SU1372609A1 - Device for eliminating the influence of switch contact clatter - Google Patents

Abstract

The invention relates to the field of pulse technology and can be used in devices for inputting information and generating control signals in automatic devices | and, telemechanics, computing. The aim of the invention is to improve the reliability of the device. The goal is achieved by the proposed circuit design of the device. The drawing shows switch 1, buses 2 and 3 sources of zero and unit voltage levels, triggers 4 and 5, frequency reference bus 6, input bus 7, zeroing inputs 8 and four triggers 5, zero output 9, single input 10 of trigger 4, unit output 11 of trigger 4, counting input 12 of trigger 5, zero input 13 of trigger 4, zero 14 and unit 15 inputs of trigger 5, counting input 16 of trigger 4 and unit output 17 of trigger 5. After the debounce at the inputs of zeroing of the triggers, the level of the logical unit is set, and after passing two pulses the reference frequency from the pins 6 to the counting bypass 16 of the flip-flop 4, the flip-flop 5 is set to a single state, and the device is returned to the initial state. 2 Il. i (L

Description

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The invention relates to a pulse technique and can be used in devices for inputting information and generating control signals in automation, telemechanics, and computing equipment.

The aim of the invention is to increase the reliability of the device.

FIG. Figure 1 shows a block diagram of a device for eliminating the influence of the bouncing of the contacts of a switch, FIG. 2, a diagram of the voltages at the main points of the device.

The device contains switch 1, buses 2 and 3 of the sources of zero and unit voltage levels, triggers D and 5, frequency reference bus 6, output bus 7, The switching contact of switch 1 is connected to inputs 8 and zeroing of triggers 4 and 5. Zero output 9 trigger 5 is connected to unit input 10 of trigger 4, unit output 11 of trigger 4 is connected to counting input 12 of trigger 5, zero input 13 of trigger 4 is connected to zero 14 and single 15 inputs of trigger 5 and is connected to bus 3 of a source of unit voltage. The counting input 16 of the trigger 4 is connected to the bus 6 reference frequency. A single output 17 of the trigger 5 is connected to the output bus 7, the closing and closing contacts of the switch 1 are connected respectively to the buses 2 and 3 of the sources of zero and unit voltage levels,

The device works as follows

In the initial state, at the inputs 8 of zeroing of the triggers 4 and 5, a single level is received from bus 3 through a closed contact pair of switch 1. At the single input 10 of trigger 4 from zero output 9 of trigger 5 a logical zero signal is received that keeps trigger 4 at zero condition. At the zero input 13 of the trigger 4, on the single 15 and zero 14 inputs of the trigger 5 and at the output of the device (bus 7) there is a signal of a logical unit. The counting input 16 of the trigger 4 from the bus 6 receives rectangular pulses of the reference frequency (the frequency is selected depending on the switching time of the mechanical switch system). On counting input 12

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trigger 5 enters a logical zero level,

At the moment of the first closing of the switching contact of the switch 1 with the output connected to the bus 2, the zeroing level of the flip-flops 4 and 5 is set to a logic zero level, the flip-flops 4 and 5 are set to the zero state, the device output level (the bus 7) appears logical zero. I

The subsequent bounce of the mechanical system of the switch near one contact or between the contacts does not change the state of the device, since the follow-up time of the reference frequency pulses is longer than the switching time of the mechanical system of the switch, i.e. triggers 4 and 5 do not have time to switch to the initial state. Thus, the device generates the necessary voltage drop across bus 7. At the moment the common output of switch 1 returns to its initial state at the output of the device (bus 7), the logic zero level remains until the bounce of the mechanical system of the switch ceases. After the end of the debounce, at the inputs 8 of the zeroing of the triggers 4 and 5, the level of the logical unit is established, and after passing two pulses of the reference frequency from the bus 6 to the counting input 16 of the trigger 4, the trigger 5 is set to one the device is reset.

Claims (1)

Invention Formula A device for eliminating the bounce effect of the switch contacts, containing a switch, two triggers, a clock pulse bus, the counting input of the first trigger connected to the reference frequency bus, and the switching contact of the switch with a zero voltage source bus, characterized in increase the reliability of the device, the disconnecting contact of the switch is connected to the bus of a single voltage level, the zero input of the first flip-flop, the zero and single inputs of the second flip-flop, and the switching rhythm - with the reset input of both flip-flops, isolated the output of the first trigger is connected to the counting input of the second trigger, the zero output of which is connected to unity 1P1flM 7 (t7) 9 (10) 6 (16) ff (l2) the single input of the first trigger, and the single output is the output of the device. u2