SU1374411A1 - Single-shot multivibrator - Google Patents

Abstract

The invention relates to pulse. technology and can be used in frequency converters. voltage, frequency - current. The purpose of the invention is to increase the stability of the duration of the formed pulse, which is achieved by compensating for the residual voltage of the discharge key and the time of the driving capacitor. The device contains a trigger 1, a current source 3, a switch 4, the time of the supply capacitor 6, a reference resistor 5, a sampling and storage unit 7, an inverter 8, a comparator 9, a device output 10, inputs 2 and 12 of the trigger 1, an output 11 flip-flops 1. Compared with the prototype, the proposed device allows to obtain the relative value of the instability of the pulse duration, not higher than + 0.15-10 for each when the temperature changes from +5 to and the supply voltage changes by 410 and -15% of the nominal. 1 il. W (O

Description

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 The invention relates to a pulse technique and can be used in transducers frequency - voltage, frequency - current. The purpose of the invention is to increase the stability of the duration of the impulse being formed by compensating for the residual voltage of the key of the time - drive capacitor discharge.

The drawing shows the scheme of the proposed multivibrator.

The device contains the trigger 1, the second input 2 of the trigger, the current source 3, the key 4 bits of the time of the driving capacitor, the reference resistor 5, the time of the driving capacitor 6, the sampling and storage unit 7, the inverter 8, the comparator 9, the output 10 of the device, the first the output 11 and the first input 12 of the trigger 1. The output of the trigger 1 is connected to the input of the key 4, the output of which is connected to the time of the setting capacitor 6 and the reference resistor 5, which is connected to the current source 3 and the input of the sampling and storage unit 7 Zana with the second input of the comparator 9, the first input of which connected to the time by the reference capacitor 6 and the output of the key 3. The output of the comparator 9 is connected to the first input 12 of the trigger 1, the first output 11 of which is connected through the inverter 8 to the control input of the sampling and storage unit 7.

The device works as follows.

In the initial state, the output of the trigger 1 has a high potential key. 4 closed. The voltage across the plates of the capacitor 6 is determined by the saturation voltage U of the transistor. The current I of the current source 3 flows through the resistor 5 and through the public key 4, creating a voltage drop

Uo, IR9 + U ,.

This voltage is remembered by the capacitor of the unit 7. It is fed to the reference input of the comparator 9.

When the pulse-forming multivibrator is applied to the input, the trigger 1 tilts and closes the key 5. Simultaneously, the trigger 1 causes the zero level to appear, the output of the inverter 8.

The time of the driving capacitor 6 is charged with a constant charging current I. The voltage across it increases linearly

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from the initial voltage of the search and „.

When the voltage U reaches the value of the reference voltage and the comparator 9, impulses the tilting trigger 1. At this time, the drive capacitor 6 is discharged through the opening of the key 4 and the waiting multivibrator returns to the initial state. The voltage U of the voltage of key 4 is part of the reference voltage U0n and part of the charging voltage on the capacitor U, therefore, fluctuations under the influence of external factors and due to differences in the characteristics of the keys are the same for both compared voltages and lei affect the change in duration generated pulse.

In all cases, the duration of the generated pulse C, i.e. is determined by the values of the passive elements: if their temperature coefficients are equal but opposite in sign, providing a higher stability of the duration of the pulse being formed. Due to the introduction of the sample and storage unit into the multivibrating standby circuit, as well as the new links between the device nodes, the effect of voltage variation on the sensing key 5 on the stability of the pulse duration is eliminated.

The device allows to obtain a relative value of the instability of the pulse duration not higher than every 10 ° C when the temperature changes from +5 to and the supply voltage changes by +10 - -15% of the nominal.

Claims (1)

Invention Formula A standby multivibrator containing a trigger on transistors of different conductivity types, series-connected current source, reference resistor and time setting capacitor, switch key time setting capacitor to the input of which the first trigger output is connected, comparator whose first input is connected to the setting capacitor, and the output to the first input of the trigger, the second input of which is the device input, characterized in that, in order to increase the stability of the duration of the pulse being formed, 313744114 A sample and storage unit has been entered, the inverter cut to the second output of the trigger input of which is connected to the output of the HCS, and the output to the second input of the current com- puter, the control input to the meter.