JPH0184091U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the circuit of the automobile clock according to the present invention, Fig. 2 is a time chart showing the signals of each part when the lamp lighting signal is DC in the embodiment of the present invention, and Fig. 3 is a diagram showing the circuit example of the car clock according to the present invention. Fig. 4 is a diagram showing a circuit example of a conventional automobile clock, and Fig. 5 is a diagram showing signals in a conventional automobile clock. Time chart diagram. 10... Clock circuit, 12... Time display section, 16
...Dimming oscillation circuit, 20...Inversion circuit, 22...
... Oscillator, 24 ... Frequency divider, 26 ... Lamp lighting signal detection circuit, 32 ... Preset circuit, 42 ...
...Up counter circuit, 50...Pulse switching circuit, 58...Down counter circuit, 64...Control signal output circuit, 68...Composition circuit.

Claims (1)

[Claim for Utility Model Registration] A clock circuit that includes a built-in crystal oscillator and outputs a time signal based on a reference signal generated by the oscillator; a dimming oscillation circuit that outputs a pulse signal with a set duty ratio as a lamp lighting signal; and a dimming oscillation circuit that displays the time based on the time signal and controls the luminance of light emission according to the duty ratio of the lamp lighting signal. A time display unit configured to display the lamp, an inversion circuit that outputs a second lamp lighting signal obtained by inverting the lamp lighting signal, an oscillator and a frequency divider, and a clock that determines whether the lamp lighting signal is output or not. a lamp lighting signal detection circuit that detects whether the lamp lighting signal is output, and outputs a non-lighting detection signal when the lamp lighting signal is not output, and a second lamp lighting signal and a second frequency divided signal _φ2 from the frequency divider. a preset circuit that outputs a load signal and a reset signal in synchronization with the lamp lighting signal when the lamp lighting signal is input and the lamp lighting signal is a pulse signal; When the frequency-divided signal φ ₂ of 2, the third frequency-divided signal φ ₁ whose cycle is shorter than the second frequency-divided signal, and the timing signal from the down counter circuit are input, and the lamp lighting signal is not output. outputting the second frequency-divided signal as a count signal;
When the lamp lighting signal is a direct current, the third frequency-divided signal is output as a count signal, and when the lamp lighting signal is a pulse signal, the second frequency-divided signal and the third frequency-divided signal are output according to the pulse period. A pulse switching circuit that outputs a count signal as a count signal, a second frequency division signal _φ2 from a frequency divider and a reset signal are input, and the circuit always outputs a count value based on the second frequency division signal and has a constant cycle. an up-counter circuit capable of outputting a full count signal at a time, and a count value from the up-counter circuit is loaded based on the full count signal and a load signal, a down-count is performed based on the count signal from the pulse switching circuit, and the count value is A down counter circuit that outputs a borrow signal as a timing signal when the down counter circuit becomes 0, a second lamp lighting signal and a timing signal are input, and when the timing signal is not output from the down counter circuit, a second lamp lighting signal is output. a control signal output circuit through which the non-lighting detection signal and the control signal are input;
An automobile timepiece, comprising: a synthesis circuit that outputs the non-lighting detection signal or control signal as a luminance signal to the time display section.