JPS5950136B2 - timer circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timer circuit in which arbitrary time settings can be made using a variable resistor. To reduce the variation as much as possible to reduce the variation in the setting time of the entire device or to simplify adjustment and correction in the manufacturing process.

2) The change characteristics of the set time with respect to the rotation angle (or slide position) of the time setting variable resistor can be set relatively easily, and the characteristics are highly accurate.

The aim is to achieve the above with an extremely simple configuration.

Conventionally, a timer circuit whose time can be adjusted using a variable resistor is shown in FIG.

In Figure 1, 1 is a DC power supply, 2 is a power switch, and 3
is a variable resistor for time setting, 4 is a semi-fixed resistor for adjustment to correct variations in the resistance value of the variable resistor, 5 is a fixed resistor that gives the minimum value for one hour of the timer, and 6 is a variable resistor This is a capacitor that is charged by the DC power source 1 via a resistor 3, a fixed resistor 5, etc.

7 and 9 are fixed resistors, and 8 is a semi-fixed resistor for correcting variations in the capacitance of the capacitor 6.

10 is the charging voltage e1 of the capacitor 6, the fixed resistor 7,
9 and the voltage e2 set by the semi-fixed resistor 8, and depending on the state thereof, the high speed high speed is a comparator that outputs a low level output.

When the output of this comparator 10 becomes high level, the transistor 13 is turned on via the resistor 11.12.
The relay 14 is turned on to energize or de-energize the load to be controlled.

15 is a diode that absorbs the back electromotive force of the relay 14.

In this circuit, the timer time T is given by:

However, C is the capacitance of the capacitor 6, and R is the value of the resistance in series with the capacitor 6, that is, the combined resistance value of the variable resistor 3, semi-fixed resistor 4, and fixed resistor 5.

Here, the main factor that causes the variation in the timer hour T is the variation in the resistance value of the variable resistor 3 (usually ±2
0%) and the capacitance of the capacitor 6 (usually ±10% or 20% for timer applications).

Therefore, in the embodiment shown in FIG. 1, the variation in the resistance value of the variable resistor 3 is first corrected by the semi-fixed resistor 4.

As a result of this adjustment, the maximum value T□ of the timer 1 hour T
This means that correction has been made so that the ratio between Tt and the minimum value Tt becomes a predetermined value.

Next, the variation in the capacitance C of the capacitor 6 will be corrected, but it is not appropriate from a cost perspective to correct the capacitance itself of the capacitor 6, and therefore, from equation (1), the voltage e2
It can be seen that this can be achieved by correcting.

For this reason, the variable resistor 3 is set so that the semi-fixed resistor 8 gives the maximum value TH for one hour of the timer, for example.
The correction is made so that the predetermined timer is set to one hour.

In this way, the correction is completed, but in this case, (1) There are two adjustment steps for correction.

(2) Semi-fixed resistor 4 (In some cases, a corresponding fixed resistor was added. In order to perform correction by connecting the resistor in parallel to the variable resistor 3, as shown in Fig. 2, Even if you desire a timer time T as shown in the solid line for the rotation angle θ (or slide position), the actual characteristic will be as shown in the dashed line, and the characteristic itself will also depend on the variation in the total resistance value of the variable resistor 5. This causes variations.

(3) When variations occur in the resistance change characteristics with respect to the rotation angle θ of the variable resistor 3, there is almost no means to correct them. This results in even more variation.

There are disadvantages such as characteristics and cost.

There were some difficulties in manufacturing.

Next, a timer circuit based on the present invention will be explained with reference to the accompanying drawings.

FIG. 3 shows one embodiment of the timer circuit of the present invention.
5 and 5 are explanatory diagrams of the operation.

First, in FIG. 3, the same symbols as in FIG. 1 indicate the same or corresponding elements.

16 is a fixed resistor, 7 is a semi-fixed resistor, and together with the capacitor 6, a charging circuit A is configured to output a charging voltage ec.

18, 19, and 20 are fixed resistors, and the tolerance for variation in resistance value is the same (for example, ±2%).
are selected.

21 is a variable resistor for time setting, and fixed resistor 19
are connected in parallel.

A set voltage ed is output from the sliding terminal of this variable resistor 21.

