A power booster circuit for use with an integrated circuit coupled to power supply circuitry. The integrated circuit includes a first circuit block that operates at a first voltage level and a second circuit block that operates at a second voltage level. The power supply circuitry includes a first regulator that receives a main supply voltage and provides a first supply voltage at the first level and a second regulator that receives the first supply voltage and provides a second supply voltage at the voltage level. The power booster circuit provides a temporary supply voltage at a third level to the second circuit block in response to the main supply voltage during a time interval between a first time at which the first supply voltage reaches the first level and a second time at which the second supply voltage reaches the second level upon power up of the integrated circuit.