A compensation circuit for protecting a lamp from a large transient
current. The compensation circuit may include a saw tooth generator
configured to generate a saw tooth signal with an amplitude corresponding
to a supply voltage of the lamp. A pulse width modulated signal may be
generated by a comparator of the compensation circuit based on the saw
tooth signal and a DC signal. The duty cycle of the pulse width modulated
signal may be used by a controller to control the duration of time that
current flows through the lamp. When the supply voltage of the lamp
transitions from a low voltage to a high voltage, the amplitude of the
saw tooth signal increases. When the amplitude of the saw tooth signal
increases, the duty cycle of the pulse width modulated signal decreases
thereby causing the controller to decrease the duration of time that
current flows through the lamp.