The sliding terminal of this variable resistor 21 provides a total resistance value of 2
Since the two terminal terminals are not directly connected, the resistance value between the two terminal terminals does not change due to the sliding of the sliding terminal.

This variable resistor 21 and three fixed resistors 18, 19.2
0 constitutes a time setting circuit B.

The comparator 10 inputs the charging voltage ec of the charging circuit A and the setting voltage ed of the time setting circuit B, and outputs a voltage V when ec<ed.

is high level, and when ec>ed, the output voltage V.

becomes low level, and this comparator 10 constitutes a voltage comparison circuit C.

A drive circuit is constructed from the resistor 11 to the diode 15, and the relay 1
Turn 4 on and off.

In the above configuration, the charging circuit A charges the capacitor 6 via the fixed resistor 16 and the semi-fixed resistor 17,
As shown in FIG. 4, after the power switch 2 is turned on, the charging voltage ec changes according to time t.

Here, variations in the capacitance of the capacitor 6 can be corrected by adjusting the semi-fixed resistor 17 (although a corresponding fixed resistor may be inserted) in series with the capacitor 6 to obtain the charging voltage e as shown in FIG.

It is corrected to have the characteristics of

In this figure, the charging voltage ec of the capacitor 6 when the time is t1 is VL, the ec when t=t2 is VH, and the time from time 1=0 to 1=11 is the minimum setting value of the timer 1 hour T. TL9 Set to the maximum setting value TH of the timer 1 hour T from time 1=0 to t=t2.

Therefore, in the time setting circuit B, if the set voltage e of the sliding terminal of the variable resistor 21 is now ed=VL, the output voltage of the comparator 10 will be V immediately after the power switch 2 is turned on.

becomes high level, the relay 14 is turned on, and at time 1=11, that is, after one time T=TL of the timer, the output voltage vo of the comparator 10 is inverted and the relay 14 is turned off.

Similarly, if ed=VH, timer one hour T=TH
After that, the output voltage V of the comparator 10.

is reversed and the relay 14 is turned off.

Therefore, in the time setting circuit B, the setting voltage ed is changed from ed=VL to ed=V from the sliding terminal of the variable resistor 21.
By configuring the timer to be variable up to H, it becomes possible to set an arbitrary timer time T between timer one time T=TL and T=T.

Therefore, the time setting circuit B consists of a fixed resistor of 18°19.2
0 is connected in series to the DC power supply 1, and a variable resistor 21 is connected in parallel with the fixed resistor 19, so that the potential of the two terminal terminals giving the total resistance value of the variable resistor 21 (i.e., fixed resistors 19 and 2) is
0 and the potential at the connection point of fixed resistors 18 and 19) are configured to be V and VH.

As a result, the potential of the sliding terminal of the variable resistor 21 can continuously change from ed=VL to ed=■□ according to its rotation angle θ (or sliding position).

Therefore, if we assume that the resistance change characteristic of the variable resistor 21 with respect to the rotation angle θ is B characteristic (a characteristic with a linear relationship), when the rotation angle θ changes from 0 to 100%, the set voltage ed changes linearly from VL to VH. do.

Therefore, as a result, the timer time T with respect to the rotation angle θ of the variable resistor 21 immediately obtains the characteristics shown in FIG. 5 from FIG. 4.

Next, in the time setting circuit B, the tolerance for variation in the total resistance value of the variable resistor 21 is normally ±20%, but as described above, the fixed resistor 18. 19. 20 are selected to have small variations (±2%).

Therefore, the total resistance value of the variable resistor 21 is set to RヮΩ, and the tolerance value of its variation is ±Kv (to) (= ±20%), or the resistance value of the fixed resistor 19 connected in parallel with the variable resistor 21 is set to RF.
Ω, the allowable value of its variation is ±KF: (To) (= ±2%
), the relationship is selected to satisfy.

That is, by satisfying this relationship, variations in the voltages □ and VL caused by variations in the total resistance value of the variable resistor 21 can be made smaller than those caused by variations in the resistance value of the fixed resistor 19.

