Patent ID: 7924189

Claim:
An apparatus for converting an input analogue signal to a digital output, the apparatus comprising: a first analogue to digital converter having a first dynamic, range, the first analogue digital converter arranged to receive the input analogue signal, to respond to an active state by converting the input analogue signal into a digital signal by enabling power-consuming circuitry, and to reduce, in response to an inactive state, power consumption of the power-consuming circuitry by disabling the power-consuming circuitry; a second analogue to digital converter having a second dynamic range that is less than the first dynamic range and that is arranged to receive the input analogue signal, and to convert the input analogue signal into a digital signal; and an activation circuit for activating, in response to detecting that the input analogue signal has an amplitude exceeding a threshold level, the first of the analogue to digital converters transitioning the first analogue to digital converter from the inactive state to the active state.