High efficiency power IC suits car audio applications

28th January 2016
Nat Bowers

ROHM has announced a system power supply IC for the car audio market that, according to the company, features the lowest power consumption in the industry. The BD49101AEFS-M leverages ROHM’s expertise in car audio power system design to achieve an optimised system based on a high-efficiency DC/DC converter, reducing power consumption by 65%, from 13.3W with ROHM’s conventional products to an industry-leading 4.66W.

Suppressing heat generation makes it possible to adopt a surface mount package without requiring an external heat sink, simplifying thermal designs considerably while contributing to greater space savings. Integrating all system power supplies required for car audio systems on a single chip, including for USB with a cable impedance function, contributes to a lighter design load.

In recent years, along with the continued computerisation has come a greater need for reducing power consumption and improving fuel consumption in vehicles. However, at the same time, the growing demand for power consumption to meet the expanding functionality of car infotainment systems (i.e. USB and Bluetooth) is becoming of increased concern. And conventional car audio system power supply ICs, although generally easy to design, are often centred around a linear regulator which suffers from poor efficiency, reducing the operating efficiency of the entire system. In response, ROHM’s DC/DC converter-based system power supply IC provides much greater efficiency, enabling support for the latest high-performance car audio systems.

The BD49101AEFS-M integrates a low-current linear regulator dedicated for continuously powering the MCU. During standby operation the IC switches from the DC/DC converter to the linear regulator, reducing quiescent current that flows when the engine is idle - typically to 100μA.

The optimised DC/DC converter-based configuration suppresses heat generation and makes it possible to offer the BD49101AEFS-M in a compact surface-mount package with small backside heatsink. This eliminates the need for thermal counter measures and results in 14 times less volume compared with conventional products.

When charging USB devices it is necessary to compensate for the drop in voltage caused by the cable wiring resistance. In response, ROHM includes a built-in compensation function that maintains the cable end voltage, minimising charging time and ensuring compliance with USB standards. An output terminal is also included for notifying the MCU of overcurrent conditions.

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