Product launch of the BD49101AEFS-M system power supply IC for car audio

Car Audio System Power Supply IC BD49101AEFS-M



The BD49101AEFS system power supply IC incorporates the multiple power supplies required for car audio systems. A 2ch DCDC converter, 5ch linear regulator, and high side switch are built in, making it possible to power an MCU, CD, tuner, USB, lighting, audio, and more using just a single IC. The optimized design, based on the high efficiency DCDC converter, minimizes heat generation and makes it possible to adopt a surface mount package without requiring thermal countermeasures. In addition, low current consumption mode switching and power supply control functions are included, improving efficiency and reducing dark current while simplifying power supply design.



  • AEC-Q100 qualified
  • Includes 7 power supplies required for car audio applications: DC/DC x 2 (1 controller type) + Regulator x 5
  • Built-in high-side switch (SWq)
  • Standby mode regulator switching function (STB_REG) integrated into the MCU power supply (DCDC2)
  • USB power supply (REG4) cable impedance compensation function included
  • I2C I/F
  • Oscillation frequency set via external resistor
  • External synchronization function
  • Power supply control function (power ON/OFF sequencer)
  • Error flag function for USB power supply overcurrent detection and battery voltage monitoring
  • Multiple protection functions (overvoltage, overcurrent, thermal shutdown)

Block Diagram (Power Supply Circuit Example)

Block Diagram (Power Supply Circuit Example)

Features 1 : Significantly reduced power consumption

■During normal operation

Conventional high-efficiency DC/DC converters require a relatively large number of external parts, leading to increased costs and larger mounting area. In response, performing a comprehensive review of the entire system and optimizing the combination of DC/DC converters and linear regulators allowed ROHM to minimize the dual DC/DC converter system and increase efficiency while reducing costs, making it possible to significantly decrease power consumption during operation (i.e. CD mechanism, MCU) to industry-low levels.

Power Consumption Comparison
■During standby

Since DC/DC converters are prone to voltage drops when the load current is light (i.e during standby), dedicated linear regulators are built in for driving continuously operating MCUs.
Switching operation from DC/DC converters to linear regulators during standby makes it possible to minimize quiescent current when the engine is stopped.

Features 2 : USB cable impedance compensation

[ Compensation Effects ]

Effects of the USB Cable Impedance Compensation Function

A function for compensating against voltage drops caused by cable wiring resistance during USB charging is built in, meeting USB standard requirements by maintaining a constant terminal voltage and preventing an increase in charging time. An output pin for notifying the MCU during overcurrent detection is also included.

Voltage drop due to cable wiring resistance

Features 3 : Space-saving surface mount package

Volume reduced 14x

A thorough review of DC/DC converter design and power supply configuration makes it possible to minimize heat generation by simply mounting the high-heat dissipation surface mount HTSSOP-A44 package directly on a substrate without a heat sink. This reduces volume by 14x compared with conventional solutions and decreases assembly costs, simplifying design load.

Related Information

 In addition to system power supply ICs for car audio, ROHM will continue to implement product development that meets customer needs in order to expand its product lineups by leveraging industry-leading proprietary technologies.

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