JPS5863884A - Electronic clock - Google Patents

Abstract

PURPOSE:To keep the output period of a clocking electronic circuit approximately at a fixed level even if battery voltage is changed and stabilize its accuracy by carrying out the logical changing processing in accordance with the value of power voltage. CONSTITUTION:The voltage of a power source 6 is detected by a voltage detecting circuit 5 in accordance with a sampling pulse outputted from a smapling pulse generating circuit 4 controlled at a prescribed step of divided outputs through a crystal oscillator 1, an oscillating circuit 2 and a frequency dividing circuit 3. In accordance with the detected voltage, a logical changing pulse is outputted from a logical changing pulse generating circuit 7 and inputted to a FF having a setting terminal in the circuit 3 to execute logical changing processing. Even if the voltage of the power source 6 is changed, the output period of the clocking electronic circuit controlling a clock driving circuit 8 etc., is kept approximately at a fixed level by the output of the circuit 3 and stable accuracy is kept. Consequently a lithium battery, a silver peroxide battery having a high potential division and a solar battery can be combined as a power battery, making it possible to form a long-life and small-sized electronic clock.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to means for correcting changes in the oscillation frequency of an everyday electronic circuit due to changes in power supply voltage.

Conventional electronic watches have had the disadvantage that when the power supply voltage changes, the oscillation 1/hard frequency of the watch electronic circuit changes. In the case of the 0-MO8 circuit, as shown in Figure 1, 0
．． It changes by about 0.5 to 0.7 ppm per 1■, which is about 1.3 to 1.8 seconds per α1■ when converted into a monthly difference. As shown in Figure 2A, tin oxide batteries conventionally used as a power source for electronic watches have a constant discharge voltage, so there was no need to take into account the aforementioned change in oscillation frequency. As electronic watches have extended their lifespans, lithium batteries, silver peroxide batteries with a high potential range, and secondary batteries that are recharged using solar cells have come to be frequently used as power sources. However, the discharge voltage of these power sources fluctuates as shown in FIG. 2B to FIG. 2E. Second
Figure B is a BR type lithium battery, Figure 2C is an OR type lithium battery, the second diagram is a silver peroxide battery with a high potential section, and Figure 2F is a secondary battery using a solar cell as a negative battery. This is an example of the discharge characteristics of a system using silver batteries. Table 1 summarizes the voltage changes of each power source and the changes in oscillation frequency due to the voltage changes.

Table 1 In Table 1, the voltage of the lithium battery is divided by 2.
This is done in consideration of the fact that in a watch electronic circuit using a 3V string lithium battery as a power source, a voltage stepped down to /2 is usually applied. As is clear from Table 1, when these power supplies are used, the frequency changes by 3 to 9 seconds per month, and for high-precision clocks with a monthly difference of 5 to 10 seconds, these power supplies with a large voltage variation b are used. That was impossible.

The present invention eliminates such drawbacks, and its purpose is to adjust the logic according to the value of 'rrL power supply n:, even if the oscillation frequency of the electronic circuit for use changes due to fluctuations in power supply voltage. The aim is to keep the output period of the watch electronic circuit almost constant and achieve stable accuracy.

Another object of the present invention is to provide a long-life and high-precision electronic clock using a lithium battery, a silver peroxide battery having a high potential range, or a secondary battery that is charged using a solar cell as a secondary battery as a power source. The present invention will be described below based on embodiments in which it is realized.

First, the outline of this embodiment will be explained with reference to the block diagram shown in FIG. Reference numeral 1 denotes a crystal resonator, which is connected to the oscillation circuit 2 and oscillates at 32768 Hz. This signal is the frequency divider circuit 3
The signals are introduced into the blocks and sequentially divided by flip-flops to generate signals required by other blocks. 4 is a sampling pulse generation circuit, which synthesizes the signals frequency-divided by 3 and generates voltage detection and logic slow/fast timing. 5 is a voltage detection circuit which detects the voltage of the power supply B when the above-mentioned sampling pulse is input. Reference numeral 7 denotes a logic regulation pulse generation circuit which combines the outputs of the sampling pulse generation circuit 4 and the voltage detection circuit and generates several types of logic regulation pulses depending on the power supply voltage. By introducing this logical adjustment pulse into a flip-flop with a set terminal in the frequency dividing circuit 3 to perform logical adjustment, an output with a stable period is introduced to the drive circuit 8.

Next, the present invention will be explained in detail with reference to detailed diagrams and timing charts of each block.

