Patent ID: 9407242
Filing Date: 2016-08-02
CPC Classification: H03K

Claim Text:
1. A voltage level shifter, comprising: a low voltage domain current mirror including first and second branches; a high voltage switch and a first resistor connected in series with the second branch; an output stage that provides an output signal that is a function of a voltage difference across the first resistor, wherein the output stage and the first resistor are in a high voltage domain; and a first unidirectional element in the low voltage domain that prevents a voltage difference appearing across the second branch when the high voltage switch is non-conducting, wherein assertion of an input signal in the low voltage domain generates a first current in the first branch, and causes the high voltage switch to pass in the resistor a second current from the second branch that is a function of the first current and that generates the voltage difference across the resistor, and de-assertion of the input signal halts flow of the first and second currents, and the high voltage switch withstands a voltage difference between the high and low voltage domains.