This invention discloses an integrated circuit, which comprises a first and a second pull-down circuit controlled by a first and second signal, respectively, and coupled between a first node and a low voltage power supply (Vss), and a controllable pull-up circuit coupled between the first node and a complimentary high voltage power supply (Vcc), wherein when either the first or second signal is asserted to a predetermined logic state, the first node is pulled down to a logic LOW state.