JPS5813015A - Monostable multivibrator - Google Patents

Abstract

PURPOSE:To realize a high-precision monostable multivibrator by using an input signal to and an output signal from a delay line as a setting and a resetting signal for a flip-flop. CONSTITUTION:An input trigger signal D is inputted to a delay line 21. The delay line 21 is composed of N stages of flip-flops, and the input trigger signal D propagates by a clock signal CK. Therefore, the signal inputted to the delay line 21 is outputted an accurate delay time later. A flip-flop 23 regards the trigger signal D as a data input D and is reset by the trigger signal D. The output of the delay line 21 is supplied to the reset input CL of the flip-flop through an NOR gate 22. Therefore, a high-precision monostable multivibrator is realized on the basis of the accurate delay time. Further, the delay line employs semiconductors to realize high integration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly integrated and highly accurate monostable multivibrator.

FIG. 1 shows a conventional monostable multivibrator. In the figure, 1 and 4 are NOR gates, 2 is a capacitor,
3 is a resistor, 5 to 7 are inverters, D is an input trigger, R is a reset signal, and Q and Q are outputs. NOR gate IC
= is input with input trigger D, reset signal R, and output of NOR gate 4 equivalent to output Q, all of which are “
When the value is 0'', the A point is 1''. capacitor 2 and resistor 3
constitutes a differential circuit. NOR gate 4:2 receives the reset signal R and the output of this differentiation circuit.

As shown in FIG. 2(a), when the input trigger D and the output Q of the reset signal R1 are both "0", the points A and B are "1" and in a steady state. At this time, when the input trigger D changes to "1", the A point changes to "10",
Furthermore, point B also instantaneously changes to "0", and the output Q is 'l'1
'-1Q is inverted to 10''. After changing to @0'', point B gradually changes to @1'' due to the time constant of capacitor 2 and resistor 30, which constitute the differentiating circuit, and exceeds the threshold voltage VTR of NOR gate 4. At that time, the output of NOR gate 4 turns to ``0'', so the outputs Q and ζ are each 10
”, '1#. Also, as shown in Figure 2 Φ),
When the reset signal R becomes ``1'' (2), the output of the NOR gate 4 changes from 0 to 1 even when the time constant 4 does not reach 2, and the outputs Q and Q change to ``0'' and ``1'' (2), respectively. It turns out.

In this way, Figure 1 shows a monostable multivibrator with a reset function, but if we try to realize a monostable multivibrator with a time constant of several tens of microseconds or more using a semiconductor integrated circuit, the area occupied by the resistors and capacitors will become large. It has the disadvantage that it becomes larger and the accuracy of the time constant becomes lower.

In order to solve these drawbacks, the present invention consists of a delay line into which an input trigger is input, and a flip-flop that is set by the input trigger and reset by the delay line output or a reset signal. Use details;-explain.

FIG. 3 shows an embodiment of the invention. In figure C, 21
is a delay line to realize the time constant of a monostable multivibrator, n is a NOR gate, le is a D-type flip-flop, and 24.25 is an inverter to ensure setup time.

An input trigger D is input to the delay line 21 and propagated by the clock signal CK. There are various ways to implement the delay line 21, but the fifth method described below is the method for implementing the delay line 21. This is realized using a dynamic master-slave flip-flop as shown in the figure, and the number of stages is N.
If the frequency N±1 of the clock signal CK is f, then it is output from the delay line to the sand diameter. The flip-flop device has an input trigger D
When data is input manually, it is a synchronized clock input CK, and is set by the input trigger D (2).

Now, as shown in Fig. 4(a), the input trigger D is "0",
When the reset signal R is 10'', the output Q maintains the state of 1o''. When the input trigger D changes to 11”,
Flip-flop n is set, and output Q becomes 1''. Simultaneous C two-person trigger D is also input to delay line 21.

The “1” signal input to the delay line 21 is the clock signal CK
The delay #j21 is transmitted and output to the Yutan sand diameter, and the N
The flip-flop device is reset via the OR gate n, and the output Q is set to "0".

Further, as shown in FIG. 4(b), the reset signal R is "1".
When it becomes #, even if the delay line output is in the 10" state, the flip-flop is forcefully reset, and the output Q becomes 10".
become. \ 1
By adopting the configuration shown in FIG. 3 in this manner, a monostable multivibrator can be realized without using resistors or capacitors.

Below, we will show a design example of a monostable multivibrator with ρμs. In the conventional type shown in Fig. 1, the time constant = 0.69RC
Therefore, R = 32 Ω, C = 1000 pF, and for example, using polysilicon as the resistor and diffusion as the capacitor,
Assuming 32Ω shoulder and 5 XIO”-'p syn-, the occupied area is about I X 10'gn2 in resistance.
, with a capacitor it becomes 2x106 x 2, which is 1,5 x
The size is 1.5 fins. Furthermore, the realized accuracy is ±10 inches or more. On the other hand, in the embodiment of the present invention shown in FIG. 3, if the realized accuracy is ±10% or less, the clock frequency f of the delay line is 500 pS since ±1/f < 2.2 pS.
KF(Z, and the number of delay line stages N is N/f=22/jS
Therefore, 11 steps can be obtained. For example, if the delay line is realized by the well-known dynamic master-slave flip-flop shown in FIG. 5, and a technology with a pattern rule of about 311 m is used, the area occupied by the embodiment shown in FIG. 3 is approximately 1×105 μm2.
, that is, 0.33 uzX O, 33vm,
It would be great if it could be significantly downsized.

In FIG. 5, 31 to 34 are inverters, 35 and 37 are transmission gates, A is a NAND gate, and 38 is a NOR gate.

As described above, according to the present invention, a highly integrated and highly accurate monostable multivibrator can be realized because resistors and capacitors that occupy a large area and are difficult to obtain high precision are unnecessary.

[Brief explanation of the drawings] Fig. 1 is a circuit diagram showing a conventional example, Fig. 2 (a) and (b)
) is a waveform diagram for explaining the operation of FIG. 1, FIG. 3 is a circuit diagram showing an embodiment of the present invention, and FIGS. 4(a) and (b)
) is a waveform diagram for explaining the operation of FIG. 3, and FIG. 5 is a circuit diagram showing a specific example of the delay line of FIG. 3. 21...Delay line, n...NOR gate, Otsu90
．． flip flop. My agent, patent attorney Makoto Suzuki, is here. Figure 1 Figure 2 φ) (b) Figure 3

Claims (1)

[Claims] 1. A monostable multivibrator comprising a delay line into which an input trigger is input, and a flip-flop that is set by the input trigger and set by the output of the delay line or a reset signal.