An old but good app note from Micrel using LDO Regulator as High Side switch controller.
The Micrel MIC5158 Super LDO™ Voltage Regulator Controller can be used as a high-side switch driver that features a relatively accurate current limit. The part is normally intended for driving the MOSFET pass device of a voltage regulator. It also has constant-current output limiting. The similarity that this circuit shares with high-side MOSFET drivers is that it includes a charge-pump for driving N-channel MOSFETs. An advantage is that its current limit is more accurate than that of most high-side drivers.