JPS5922432A - monostable multivibrator - Google Patents

Abstract

PURPOSE:To reduce power consumption, by constituting a titled device so that a constant current source for charging a capacitor stops the generation of a current when a monostable multivibrator is in a stable state. CONSTITUTION:A switch circuit 10 is provided between the constant current source 7 and a DC voltage source 8 and the turning-on and -off is controlled with an output signal (b) of an R-S FF circuit 2. The FF circuit 2 is triggered with a trigger signal (a) from an input terminal 1 and is operative, then the output signal (b) goes to L to turn on the switch circuit 10 and the constant current source 7 generates a current I0. On the other hand, the output signal (b) being at the L state turns off a transistor 5, then the current I0 from the constant current source 7 is supplied to a capacitor 6, which is charged. The FF circuit 2 is inoperative with an output signal (c) of a level detector 3 generated when a charging voltage Vc is coincident with a reference voltage V0, the signal (b) goes to H and the switch circuit 10 is turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control means which is brought into operation by a trigger signal and which is brought into operation after a fixed time determined by a time constant circuit, in particular a monostable multi/4-channel motor with an R-87 Ritzo-Flop circuit. Regarding ibrators.

FIG. 1 is a block diagram showing an example of such a conventional monostable multi/J ibrator, in which 1 is an input terminal and 2 is an R/J ibrator.
-8 flip-flop circuits, 3 is a level detector, 4 is a resistor, 5 is a transistor, 6 is a capacitor, 7 is a constant current source, 8 is a DC voltage source, and 9 is a reference voltage source. 2 is a timing chart for explaining the operation shown in the figure, and each signal is given the reference numeral of the corresponding signal in FIG. 1.

Next, in FIGS. 1 and 2, which explain the operation of this prior art, when the R-8 flip-flop circuit 2 is in a stable state, the Q output is at a high level (hereinafter referred to as 'H').
), the output signal is °IHj1.

For this reason, transistor 5 is in the on state, current from constant current source 7 driven by DC voltage source 8 passes through transistor 5, and capacitor 6 is not charged.

When the trigger signal a is supplied from the input terminal 1 to the reset terminal R of the R-8 flip-flop circuit 2, the R-8 flip-flop circuit 2 receives the rising edge of the trigger signal a (time t).
L ) is triggered and enters the operating state, the Q output becomes a low level (hereinafter referred to as 'L#) and the output signal becomes L.
becomes #. The output signal is connected to the transistor 5 via the resistor 4.
The current from the constant current source 7 is supplied to the capacitor 6, and the capacitor 6 starts charging to the charging voltage vc.
becomes larger sequentially with a predetermined time constant. The charging voltage vc is supplied to the non-inverting long sword terminal ←) of the level detector 3, and the reference voltage v0 from the reference voltage source 9 is supplied to the inverting long sword terminal (c).
is supplied. When the charging voltage vc matches the reference voltage v0 (time 1), the level detector 3 generates an output signal C of °゛H'', and the output signal C is connected to the set terminal S of the R-3 flip-flop circuit 2. is supplied to the R-S flip-flop circuit 2, and becomes inactive (time t2).However, the output signal of the Rs-flip-frog circuit 2 is °'H.
'', the transistor 5 is turned on and the capacitor 6 is discharged.Therefore, the charging voltage vc rapidly decreases and becomes zero at time t3, and the output signal C of the level detector 3 becomes ltl,'', which is simply A stable multivibrator is in a stable state.

Note that the charging period of the capacitor 6, and hence the "L# period T of the output signal of the R-8 flip-flop circuit 2, is
Assuming that the capacitance of the capacitor 6 is C1 and the current from the constant current source 7 is Io, as is well known, T = (CXVo)
/I.

It is expressed as

As described above, the conventional monostable multivibrator operates. However, in such a monostable multivibrator, the constant current source 7 is a current generator even in a stable state. is generated, and the current flows through the transistor 5 which is in the on state so as not to charge the 0H capacitor 6. That is, the above-mentioned monostable multi-noibrator is configured to constantly flow a current unrelated to the basic operation in a stable state, and therefore has the disadvantage that it consumes a large amount of wasted power.

SUMMARY OF THE INVENTION An object of the present invention is to provide a monostable multivibrator that eliminates the drawbacks of the prior art described above and can reduce power consumption.

To achieve this objective, the invention is characterized in that the constant current source for charging the capacitor is able to stop generating current when the monostable multivibrator is in a stable state. do.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of the monostable multivibrator according to the present invention, in which 1o is a switch circuit, parts corresponding to those in FIG. 1 are given the same reference numerals, and some explanations Fy3 are omitted. do.

FIG. 4 is a timing chart for explaining the operation of FIG. 3, and each signal is given the reference numeral of the corresponding signal in FIG.

Next, the operation of this embodiment will be explained.
Other than the provision of the switch circuit 1o, it has the same configuration as the conventional technique shown in FIG. 1, and its operation is also partially the same, so explanations of parts that overlap with the conventional technique described above will be omitted. do.

Now, in FIGS. 3 and 4, a switch circuit 10 is provided between the constant current source 7 and the DC voltage source 8, and is controlled on/off by the output signal of the R-S flip-flop circuit 2. In other words, the switch circuit 10 is in an off state when the output signal is "H", and when the output signal is "L"
It is in the on state when . And switch circuit 1o
When the constant current source 7 is in the on state, the constant current source 7 is driven by the DC voltage source 8 and generates a current I0.