Figure 4A shows the oscillation circuit 2I frequency division g3+ used in this example.
It is a connection diagram of the sampling pulse generation circuit 4, and FIG. 4B is its timing chart. In Fig. 4A, 1 is a crystal resonator, 2 is an oscillation circuit, 9, 10, 11, 12
．． 13 is a master-slave type flip-flop whose output Q changes when the clock (hereinafter referred to as OL) falls, and whose outputs Q and M change when OL rises. Furthermore, when the flip-flop 10 is "H", θ is "H".
, ■ is provided with a set terminal S that becomes L#. 14.
15, OL passes the data @ 1, 1 #, OL "
It is a latch circuit that holds data at “L”.Terminal o
A differential signal with a pulse width of 9.81 nsec obtained by combining a 100 second counter and a 512 Hz signal is added to c1. The oscillation circuit 2 generates a reference signal of 327 (S8H2) using the crystal oscillator 1 as a source oscillation. This reference signal is sequentially frequency-divided by flip-flops 9, 10, 11, 12.
S4 mSs lS6*S'r, S, generates a signal. In the sampling pulse generation circuit 4, the signal "B"
+"+1 is introduced into the latch circuit 14 and the signal "5sS11 is introduced into the latch circuit 15 to create the signal SOs"1G, xl
e S11 e “I tSII+S9t”1
0 signal to gates 16, 17.18° 19.20, 21
, 22.23 are synthesized to produce a four-phase sampling pulse z1
．． ZI, z3, z4 and sampling pulse z1
* zt # z3 1 OR gate 24 for Z4
FIG. 6A is a connection diagram of the voltage detection circuit 5, the power supply 25, and the logic pulse generation circuit 7. 25 is an ideal battery that generates a battery circuit voltage VD, and terminals VD and Vs are terminals of the circuit C. In the figure, everything except the battery 25 is built into the unit 0.

The voltage detection circuit includes a comparator 26 and a reference voltage generator 27
It consists of three blocks: and a voltage dividing section 28 of the power supply. The comparator 26 compares the voltage levels of the input crab + and knee, and when the input voltage is higher than knee, the output becomes "H". Inverter 29 serves as a buffer for the comparator and at the same time inverts the comparator output. V comp is the output of inverter 29. Since the comparator generally consumes power when operating, NMO8 is activated only when the z0 signal is 'H#.
The FKT 30 turns on and the comparator 26 operates.

The reference voltage generating section 27 can be equivalently considered as a battery with a voltage v0. Since power is consumed to generate this reference voltage, the switch 31 is equivalently turned on and operates only when the 2° signal is "H". An example of the reference voltage generating section 27 is shown in FIG. 5B. HMO8? The ICT37 is controlled to have a threshold voltage VTIII, and the NMO5FFliT36 is controlled by ion implantation to be a threshold voltage VTII2.

This will output ■. is V(1=VTH1-VTII2).The operation of the reset inch 31 becomes possible by applying a control signal of 2 degrees to the gate of NMO8TIF!T37.

Next, the operation of the voltage section 28 of the power supply will be explained. If terminal z1
When becomes 1H”, NIJOEIF11nT32 turns ON, and ON resistance of NMOS, ? Ei T32 = 0
Then, ■M=v1@R1(Ro-1-R,), and this VM is input to the + terminal of the comparator 26 and compared with vo. Now, if the voltage to be detected when the drive voltage Vn changes is Vnt t''ts■Dm+■D4, then the ratio of R6, R19R19RR#R4 can be determined from the following equation.

vn, = (1+Ro/Rs)v.

VDv=(1+Ro/(Rs+R2))V.

Va, =(1+Ro/(J+J+Rs))
V.

VD4-(1+Ro/(Rt+Rz+Rs+
R4))V.

■ In these formulas. is a constant value, and the ratio of the resistances in each equation can be set by the length ratio of the pattern on the surface, so the value of yn in each equation can be set accurately. With the above settings, connect the terminals zo and zl lz2.

zSoz4 to 4th (] E's zOw"1 rz2
Introducing the ezBrz4 signal, V oomp and z. When the signals are combined by an AND gate 38, one of the signals shown in FIG. 5C is obtained at the output terminal T of the AND gate 38. In FIG. 5C, when T1 is VD>vDl, T2 is 'VD;when>'VD>VD, T is V D2''
:) V D>'V o, When LD, T is VD,>V
When D>VD4(7), T is a signal generated at terminal T when VD4>VD.