As a result, the total resistance RvΩ of the variable resistor 21 is ±2
Even if a variation of 0% occurs, the resistance value R of the fixed resistor 19
This can be considered to be equivalent to or less than ±1% variation in FO, and as a result, the variable resistor 21
This means that the variation in the total resistance value can be significantly reduced.

It is desirable to select fixed resistors 18 and 20 that have the same tolerance for variation as that of fixed resistor 19.

As a result, the time setting circuit B can set the maximum value of the set voltage with high precision while using the variable resistor 21 which has large variations.
□ and the minimum value V can be given.

When VH and VL are set, the set voltage e from the sliding terminal of the variable resistor 21 changes continuously from the minimum value VL to the maximum value VH depending on its rotation angle (or slide position). It changes linearly, and it is possible to obtain the characteristics of the timer time T as shown in FIG. 5 mentioned above.

In the time setting circuit B, the relationship between the resistance values of the variable resistor 21 and the fixed resistor 19, that is, equation (2), shows that the greater the degree of inequality, the greater the resistance value R of the fixed resistor 19.
The smaller F is, or the tolerance for its variation ±KF%
), the influence of variations in the total resistance value Rv of the variable resistor 21 on the set voltage ed can be made smaller.

Further, the fixed resistors 18 and 20 are usually fixed resistors 1
It is appropriate to set it to the same level as the variation in the resistance value of fixed resistors 18 and 19, but calculate the degree of variation that the variation in the resistance value of these fixed resistors 18 and 19 gives to the set voltage ed (or VH, vt). , it is considered that a reasonable design can be achieved by selecting a tolerance for variation that is equal to or less than the influence of the fixed resistor 19.

Note that the correction by the semi-fixed resistor 17 in this embodiment is as follows:
Normally, since it is possible to compensate for variations in the time setting circuit B, the rotation angle θ (or sliding position) of the variable resistor 21 is set to the minimum or maximum, that is, ed=VL or ea=VH.
If the semi-fixed resistor 17 is adjusted so that the predetermined timer hour T=TL or T=T, &, a highly accurate timer hour T can be obtained.

Next, in the case of the embodiment shown in FIG. 3, the relationship between the rotation angle θ of the variable resistor 21 and the timer time T is a non-linear relationship as shown in FIG.

From the viewpoint of usability, as shown in Fig. 5, the smaller the timer hour T, the greater the degree of change in the rotation angle θ, making it easier to set, but in particular, the rotation angle θ and the timer hour T must have a linear relationship. There are cases where

. An embodiment of a time setting circuit B suitable for such a case is shown in FIG.

In Fig. 6, 26 is a variable resistor whose resistance change characteristic is B characteristic, and 27° 28.29 is a tap terminal provided on the variable resistor 26, each having a value of 75% of the total resistance value.
, 50%.

It is provided at a position that outputs a resistance value of 25%, and corresponds to the rotation angle θ.

22. 23, 24, and 25 are fixed resistors, respectively.
A terminal terminal that provides the total resistance value of the variable resistor 26 is connected in parallel between adjacent terminals of the three tap terminals.

A set voltage e is output from the sliding terminal of the variable resistor 26.

In this configuration, the two terminal terminals of the variable resistor 26 are
The three tap terminals 29, 28.27 are connected so that the voltages VL and VH are respectively set so that the timer time T is 25%, 50%, and 75% between the maximum value TH and the minimum value TL, that is, TMI. , TM□9 Voltage corresponding to TH3■8□
9 VH2 and VH3.

As a result, for example, the rotation angle θ of the variable resistor 26 can be set to 50
%, the set voltage e at that time is the tap terminal 28
is equal to the voltage VM2 given by the timer one hour TM2
is the intermediate value between TL and TH, i.e. (TL + TH)/2
becomes.

The rotation angle θ corresponding to the other tap terminals 29 and 27 ('even if there are two, the timer 1 hour TM□, TH2).

As a result, the timer time T with respect to the rotation angle θ of the variable resistor 26 has a characteristic as shown in FIG.

In FIG. 7, the retrospective angle θ=0.25°50,75.
Tire hour T-TL, T8□, T for 100%
M□, TH3, and TH are given in a linear relationship with respect to the rotation angle θ.

Strictly speaking, when the rotation angle θ is between 0 and 25%, it is given by a part of a curve as shown in FIG. 5, but in practical use, it is almost acceptable to see a linear relationship.

