JPS5919315B2 - Computer wristwatch - Google Patents

Description

[Detailed description of the invention] The present invention relates to a wristwatch with an electronic computer.

In recent years, wristwatches that display the time digitally using electro-optical display devices such as liquid crystals, light-emitting diodes, or electrochromic materials have rapidly developed, and along with the development of integrated circuits, they have become smaller and more functional, resulting in longer lifespans. etc., have become sufficiently practical. For example, the battery life of a crystal oscillation type Digitano I watch that uses liquid crystal for its display is already two years. On the other hand, electronic desktop calculators, like wristwatches, have become smaller and more functional with the development of integrated circuits, and low-power display devices such as liquid crystals have come to be used for display devices. The present invention focuses on the common features of the above-mentioned electronic calculator and digital display type wristwatch, and provides an electronic calculator that can house the digital wristwatch and the electronic desktop calculator in the same watch case and display the time and calculation function on the same display device. This invention relates to the improvement of a power supply device for a wristwatch.

Generally, the system of a wristwatch with an electronic computer is as shown in FIG.

In FIG. 1, 1 is a digital clock system, which includes an oscillator 2, a frequency divider 3, a counter 4, a drive circuit 5, a display device 6,
It is roughly composed of a power supply T, etc.

On the other hand, the system of the electronic computer 10 includes a calculation oscillation circuit 11,
It is generally composed of an arithmetic circuit 12, a display device 13, a power supply device 20, and an external operation device 16 including numeric keys, calculation keys, and the like. The power supply device 20 includes a battery 18 and a boost oscillation circuit 1.
4. It consists of a booster circuit 15. The present invention relates to an improvement of the power supply section 20 of a wristwatch with an electronic computer.As mentioned above, the current consumption can be reduced in watches and electronic computers that use liquid crystal as a display device. A lifespan of 2 years is guaranteed.

However, the power consumption of the electronic computer part is higher than that of the clock part due to the stability of the arithmetic circuit and the calculation speed. Also, unlike the static drive of the clock section, the display system of the electronic computer section uses a matrix drive system in order to minimize the number of lead terminals of the display device. The matrix drive system requires not a single power supply voltage but multiple power supply voltages of two or more power supplies, and it is impossible to connect many batteries in a series because it must be stored in a watch case with limited space. Therefore, a Kotscroft type booster circuit is required. FIG. 2 shows an embodiment of a booster circuit used as a power source for the computer section of the computer wristwatch of the present invention.

14 is an oscillator for adding alternating current to the booster circuit 15, and is approximately 3
The inverter amplifier 21 , 22 , 23 oscillates at 00 Hz, is amplified and waveform-shaped by inverters 21 and 22 , drives an output inverter 23 , obtains a rectangular wave output on an output line 24 , and adds it to the booster 15 . By using a C-MOS and making it a rectangular wave whose waveform has been shaped, unnecessary voltage flowing during switching of the C-MOS inverter used in the output inverter amplifier 23 is made as small as possible.

Furthermore, when the threshold voltage Vth of the CMOS transistor of the output inverter amplifier 23 is set close to the power supply voltage, the input waveform applied to the output inverter becomes S.
Even if it is an in waveform component, the through current during switching of the C-MOS transistor is small, so the threshold voltage of the output inverter amplifier 23 should be set to at least 80% of the power supply voltage 18 to the same as the power supply voltage. It is effective to leave the oscillator 14 as an independent C-MOS chip because it will almost eliminate unnecessary current consumption in the output inverter amplifier 23.
If it is provided separately from the C chip and used as a threshold voltage Th that approximates the voltage of the oscillation section power supply 18, the above-mentioned effect will help save power consumption.

15 is a booster circuit section, and assuming that the voltage of the battery 18 is 3, each section voltage Vl, V2, V3, V4 is a diode 29.
, 30, 31, 32, 33, 34 -
3V1-4.

6V1-6.3V18.3V.

Also, when compared with the potential of the output terminal VO of the diodes 27 and 28, there is a voltage drop due to the diodes 27 and 28, and the respective potentials are -1.9V1-3.6, -5.3V, -7.
The voltage becomes 3V and serves as a power source for matrix drive. Since the diodes 27 and 28 are voltage drop diodes, resistors may be used, and other semiconductors, transistors, thermistors, etc., which are thermally formed resistance elements, may also be used for temperature compensation.

When performing matrix drive, if the potential of V2 from the ground is -4.6V as a reference, and the potential of IV3-2 is taken as a reference, V2, then IV4-V2l-3.7 and VG-21=14.
61, there is a large difference in voltage and the voltage becomes asymmetrical.

This difference becomes a direct current component when matrix driving is performed, which only makes the driving of the liquid crystal unbalanced and deteriorates the liquid crystal. In order to prevent this, the booster circuit of the present invention includes diodes 29, 30, 31,
Diode 27 with the same characteristics corresponding to 32, 33, 34
, 28 in series, the potential of each part is corrected by the voltage dropped by the current flowing through the diode. , Vl, V2, V3, and V4 are 01-1.
9, -3.6, -5.3, 7.3, and if the potential of V2 is used as a reference matrix power supply, the V with respect to V2. ，
The difference in potential between Vl, V3 and V4 is 3.6, 1.9, 1.7
, 3.7, which is almost symmetrical, so that the direct current component is almost eliminated, and wasteful power consumption and deterioration of the liquid crystal can be prevented. Since the voltage boosting circuit 15 differs depending on the frequency of the output from the oscillation circuit 14, the oscillation frequency is adjusted by the variable capacitor C and variable resistor R1 of the oscillation circuit in order to obtain the matrix drive voltage most suitable for driving the liquid crystal. shows a system diagram of the computer wristwatch of the present invention, however, the boosting oscillation circuit 14 may not be provided and a frequency of about 300 Hz may be inputted from the watch frequency divider 3.

In addition, when the frequency of the watch crystal oscillator 2 is a high frequency of 30 KHz or more, for example, when a 4 MHz band crystal oscillator is used, the oscillator 11 for the electronic computer is about 300 KHz, so the calculation is performed from the watch frequency divider 2. Since the clock pulse of the manual oscillator 11 can be obtained, the electronic computer oscillator 11 can be omitted. As described above, the electronic computer wristwatch of the present invention has a matrix in the display device of the electronic computer section, an improvement in the step-up method of the power supply section when performing the drive method, and a common use of clock pulses for the electronic computer. This is to reduce power consumption as much as possible, and has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a wristwatch with an electronic computer according to the present invention;
FIG. 2 is a circuit diagram of an embodiment of the step-up section of the computer wristwatch of the present invention, FIG. 3 is a voltage waveform diagram for driving the display of the computer section of the present invention, and FIG. FIG. 1 is an external view of a wristwatch with a computer. 2... Oscillation circuit for watches, 3... Frequency divider for special measurements, 11... Oscillator circuit for calculations, 14...
... Oscillation circuit for boosting, 21, 22... Waveform shaping and amplifier, 23... Output inverter amplifier,
27, 28...Voltage drop diode, Cl,
Rl...Oscillation frequency adjustment element.

Claims (1)

[Claims] 1. In a booster circuit that supplies voltage for driving the display in a matrix manner to the display section of a computer wristwatch,
The booster circuit includes a Cottcroft type booster circuit connected to a power source, and a voltage drop diode that has substantially the same characteristics as a booster element of the booster circuit and is connected in series to the power source on the opposite side of the booster circuit. A computer wristwatch characterized in that a plurality of boosted matrix voltage groups have voltage widths that are mutually symmetrical with respect to a center voltage value of the voltage group.