Patent ID: 7696804
Filing Date: 2010-04-13
Classification: H03K

Abstract:
1. A method for level shifting an input signal corresponding to a first voltage domain, to generate complementary first and second output signals corresponding to a second voltage domain larger in magnitude than the first voltage domain, said first and second output signals conveyed on respective first and second output nodes, said method comprising: in response to a change of the input signal from a first state to a second state of the first voltage domain: coupling the first output node to a second voltage supply node by way of a first current path that includes a first voltage shifter circuit in series with a first switch device, to partially drive the voltage of said output node toward the second voltage supply node voltage, said first voltage shifter circuit providing a large enough voltage drop thereacross to ensure that, for a voltage of said first output node equal to the highest voltage in the second voltage domain, and the first switch device being fully enabled, a voltage across the first switch device does not exceed its maximum snap-back voltage; then coupling the first output node to the second voltage supply node by way of a second current path that includes a first bypass device in series with the first switch device, but excludes the first voltage shifter circuit, to drive the voltage of the first output node fully to the second voltage supply node voltage; and de-coupling the second output node from the second voltage supply node by disabling a third current path therebetween that includes a second switch device, and coupling the second output node to a first voltage supply node, to drive the voltage of the second output node substantially to the voltage conveyed on the first voltage supply node; wherein the first switch device is enabled by, and the second switch device is disabled by, first and second complementary control signals coupled to both the first and second switch devices.