US Patent 7545172 Voltage converter apparatus

A voltage converting device (1) receiving a input signal (Si1) having a high input voltage (Vi_high) and a low input voltage (Vi_low), converting a voltage level of the input signal (Si1), and outputting the input signal (Si1) as a output signal (So1), wherein the voltage converting device (1) comprises a first input portion (In1) for receiving the input signal (Si1), a first output portion (Out1) for outputting the first output signal (So1), and a voltage converting means for converting at least one of the first high input voltage and the first low input voltage, the voltage converting means having a TFT (2) for switching among at least two states containing a connection state in which the first input portion (In1) is connected to a first node (N1) and a disconnection state in which the first input portion (In1) is disconnected from the first node (N1), and wherein the voltage converting means comprises a first voltage dropping means for dropping a voltage on the first node (N1) before changing from a state in which the first input portion (In1) is disconnected from the first node (N1) to a state in which the first input portion (In1) is connected to the first node (N1).