Apple Inc.
Method and apparatus for reducing capacitor-induced noise

Abstract:

A method and apparatus for reducing capacitor noise in electronic systems is disclosed. A system includes at least one functional circuit block coupled to receive a variable supply voltage. The value of the supply voltage is controlled by a power management circuit. Changing a performance state of the functional circuit block includes increasing the supply voltage for higher performance, and reducing the supply voltage for reduced performance demands. The power management circuit, in changing to a higher performance state, increases the supply voltage at a first rate. A rate control circuit causes the power management circuit to reduce the supply voltage, when changing to a lower performance state, at a second rate that is less than the first rate.