Therefore, by trigger signal a from input terminal l, R-
8 flip-frog circuit 2 is triggered (time 11
) When the operating state is reached, the output signal becomes IIL and the switch circuit 10 turns on, and the constant current source 7 generates a current. Since the constant current source 7 is turned off, the current I0 from the constant current source 7 is supplied to the capacitor 6, and the capacitor 6 starts charging.

The output signal C of the level detector 3 generated at the time when the charging voltage va of the capacitor 6 matches the reference voltage v0 (time tz) causes the R-S flip-flop circuit 2 to become inactive, and the output signal becomes 'H'. '', the switch circuit 10 is turned off, and the constant current source 7 stops generating current. At the same time, the transistor 5 is turned on, and the capacitor 6 is discharged via the transistor 5.
When the charging voltage v0 becomes zero (time ts), the monostable multi-pieflation becomes a stable state.

This embodiment operates as described above, but the constant current source 7 supplies the current I only during the period when the output signal of the R-8 flip-flop circuit 2 is L#. Moreover, this current I
0 is monostable because it is used only to charge the capacitor 6 in order to generate the output signal C of the level detector 3 to disable the R-8 flip 70 tube circuit 2. It only contributes to the basic operation of the multivibrator. However, there is no wasted power consumption; 1. Power consumption will be significantly reduced.

5 is a circuit diagram showing a specific example of the constant current source and switch circuit of FIG. 3, where 11, 14° and 16 are resistors;
2, 15.18 is a transistor, 13 is a DC voltage source, 1
7 is a diode, and the parts corresponding to those in FIG. 3 are given the same reference numerals and the explanation thereof will be omitted.

FIG. 6 is a timing chart for explaining the operation of FIG. 5, in which each signal is given the reference numeral of the corresponding signal in FIG.

This specific example is based on the constant current source 7 and the switch circuit 10 shown in FIG.
and PNP) Lanzosta 18.

Transistors 12, 15, resistor 11゜14.16, DC voltage source 13, diode 17 are PNP) transistor 1
8 drive circuits are constructed.

Next, the operation of this specific example will be described, but since the operation of the parts other than the PNP transistor 18 and its drive circuit is the same as that in FIGS. 1 and 3, the explanation will be omitted.

In FIGS. 5 and 6, the trigger signal a causes the R-S
When the flip-flop circuit 2 becomes operational (time t
, ), j%'' is supplied to the pace terminal of the transistor 12 via the resistor 11.The transistor 12 is turned off, and the collector voltage V'1 of the transistor 12, which was zero, is supplied to the pace terminal of the transistor 12. becomes equal to the voltage vl of the DC voltage source 13. Therefore, the emitter voltage of the transistor 15 becomes vl - vF (where V is the voltage when the diode 17 is on), and if the pace current of the transistor 15 is ignored, the transistor 15 (where R: the resistance value of the resistor 16) flows through the collector of the resistor 15.If the pace current of the PNP transistor 18 is ignored, the above-mentioned current also flows through the diode 17 as it is.

The diode 17 and the PNP transistor 18 are paired, so that the same amount of current flows through the PNP transistor 18 as the current flowing through the diode 17, and this current becomes the charging current. The signal is then supplied to the capacitor 6.

Next, the R-871J is detected by the output signal C of the level detector 3.
When the pfrozzo circuit 2 becomes inactive (time t2)
, the output signal becomes H#, the transistor 12 turns on, and the collector voltage v'l of the transistor 12 becomes '
°L#. For this reason, the transistor 15 is turned off and no current flows through the diode 17, so that no charging current flows through the PNP transistor 18. does not flow.

It should be noted that the diode 17 and the PNP transistor 18 do not necessarily have to be a pair, and by arbitrarily selecting the resistance value of the resistor 16, the diode 17 and the PNP transistor 18 can be connected as a pair.
The value of the current from can be set as desired.

In this specific example, the constant current source 7 and the switch circuit 1 shown in FIG.
0 and PNP) transistor 18, a monostable multivibrator with such a configuration has I
In this case, the charging current flowing through the capacitor 6 is uniquely determined by the value of the resistor 16, so the capacitor 6 and resistor 16 should be removed to avoid being affected by IC variations. Attachments are for parts.

As explained above, according to the present invention, the generation of current by the constant current source is limited only to the charging period of the capacitor, so power consumption can be significantly reduced.
A monostable multivibrator with excellent functionality can be provided without the drawbacks of the prior art described above.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional monostable multivibrator, Fig. 2 is a timing chart for explaining the operation of Fig. 1, and Fig. 3 is an example of a monostable multivibrator according to the present invention. 4 is a timing chart for explaining the operation of FIG. 3, and FIG. 5 is a block diagram shown in FIG.
This figure is a circuit diagram showing the integrated circuit of the constant current source and switch circuit of FIG. 3, and FIG. 6 is a timing chart for explaining the operation of FIG. 5. 1... Input terminal, 2... R-87 lip flop circuit, 3... Level detector, 4... Resistor, 5... Transistor, 6... Capacitor, 7... Constant current source ,
8... DC voltage source, 9... Reference voltage source, 10...
switch circuit. Figure 1 Hayabusa Figure 3 Figure 4 Figure 5 Figure 6 Figure 77

Claims (1)

[Claims] comprising a first control means that is brought into an operating state by a trigger signal and becomes an inoperative state by rising to an output signal of the level detector;
The output signal is obtained during the operation of the first control means when the charging voltage of the capacitor charged by the current from the constant current source matches the reference voltage of the level detector. In the stable multi-pipe lake, a second control means is provided which is supplied with the output signal of the first control means and controls the constant current source, and the constant current source supplies current only during the operation period of the first control means. A monostable multivibrator characterized in that it is configured such that it can generate electricity.