SU566326A1 - Sawtooth voltage generator - Google Patents

Description

I

The invention relates to electronics and can be used in electronic circuits for various purposes, for example, as a horizontal scan generator in oscilloscopes.

A sawtooth generator is known, containing a shaping capacitor, a discharge element, a comparison unit, tunnel diodes Ij.

The disadvantage of such a generator is complexity and, consequently, low reliability.

A sawtooth generator is known that contains a shaping capacitor, in parallel with which a discharge transistor is connected, and a series resistor and a diode f 2.

The disadvantage of this generator is the low frequency of the output pulses and their low linearity.

The purpose of the invention is to increase the maximum frequency of the output sawtooth voltage while ensuring its high linearity.

This is achieved by introducing an emitter follower on the transistor into the sawtooth generator, the base of which is connected via a diode to the collector of the discharge transistor and to the forming capacitor, and the emitter through a resistor to the base of the discharge transistor, and tunnel diodes connected in series between the base and the emitter of the bit transistor.

The basic electrical circuit of the saw-tooth generator is shown in the drawing.

Claims (2)

The generator contains a discharge transistor 1 of type n - p - n comparison unit, tunnel diodes 2, switching trans -. . a resistor, a charging resistor 3, a capacitor-forming capacitor 4, a separating diode 5 for separating external sakhronization pulses, a transistor 6 of the pnp emitter follower type, the load of which is connected in series by a resistor 7 and diodes 2, a continuous or standby mode diode 8 generator operation, switch 9 of the generator operation mode. The generator works as follows. In the initial (static) state, a high voltage is applied to the resistor 3 and the shaping capacitor 4, which is a common point. The supply voltage of the emitter repetition of the bodies is applied to the collector of the transistor 6 of this repeater and the common point of the device. The output sawtooth voltage, which is part of high voltage, is removed from the connection point of diode 8, collector of transistor 1, resistor 3, anode of diode 5, forming capacitor 4, Part of the output potential of the emitter follower on transistor 6 through resistor 7 is fed to the connection point key diodes 2 and the base of the transistor 1. The device in the continuous mode works as follows. When the supply voltage is applied at the initial moment of time, transistor 1 is closed, because its base is connected to the emitter through a low resistance of tunnel diodes 2. Forming capacitor 4 begins to charge with through resistor 3, increasing the base potential of transistor 6 emitter follower. Through the resistor 7, a current begins to flow, displacing the operating point of the tunnel diodes 2 upward along the first upward curve of its current-voltage characteristic. Upon reaching the inflection point of the current-voltage characteristic, the operating point of the tunnel diodes 2 instantly switches to the second upstream branch and opens the full transistor 1. The capacitor 4 is quickly discharged through the open transistor 1, and the emitter follower transistor 6 closes, transferring the working point of the diodes 2 in the initial position. Standby mode of the generator is impl. is so. The switch 9 stacks into the standby mode, the variable resistor slider in the switch circuit is set in a position where the potential is removed from this resistor, which is lower than the amplitude voltage of the saw, the diode 8 opens and shuns the charge circuit. the capacitor 4, the translation of the key stage on the diodes 2 in a steady state. When a positive pulse is applied to the input of a 4-bit repeater on transistor 6, the tunnel diodes 2 form a pulse to open transistor 1. Forming capacitor 4 is discharged through transistor 1, the feedback circuit is diode 5, transistor b, resistor 7. through diodes 2, as a result of which these diodes are transferred to the initial low-voltage state. Potential at the con. the capacitor 4 rises to the value determined by the position of the slider of the potentiometer in the circuit of the switch 9, at which the bypassing effect of the diode Q begins to affect, the generator turns into a steady state. The use of the proposed generator allows simple and cheap means to obtain a high-quality high-frequency sawtooth voltage (tens of megahertz). Claims A sawtooth generator, comprising a shaping capacitor, in parallel with which a discharge transistor is connected, and a series-charged, resistor, and a diode, characterized in that in order to increase the maximum frequency of the output sawtooth voltage while ensuring its high linearity, An emitter follower on a transistor, the base of which through a diode is connected to the collector of the discharge transistor and to the shaping capacitor, and the emitter through the resistor of the base of the discharge transistor A source, and tunnel diodes connected in series between the base and the emitter of the discharge transistor. Sources of information taken into account in the examination: 1. US patent number 3214607, cl. 30788 .5., 1965 2. Authors certificate of the USSR №303718, M. Cl. H 03 K 4 / O8, 1971 t j -L continuous rare -A four