Abstract: Disclosed is a method of taking electric power from a low voltage bypass for providing low voltage power supply for an integrated circuit. Also provided is an alternating current (AC) directly driven LED integrated circuit adapted to use the method; the integrated circuit includes a voltage stabilizing circuit, a low voltage electronic switch circuit, an under-voltage control circuit, and a comparative amplification circuit, and has three pins, a positive power supply terminal, a zero potential reference terminal, and a common terminal for current sampling and for the low voltage electronic switch. The method of taking electric power from a low voltage bypass for providing low voltage power supply for an AC directly driven LED integrated circuit, and the integrated circuit adapted to use the method have the advantages of low power consumption and cost, high efficiency and reliability, and fewer pins and external devices, and are easy to use.