JPS58113889A - Timer device - Google Patents

Abstract

PURPOSE:To enable the back-up with a power source of small capacity, such as a capacitor, by switching for driving to an output of an oscillator which consumes little power and has a low frequency at the time of the stoppage of power supply, as an extraordinary case. CONSTITUTION:At the time of normal operation, a timer means 4 is operated by the output of an oscillator 1 which has a high oscillation frequency and wherein a high-precision quartz crystal oscillator X1 having excellent thermal characteristics is used. On the other hand, at the time of the stoppage of power supply, a power supply stoppage detecting circuit 9 operates to switch movable contacts of a selector switch 3 to contacts B1 and B2 respectively, and the timer means 4 is operated by the output of an oscillator 6 wherein a quartz crystal oscillator X2 having a low oscillation frequency is used. According to this constitution, a power source of small capacity can be used as a back-up power source at the time of the stoppage of power supply, and thus it can be constituted, for instance, by a double-lamination type capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is built into an electronic device such as a video tape recorder, and is capable of performing various functions such as recording/reproducing television channel selection at a preset scheduled time along with time counting. This invention relates to a timer device that operates.

Timer devices used in video tape recorders, etc.
With the exception of some types, timer bank up during power outages is one of the important functions. In order to perform bank up for a long time, it is necessary to suppress current consumption. On the other hand, in order to make the timer multi-functional, it is desirable to operate the system at high speed, which increases power consumption, and these two are contradictory. Conventionally, this goal was achieved by using a rechargeable battery with a relatively large capacity as a backup power source during a power outage. However, the present invention has the disadvantage that a sufficient backup cannot be made until after the power outage occurs.In the present invention, the only necessary operations of the timer device during a power outage are to hold the memory contents and move the time hand, and the 3 page Since the operation is satisfactory, a high-precision crystal resonator with a high oscillation frequency and good temperature characteristics is used as the system clock signal and time base clock signal source for the system during normal operation, and a crystal resonator with a low oscillation frequency is used during power outages. By using it, it is possible to operate as a highly accurate and highly functional timer device during normal times, and it can also be backed up by a capacitor in the event of a power outage, realizing an inexpensive and highly reliable system.

An embodiment of the present invention will be described below with reference to the drawings.

In the drawing, 1 has a high oscillation frequency (4,9430
4 stones) and high precision crystal oscillator X+ with excellent temperature characteristics
The oscillation output is divided by the first frequency divider 2 to a predetermined system clock frequency, and then transmitted through the contact A1 of the changeover switch 3.
The signal is applied as a system clock signal to a timer means 4 including a microcomputer.

Further, a part of the output of the first frequency divider 2 is divided by a second frequency divider 5 to a predetermined time base clock frequency, and then passed through the contact 2 of the changeover switch 3 to the The timer means 4 is applied as a time base clock signal.

6 is a low frequency (32,768 kHz) crystal resonator x1 that does not require severe temperature characteristics and can oscillate with low power.
), and its oscillation output is directly connected to contact B of the changeover switch 3.
A timer means 4 as a system clock signal via 1
is applied to.

Further, a part of the output of the second oscillator 6 is divided by the third frequency divider 7 to the predetermined time base clock signal frequency, and then transmitted to the timer via the contact B2i of the changeover switch 3. One means 4 is applied as a time base clock signal.

8 is a power supply circuit during normal operation, and the diode D+' (
i=through said second excavator 6. The third frequency divider 7° supplies power to the timer means 4 and the power failure detection circuit 9, and also supplies power to the first oscillator 1 through the diode D2. First frequency divider 2. A power supply 5 is supplied to the second frequency divider 5.

Further, C is a capacitor for backup power supply inserted between the anode side of the diode and ground.

In the above configuration, under normal conditions (when energized), the power failure detection circuit 9 does not operate, and the movable contacts of the changeover switch 3 are connected to contacts A1, . The timer means 4 is operated by the output of the first oscillator 1. On the other hand, in the event of a power outage, the power outage detection circuit 9 is activated and the movable contacts of the changeover switch 3 are connected to contacts B1 and B2. Switch to
The timer means 4 is configured to be operated by the output of the second oscillator 6. Further, a part of the output of the power failure detection circuit 9 at the time of power failure is also applied to the timer means 6, so that only the minimum necessary operation such as clock operation is possible, thereby preventing unnecessary power consumption. Also, during this power outage, the output of the capacitor C causes the second oscillator 6. Third frequency divider 7° timer means 4. The power failure detection circuit 9 is activated.

As described above, according to the present invention, the emergency
´ During power outage, the power supply is configured to be switched to the output of a low-frequency oscillator with low power consumption, so a small-capacity backup power supply in the event of a power outage is sufficient, such as a double-layered capacitor, etc. It is possible.

[Brief explanation of drawings]

The drawing is a block diagram of a timer device in one embodiment of the present invention. 1.6... Oscillator, 2, 5.7... Frequency divider, 3... Changeover switch, 4... Timer means, 8... ...Power supply, 9...Power failure detection circuit, xl, x2...Crystal oscillator, C...
...Condenser, Dl, B2...Diode.

Claims (1)

[Claims] a first clock signal generation means for dividing the output of a first oscillator using a first crystal resonator to generate a system clock signal and a time base clock signal of a predetermined frequency; a second clock signal generating means that generates a system clock signal and a time base clock signal from the output of a second oscillator which has a lower frequency and lower power consumption than the first oscillator; a rechargeable capacitor that serves as a power source for the second clock signal generating means, and a timer that uses a clock signal from the second clock signal generating means in place of the clock signal of the first clock signal generating means in the event of a power outage. A timer device having a changeover switch for selectively applying voltage to the means.