Power Electronics
Wide Input Voltage Automotive Buck Regulators

Wide Input Voltage Automotive Buck Regulators

Allegro MicroSystems introduced two new adjustable high-frequency DC-DC step-down switching regulators with an integrated high-side power MOSFET ideal for power supply requirements of the latest infotainment systems. Allegro's A8586 provides up to 3.5 A output current, while the A8587 has output current of up to 2.0 A. Both devices are automotive, AEC-Q100 qualified and incorporate current-mode control for fast transient response.

The wide input range of 3.8 to 36 V makes both devices suitable for a wide range of step-down applications, including those in an automotive input environment. Battery-driven "keep-alive" applications benefit from the low 30 μA operational quiescent current. Both devices are designed to robustly handle a load dump condition with 40 V maximum rating as well as idle-stop and cold crank conditions with 3 V UVLO rating.

These new regulators maintain high-efficiency across a wide range of loads in the PWM mode and incorporate pulse frequency modulation (PFM) as the load reduces. This in turn reduces switching and gate driver losses at light loads. Both the A8586 and A8587 incorporate frequency foldback to help prevent inductor current runaway during startup and provide enhanced dropout performance.

Extensive safety and robust protection features include, pulse-by-pulse current limit, hiccup mode short-circuit protection, open/short freewheeling diode protection, BOOT open/short voltage protection, VIN under-voltage lockout, and thermal shutdown. The A8587 also has a Negative Power-On-Reset (NPOR) function to indicate in-regulation and out-of-regulation status. 

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