Integrated circuit for remote keyless entry system

A method comprising:

• providing a supply voltage VDS to a first driver having an output coupled to a common node, where VDS is higher than a voltage supply, the first driver configured to reverse bias a first set of parasitic diodes of a first set of transistors of the first driver to prevent a current present at the common node from entering the first driver due to a second signal being present at the common node due to operation of a second driver during a second mode of operation;
• detecting a first mode of operation;
• driving a first signal at the common node with the first driver during the first mode of operation;
• detecting the second mode of operation;
• providing a regulated supply voltage VTX to the second driver coupled in parallel to the first driver and having an output coupled to the common node;
• and
• driving the second signal at the common node with the second driver, the second driver configured to reverse bias a second set of parasitic diodes of a second set of transistors of the second driver to prevent the current from entering the second driver due to the first signal being present at the common node due to operation of the first driver during the first mode of operation.

A system comprising:

• a dual mode antenna coupled to a common node;
• a first driver having an input coupled to a supply voltage VDS and an output coupled to the common node, the first driver configured to drive the dual mode antenna during a first mode of operation, the first driver configured to reverse bias a first set of parasitic diodes of a first set of transistors of the first driver to prevent a current present at the common node from entering the first driver due to a second signal being present at the common node due to operation of a second driver during a second mode of operation;
• a regulator coupled to the supply voltage VDS and configured to output a regulated supply voltage VTX during the second mode of operation;
• and
• the second driver coupled in parallel with the first driver, the second driver having an input coupled to the regulator output and having an output coupled to the common node, the second driver configured to receive the voltage supply VDS during the first mode of operation and to receive the regulated supply voltage VTX during the second mode of operation, the second driver configured to drive the dual mode antenna during the second mode of operation, the second driver configured to reverse bias a second set of parasitic diodes of a second set of transistors of the second driver to prevent the current from entering the second driver due to the first signal being present at the common node due to operation of the first driver during the first mode of operation.