Other Parts Discussed in Thread: LM5161, LM5166
Hello,
When using a LM5006 to supply a 5V rail from a 15-70V source, I encountered an unexpected behavior concerning the shutdown/start-up sequence. If the LM5006 is started after a shutdown duration that is too low, the voltage output is not regulated at 5V as expected.
Here are a few pictures showing that, for a shutdown duration of 100ms, the LM5006 works as intended, but for a shutdown duration of 10ms, the output seems to be uncontrolled between 20V and 25V. Other durations have been tested: the LM5006 works properly for with any shutdown duration over 20ms.
The signal 1 (dark blue) is the shutdown signal controlling a MOS that pull the RT pin of the LM5006 down. The signal 2 (light blue) is the voltage output of the power supply.
The pictures are taken from a LM5006 operating with a 30V source and a load of 80mA. Here is the schematic of the system used:
As the shutdown pin is driven by a microcontroller, I could force the shutdown duration for at least 100ms. The problem is then: how can I be sure this behavior will not happen under other conditions? May I have your opinions about this unexpected behavior?
Best regards,
Fabien