Patent ID: 7505600

Claim:
A circuit for generating sound in the audible frequency range, the circuit including input voltage terminals for powering the circuit and comprising: (a) an audio transducer, for transforming electrical power in the audio frequency range to audible power; (b) a driving circuit connected to an input voltage terminal and having an output coupled to the transducer for supplying electrical drive power to the transducer in the audible frequency range, the driving circuit including at least one energy storing inductor and one or more electronic switches adapted for energizing the energy-storing inductor and for transferring energy from the inductor to the audio transducer; and (c) a controller having one or more controller outputs coupled to the one or more electronic switches for controlling said energy storage and said energy transferring, the controller having a finite state machine program which outputs a sequence of pulses to the one or more switches of the driving circuit at a rate and duty cycle to generate a desired audio tone and amplitude in said transducer.