Pen for use with a touch screen

A pen for use with a touch screen, the pen comprises:

• a first AC coupling circuit operable to receive a sense signal from the touch screen;
• a sense-regulation circuit operable to:
• receive the sense signal from the first AC coupling circuit;
• compare the sense signal to a reference signal to produce a comparison signal;
• generate a regulation signal based on the comparison signal;
• and
• regulate receiving of the sense signal based on the regulation signal;
• a response circuit operable to generate a transmit signal based on the comparison signal and data;
• and
• a second AC coupling circuit operable to transmit the transmit signal to the touch screen, wherein the touch screen is capable of interpreting the transmit signal as an input to the touch screen.