having a transformer, each torus and a two-way limiter, whose secondary winding is through voltage. The bilitron is connected to the control input of the corresponding transistor, characterized in that, in order to increase the reliability of the voltage limitation on the elements, the input damping chain is inserted parallel to the primary winding of the transformer, made in the form of series-connected capacitor and double-sided voltage limiter. "I at / b t IA Of t, tthts L Gb tf t,