Patent ID: 8395433
Filing Date: 2013-03-12
Classification: H03K

Abstract:
1. A cascoded input-output device configured to receive at an input node a lower voltage input signal and to generate at an output node a higher voltage output signal, said cascoded input-output device having a lower voltage domain and an upper voltage domain, said cascoded input-output device comprising: a first driver switch in series with a first cascode switch in said lower voltage domain; a second driver switch in series with a second cascode switch in said upper voltage domain; a bias switch configured to set a bias voltage selected from a high bias voltage and a low bias voltage in dependence on a bias steering signal, said bias voltage being applied to a protected node of said cascoded input-output device; clamp circuitry configured to provide a clamped voltage, said clamped voltage being a clamped version of said output signal and being clamped at a maximum voltage of said lower voltage domain; and switch steering circuitry configured to perform bias switching by generating said bias steering signal to cause said bias switch to change said bias voltage from an initial value in response to a transition of said input signal and to cause said bias switch to return said bias voltage back to said initial value in response to said clamped voltage reaching said maximum voltage of said lower voltage domain.