JPH0364974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an electronic timepiece circuit that is effective when applied to a device including a timekeeping and display circuit, such as a crystal oscillation type electronic timepiece.

[Description of Prior Art] In liquid crystal display type digital watches, in order to minimize the power consumption of the integrated circuit as the electronic watch circuit, the operating voltage of the oscillation circuit, frequency dividing circuit, timekeeping data storage circuit, etc. ,for example
It is designed to be around 1.5V. On the other hand, the liquid crystal drive circuit part has a high operating voltage limit, so
It is necessary to operate at around 3.0V, which is twice as high. For this reason, integrated circuits that incorporate traditional timekeeping and display circuits on a single chip require each chip to be individually designed to match the power supply voltage used, which reduces design effort and manufacturing control. However, this was inconvenient because it required man-hours for two types of products.

[Object of the invention] The object of the invention is to use two types of power sources, e.g.
An electronic clock circuit that can use both 1.5V and 3.0V, allowing one type of integrated circuit chip to handle two types of power supplies, reducing design and manufacturing management time. Our goal is to provide the following.

[Summary of the Invention] An electronic timepiece circuit according to the present invention includes a timepiece circuit, a drive circuit that generates a drive signal for a display element in response to a signal from the timepiece circuit, and a battery having a first voltage connected to each other. a first terminal to which a battery having a second voltage is to be connected; a second terminal to which a battery having a second voltage is to be connected;
The voltage conversion circuit executes a voltage conversion operation in response to a clock signal from the clock circuit, and when a battery is connected to the first terminal, a boosted voltage obtained by boosting the first voltage is transferred to the first terminal. a voltage converter circuit that generates a step-down voltage at the second terminal and generates a step-down voltage obtained by stepping down the second voltage at the first terminal when a battery is connected to the second terminal; means for connecting to the drive circuit as a power supply terminal;
means for generating an activation signal having an amplitude equal to the voltage of the battery of the terminal to which the battery is connected among the first and second terminals; In response to the activation signal, the one of the first and second terminals to which the battery is connected is connected to the clock circuit to activate the clock circuit, based on the amplitude of the activation signal. and a power supply switching circuit that connects the first terminal to the clock circuit as a power supply terminal in response to the stoppage of the clock circuit.

In this way, an electronic timepiece can be configured with a common circuit for two types of power supply voltages. Moreover, at startup, the same voltage is directly supplied to the clock circuit to start it regardless of the type of power supply voltage, so it is possible to prevent the problem of the clock operation and display operation not working.

[Explanation based on examples] Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the same figure, this circuit includes oscillation/frequency divider circuit 1
, a clock data storage unit 2 controlled by control input terminals S ₁ to S _o , a liquid crystal drive circuit 3 that drives a liquid crystal display, and a voltage conversion circuit that operates with a clock supplied from the oscillation/frequency dividing circuit 1 4 and oscillation/frequency divider circuit 1
It also includes a power supply switching circuit 5 for supplying a power supply voltage to the time data storage section 2, and a switch circuit 6 consisting of a gate circuit that controls switching of the power supply switching circuit 5.

The voltage conversion circuit 4 has terminals 7 to 10, and when a 1.5V battery is used as a power source for this device, the battery is connected to terminal 9, and when a 3.0V battery is used, the battery is connected to terminal 10. . This voltage conversion circuit 4 is a voltage conversion circuit such as a DC-DC converter operated by a clock supplied from the oscillation/frequency dividing circuit 1, and has a terminal 9 of 1.5V.
This circuit performs voltage conversion such that when a 3.0V battery is connected to the terminal 10, a 3.0V boosted voltage is output to the terminal 10, and when a 3.0V battery is connected to the terminal 10, a 1.5V boosted voltage is output to the terminal 9. A smoothing capacitor is connected between terminals 7 and 8 of voltage conversion circuit 4, terminal 10 is connected to a power supply circuit of liquid crystal drive circuit 3, and terminals 9 and 10 are respectively connected to power supply switching circuit 5. Further, of the terminals 9 and 10, the terminal to which the battery is connected is connected to the terminal 11 of the switch circuit 6.

The switch circuit 6 is a circuit that sends a signal corresponding to the voltage applied to the terminal 11 to the power supply switching circuit 5 via the signal line 12 by grounding its control input terminal _S1 .

The power supply switching circuit 5 normally switches the voltage of 1.5V at the terminal 9 to be applied to the oscillation/frequency dividing circuit 1 and the time measurement data storage section 2, but the power supply switching circuit 5 is switched so that the voltage of 1.5V at the terminal 9 is applied to the oscillation/frequency dividing circuit 1 and the time measurement data storage section 2. When a signal is received, the circuit switches to directly apply the voltage of the terminal 9 or 10 to which the battery is connected to the oscillation/frequency divider circuit 1 and the time data storage section 2.

Next, the operation of this embodiment will be explained.

First, we will discuss the case where a 1.5V battery is used as a power supply battery for the device.

In this case, a 1.5V battery is connected between terminal 9 and ground, and terminal 11 is connected to this terminal 9. Also, to boost and smooth the battery voltage,
A capacitor is connected between terminals 7 and 8 and between the ground and terminal 10, respectively. Furthermore, the BKC terminal 13 of the power supply switching circuit 5 is grounded.

