JPS6337451B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a long time timer using an electrochemical timer.

Conventional timers using electric circuits utilize the time constants of a resistive element and a capacitor element, but the timer time of these timers is short. In contrast, electrochemical timing elements can provide long timer times. This electrochemical timer applies the principle of a coulometer, and its basic configuration is that a metal electrode that is active with respect to the electrolyte and a metal electrode that is inactive are opposed to each other through an electrolyte. provided. When a direct current is passed through this element from its active electrode to its inactive electrode (this current is called a set current), an amount of metal in the active electrode is transferred to the inactive electrode in an amount proportional to the magnitude of the current and the duration of the current. Plating on top. When current is applied from the inactive electrode to the active electrode in this state (this current is called a clearing current), the plated metal on the inactive electrode is transferred to the active electrode by an amount proportional to the magnitude of the clearing current and the current application time. When the entire amount of plated metal has transferred to the active electrode, the clear current stops passing (this state is called the stop state), and at the same time, the potential difference rapidly rises between the two electrodes of the element (this is called the stop voltage). ) appears. Therefore, the magnitude of the set current and the energization time are appropriately selected, an appropriate amount of active metal is coated on the inert electrode in advance, the magnitude of the clear current is appropriately set, and the stop voltage when the clear current is stopped is determined. By detecting the occurrence, the period from when the clear current starts flowing until the stop voltage is generated can be used as the timer time.

The longest timer period obtainable using such an electrochemical timing device is determined by the maximum setting amount of active metal deposited on the inert electrode in the timing device and the magnitude of the minimum clearing current. For example, a typical electrochemical timer is an element manufactured by Plessy, Inc. in the United States and known under the trade name E-Cell. This element has a metal electrode as an inactive electrode and a silver electrode as an active electrode provided in a container via an electrolyte, and in many cases, the container wall itself is the silver electrode. The general specifications of this E-Cell are that the maximum set current is 1000 μA, the minimum clear current is 1 μA, and the timer time obtained under normal usage is 1000 hours.

In this way, a long time timer can be attached to a device, for example, and can be used by setting the timer time so that the timer operates when the device exceeds a reliable time. From this point of view, a device with a longer timer time is desired. For this reason, a pulse current is used as the clear current to extend the timer time. The timer time can be lengthened by flowing a pulse current with the amplitude of the minimum clear current, narrowing the pulse width, and lengthening the pulse interval. But it turns out that this too has its limits. The reason for this is that when the electrochemical timer approaches the completion of clearing, a voltage is generated between the electrodes that approaches the stop voltage, but the pulse width is narrow.
If the pulse interval is long, a set current will flow between the pulses due to the self-cell effect based on the voltage generated between the electrodes, so once the voltage starts to be generated between the electrodes, it will reach the stop voltage. The results of experiments and research have shown that this is because the time it takes to complete the clearing is significantly delayed, or the clearing is not completed at all.

SUMMARY OF THE INVENTION An object of the present invention is to further lengthen the maximum timer time in a long-time timer that applies a pulse current to an electrochemical time element, and to significantly improve the accuracy of the timer.

According to this invention, the clear current generating circuit is driven by a square wave signal, and a pulse clear current corresponding to the square wave signal is caused to flow through the electrochemical time element. A diode is inserted into the clear current generating circuit so that the direction is opposite to the set current due to the self-cell action of the electrochemical time element. In this way, when the clearing is nearing completion and a voltage is generated between the electrodes of the electrochemical timer, the above diode prevents the set current from flowing due to that voltage, and the stop voltage is rapidly approached. As a result, the precision of the timer is improved, and the pulse interval of the clear current can be lengthened, making it possible to lengthen the timer time.

Next, an embodiment of a long time timer according to the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 11 denotes a square wave oscillation circuit, and this square wave oscillation circuit 11 can be constructed by, for example, combining programmable union transistors, so-called PUTs 12 and 13, for push-pull operation. PUT
A capacitor 14 connected between the anodes 12 and 13, and one terminal 1 of the power supply and each anode.
resistors 16 and 17 respectively connected between
The oscillation time constant is determined by Both terminals of power supply 1
Each resistor connection point of resistors 19, 21 and 22, 23 connected in series between 5 and 18 is
It is connected to each gate of PUTs 12 and 13, and a gate voltage is applied thereto. The cathode of the PUT 12 is directly connected to the power supply terminal 18, and the cathode of the PUT 13 is connected to the power supply terminal 18 through the output take-out resistor 24. The pulse width of this square wave oscillation circuit 11 is the time constant of the resistor 16 and the capacitor 14, and the pulse interval is the time constant of the resistor 16 and the capacitor 14.
Each is determined by the time constant of

A clear current generating circuit 25 is driven by the square wave output obtained from the resistor 24. A square wave clear current obtained by the clear current generating circuit 25 is passed through the electrochemical timer 26. For example, the clear current generating circuit 25 is provided with a transistor 27,
Its collector is connected to the power supply terminal 15 through resistors 28 and 29 in turn, and its emitter is connected to the power supply terminal 18.
, and the resulting square wave output is given to the resistor 24 at its base. The junction of the resistors 28 and 29 is connected through a resistor 31 to the cathode side of a diode 32, and the anode side of the diode 32 is connected to the active electrode 33 of the electrochemical timer 26. The inert electrode 34 of the electrochemical timer 26 is connected to the power supply terminal 15. The diode 32 is in the forward direction with respect to the clearing current of the electrochemical timer 26;
The anode side of the diode is the active electrode 33 side so as to be in the opposite direction to the set current generated in the electrochemical timing element 26.

