Protect vehicle ECUs against reverse-battery connections

October 28, 2015 // By Graham Prophet
The DMP4015SPSQ 40V P-channel MOSFET introduced by Diodes Inc. is designed to protect automotive electronic control units (ECUs) against the risk of reverse-battery connection.

The DMP4015SPSQ MOSFET acts as an “ideal diode”; driving this device only requires a minimal number of passive components. By comparison, N-channel MOSFETs require a charge pump to provide the gate drive voltage, adding complexity, cost and component count. Eliminating the switching topology of a charge pump also avoids issues with EMI emissions.

The avalanche rugged DMP4015SPSQ is 100% unclamped-inductive switch (UIS) tested to ensure the MOSFET will withstand the worst-case ISO7637 energy pulse that would occur if the supply was disconnected while powering an inductive load. The low R DS(on) of the DMP4015SPSQ, less than 11 mΩ, ensures that power loss is minimised, resulting in lower temperature operation; this eases thermal design considerations and improves reliability. The parallel configuration of several MOSFETs can further reduce power losses, by a factor of n ².

The DMP4015SPSQ comes in a PowerDI5060 package priced at $0.38 (1000). Also available, for the same application, are the DMP4015SK3Q in TO252 (DPAK) package and DMP4015SSSQ in SO-8 package.