Patent ID: 7589510

Claim:
A voltage regulator comprising: a power field effect transistor having a threshold voltage, a drain terminal receiving an input voltage, a source terminal providing an output voltage and a load current, a gate terminal responsive to a control signal, and a bulk terminal; a control-loop circuit responsive to the output voltage and providing the control signal, the control-loop circuit being configured to adjust the control signal to such a value that the output voltage is regulated to a constant value, wherein the threshold voltage of the power field effect transistor is modified dependent on the load current; a switching circuit configured to connect the bulk terminal with the source terminal or with a constant potential dependent on the load current and/or the output voltage, wherein the switching circuit is configured to, connect the bulk terminal with the source terminal if the load current is higher than a reference current, and connect the bulk terminal with the constant potential if the load current is lower than the reference current; or connect the bulk terminal with the source terminal if the output voltage is lower than a reference voltage, and connect the bulk terminal with the constant potential if the output voltage is higher than the reference voltage.