APEC: Rohm claims 20ns on-time for automotive dc-dc

Rohm is claiming industry’s shortest minimum on-time for a synchronous buck converter aimed at 48V vehicles.

Rohm BD51180TL on-time

It’s aim is to allow 48V to 3V (or 5v) conversion at over 2MHz to avoid interference with AM radio bands.

“To meet these market needs for high input, low output, and high switching frequency it is necessary to shorten the switching ON time,” said Rohm. “Proprietary technology for controlling pulses in a very short time allowed Rohm to reduce the minimum on-time to 20ns.”

Rohm BD51180TL circuitThe chip, the BD51180TL, operates in current mode for easy phase compensation.

The integrated mosfet works up to 65V. Minimum input voltage is 12V.

Features include multiple protection circuits (see below) and AEC-Q100 qualification for automotive use.


  • Over-current
  • Input under-voltage lockout
  • Input over-voltage
  • Output over-voltage
  • Thermal Shutdown
  • Short-circuit

According to the company:

Proprietary technology for controlling pulses in a very short time allowed ROHM to reduce the minimum ON time to an unprecedented 20ns – 6x shorter than conventional solutions – enabling stable step-down operation from 48V to 3.3V at a constant switching frequency of 2MHz. In addition, current mode control provides easy phase compensation required for constant voltage output with fewer external parts, contributing to greater end-product miniaturization while reducing customer design load.

The firm will be showing the chip at APEC 2016 in Long Beach this week.

See also: 48V dc-dc converter protected to 76V for industry

See also: All SiC switching fits 10kW converter into five litre box

See also: Rohm buys Renesas fab for IGBTs and MEMS
Read more Rohm new stories on Electronics Weekly »


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