Patent ID: 8841955

Claim:
A voltage level shifter, comprising: a first voltage shift circuit, connected to a ground voltage, and the first voltage shift circuit receiving a first input voltage; a second voltage shift circuit, connected to the ground voltage, and the second voltage shift circuit receiving a second input voltage, wherein the first input voltage and the second input voltage are anti-phase; a first switch circuit, connected to the first voltage shift circuit through a first terminal, and outputting a first voltage; a second switch circuit, connected to the second voltage shift circuit through a second terminal, and outputting a second voltage, wherein the second switch circuit is controlled by a second output voltage outputted by the first terminal to determine whether to be open or closed, and the first switch circuit is controlled by a first output voltage outputted by the second terminal to determine whether to be open or closed; a third switch circuit, connected between a system voltage and the first switch circuit, and controlled by the second voltage to determine whether to be open or closed; and a fourth switch circuit, connected between the system voltage and the second switch circuit, and controlled by the first voltage to determine whether to be open or closed; a first current-limiting circuit, connected between the system voltage and the first switch circuit, and the first current-limiting circuit receiving a reference voltage to limit a first current; and a second current-limiting circuit, connected between the system voltage and the second switch circuit, and the second current-limiting circuit receiving the reference voltage to limit a second current; wherein when the first input voltage is at high voltage level, the second output voltage and the first voltage will be transited to the ground voltage so as to open the second switch circuit and the fourth switch circuit, and accordingly the first output voltage is transited into the system voltage, wherein when the second input voltage is at high voltage level, the first output voltage and the second voltage will be transited into the ground voltage so as to open the first switch circuit and the third switch circuit, and accordingly the second output voltage is transited into the system wherein when the first input voltage is at the high voltage level, the second voltage is transited to the system voltage it close the second current-limiting circuit and wherein when the second input voltage is at high voltage level, the first voltage is transited to the system voltage to close the first current-limiting circuit.