Patent ID: 7075335
Filing Date: 2006-07-11
Classification: H03K

Abstract:
1. A level shifter configured to convert an input signal having an amplitude varying between a first reference voltage and a first supply voltage into an output signal having an amplitude varying between a second negative reference voltage and a second supply voltage, said level shifter comprising: a first and a second semiconductor switching elements provided in parallel between said first supply voltage and said second negative reference voltage and configured to become conductive based on said input signal; a first and a second high breakdown voltage semiconductor switching elements provided in serial to said first and second semiconductor switching elements respectively and kept normally conductive, said first and second high breakdown voltage semiconductor switching elements being higher in breakdown voltage than said first and second semiconductor switching elements; a first current source circuit provided to supply a first current to said first and second semiconductor switching elements; a second current source circuit connected in parallel with said first current source circuit to supply a second current to said first or second semiconductor switching element only for a certain period of time on reception of a signal employed to switch said first or second semiconductor switching element from a current-blocked state to a current-allowed state; and an output circuit provided to create said output signal based on an electric signal originated from a current flowing in said first and second semiconductor switching elements.