New Low Power Microcontroller Equipped with High Efficiency Class D Speaker Amplifier
and Audio Playback Function

LAPIS Semiconductor, a ROHM Group Company, has recently announced the development of a low power microcontroller that integrates an 8bit low power MCU core, speech synthesis circuit, high efficiency Class D speaker amp, non-volatile memory, and oscillator circuit on a single chip, making audio playback possible by simply connecting to a speaker.
The ML610Q304 also provides hardware-based audio playback operation that minimizes the load placed on the MCU for system control processing, and the newly designed high-efficiency Class D amp reduces current consumption during audio playback by approx. 40% while maintaining volume and is easier to incorporate into battery-driven devices.

In recent years a growing number of electronic products are adding voice playback functionality, particularly battery-driven devices that require increased miniaturization and lower power consumption for longer operating life.
In addition, improvements in sensor technology along with greater awareness for safety and security have resulted in the increased adoption of alarm equipment that demand redundant safety measures such as advanced detection of abnormal audio playback in order to ensure reliable performance during emergencies and other unforeseen events.

To meet the growing need for lower power consumption in compact portable devices, LAPIS Semiconductor will continue to expand its low power microcontroller lineup and contribute to society through energy-saving products, solutions, and initiatives.

Hardware-based audio playback function simplifies design

• Hardware-based voice playback function simplifies design
  • Voice playback operation is performed using hardware, which significantly lightens the load on the MCU for system control processing and simplifies playback considerably.
• 40% less current consumption during voice playback (vs. our conventional products)
  • A class-leading low power consumption 8bit microcontroller is integrated along with a newly developed Class D speaker amp that provides digital output, resulting in higher power efficiency and 40% less current consumption during voice output compared with conventional analog Class AB speaker amps – while maintaining volume levels.
    (*based on LAPIS Semiconductor evaluation criteria)
  
  
• Monolithic design with integrated microcontroller and audio playback function reduces the number of parts required and contributes to device miniaturization
  • All functions required for audio playback are incorporated into a single chip, including a low-power MCU, speech synthesis circuit, high efficiency Class D speaker amp, non-volatile memory, and high accuracy oscillator circuit.
    Offered in a compact (5mm × 5mm) 28pin package (WQFN) that contributes to end-product miniaturization.


Miniaturization enabled with equipped peripherals



• Multiple fail-safe functions provide superior reliability
  • Speaker terminal disconnection detection
    • Detects no-playback condition due to disconnection between the microcontroller and speakers by monitoring for changes in resistance value between the speaker terminals and can alert users
      beforehand by lighting up LEDs.
  • Speaker terminal short-circuit detection
    • Detects no-playback condition due to short-circuit by monitoring the voltage level of
      the speaker terminals and shuts down operation in order to prevent possible damage.
  • Class D speaker amp overcurrent prevention
    • Ensures that the sound generator circuit (PWM circuit) does not stay fixed at the H level for over
      a specified amount of time in order to prevent excessive heat generation due to overcurrent.
Multiple fail-safe functions provide superior reliability