Efficient car audio system PSU IC makes 2/3 power saving

January 29, 2016 // By Graham Prophet
Addressing the car audio market for multifunction power supplies, Rohm has developed a system power supply IC for which it claims lowest-available power consumption. BD49101AEFS-M is based on a high-efficiency DC/DC converter, achieving power consumption reduction of 65%, from 13.3W with Rohm’s conventional products to 4.66W.

Less 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 DC/DC converters, because efficiency drops when the load current deceases (i.e. during standby), 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 to 100 µA (typ.).

The device somes in a compact surface-mount package with small backside heatsink. This eliminates the need for thermal counter measures and results in 14x 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. 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 included for notifying the MCU of overcurrent conditions.

Rohm Semiconductor;  www.rohm.com/web/global/products/-/product/BD49101AEFS-M