The appeal and use cases of the space-saving, high-sound-pressure, load-diagnostic LOUDSPEAKERS driver "NA1150" | NEXTY Electronics, an electronic components and semiconductor trading company

Nisshinbo Micro Devices' LOUDSPEAKERS driver (LOUDSPEAKERS amplifier) IC "NA1150" is a PWM signal input SWITCHES driver with a built-in load diagnostic function using a CMOS process. It inputs a PWM signal (pulse width modulation) from a microcontroller and drives LOUDSPEAKERS as a Class D LOUDSPEAKERS amplifier. In addition, the load diagnostic function can detect LOUDSPEAKERS disconnections and short circuits, making it ideal for various applications that emit audio information.
This article provides a detailed overview and features of the "NA1150," which achieves space-saving, high sound pressure, and high reliability, as well as an example of its use in an automotive ECU, explaining the appeal and benefits of the product.

What is NA1150?

The NA1150 is LOUDSPEAKERS driver with PWM input and PWM output audio amplifier functionality. It features a dead-time control circuit, a Class-D amplifier output stage (H-bridge) with overcurrent detection, overheat detection, and low-power standby control. Furthermore, a load diagnostic function that can detect open/short circuits and short circuits to power and ground in LOUDSPEAKERS harness is integrated into a compact package.
It can output 1.5W (THD+N=10%, at 5V POWER SUPPLIES supply) to an 8Ω LOUDSPEAKERS, and is also compatible with LOUDSPEAKERS up to 4Ω. (*THD+N: Total Harmonic Distortion + Noise)

In the development of ECUs equipped with voice announcement functions, there is a growing need for simple one-chip devices that can output voice from the microcontroller with as few peripheral components as possible and that can also detect abnormalities such as broken or shorted LOUDSPEAKERS harnesses.
To address these issues, Nisshinbo Micro Devices offers a solution that achieves high-quality audio playback with a minimal number of components by equipping a microcontroller with the PWM audio signal middleware "CRI D-Amp Driver" and connecting the PWM signal output from that to the NA1150. Furthermore, the NA1150's load diagnostic function can detect LOUDSPEAKERS disconnections and short circuits, and notify the microcontroller if an abnormality occurs.
* "CRI D-Amp Driver" is middleware for embedded microcontrollers provided by CRI Middleware that uses a microcontroller + H-bridge circuit configuration to output sound without using an audio IC (audio IC-less).

Main features of NA1150

The NA1150 integrates key functions into a small package, significantly reducing the number of peripheral components and enabling a simple and reliable system configuration.
The NA1150's major feature is that it outputs a PWM-modulated audio signal from a microcontroller port, allowing you to easily drive LOUDSPEAKERS simply by connecting the NA1150. It also has a load diagnostic function that can detect abnormalities such as LOUDSPEAKERS disconnections and short circuits and notify the microcontroller. It also has a built-in dead time control circuit, which is difficult to design with DISCRETE circuits, and effectively suppresses through current. It also has overcurrent detection and thermal shutdown functions, enhancing system safety.
When not outputting audio, the device goes into standby mode, consuming an extremely low current of less than 1μA. With few peripheral components, it contributes to space-saving designs, making it an ideal device for use in combination with CRI middleware.

Examples of using NA1150 in automotive ECUs

Automotive meter ECUs are equipped with multiple functions to ensure safe driving. Typical examples include warnings to prevent drowsiness and voice notifications when control is switched from the system to the driver during autonomous driving. These functions require a high level of functional safety. Voice announcements and warning sounds are becoming increasingly important in automotive ECU development, as delayed notifications or malfunctions can lead to serious accidents. Nisshinbo Micro Devices' LOUDSPEAKERS driver, the "CRI D-Amp Driver + NA1150," can drive LOUDSPEAKERS at a louder volume than conventional audio playback ICs and Class-D amplifier ICs. Furthermore, its load diagnostic function is making it increasingly popular for use in automotive ECUs.
Below we compare the differences between a conventional LOUDSPEAKERS system and a configuration using the NA1150.

Comparing a conventional LOUDSPEAKERS system with a configuration using the NA1150

	Conventional configuration (image)	NA1150 (image)
circuit
Mounting area	×	〇
Number of parts	×	◎
Functional safety*	×	〇
Design man-hours	×	〇

*Not ISO26262 compliant

This is just one example, but by using the NA1150, the mounting area of LOUDSPEAKERS driver, including wiring, was reduced to about 1/4 or less, contributing to the miniaturization of the board. Furthermore, we have received feedback that the reduction in the number of components has reduced costs, increased freedom in board design, made it easier to secure GND lines in the board layout, and is also effective in preventing noise. In addition, integrating safety functions into a single chip has contributed to reducing design man-hours and improving functional safety, making it possible to build a more reliable system.

Summary

The NA1150 achieves the high sound quality and reliability required for automotive ECU voice notification and warning functions in a small footprint. It supports PWM audio signals and integrates load diagnosis and safety functions on a single chip, significantly reducing design time and the number of components. The NA1150 is the ideal choice for those who require a more high-performance, efficient audio system in ECU development.
If you would like to experience the sound quality of a system equipped with the audio playback middleware "CRI D-Amp Driver," we can provide a demo unit. Please feel free Inquiry for product details or to inquire about a demo.

Related Information.

About Nisshinbo Micro Devices Inc.

https://www.nexty-ele.com/product/nisshinbo/

Disclaimer

The adoption cases and comparison table in this article are examples only and may not apply to all situations. Please use them as reference information.