If the terminal T is introduced into the set terminal of the flip-flop 10 in FIG. 4A, one of T1 to T in FIG. When VD>VD, □x-!-= o ppm1658
4 100 V nl) When V D>V D, 16684 ×〒
00=0.6ppm'V D When D>V D, 16384 x 100 = "2p""1 When VD3>VD>VD4 1631J4 x 100
” “8pp” When VD4>VD □X
-'-=2.4ppm16384 100 The output cycle advances. If this situation is shown by N, the sixth
It becomes 39 in the figure. From VD to VD, r: 1.1v
If the difference is set, the power supply voltage-frequency characteristic 40 of the Cj-MO8 oscillator is corrected as in the sixth factor 41, which is equivalent to suppressing the fluctuation of the power supply voltage to ±0.05 V.

The present invention has the excellent effect of being able to keep the output cycle of the timepiece electronic circuit substantially constant even if the power supply voltage fluctuates. For this reason, lithium batteries and silver peroxide batteries with a high potential range could not be used in conventional high-precision clocks.

- A secondary battery that is charged using a solar cell as a secondary battery can be used in a high-precision timepiece, and as a result, it becomes possible to realize a highly accurate and long-lasting electronic timepiece. In addition, each of the power sources mentioned above has a higher energy density than the conventionally used silver oxide batteries, making it possible to make the power supply section thinner and smaller.As a result, it is possible to create a smaller and thinner movement. An electronic clock with excellent design can be obtained.

The embodiments described so far are just examples of the present invention, and it is possible to change the period of the signal .13 is also provided with a set terminal similar to that of the flip-flop 10, and by introducing a terminal T, etc., it is possible to set the optimum logical peak value for each electronic circuit for a watch. Further, by increasing the number of stages of the voltage dividing section 28 of the power supply, more fine-grained correction is possible.

FIG. 1 is an example of the power supply voltage-oscillation frequency characteristic of the 0-MO8 oscillator.

Figure 2 shows an example of the discharge characteristics of various power sources, where A is a silver oxide battery, B is a BR lithium battery, 0 is an OR lithium battery, D is a silver peroxide battery with a high potential section, and E is a primary battery. FIG. 3 is a block diagram of an embodiment of a system using a solar cell as the battery and a silver oxide battery as the secondary battery.

FIG. 4A shows a configuration example of the oscillation circuit, frequency dividing circuit, and sampling pulse generation 1'ijl path of the embodiment, and FIG. 4B is a timing chart thereof.

Fig. 5A shows an example of the configuration of the voltage detection +i''1 circuit and the logic pulse generation circuit of the embodiment. @ 51ffl B shows an example of the structure of the reference voltage generation section. Fig. 5C shows various types of the embodiment. It is a timing chart of the logical adjustment pulse.

FIG. 6 shows power supply voltage-frequency characteristics corrected according to the embodiment.

1... Crystal resonator 2... Oscillation circuit 3... Frequency divider circuit 4... Sampling pulse generation circuit 5...
... Voltage detection circuit 6 ... Power supply 7 ... Logical adjustment pulse generation circuit 8 ...
・Drive circuits 9 to 13...Flip-flops 14.15...
...Latch circuits 16 to 19...NOR gates 20-, -23...AND gate 24...
...OR gate 25 ...Ideal battery 26 ...Comparator 27 ...Reference voltage generation section 28 ...Power supply voltage dividing section 29 ...・Inverter 30・Old・・NMO8IFET 31・・Switch 32 to 37・・1・・NMO3FIIT38・・・
・AND gate and above Applicant Rei Suiha Seikosha Co., Ltd. Agent Patent Attorney Tsutomu Mogami

Claims (3)

[Claims] (1) In an electronic timepiece comprising at least a power supply and a timepiece electronic circuit, a voltage detection circuit for the power supply and a logic regulation circuit are provided in the timepiece electronic circuit, and the logic regulation regulation circuit is configured to adjust the logic regulation according to the output of the voltage detection circuit. An electronic clock characterized by operating a circuit. (2) The electronic device according to claim 1, characterized in that the voltage detection circuit is capable of detecting the power supply voltage stepwise and controls the operation of the logical adjustment circuit according to the value of the power supply voltage. clock. (3) Claims 1 and 2, characterized in that the power source is a lithium battery, a silver peroxide battery having a high potential section, or a secondary battery that is charged using a thick @ battery as a negative battery. Electronic clock as described in section.