Voltage generating system and memory device using the same

A memory device, comprising:

• an integrated circuit, wherein the integrated circuit is a memory cell array or a memory peripheral circuit;
• and
• a voltage generating system comprising:
• a first internal voltage regulator, configured to supply a current to pull an internal supply voltage to substantially a regulated level and maintain substantially at the regulated level;
• and
• a first substrate-bias controlled selector, configured to receive a regulator power-up mode signal, a regulating-mode signal and a substrate-bias voltage, and control the first internal voltage regulator such that when the substrate-bias voltage is smaller than a first predetermined voltage, the first internal voltage regulator powers up and operates normally by respectively taking the regulator power-up mode signal and the regulating mode signal into consideration, and when the substrate-bias voltage is larger than or equal to the first predetermined voltage, the first internal voltage regulator is disabled, wherein the first predetermined voltage is smaller than or equal to a forward voltage of a p-n junction formed with the substrate;
• and
• a power bus coupled to the integrated circuit and configured to distribute the internal supply voltage to the integrated circuit.