Nordic Semiconductor ASA
VOLTAGE REGULATORS

Abstract:

A voltage regulation circuit (2) comprises first (4) and second (6) voltage regulators each arranged to receive an input voltage (V.sub.in) and a respective reference voltage; and first (18) and second (30) reference voltage sources arranged to provide the first and second reference voltages respectively. In a first mode of operation, the first regulator varies the regulated output voltage in response to a difference between the regulated output voltage (V.sub.out) and the first reference voltage. In a second mode of operation, the second regulator varies the regulated output voltage in response to a difference between the regulated output voltage and the second reference voltage. The second voltage regulator is arranged to provide a greater maximum output current than the first voltage regulator. The circuit further comprises a switch portion (8) arranged to provide a third mode of operation in which the first regulator provides the regulated output voltage and the second regulator provides additional output current.