A control structure and method for controlling a sensor heater including a
power supply connected to a switching device for pulse width modulating a
voltage from the power supply. The switching device is further connected
to a resistance heater. A microcontroller having a single output is
connected to the switching device and a single input from the
microcontroller is connected to a high side of the resistance heater. The
microcontroller determines a pulse width modulation duty cycle to maintain
a constant power dissipation of the resistance heater.