Therefore, the timer one hour T is the rotation angle θ of the variable resistor 26.
There is a linear relationship.

In this embodiment of FIG. 6, fixed resistors 22, 23,
The relationship between 24 and 25 and the resistance value and variation tolerance of the variable resistor 26 basically conforms to the above-mentioned equation (2).

However, in this case, the relationship between the respective resistance values between adjacent terminals of the two terminal terminals and three tap terminals of the variable resistor 26 and the resistance value of the fixed resistor in parallel relationship is expressed by the formula (2 ) should be selected according to the following.

In other words, the resistance value between the terminals of the variable resistor 26 is set to RV'Ω, and the tolerance for variation (or variation in the total resistance value Rv) is ±K.
v (to), the resistance value of the corresponding fixed resistor is RF'Ω, and the tolerance for its variation is ±KF' (to). If the relationship is satisfied, the variable resistor 26 The variation in the set voltage e due to the variation in the corresponding fixed resistor 22. 23. 24 and 25 can be made equal to or less than the variation given to the set voltage ed, and the variation in the resistance value of the variable resistor 26 can be reduced as much as possible.

In addition, in the case of the embodiment shown in FIG. 6, even if the variable resistor 26 has variations in resistance change characteristics with respect to the rotation angle θ, the set voltage ed at the rotation angle θ corresponding to the tap terminal described above can be set with high accuracy. Therefore, variations in resistance change characteristics can be sufficiently reduced.

Next, another embodiment of the present invention shown in FIG. 8 will be described.

In Figure 8, A is a charging circuit, 30.31.3
5 is a resistor, 32 and 33 are transistors, 34 is a semi-fixed resistor, and 6 is a capacitor.

B is a time setting circuit, 36.37 is a fixed resistor, 3
8 is a variable resistor, and 39 is a center tap terminal of the variable resistor 38.

The charging circuit A constitutes a constant current circuit mainly including a transistor 33.

That is, a resistor 30, a transistor 32, a semi-fixed resistor 34,
The resistor 35 sets the bias voltage of the transistor 33, and the transistor 33 operates so that the current flowing through the resistor 31 is always constant.This constant current is transferred from the collector of the transistor 33 to the charging capacitor 6. The current flows and the capacitor 6 is charged.

The transistor 32 exhibits diode characteristics, and its function is to compensate for the temperature of the base-emitter voltage of the transistor 33.

Due to the configuration of this charging circuit A, the charging current of the capacitor 6 is always constant, so the charging voltage ec increases in proportion to the charging time.

In addition, in this circuit, if there are variations in the capacitor 6 or others, by adjusting the semi-fixed resistor 34, it is possible to easily change the rate of increase in the charging voltage ec, and the charging time can be changed. The proportionality of the charging voltage ec remains intact.

Next, time setting circuit B uses a B characteristic variable resistor 38 having a center tap terminal 39 to generate a setting voltage e.

The fixed resistors 36 and 37 are connected in parallel between the terminal terminal of the variable resistor 38 and the center tap terminal 39,
Each resistance value is equal.

The relationship between the resistance values of the variable resistor 38 and the fixed resistors 36 and 37 is selected so as to satisfy the above-mentioned formula (3).

From the above explanation, the charging voltage ec output by the charging circuit A is proportional to the charging time t, as shown in FIG. 9, and the setting voltage e output by the time setting circuit B.

is given linearly with respect to the rotation angle θ of the variable resistor 38, so the timer time T with respect to the rotation angle θ of the variable resistor 38 is given in an extremely linear relationship as shown in the characteristic C1 of FIG. , it is expected that the linearity will be equal to or better than the characteristic of the embodiment shown in FIG. 6 described above.

The purpose of using the center tap terminal 39 of the variable resistor 38 is to reduce variations in resistance change characteristics.
-6 does not use the center tap terminal 38, an extreme example would be the characteristic q in FIG.

If the center tap terminal 39 is used as shown in Figure 8,
The characteristic C2 becomes the characteristic C1, and the linearity is greatly improved.

