Active rectifier controller endures cold-crank conditions

November 20, 2017 // By Christoph Hammerschmidt
With the “Power by Linear “LT8672, Analog Devices is introducing an active rectifier controller for an input voltage range from 3 to 42V. With this feature, the company is addressing the needs of automotive applications which must regulate through cold-crank and stop-start scenarios with minimum input voltages as low as 3.0V and load dump transients up to 40V.

The LT8672 drives an external N-channel MOSFET, offering a voltage drop of just 20mV. This translates into a reduction of power dissipation by 90% compared to a Schottky diode and enables designers to eliminate a heat sink. The ultrafast transient response enables it to meet stringent automotive applications requiring AC input ripple rectification up to 100kHz. Additionally, its 20µA quiescent current while operating and 3.5µA in shutdown are ideal for always-on systems. The combination of the MSOP-10 package and external MOSFET ensures a compact solution footprint.

The LT8672 offers the combination of 3V minimum input capability and a 20mV drop, enabling it to ease the minimum input voltage requirement during cold-crank and stop-start, providing simpler and more efficient circuits. If the input power source fails or is shorted, a very fast turn-off minimizes reverse current transients. Also, a power good pin signals when the external MOSFET is ready to take load current.

The LT8672EMS comes in an MSOP-10 package. An industrial temperature version, the LT8672IMS, is tested and guaranteed to operate from a –40°C to 125°C operating junction temperature. The LT8672HMS version is tested and guaranteed to operate from a –40°C to 150°C operating junction temperature.

 

More information: www.linear.com/product/LT8672.


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