JPS6032831B2 - electronic clock - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has an oscillating section, a dividing section, a display driving device, and a display device, and a power supply system that converts the power supply voltage by a power supply voltage (for example, battery voltage) and a voltage conversion section. This relates to a crystal oscillation type electronic watch that uses a combinary MOS transistor (hereinafter abbreviated as CMOST), which consists of a two-power supply system with a reduced low voltage section, and a voltage converter section that inputs a reference voltage section and a reference voltage. By constructing a current amplification section to supply a constant low voltage to the load, which is a low voltage section, a stable low voltage can be obtained, and the circuit can be operated at the minimum voltage necessary for operation. The aim is to reduce the power consumption of electronic watches.

A block diagram of the electronic timepiece used in the present invention is shown in FIG. 1, an explanation of the voltage converter is shown in FIG. 2, and a circuit diagram of one embodiment of the fin pressure converter is shown in FIG.

In FIG. 1, an oscillating section 1, a minute section 2, a display driving device 3,
, a display device 4, a voltage converter 5, and a power supply 7, the voltage terminal (2) of the power supply 7 is set to VoD, the e voltage terminal is set to Vss, and the power supply voltage is obtained by obtaining a low voltage VssL via the voltage converter 5,
The electronic circuit 8 within the broken line has Voo in common and Vss
Two power supplies, VssL and VssL, are supplied. Generally, when an electronic circuit using CMOST is operated on battery voltage,
Perfect operation is guaranteed at IV level or higher. Therefore, except for the display driving device 3 which requires energy, it is sufficient to apply the minimum necessary voltage to other electronic circuits, and the present invention provides 1. It efficiently supplies a stable low voltage of about IV from a battery of about 6V, reducing power consumption. By the way, CMOS
Since the power consumption P of T is shown by the following formula '1}, P=C.

VSS2 na...(11Co: Parasitic capacitance Vss: Power supply voltage ": Operating frequency IV When operated, 1. 40% of the energy of starvation operation is required.

Hereinafter, the voltage converter 5 will be explained in detail according to the drawings. In FIG. 2, the area inside the broken line is the voltage converter 5,
It has a reference voltage section 51 and a current amplification section 52 which receives a reference voltage Vs as input and supplies a constant low voltage VssL to the load.
However, a voltage section 6, which is a load, is connected between VssL and VDo, and VssL and VDo. . However, a voltage section 6, which is a load, is connected between them. The third example is a specific example.
In the figure, the reference voltage section 51 includes two PMOSTs 5 1
1,5 1 3 and 2 NMOST resistors 512
, 514. In Figure 3, as resistance, NM
Although OST is used, a thin region of P-type impurity, that is, P
It is also possible to use a diffused resistor that can be diffused simultaneously with the well. Lease S of PMOST511 in Fig. 1 is V
oo, the gate G and drain D are commonly connected, . It becomes the terminal of intermediate standard rank V3o, and Vso is the first resistor 5.
12 to Vss, and further connects Vso to the lease S of the second PMOST 513, and
The gate G and drain D of T are commonly connected to serve as a reference voltage Vs terminal, and are connected to Vss via a second resistor 514. First, the intermediate reference potential Vso is the resistor NMOS
It can be calculated as shown in the following equation under the condition of T51211 resistance NMOST514. ID8=Year (vS.

-vP5...)2 ・Hada'2)10S=Study (vSS-
VN58)2. ．．・．． ．．・[3'los:Voo~
Current between Vss 85, . :PMOSL,. Amplification factor 8512: Amplification factor VP5 of NMOST512, : Threshold voltage VN5,2 of PMOST511
: Threshold voltage of NMOST512 V from formula '2' and '3'
So, if B511》85.2, then Vso NiVP5, . ……
■The intermediate reference voltage Vso is P-channel MOS
T51 1 threshold voltage VP5, . becomes.

When the reference fin pressure Vs is found in exactly the same way, Vs is expressed by the following equation: Vs3VP5, . 10 VP5,3
"""'51VP5.3: PMOST513
Therefore, the reference voltage Vs is equal to the voltage of the two PMOs.
The threshold of ST becomes the sum of the voltages, and the power supply voltage becomes VP5, .
Vs decreases to 3 VP5, . . . until it drops to 10 VP5,3. 10V
It becomes P5.3. For example, VP5, . =VP5,3=-0
．． If it is 55V, Vs = -1.6 to -1.1V
In the range of , it is approximately -1.1V. Also at this time, resistance 5
If the value of 12,513 is applied by 10 to 10 mW, the power loss will be very small. Next, the current amplifying section 52 will be explained.

