SU1387179A1 - Triangular voltage generator - Google Patents

Abstract

The invention relates to a pulse technique and can be used in forming devices, a triangular voltage. The invention makes it possible to increase the linearity of the output voltage in the region of infra-low frequencies, while at the same time increasing the reliability of its operation. For this purpose, field-effect transistors 7 and 8 are included in the generator, connected in accordance with the scheme shown in the drawing. The drawing also shows an operational amplifier 1, a capacitor 2, resistors 3-6. The presence of positive feedback through a divider on resistors 3 and 4 and negative feedback closed through the current source on transistors 7 and 8 provides two quasistable states in the generator. By comparison with the prototype, the proposed generator allows to increase the linearity of the output voltage in the field of infra-low frequencies due to the use of a current source in field-effect transistors, as well as to increase reliability by reducing the number of circuit elements. 1 il. with (L

Description

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The invention relates to a pulse technique and can be used in devices for the formation of a triangular voltage.

The purpose of the invention is to increase the linearity of the output voltage in the region of infrared frequencies, while at the same time increasing the reliability of its operation by simplifying.

The drawing shows the electrical circuit of the generator.

The triangular voltage generator contains an operational amplifier I, the first input of which is through a capacitor 2, and the second input is connected through the first resistor 3 to the total generator, the second input through the second resistor 4 is connected to the output of the operational amplifier, the third 5 is the fourth 6 resistors, the first 7 and the second 8 field-effect transistors, the drain of the first transistor is connected to the first input of the operational amplifier 1, the source to the first output of the third resistor 5, the gate to the second output of the third 5, the first output of the fourth 6 resistors and the driver the second field-effect transistor 8, the drain of which is connected to the output of the operational amplifier 1, the source - with the second output of the fourth resistor 6.

The generator works as follows. Due to the presence of positive feedback through a divider on resistors 3 and 4 and negative feedback closed through the current source on transistors 7 and 8, the generator has two quasistable states. In one of them, the output of the operational amplifier 1 is set to a voltage close to the value of + Ep, a part of which is fed to its non-inverting input through a divider of resistors 3 and 4.

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R3

R3 + R4

where R3, R4 are the resistances of resistors 3 and 4, respectively.

The current, the magnitude of which is determined by the source at resistor b and transistor 8, flows through the displaced gate – drain junction of transistor 7, charges capacitor 2, which leads to a linear increase in the voltage on the inverting input of the operational amplifier 1. When the voltage on the inverting voltage reaches a regenerative process is developed at the input of an operational amplifier of 1 magnitude

and the generator jumps to the second state. The voltage UBX is set at the non-inverting input, and the output voltage is close to the value.

A recharge of capacitor 2 begins with a current, the magnitude of which is determined by the current source at resistor 5 and transistor 7 flowing through the biased-gate-to-drain transistor of the transistor 8. The voltage across the capacitor 2 decreases linearly. When it reaches the UBX value, the device switches to the first state. Thus, at the output of the device, pulses are formed with linearly increasing and linearly falling

5 fronts, i.e. triangular voltage. This ensures a high linearity of the output voltage, since the charge and discharge of the capacitor 2 is produced by a direct current. The rate of rise and fall of the output voltage can be adjusted by changing the values of resistors 5 and 6, respectively. The amplitude of the output voltage can be adjusted by changing the ratio of resistors 3 and 4. Compared with the known,

5, the generator makes it possible to increase the linearity of the output voltage in the region of infra-low frequencies by applying a current source to field-effect transistors, as well as to increase reliability by reducing the number of circuit elements.

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Claims (1)

Invention Formula A triangular voltage generator containing an operational amplifier whose first input is through a capacitor, and The second input through the first resistor is connected to the total generator width, the second input through the second resistor to the output of the operational amplifier, the third and fourth resistors, characterized in that, in order to increase the linearity of the output voltage of the generator in the field of infra-low frequencies while increasing its reliability , the first and second field effect transistors are introduced into it, the drain of the first of which is connected to the first the input of the operational amplifier, the source with the first output of the third resistor, the gate with the second output of the third, the first output of the fourth resistor and the gate of the second field-effect transistor, the drain of which is connected to the output of the operational amplifier, the source with the second output of the fourth resistor.