Take The Edge Off High dV/dt Supplies

Focus:

High dV/dt rise times on the power supply can cause problems with downstream components. This is especially true in 24-V powered industrial and automotive systems with high-current output drivers. This design idea describes how to control the rise time while limiting the power loss through the control FET. Rather than using a p-channel MOSFET as the current-limiting element, this circuit employs an n-channel MOSFET, which offers lower on-resistance and therefore limits power dissipation better. This circuit is well suited for applications where supply current is 8 A or greater. The circuit is built around the MAX16127 controller, which features a power-good/FLAG output that gives it the ability to enable downstream devices when the controlled voltage is at 90% of the input voltage. This is an improvement over setting a fixed turn-on voltage or delay time, especially where input voltages can vary over a wide range.

What you’ll learn:

• How to control power supply rise times while minimizing losses for current levels of 8 A or greater

View the Source

Author & Publication:

Rob McCarthy, Maxim Integrated, San Jose, Calif, How2Power Today, May 15 2015

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