A power architecture for providing voltage modulation power is applied to a power supply including a PFC (Power Factor Correction) unit and a transformer, and the power supply further includes a power level correction unit, wherein the PFC unit decides a voltage modulation power level and converts the input power into a voltage modulation power, and the voltage modulation power is transformed into an output power through the transformer. A power level correction unit acquires a load utilization power signal from the output power and produces a power level correction signal to adjust the voltage modulation power level, which is decided by the PFC unit. Through adjusting the voltage modulation power level of the PFC unit, the PFC unit can produce voltage modulation power with different voltages according to the load variation, so as to reduce the internal loss of the power supply.