SU809561A1 - Voltage-to-frequency converter - Google Patents

Description

(54) VOLTAGE CONVERTER IN FREQUENCY

one

The invention relates to information and measuring technology and can be used in devices of avtomatics and computer engineering.

A voltage-to-frequency converter is known, which contains an integrator, to the output of which a zero-organ is connected, and a discharge circuit controlled by the zero-organ l.

Its disadvantage is complexity

A voltage-to-frequency converter is known, which contains an integrator made on an operational amplifier and a capacitor, a comparator whose input is connected to the integrator output via an integrating circuit, and a key device connected to the integrator, whose control input is t2,

The disadvantage of this converter is the reduced reliability associated with the presence of a key device.

The purpose of the invention is to increase the reliability of the converter.

The goal is achieved by the fact that in a known voltage-to-frequency converter containing an integrator made on an operational amplifier and a capacitor, and a comparator whose input is connected to the integrator output through an integrating circuit, the input of the operational amplifier is shunted by the first diode and its input

5 intermediate stage through the second diode is connected to the output of the comparator. The drawing shows the block diagram of the Converter.

The device contains an integrator 1,

o made on the capacitor 2 and the operational amplifier 3, whose input is shunted by a diode 4. The output of the integrator 1 is connected via an integrating circuit on resistor 5 and capacitor b, the input of the comparator 7, the output of which is connected through the diode 8 and the resistor 9 to the intermediate cascade input operational amplifier.

0 The device works in the following way.

Under the influence of the input signal of positive polarity, the output voltage of the integrator varies according to

5 linear law. The constant time of the integrating circuit made on the resistor 5 and the capacitor 6 is chosen to be much less than the time constant of the integrator 1, therefore the voltage

0, the capacitor b almost repeats.

the output voltage of the integrator 1. When this voltage reaches the threshold of operation of the comparator 7, the latter triggers, and at its output a positive polarity appears, which, flowing through the diode 8 and the resistor 9 to the input of the intermediate stage amplifier 3, causes the voltage at its output, the voltage of positive polarity is equal in magnitude to the limit. As a result, the capacitor 2 recharges: s through diode 4. The operation of the comparator 7 after the occurrence of the positive: voltage drop at the output of the amplifier 3 occurs with a delay. The determined constant time of the integrated circuit, made on the re: resistor 5 and the capacitor b, and the hysteresis of the comparator 7. The delay value is chosen sufficient for complete recharging of the capacitor 2. Then the whole process is repeated.

In the proposed converter there is no key device connected to the integrator, as a result of which an increase in reliability is achieved.

Claims (2)

1. USSR author's certificate No. 417731, cl. H 03 K 13/20, 10,01.72. 2. Design and use of operational amplifiers. Ed. Graham J.M.Mir, 1974, p. 442, FIG. 11. 10 (prototype). Jul