A sensor, device, system and method for sensing temperature includes a pull up circuit coupled to a pull down circuit for generating a variable pull up output current and a variable pull down output current varying according to circuit elements responsive to temperature change. A pull up transistor and a pull down transistor are respectively serially coupled to first and second switches for alternatingly respectively switching additional pull up and pull down current into the pull up output current and the pull down output current. A comparator controls the additional pull up and pull down currents in response to a comparison of a summed output voltage and a reference voltage.