Drive Circuit to adjust a luminance of a light emitting element based on a PWM signal, and a portable information terminal including the drive circuit

摘要

A drive circuit (100) includes an operational amplifier (OP1) that compares a voltage applied to an inverting input terminal with a reference voltage applied to a non-inverting input terminal, a MOS transistor (M1) that has an output connected to the inverting input terminal of the operational amplifier (OP1) and supplies a current to a load (3) depending on a comparison result of the operational amplifier (OP1), and a switch (SW1) that switches, based on a control signal, between outputting the comparison result of the operational amplifier (OP1) to the MOS transistor (M1) and outputting a predetermined voltage to the MOS transistor (M1) to turn off the MOS transistor (M1).