Patent attributes
A light emitting element driving apparatus includes the following: current source; error amplifier generating error signal based on comparison of a first reference voltage with the highest voltage among total forward drop voltages of element arrays or feedback voltage corresponding to a drive voltage; first and second switches for ON/OFF control to apply the feedback voltage to first and second input terminals of the error amplifier respectively; slope voltage generating circuit; PWM comparator generating a pulse modulation signal; drive amplifier controlled by the pulse modulation signal and drives a switching element supplying the drive voltage to the element arrays; PWM width detector that outputs a pulse width detection signal having different levels between when the pulse width is less than predetermined threshold value and when equal to or greater than the threshold value, and switches ON/OFF of the first and second switches based on the pulse width detection signal.