The input voltage of the gate G of the P-channel MOST 52 1 of the current amplifying section 52 is the reference voltage Vs. - If the impedance of the PMOST 521 is designed to be sufficiently small compared to the low voltage section 6 that is a load, the voltage Vs between the lease S and Voo will be reduced because the current amplifying section 52 is a lease follower type.
sL is expressed by the following formula:
``'''''6) V legs, :PMOST521
Accordingly, from formula '51' and '61, the tortoise pressure VssL supplied to the low voltage section 6 is VssL=VP5, .
10 VP5, 3-VP52, ``'''''61.

For example, if VP unevenness = -0.1V, VssL is stabilized at approximately -10.1V in the range of source voltage Vss = -1.6V to -1.1V. To partially change the threshold voltage of the MOST, channel doping may be performed by ion implantation or channel length and channel width may be changed. In the case of this embodiment, the PMOST 52 of the current amplification section 52
The easiest way to reduce the threshold voltage VP52 of 1 is to reduce the threshold voltage by reducing the channel length. In the embodiment of the present invention, the reference voltage of the reference voltage section is the sum of the threshold voltages of two PMOSTs, but it goes without saying that it can also be the sum of the threshold voltages of a plurality of PMOSTs. Nor. As explained above, if the voltage converter of the present invention is used, the power supply voltage can be stably converted to a low voltage with little power loss, which is extremely effective in reducing the power consumption of electronic watches, especially for high frequencies on the MHZ order. The system is an effective tool.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a crystal oscillation electronic timepiece consisting of two power supply systems used in the present invention, Fig. 2 is an explanatory diagram of the voltage converter, and Fig. 3 is a specific example of the voltage converter of the present invention. A circuit diagram showing. 1... Oscillation section, 2... Frequency division section, 3...
...Display drive device, 4...Display device, 5.
... Voltage conversion section, 6 ... Low voltage section, 7.
...Power source (for example, battery), 51...Reference voltage section, 52...Current amplification section, 51 1...
...PMOST, 512...Resistance (NMOST)
, 521...PMOST, 51 3...
・PMOST, 5 1 4... Resistor (NMOS
T) Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A power supply system that includes an oscillation section, a frequency division section, a display driving device, and a display device, and that the supply power system is a power supply voltage system and a low voltage system in which the power supply voltage is lowered by a voltage conversion section. In a crystal oscillation electronic watch that uses complementary MOS transistors and has two power supply systems, the voltage conversion section inputs the reference voltage section and the reference voltage to supply a constant low voltage to the load, which is the low voltage section. The reference voltage section uses the sum of the threshold voltages of the P-channel MOS transistors as a reference voltage, and the current amplification section uses the reference voltage as an input to generate a lease-follower type output circuit of the P-channel MOS transistors. An electronic clock characterized in that it supplies a constant voltage to a load using an electronic clock. 2. The reference voltage section consists of first and second P-channel MOS transistors and first and second resistors, and the lease of the first P-channel MOS transistor is connected to the voltage terminal, and the gate and drain are commonly connected. , is connected to the voltage terminal via a first resistor formed by diffusion or a MOS transistor, further connects the drain of the first P-channel MOS transistor to the lease of the second P-channel MOS transistor, and connects the drain of the first P-channel MOS transistor to the lease of the second P-channel MOS transistor. The gates and drains of the transistors are connected in common to form a diffusion or MOS transistor.
By connecting to the voltage terminal through a second resistor by a transistor, the voltage terminal and the second P-channel MO
2. The electronic timepiece according to claim 1, wherein the reference voltage between the drains of the S transistors is the sum of the threshold voltages of the first and second P channel MOS transistors when the reference voltage is equal to or higher than a certain voltage. 3 The current amplification section inputs a reference voltage between the gate and ■voltage terminal of the P channel MOS transistor, the drain is connected to the ■voltage terminal, and the lease is connected to ■through the low voltage that is the load.
The voltage terminal is connected to the voltage terminal so that a voltage lower than the reference voltage by the threshold voltage of the P-channel MOS transistor of the current amplifying section is applied to the load, and the P-channel MOS transistor is connected to the voltage terminal.
Claim 1, characterized in that the on-resistance of the S transistor is 1/10 or less of the load impedance of the low voltage section, and the threshold voltage is lower than the threshold voltages of other logic sections. Electronic clock as described in section.