Further, in the charging circuit A in this embodiment, the constant current flowing through the capacitor 6 is a value corresponding to the voltage value Vcc of the DC power source 1, that is, as Vcc increases, the charging current increases, and V
Since the configuration is such that the charging current decreases as cc decreases, it works to compensate for fluctuations in the set voltage ed output from the time setting circuit B with respect to changes in Vcc. The change in timer time T due to variations in configuration is very small, and high accuracy can be expected.

Still another embodiment is shown in FIG.

In the figure, A is a charging circuit, 40.41 is a resistor,
42 is a semi-fixed resistor, 43 is an operational amplifier, 44, 45 is a resistor, and 46 is a transistor, which constitutes a constant current circuit that allows a constant charging current to flow through the capacitor 6.

47 and 48 are transistors, and transistor 47
starts and stops the charging action of the capacitor 6, and the transistor 48 performs a reset action to make the charge charged in the capacitor 6 zero.

The time setting circuit B and the voltage comparison circuit C have substantially the same configuration as in FIG. 8.

In the charging circuit A, the operational amplifier 43 has a resistor 40.4
1, and the transistor 46 is driven so that the voltage v1 given by the correction semi-fixed resistor 42 and the voltage v2 at the connection point between the resistor 45 and the transistor 46 are equal to each other.

Since the normal voltage v1 is constant, the voltage v2 is also constant, so that the charging current flowing through the capacitor 6 becomes a constant current, and as in the embodiment shown in FIG.
The charging voltage ec increases in proportion to the charging time.

This constant current circuit, which mainly includes the operational amplifier 43, does not depend on the temperature characteristics of the pace-emitter voltage of the transistor 46, and also makes the constant current value completely proportional to the voltage value VCC of the DC power supply 1. Compared to the characteristics of the constant current circuit shown above, the characteristics are much improved.

The relationship between the rotation angle θ of the variable resistor 38 and the timer time T shown in FIG. 11 is almost the same as the characteristic shown by characteristic C1 in FIG. 10 in the embodiment shown in FIG.

Next, in the charging circuit A, when the transistor 47 is turned on by an external signal, the operation of the constant current circuit mainly composed of the operational amplifier 43 is turned off, and the charging current to the capacitor 6 becomes zero. The charging voltage ec output from the capacitor 6 does not increase, and the transistor 47
The current is held almost constant until the constant current circuit is turned off and the constant current circuit is activated.

Further, when the transistor 48 is turned on by an external signal, the charging voltage e of the capacitor 6 is generated.

Regardless of the value of , it is instantaneously discharged to bring the charging voltage ec to zero.

In this way, the transistor 47 stops or starts charging the capacitor 6, and the transistor 48
functions to reset the charging voltage ec or control the start of the charging operation, and has functions that can be used for various purposes.

In the time setting circuit B in the embodiment shown in FIG. 11 and the embodiment shown in FIG. ) while satisfying the relationship shown in FIG.
Lower than the middle between H and ■, center tap terminal 3
The timer time T at the rotation angle θ=50% corresponding to 9 becomes small.

This becomes characteristic C3 in FIG.

At rotation angle θ-50%, timer one hour T = TM
' is the characteristic C1 obtained in the embodiments of FIGS. 8 and 11.
The timer hour T=T becomes smaller, and the change in the timer hour T between rotation angle θ=0 and 50% is gradual, and the change in the timer hour T between θ=50 and 100% is abrupt. Become.

In other words, it is possible to configure a timer in which the scale of the timer hour T is divided into unequal divisions with the rotation angle θ = 50% as the boundary.
It is effective in terms of usability depending on the intended use.

The timer circuit according to the present invention has been described above based on the embodiments, but in addition to the embodiments, (1) depending on the required accuracy of the timer, the semi-fixed resistor for correction may be omitted, or the semi-fixed resistor may be omitted; A fixed resistor with a corresponding value may be inserted in place of the resistor.

(2) In all of the embodiments, the charging circuit A takes the form of charging the capacitor over time, but it can also be configured as a discharge type timer that temporally discharges the charge charged in the capacitor.

(3) The resistance change characteristic of a variable resistor is normally B characteristic, which is easy to design, but if necessary, A characteristic, C characteristic, etc., which do not change linearly, can be used. By being selectable and providing tap terminals as necessary, the degree of freedom in designing setting accuracy and timer hour change characteristics is improved.

