JPH0325756B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic timepiece having a heavy load device, and more particularly to heavy load control at the time of starting oscillation of an oscillation circuit that generates a signal serving as a time standard for the electronic timepiece.

An object of the present invention is to obtain a heavy load control method for reliably starting oscillation of an oscillation circuit.

Conventionally, in an electronic timepiece having a heavy load device, heavy load control has not been performed when oscillation is started by turning on the power or the like. Therefore, the heavy load device may start driving before the oscillation has stabilized. Recently, electronic watches have become smaller and thinner, and along with this, batteries used as power sources have also become smaller and thinner, and this trend has become particularly strong in electronic wristwatches.
Such a battery has a high internal impedance, and when a large current such as that used to drive a heavy load device is passed through the battery, a voltage drop occurs. Therefore, if a heavy load device starts driving and a power supply voltage drop occurs before the oscillation is stabilized, the oscillation may become unstable or stop. This risk increases, especially at low temperatures, as the battery's internal impedance increases.

The present invention eliminates such problems and provides a method for starting stable oscillation, and will be described in more detail below with reference to the drawings.

FIG. 1 shows an example of the configuration of an electronic circuit of an electronic timepiece according to the present invention.

In FIG. 1, 1 is an oscillation circuit that generates a signal serving as a time standard, and 2 is a frequency dividing circuit that divides the frequency of the time standard signal to produce a signal CL with a period of 1 second. 3
is a group of time counters, which measures time using a signal with a period of 1 second. Reference numeral 4 denotes a function control circuit, which controls various functions of the electronic watch, including heavy load devices such as lighting devices and sound generators, and also generates drive signals 5 for each heavy load device. 6 is a heavy load device, which operates when the input is logic "1". 7 is a power on detection circuit that detects when the power is turned on or an oscillation stop detection circuit that detects the stop of oscillation;
When each state is detected, "0" is output. 8 and 9 are a D-type flip-flop 8 (hereinafter abbreviated as F/F) and a master-type latch 9, respectively, and both of them measure time using the 1-second periodic signal CL obtained from the frequency divider circuit 2 as a reference signal. Configure a timer circuit to measure the
Together with NAND gates 10 and 11, it constitutes a heavy load drive prohibition circuit.

FIG. 2 is a timing chart for the circuit of FIG.

In Fig. 2, CL is a 1-second periodic signal obtained from the frequency divider circuit 2, and CL is the output of the detection circuit 7, which serves as a reset signal for the F/F at 8 and the latch at 9, and is set to logic "0". Apply a reset.
Q is the output of 8 F/Fs, and M is the output of 9 latches. When the reset signal is “0”,
M is also "0", and once it becomes "1", M remains fixed at "0" for at least t seconds (t<1) due to the action of the timer circuit composed of 8 and 9. Ru. During the period when M is "0", the heavy load drive signal 5 is inhibited by the NAND gates 10 and 11, so the input of the heavy load device 6 becomes "0" and the heavy load is not driven.

As described above, according to the present invention, heavy load driving can be prohibited for a certain period of time at the start of oscillation to prevent a drop in the power supply voltage, thereby making it possible to start stable oscillation. Furthermore, even if the heavy load drive prohibition time is changed depending on the characteristics of the oscillation circuit, this can be easily applied by making slight changes to the timer circuit. Furthermore, the timer circuit used is not limited to this embodiment, and various timer circuits can be used to implement the present invention.

[Brief explanation of the drawing]

FIG. 1 shows an example of the electronic circuit configuration of an electronic timepiece according to the present invention, and FIG. 2 shows a timing chart of the circuit shown in FIG.

Claims (1)

[Claims] 1. In an electronic watch that has at least one of the heavy loads of a lighting device and a sound generating device, a power-on detection circuit that detects power-on, an oscillation circuit that starts oscillation when the power is turned on, and an output of the oscillation circuit a frequency divider circuit that divides the frequency of a signal; a timer circuit that is reset by the output signal of the power-on detection circuit and starts counting output pulses from the frequency divider circuit when the output signal is inverted;
A heavy load drive inhibiting circuit is controlled by an output signal of the timer circuit and prohibits driving of the heavy load until the timer circuit counts a predetermined number of pulses, and the time period for the timer circuit to count the predetermined number of pulses is within the range of the timer circuit. An electronic clock characterized in that the oscillation circuit is set at a time sufficient for stable oscillation.