| 摘要 |
Each driver circuit for a six-by-four array of light emitting diodes illuminating a pushbutton switch switches three pairs of the light emitting diodes between series connection and parallel connection based on changes to an applied input voltage. Driving six light emitting diodes instead of only four allows illumination of a larger area and improves power efficiency at higher applied input voltages, while retaining dimming compatibility at low voltage levels. Each driver circuit also includes a rectifier allow illumination of the pushbutton switch with direct current voltages of either polarity. The quiescent current limiting resistance is split into multiple resistors for further improved power efficiency. Each driver circuit also includes a bridge rectifier to allow illumination of the pushbutton switch with direct current voltages of either polarity or alternating current voltages.
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