With the above connection, a voltage of 1.5V is supplied from terminal 9 to the timekeeping circuit consisting of the oscillation/frequency dividing circuit 1 and the timekeeping data storage section 2 via the power supply switching circuit 5, and the liquid crystal drive circuit 3 is supplied with a voltage of 1.5V from the terminal 10. A voltage of 3.0V, which is boosted to twice the battery voltage by the voltage conversion circuit 4, is supplied.

Next, let's talk about the case where a 3.0V battery is used. In this case, between terminal 10 and ground,
Connect a 3.0V battery and connect terminal 11 to this terminal 10.
Connect to. Step-down/smoothing capacitors are connected between terminals 7 and 8 and between terminal 9 and ground, respectively, and BKC terminal 13 is connected to ground.

With this connection, a battery voltage of 3.0V is directly applied to the liquid crystal drive circuit 3, and a voltage of 1.5V, which is halved by the voltage conversion circuit 4, is applied to the oscillation/frequency divider circuit 1 and the timekeeping data storage section 2. It is applied via the terminal 9 and the power supply switching circuit 5.

When starting up this device, it is necessary to directly apply battery voltage to the oscillation/frequency divider circuit 1 in order to start the oscillation/frequency divider circuit 1. Next, this method will be explained.

When using a 1.5V battery, when the control input terminal _S1 is set to ground level by external operation when starting the device, a signal corresponding to the voltage applied to the terminal 11 from the switch circuit 6 is generated. The voltage is output to the power supply switching circuit 5, and the power supply switching circuit 5 directly supplies the battery voltage at the terminal 9 to the oscillation/frequency dividing circuit 1. After the oscillation of the oscillation/frequency divider circuit 1 becomes stable, the terminal _S1 is opened to continue supplying the voltage at the terminal 9 to the oscillation/frequency divider circuit 1.

On the other hand, when using a 3.0V battery, connect input terminal S ₁ is set to ground level in the same way as above, and a signal corresponding to the voltage of terminal 11 is sent from switch circuit 6 to power supply switching circuit 5. The power supply switching circuit 5 is switched so as to directly supply the battery voltage at the terminal 10 to the oscillation/frequency dividing circuit 1 and the time data storage section 2. After the oscillation/frequency division circuit 1 is activated and the oscillation is stabilized, the connection input terminal _S1 is opened, and the step-down voltage at the terminal 9 is supplied to the oscillation/frequency division circuit 1 via the power supply switching circuit 5.

As explained above, in this embodiment, terminal 1
By connecting 1 to the terminal 9 or 10 on the side where the battery is connected, the battery voltage can be directly applied to the clock circuit at startup, and the clock required by the voltage conversion circuit 4 for voltage conversion operation can be applied directly to the clock circuit at startup. After the signal is obtained and the timing circuit starts operating, the starting signal can be stopped by an external switching operation to return to normal operation, and the circuit is designed to operate at low voltage for the purpose of reducing power consumption. The original purpose of the clock circuit has also been achieved.

2 and 3 show connections when the circuit of FIG. 1 is implemented by an integrated circuit,
Figure 2 is a connection diagram when a 1.5V battery is used, and Figure 3 is a connection diagram when a 3.0V battery is used.

In addition, in this example circuit, the battery voltage is
Although 1.5V and 3.0V were used, it is clear that the present invention can be applied to all batteries in which the two types of battery voltages have a relationship of approximately 1:2. It can also be applied to things obtained by

[Description of Effects] Since the present invention has the above-described structure and operation, it is possible to use one type of integrated circuit chip for two types of batteries by simply changing the connection of the terminals. , design man-hours and manufacturing management man-hours can be reduced. Since the clock circuit and display circuit within the device are operated at their respective optimum operating voltages, the power consumption of the device can also be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing connections of a power supply and a capacitor when the circuit of FIG. 1 is implemented as an integrated circuit. DESCRIPTION OF SYMBOLS 1... Oscillation/frequency dividing circuit, 2... Timing data storage section, 3... Liquid crystal drive circuit, 4... Voltage conversion circuit,
5...Power switching circuit, 6...Switch circuit.

Claims (1)

[Claims] 1 A clock circuit, a drive circuit that generates a drive signal to the display element in response to a signal from the clock circuit, a first terminal to which a battery having a first voltage is to be connected, and a second terminal. a second terminal to which a battery having voltage is to be connected; and a voltage conversion circuit for performing a voltage conversion operation in response to a clock signal from the clock circuit, the battery being connected to the first terminal. When a battery is connected to the second terminal, a step-up voltage obtained by stepping up the first voltage is generated at the second terminal, and when a battery is connected to the second terminal, a step-down voltage obtained by stepping down the second voltage is generated at the first terminal. a voltage conversion circuit that generates voltage at a terminal; means for connecting the second terminal to the drive circuit as a power supply terminal; and a battery at the terminal of the first and second terminals to which the battery is connected. means for generating a starting signal having an amplitude equal to a voltage of the first and second terminals; A power supply that connects the terminal to which the battery is connected to the clock circuit to start the clock circuit, and connects the first terminal to the clock circuit as a power supply terminal in response to the stop of the startup signal. An electronic clock circuit comprising a switching circuit.