| 摘要 |
LED pairs each consisting of two LEDs are arranged in a matrix form to constitute a LED module. Receiving an external clock signal, a timing control circuit generates common signals that set on-periods of drive currents for the LEDs. Each display drive circuit includes first and second drive elements. The first drive element commonly serves the two LEDs of the LED pair, and is turned on during the on-period set by the common signal. The second drive element has two transistors that separately serve the two LEDs of the LED pair and are turned on in accordance with respective color selection signals. The display drive circuits selectively provide drive currents to the LEDs through the first and second drive elements being turned on. When detecting a stop of the clock signal, a common signal control circuit cut off the first drive elements by canceling the common signals.
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