When transistor 27 is turned on by the square wave output, a constant current flows through resistor 29 and a constant voltage developed across resistor 29 is applied to electrochemical timer 26.
A clear current flows through this.
Between one square wave output and the next square wave output, transistor 27 is non-conducting, thus causing a pulsed clearing current to flow through electrochemical timer 26.

A timer output circuit 35 is provided to detect when a stop voltage is reached between the electrodes 33 and 34 of the electrochemical time element 26. For example, the electrodes 33 and 34 are connected to the gate and anode of the PUT 36, respectively,
The cathode of PUT 36 is connected to power supply terminal 18 through resistor 37 and also to transistor 38 . The collector of the transistor 38 is connected to the power supply terminal 15 through a relay 39, and the emitter is connected to the power supply terminal 18. When the voltage between the electrodes of the electrochemical time element 26 becomes greater than the stop voltage, the PUT 36 becomes conductive, which causes the transistor 38 to also conduct, and its collector current activates the relay 39 to detect that the timer time has elapsed. and output.

Electrochemical timer 26 is incorporated into the circuit after it has been set by a predetermined set amount. The clear current generating circuit 25 is driven by the square wave output of the oscillation circuit 11, and a pulsed clear current flows through the electrochemical timer 26 in accordance with the square wave output, as described above. Due to this clear current, the active metal plated on the inert electrode 34 gradually moves to the active electrode 33. While the active metal is sufficiently attached to the inert electrode 34, the voltage E between the electrodes 33 and 34 is a small constant value _E1 as shown in FIG. When the clearing is near completion, electrodes 33 and 34
The voltage between them will rise. When the diode 32 is not used, a voltage is generated between the electrodes 33 and 34 during the pulse interval of the clearing current, and the voltage flows from the electrode 33 through the electrode 34, the resistor 29, and the resistor 31 due to the self-cell effect. A set current flows in the circuit back to 33, so that active metal from active electrode 33 is deposited on inactive electrode 34 in response, and the voltage between electrodes 33 and 34 increases as shown by curve 4 in FIG.
As shown in 1, it decreases by ΔE ₁ . For this reason, even when the clearing is near completion, the overall slope of the curve 41 becomes very gentle, and the time to reach the stop voltage E ₂ is longer than the previous period T ₁ when the voltage between the electrodes 33 and 34 began to rise. This cannot be ignored, and even if the slope of the curve 41 changes slightly, the timer time changes greatly, making it impossible to obtain a highly accurate timer. In some cases, if ΔE ₁ is large, the stop voltage E ₂ will not be reached forever.

However, in this invention, for example, the diode 32 is used, so when the voltage between the electrodes 33 and 34 starts to rise, a set current flows due to the self-cell action of the electrochemical time element 26 during the pulse interval of the clear current. Even if an attempt is made to do so, this is blocked by the diode 32, and only the leakage current from the diode 32, etc., causes the set current to flow. Therefore, as shown by the curve 42 in FIG. 2, the voltage drop between the electrodes 33 and 34 during the pulse interval of the clear current is ΔE ₁ when the diode 32 is not inserted.
The value ΔE ₂ is significantly smaller than that of electrode 3.
The voltage between 3 and 34 rapidly approaches the stop voltage E ₂ ,
When the stop voltage _E2 is reached, this is detected by the timer detection circuit 35 as described above. In this way, since the curve 42 suddenly approaches the stop voltage, even if there is a slight variation in its slope, it can be ignored compared to the entire timer time, and a highly accurate timer can be obtained.
Since the set current due to self-battery action can be prevented in this way, the interval between clear current pulses can be increased, and the timer time can be lengthened accordingly.

In addition, in FIG. 1, electrochemical time blocking 26
The voltage applied to resistor 3 is the voltage drop across resistor 29 and can be relatively low, so resistor 3
Even if the resistance value of resistor 31 is selected to be relatively small, a small clearing current can be passed through the electrochemical timer 26. If the resistance value of this resistor 31 is made very large to provide a clearing current, Although it is necessary to pay close attention to the leakage current of the wiring board to which these resistors and the like are attached, this is not necessary in this embodiment. Furthermore, when similar circuits are combined as the square wave oscillation circuit 11 as described above and the common capacitor 14 is subjected to push-pull control, the ratio of the ON time to the OFF time becomes less susceptible to temperature changes. In the configuration shown in FIG. 1, when a general E-Cell was used as the timer element 26, a timer time of 10,000 hours or more, which is more than 10 times its rating, could be obtained with sufficient accuracy.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an example of a long-time timer according to the present invention, and FIG. 2 is a curve diagram showing the relationship between the inter-electrode voltage and elapsed time of an electrochemical timer. 11: square wave oscillation circuit, 25: clear current generation circuit, 26: electrochemical time element, 35: timer output circuit.

Claims (1)

[Claims] 1. A square wave oscillation circuit, a clear current generation circuit connected to the square wave oscillation circuit and to which a square wave output from the square wave oscillation circuit is applied, and a clear current generation circuit connected to the clear current generation circuit. , an electrochemical time period in which a clearing current of a constant magnitude is intermittently passed between the active electrode and the inactive electrode in the direction from the inert electrode to the active electrode by applying the square wave output to the clearing current generating circuit; and a timer output circuit connected between the active electrode and the inactive electrode of the electrochemical time-limiting element to detect and output that the voltage between the active electrode and the inactive electrode has exceeded a predetermined value. In the long time timer, the clear current generating circuit has a transistor whose base is supplied with the square wave output, the collector of the transistor is connected to the power supply terminal through first and second resistors, and the collector of the transistor is connected to the power supply terminal through first and second resistors. and a power supply terminal are connected to the inactive electrode of the electrochemical timer, and a connection point of the first and second resistors is connected to the active electrode of the electrochemical timer through a third resistor and a diode. A long time timer, characterized in that the anode of the diode is connected to the active electrode side.