Open drain driver having enhanced immunity to I/O ground noise

A driver, comprising;

• an input node;
• an output node;
• a first reference node;
• means for uncoupling the output node from the first reference node in response to an input voltage applied to the input node;
• and
• means for keeping the output node uncoupled from the first reference node during an occurrence of noise in a first reference voltage applied to the first reference node that causes an open conducting path created by the means for uncoupling to close.

A driver comprising:

• an input node;
• an output node;
• a first reference node;
• means for uncoupling the output node from the first reference node in response to an input voltage applied to the input node;
• means for keeping the output node uncoupled from the first reference node during an occurrence of noise in a first reference voltage applied to the first reference node;
• a first transistor having a gate coupled to the input node and a conducting path coupled in series with the output node and the first reference node;
• means for preventing the first transistor from turning on during the occurrence of noise in the first reference voltage;
• and
• a second reference node;
• wherein the means for preventing comprises a second transistor having a gate coupled to the input node and a conducting path coupled in series with the second reference node and a source of the first transistor.

A method of performing a driver function, comprising the steps of:

• receiving an input voltage at an input node;
• receiving a first reference voltage at a first reference node;
• uncoupling an output node from the first reference node in response to the input voltage;
• and
• keeping the output node uncoupled from the first reference node during an occurrence of noise in the first reference voltage that causes an open conducting path created by the step of uncoupling to close.

A method of performing a driver function, comprising the steps of:

• receiving an input voltage at an input node;
• receiving a first reference voltage at a first reference node;
• uncoupling an output node from the first reference node in response to the input voltage;
• keeping the output node uncoupled from the first reference node during an occurrence of noise in the first reference voltage;
• establishing a first transistor having a gate coupled to the input node and a conducting path coupled in series with the output node and the first reference node;
• preventing the first transistor from turning on during the occurrence of noise in the first reference voltage;
• establishing a second transistor having a gate coupled to the input node and a conducting path coupled between a second reference node and a source of the first transistor;
• and
• turning the second transistor on in response to the input voltage.

A method of performing a driver function, comprising the steps of:

• receiving an input voltage at an input node;
• receiving a first reference voltage at a first reference node;
• establishing a first transistor having a gate and a conducting path with the gate coupled to the input node and the conducting path coupled in series with an output node and the first reference node;
• turning the first transistor off in response to the input voltage;
• and
• keeping the output node uncoupled from the first reference node during an occurrence of noise in the first reference voltage that causes the first transistor to change from an off state to an on state.