Patent ID: 8736304

Claim:
A method for translating signals from a first voltage of a first voltage source to a second voltage of a second voltage source, wherein a first level shifter that has an input and an output is connected to the first voltage source, and wherein a second level shifter that has an input and an output is connected to the second voltage source, the method comprising: receiving, by an intermediate level shifter, an input signal from said first level shifter, said input signal having a first duty cycle and a maximum voltage that is said first voltage, wherein said intermediate level shifter has an input and an output, and further wherein the input of the intermediate level shifter connects to the output of the first level shifter; the output of the intermediate level shifter connects to the input of the second level shifter; and wherein the intermediate level shifter includes an intermediate p-channel transistor and an intermediate n-channel transistor, and further wherein an intermediate source of the intermediate p-channel transistor is connected to a constant intermediate voltage source having an intermediate voltage about midway between the first voltage of the first voltage source and the second voltage of the second voltage source; wherein the first voltage is a higher voltage than the second voltage; shifting, by said intermediate level shifter, said input signal from said first voltage to said intermediate voltage to generate an intermediate signal, wherein said intermediate signal is inverted with respect to said input signal, and wherein positive pulses of said intermediate signal are shrunk and inverted with respect to corresponding pulses of said input signal and negative pulses of said intermediate signal are stretched and inverted with respect to corresponding pulses of said input signal; receiving, by said second level shifter, said intermediate signal and shifting said intermediate signal to generate an output signal that is inverted with respect to said intermediate signal, said output signal having said first duty cycle and a maximum voltage that is said second voltage; and wherein the second level shifter includes a first p-channel transistor having a first source that is connected to the second voltage source and a first drain that is connected to a second drain of a first n-channel transistor, and wherein the connection of the first drain of the first p-channel transistor and the second drain of the first n-channel transistor form an output that is the output signal, and further wherein a second source of the first n-channel transistor is connected to ground, and still further wherein the second voltage source is a constant voltage source.