(4) In the embodiment, the voltage comparator circuit C outputs the voltage V until the timer reaches one hour T.

is at a high level, but the input terminals of the two input voltages ec and ed can be swapped so that they are at a low level.

Also, when the charging voltage ec approaches the set voltage e,
The output voltage V changes due to external noise and ripples in the voltage value Vcc of the DC power supply 1.

If this becomes unstable, it is effective to provide a capacitor between the two input terminals of the comparator 10 or provide hysteresis using a positive feedback resistor or the like.

The timer circuit according to the present invention can: a) Extremely reduce variations in the resistance value of the variable resistor for setting the timer one hour, and can also be used to correct variations in the timer hour due to variations in ground elements such as capacitors; , it is possible to minimize variations in the timer's one-hour change characteristics with respect to the rotation angle of the variable resistor.

b) The change characteristics of the timer hour with respect to the rotation angle of the variable resistor can be designed relatively easily and freely, and it is possible to obtain appropriate characteristics according to the actual usage conditions, and it is possible to Accuracy can also be easily improved if necessary.

C) It can be realized with a simple configuration and is excellent in terms of price and mass production.

It is expected to have various effects such as these, and is extremely useful in industrial production.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit diagrams and characteristic diagrams showing conventional examples, and Figures 3 and 2 are circuit diagrams showing conventional examples and their characteristic diagrams.
Fig. 5 is a circuit diagram of a timer circuit according to the present invention and its characteristic diagram; Figs. 6-7 are partial circuit diagrams showing other embodiments of the timer circuit according to the present invention and its characteristic diagram; Figs. 8-10. 11 is a circuit diagram of still another embodiment of the present invention and its characteristic diagram. FIG. 12 is a characteristic diagram of another embodiment of the present invention. 1...DC power supply, 2...Power switch, 10...Comparator, 14...Relay, 17...Semi-fixed for correction Resistor, 21.
・・・・・・Variable resistor, 27゜28.29・・・・・・
Tap terminal, 43... operational amplifier, θ...
...Rotation angle, T...Timer one hour.

Claims (1)

[Scope of Claims] 1. A DC power supply, a charging circuit that causes a charging current to flow from the DC power supply to charge a capacitor, and a plurality of fixed resistors connected in series to the DC power supply, and Give at least one variable resistor its total resistance2
a time setting circuit that outputs a set voltage from a sliding terminal of the variable resistor that is connected in parallel through two terminal terminals and does not change the resistance value between the two terminal terminals; and a charging voltage of a capacitor of the charging circuit; It consists of a voltage comparator circuit that compares the set voltage of the time setting circuit and generates a predetermined output according to its state, and determines the total resistance value of the variable resistor and the allowable value of its dispersion by RAΩ and ±Kv Fd k, respectively. , when the resistance value (or sum of resistance values) and tolerance of variation of the fixed resistor connected in parallel with the variable resistor are RFΩ and ±KF (to), respectively, there is a relationship as follows, and the above-mentioned A timer circuit characterized by a scale that allows the timer hour to be varied by adjusting the sliding terminal of a variable resistor. 2. Each adjacent terminal of the two terminal terminals giving the total resistance value of the variable resistor and at least one tap terminal giving the resistance value of a predetermined ratio is connected to both ends of the corresponding fixed resistor. The timer circuit according to claim 1, characterized in that: 3 Let the tolerance values of the resistance value and its variation (or the variation of the total resistance value) between adjacent terminals of the variable resistor be Rv'Ω and Kv' (to), respectively, and set the corresponding fixed resistor between each of the terminals. 3. The timer circuit according to claim 2, wherein the following relationship is given when the resistance value and the allowable value of the variation thereof are respectively assumed to be RF'Ω1g KF/(to). 4. The timer according to claim 1, wherein the charging circuit is configured to charge the capacitor from a DC power supply via a resistor, or to charge the capacitor with a constant charging current corresponding to the DC power supply. circuit. 5. The timer circuit according to claim 4, wherein the charging circuit is configured to start and stop charging the capacitor or instantaneously discharge the charge in the capacitor in response to an external signal using a transistor.