Patent ID: 7460416

Claim:
A voltage supply circuit comprising a first voltage supply part and a second voltage supply part that are provided in parallel with respect to an output node, wherein: said first voltage supply part includes a first differential amplifier that receives a voltage of said output node and a first voltage as input voltages, and activates its output signal when the voltage of said output node is lower than said first voltage, a second differential amplifier that receives the voltage of said output node and a second voltage which is higher than said first voltage as input voltages, and activates its output signal when the voltage of said output node is higher than said second voltage, and a first driving circuit that connects said output node to a high power supply line in response to the activation of the output signal of said first differential amplifier, and connects said output node to a low power supply line in response to the activation of the output signal of said second differential amplifier; and said second voltage supply part includes a third differential amplifier that receives the voltage of said output node and said first voltage as input voltages, and, only during an activation period of a drivability control signal, activates its output signal when the voltage of said output node is lower than said first voltage, a fourth differential amplifier that receives the voltage of said output node and said second voltage as input voltages, and, only during the activation period of said drivability control signal, activates its output signal when the voltage of said output node is higher than said second voltage, and a second driving circuit that connects said output node to said high power supply line in response to the activation of the output signal of said third differential amplifier, and connects said output node to said low power supply line in response to the activation of the output signal of said fourth differential amplifier, only during the activation period of said drivability control signal.