1. Downsizing

Clean up the circuits in your audio playback system!

First, the first point: miniaturizationWe will explain about:
Nisshinbo Micro Devices has announced that it has developed the "CRI D-Amp Driver" from CRI Middleware, an embedded software vendor. This combination achieves high quality audio playback.
We have developed the speaker driver IC "NA1150".

Conventional audio playback systems(See Figure 1)
In conventional discrete/audio ICs, the typical circuit configuration is as follows: PWM-modulated audio signals are converted to analog signals by a digital-to-analog converter (DAC), then passed through signal processing such as a low-pass filter (LPF) and electronic volume control (EVR), before being amplified by an audio amplifier and used to drive speakers.

In the case of an audio playback system using "NA1150" (See Figure 2)
On the other hand, when using Nisshinbo Device's "NA1150", the configuration is as follows: Simply connect it to a microcontroller equipped with audio playback middleware,"Microcontroller", "Audio playback sound middleware", "NA1150", and "Speaker" With such an extremely simple configuration that drastically reduces the number of parts, a high-quality audio playback system can be realized.
The number of parts is significantly reduced, Contributes to miniaturization (reduced mounting area and development man-hours) and cost reduction I will.

Figure 1 (OLD configuration) Figure 2 (NEW configuration)


*When combined with CRI Middleware Inc.'s (hereinafter referred to as "CRI") sound middleware "CRI D-Amp Driver®", it achieves power-saving, highly efficient and high-quality audio playback.

<Audio playback middleware "CRI D-Amp Driver®" and audio amplifier "NA1150">

As the processing speed of microcontrollers has increased in recent years, it is now possible to output PWM-modulated voices and sound effects from a microcontroller using software (sound middleware).
Compared to systems that use hardware (DAC or speech synthesis LSI), sound middleware offers the benefits of reduced mounting area, reduced development time, and fewer components, and so an increasing number of customers are adopting systems that use this sound middleware.

The "NA1150" is an audio amplifier that, by simply connecting it to a microcontroller equipped with this sound middleware, can achieve high-quality voice and sound effect playback while saving power with a simple configuration.
Using the "NA1150" makes EMI countermeasures easy, and by using the "NA1150" in a microcontroller, you can easily build an audio playback system.

Sound middleware for this system
​Click here for details on the "CRI D-Amp Driver®"

2. High quality sound

High quality sound is achieved by directly driving the speakers with a differential PWM signal from a microcontroller, etc.!

The second point is "high quality sound." We will explain about:
Let's break it down a bit and look at the data sheet.
The image below shows a basic application using "NA1150".
The input terminal of the "NA1150" is directly connected to the GPIO of the MCU, and the speaker is driven by the PWM signal output from the MCU.
The PWM signal is input directly from the microcontroller without being converted back to an analog signal (all data is transmitted digitally), Extremely little deterioration in sound quality, achieving high sound quality I will.
In addition, using the PWM signal directly, without the need for multiple devices, also leads to higher sound quality.

The operating principle is described below. NA1150 Datasheet / Excerpt from P10)

It also supports differential PWM input, making it resistant to noise, providing high sound quality and power savings.
To see just how high quality the sound can actually be reproduced, please check out the demo video of audio playback using the "NA1150" at the bottom of this article.

3. Safety and security

Equipped with a "load diagnosis function" for peace of mind and safety! Early detection of abnormalities and signs of overload

Finally, I would like to explain the third point, "Safety and Security."​
The NA1150 has a built-in load diagnostic function* required for systems where voice alerts are important.
(*Load diagnosis function: A function that monitors the system's operating status and performance to detect abnormalities or signs of overload at an early stage.)
The "NA1150" detects breaks or shorts in the speaker harness, as well as power or ground faults to its own power supply, and notifies the microcontroller.
The NA1150 audio amplifier has a built-in load diagnostic function, making system design more flexible and facilitating designs that take future expansion into account.
This provides customers who design systems with more stable, efficient and reliable system operations.

Comparison with current Class D amplifiers

3.0W Output Filterless Mono Class-D Amplifier "NJU8759A"

Input Preamplifier
PWM Modulator
Class D Output Driver
Under Voltage Lockout Protection (UVLO)
Overcurrent protection circuit
Thermal Shutdown Circuit

*Excerpt from NJU8759 datasheet​

PWM signal input D-class speaker amplifier/driver "NA1150"

Logic Circuit
Load diagnosis function
Standby function
Class D Output Driver
Under Voltage Lockout Protection (UVLO)
Overcurrent protection circuit
Thermal Shutdown Circuit

*Excerpt from NA1150 datasheet​

Main audio product lineup

You can purchase the NA1150 and other audio products at Macnica-Mouser.

Driver for Microcomputer Audio Playback System [Audio Amplifier] Series (Application products based on NA1150)

*Status is subject to change. Please check the Nisshinbo Micro Devices website for the latest status.