Synaptics Incorporated
PULSE DENSITY MODULATION SYSTEMS AND METHODS

Abstract:

Systems and methods for programmable pulse density modulation (PDM) components enable backwards compatibility while maintaining reasonable tolerances. A system includes a programmable PDM device, a PDM master device and a bus communicably coupling the programmable PDM device to the PDM receiver. The PDM device may include an audio sensor, audio input circuitry, a delta-sigma converter and a PDM transmitter and receiver. The PDM transmitter and receiver may send out PDM data from the PDM device and receive programming data from the PDM Master device. The PDM device may further include register space controlled by the PDM master device, a buffer storing audio data for wakeup word systems that store audio data when the PDM receiver is powered down, a bus holder to hold the previous value on the bus if no device is driving it, and/or a clock multiplier to multiply the incoming clock by a factor.