JPH0547892U - Fluorescent display clock for automobile - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to reduce the current consumption when the fluorescent display timepiece for automobiles is turned on and off by turning on and off the accessory switch to turn on and off the time display. [Structure] A constant voltage circuit for supplying a voltage for operating the timepiece IC with a battery power source and applying an input voltage from an accessory switch to the timepiece IC and a grid is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluorescent display timepiece for an automobile, and more particularly to a voltage supply for turning on / off a time display by turning on / off an accessory switch.

[0002]

[Prior Art]

 In order to eliminate wasteful current consumption, the fluorescent display timepiece for automobiles displays the time when the accessory switch is on, and when it is off, only the timekeeping operation is performed and not displayed. This circuit is performed by supplying the voltage from the battery to the timepiece IC 18 and the grid 20b of the display tube 20 and the input voltage from the accessory switch to the filament 20c of the display tube 20 as shown in FIG. .

[0003]

[Problems to be solved by the device]

 However, in the conventional fluorescent display timepiece for automobiles described above, the current consumed when the lamp is turned off is only reduced by the amount consumed by the filament, and the timepiece IC has an unnecessarily high voltage that is the same as when it is turned on. It was being applied and was consuming current. An object of the present invention is to suppress the increase in the number of parts as much as possible and reduce the current consumption when the light is turned off with a simple circuit configuration.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a timepiece IC that appropriately divides a reference signal to measure the time and outputs a display drive signal that displays the time, and a fluorescent display that displays the display drive signal. A fluorescent display for automobiles, which has a tube and a power supply input from a battery, and which outputs a voltage input to the grid of the display tube to the watch IC and supplies the input voltage from the accessory switch to the filament of the display tube. In the timepiece, the constant voltage circuit is a constant voltage circuit that supplies a voltage according to an input voltage from a battery power source and an accessory switch.

[0005]

[Action]

 When the accessory switch is turned on and off, the output voltage of the constant voltage circuit becomes high and low, respectively, and the voltage supply required for display is controlled.

[0006]

【Example】

 FIG. 1 is a circuit diagram of an automobile fluorescent display timepiece according to an embodiment of the present invention. Reference numeral 18 denotes a timepiece IC, which divides the reference signal to time the time and outputs a display drive signal for displaying the time. Reference numeral 20 denotes a display, which is composed of a fluorescent display tube including an anode 20a, a grid 20b, and a filament 20c, and displays the time by the display drive signal. Reference numeral 14 denotes a constant voltage circuit, which supplies the voltage from the battery to the timepiece IC and the grid 20b via the backflow prevention diode 2, the constant voltage circuit including the resistor 8 and the zener diode 12. The voltage from the accessory switch is input to the connection point between the resistor 8 and the Zener diode 12 via the diode 6 and the resistor 10. The resistor 8 is set so as to have a current necessary for the timepiece IC to operate, and the resistor 10 is set so as to supply a current required for a display state. Therefore, the voltage control circuit 14 outputs a low voltage when the accessory switch is off and a high voltage when the accessory switch is on. The input voltage from the accessory switch is supplied to the filament 20c of the display tube 20 via the diode 4 and the resistor 16.

Next, the operation of the automobile fluorescent display timepiece of the present invention having the above-mentioned configuration will be described. First, when the accessory switch is off, the constant voltage circuit 14 outputs a low voltage obtained by dividing the voltage from the battery by the resistor 8 to cause the timepiece IC 18 to perform timekeeping operation. When the accessory switch is turned on, this input voltage is supplied to the filament 20c and also to the constant voltage circuit 14. Therefore, the high voltage, which is added to the output voltage, is output from the constant voltage circuit 14 and supplied to the grid 20b and the timepiece IC 18, so that the display drive signal output from the timepiece IC 18 causes the display tube 20 to display the time. It will operate.

[0008]

[Effect of the device]

 As described above, according to the present invention, by providing the constant voltage circuit for adding the input voltage from the accessory switch, only the timekeeping operation is performed by the voltage from the battery when the display is not displayed. Since the voltage for display operation is supplied by the input voltage of, the current consumption can be easily set to the minimum.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an automobile fluorescent display timepiece according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional fluorescent display timepiece for an automobile shown in FIG. 1 showing a conventional example.

[Explanation of symbols]

 14 Constant voltage circuit 18 Clock IC 20 Display

Claims (1)

[Scope of utility model registration request] 1. A timepiece IC that appropriately divides a reference signal to clock the time and outputs a display drive signal that displays the time, a fluorescent display tube that displays the display drive signal, and a battery A constant voltage circuit for outputting a power input to the watch IC and the grid of the display tube;
In a fluorescent display timepiece for an automobile for supplying an input voltage from an accessory switch to a filament of the display tube, the constant voltage circuit is a constant voltage circuit for supplying a voltage by a battery power source and an input voltage from the accessory switch. Fluorescent display clock for automobiles.