Abstract

Many current designs for smoke alarm sounders are implemented with discrete circuits and can require multiple sounding elements to produce different tones depending on the application, leading to increased power and design cost. In this application note, a three-chip design is presented to obtain a cost and power optimized smoke alarm sounder sub system that provides dual frequency output as well as audio playback using the DRV8220 low voltage H-bridge motor driver with low power sleep mode and the MSPM0G350x Mixed-Signal Microcontroller with Arm® 32-bit Cortex®-M0+ CPU. The presented design satisfies SPL requirements for smoke alarms and provides a wide output frequency range with a single piezo element with an approximately flat response over the range.