An apparatus that generates and limits a bias current of a power amplifier is provided. The apparatus includes a bias current circuit that generates a bias current to bias the power amplifier, and critically limit an increase in bias current, and a band gap reference circuit that provides a reference voltage or a reference current to the bias current circuit. The bias current circuit is configured to critically limit the increase in bias current, as a first bias transistor that generates the bias current is converted from a triode region to a saturation region, based on the reference voltage or the reference current.