Ultra low voltage white LED drive circuit

Published:2011/6/24 22:36:00 Author:TaoXi | Keyword: Ultra low voltage, white LED, drive circuit | From:SeekIC

The positive voltage of the white LED is 3~5V, it is difficult that if we use only one battery to drive the white LED. This design uses the ultra-low operating voltage performance of the single-gate Schmitt inverter such as the 74HC14 or NC7SP14 (figure 1). When you add the battery power supply, the Schottky diode D1 conducts, the Schmitt trigger unsteady state multiple frequency oscillator starts working. The oscillation frequency depends on the timing components C2 and R1. When the output of IC1 is high level, the transistor Q1 conducts, the current of the inductor L1 increases gradually. Figure 1 Ultra low voltage white LED drive circuit



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