Patent ID: 7772885
Filing Date: 2010-08-10
Classification: H03K

Abstract:
1. A voltage level shifter circuit for shifting an input signal from a low voltage domain to a high voltage domain, comprising: a reference voltage circuit configured to use a high voltage supply from the high voltage domain and produce a reference voltage signal that is independent of the high voltage supply and ranges in value between a minimum voltage value and a maximum voltage value, the minimum voltage value equal to the sum of a low voltage supply of the low voltage domain and a threshold voltage of a transistor configured to operate in the high voltage domain and the maximum voltage value equal to the difference between the high voltage supply and the threshold voltage of the transistor configured to operate in the high voltage domain; and a circuit configured to receive the input signal from the low voltage domain and the reference voltage signal and produce an output signal that equals the high voltage supply when the low voltage supply is applied to the input signal and equals a ground when the ground is applied to the input signal.