| 摘要 |
PROBLEM TO BE SOLVED: To make even many LEDs controllable, and to control a fluorescent display tube and the LEDs simultaneously. SOLUTION: A control signal from a timing control circuit 11 is supplied to a gate electrode of a high voltage FET 12. The drain electrode of the FET 12 is pulled up to +5 V, and the source electrode thereof is connected with a fluorescent display tube voltage circuit 16' via a pull-down resistor 13 and a terminal 15. The voltage circuit 16' is grounded. A grid driving signal/an anode driving signal is outputted from the source electrode of the FET 12 to the fluorescent display tube via an output terminal 14. When the FET 12 is OFF, the grid/anode electrode is pulled down to a negative voltage and thus electrons cannot get to the anode electrode, therefore, the fluorescent display tube is turned off. When the FET 12 is ON, the grid or anode electrode is pulled up to a positive voltage and thus the electrons are accelerated and get to the anode electrode, therefore, the fluorescent display tube is turned on.
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