SU1387175A1 - Pulse generator - Google Patents

Abstract

The invention can be used in devices of pulsed technology and in power sources with frequency-pulse modulation. The pulse generator (GI) contains a Schmitt trigger 1 with an inverting output, an emitter follower 2, a grounded capacitor 3, a discharge resistor 7, a HE 4 element, loaded into two HE 5 and 6 elements with an open collector, a resistor 9, a diode 10 and transistor 8. Stabilization of the pulse duration is achieved by changing their frequency by connecting a charge circuit and a separate discharge circuit to the capacitor in accordance with the time organization of the GI. 1 il.

Description

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The invention relates to digital technology and can be used as a generator in devices of pulsed technology and in power supplies with pulse frequency modulation.

The purpose of the invention is to stabilize the duration of the pulses when their frequency changes by connecting a charge circuit to the capacitor and a discharge circuit separately in accordance with the temporary organization of the generator.

The drawing shows a diagram of the pulse generator.

The generator contains a Schmitt trigger 1 with an inverting output, the input of which is connected via the emitter follower 2 to the first output of the capacitor 3, the second output of which is connected to the common bus, the output of the Schmitt trigger 1 to the HE 4 element loaded on two HE 5 elements and 6 open a collector, while the output of one of the indicated elements is NOT connected via a discharge resistor 7 to a grounded capacitor 3, a charging circuit consisting of a transistor 8, whose base is connected to a control voltage source, an emitter through a resistor 9 under It is connected to the power supply bus and the collector is connected to the output of another of the indicated elements NOT and through the diode 10 to the grounded capacitor 3.

The pulse generator works as follows.

When the power is off, the grounded capacitor is 3 discharged. After the power is turned on at the initial moment, this condition for capacitor 3 is preserved and, as a result, the output of the Schmitt trigger 1 has a high potential, which corresponds to the nonconductive state of the HE elements 5 and 6. The capacitor 3 begins to charge with the current flowing through the circuit : power supply bus, resistor 9, transistor 8, diode 10, wherein the charge rate (charge current) of the capacitor 3 is determined by the level of the control voltage at the base of the transistor 8. When the voltage on the capacitor 3 reaches the trigger threshold Schmitt trigger 1, the latter changes its state and at the outputs of the elements HE 5 and 6 low potentials appear, the diode 10 goes into a non-conducting state and the charging process

the capacitor 3 is stopped, and the previously flowing current of the set value is closed through the output of the HE element 5. The discharge of the capacitor 3 through the discharge resistor 7 and the output of the HE element 6 begin with a constant time determined by the value of the resistor 7. Upon reaching the capacitor 3 the level of the lower threshold of the Schmitt trigger 1, the latter returns to its original state and, as a result, the element would NOT prohibit the discharge of capacitor 3, and the element NOT 5 will allow the connection of the charging circuit - the process of charging the capacitor 3 is repeated p is. Thus, the introduction of a charging circuit that is connected autonomously to the capacitor 3 and the use of a separate discharge circuit makes it possible to reduce or eliminate the influence of the charging current on the discharge process of the capacitor 3, thus stabilizing the duration of the pulses when changing (controlling) their frequency.

In addition, by implementing the charge circuit in the form of a controlled current source, the range is extended.

5 control in the low-frequency region, i.e., in the pulse generator circuit, without additional hardware costs, the frequency control range is expanded, and the impulse duration of the discharge resistor 7 can be independently controlled.

Claims (1)

Invention Formula Pulse generator, containing Schmitt trigger with inverting output, input 5 of which is connected via an emitter follower to a grounded capacitor and to one of the terminals of the discharge resistor, characterized in that, in order to stabilize the duration of the pulses when their frequency changes, they are entered into it 0 element NOT loaded on two elements NOT with an open collector, a resistor, a diode and a transistor, the base of which is connected to the generator input, the emitter is connected through a resistor to the source bus  power supply, and the collector - with the output of one of the elements NOT and through the diode - with the input of the emitter follower and the discharge resistor, the second output of which is connected to the output of the other element NOT with the open collector.