A circuit includes a first node; a second node; a first PMOS transistor having a source coupled to the first node, a drain coupled to a first control transistor, and a gate driven by a first voltage; and a first NMOS transistor having a source coupled to the second node, a drain coupled to the first control transistor, and a gate driven by a second voltage. The first PMOS transistor is configured to automatically turn off based on the first voltage and a first node voltage at the first node. The first NMOS transistor is configured to automatically turn off based on the second voltage and a second node voltage at the second node. When the first PMOS transistor, the control transistor, and the first NMOS transistor are on, the first node voltage is lowered while the second voltage is raised.