| 摘要 |
PROBLEM TO BE SOLVED: To maintain other LEDs to be light emittable even when one LED is disconnected in the LED set lamp circuit of a serial connection type and also to protect LEDs from static electricity. SOLUTION: Each forward drop voltage of red LDEs 11 to 16 is 2.2 volts. A zener diode for bias 2 whose zener voltage is 2.4 volts is connected in parallel with each LED of the red LEDs 11 to 16 in a reverse polarity. Each forward drop voltage of green LEDs 21 to 23 and blue LEDs 31 to 33 is 3.5 volts. A zener diode for bias 3 whose zener voltage is 3.9 volts is connected in parallel with each LED of the green LEDs 21 to 23 and the blue LEDs 31 to 33 in a reverse polarity. Moreover, zener diodes for absorbing surge 4a, 4b, 4c are connected to each other among a common terminal 1 and a red signal terminal 10, a green signal terminal 20 and a blue signal terminal 30 in a polarity reverse to those of the LEDs. Since each zener voltage of the diodes 4a to 4c is 20 volts, the diodes 4a to 4c are not be brought into conduction at the normal driving voltage of respective LED serial circuits.
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