Hello,
I am currently developing a device that uses the L7983PU50R as a 5V power source, based on the L7983PU50R - Evaluation board schematic.
In the circuit, the 5V output is further used to power an LDO with a 3.3V output and a reference voltage source with 3.3V and 1.65V outputs.
The power source for the DCDC L7983PU50R is rectified by a diode bridge and smoothed with capacitors, thus the converter is powered by up to 42VDC.
For debugging purposes, the circuit includes a connector that allows for the connection of an external 5V to power the LDO and the reference voltage source.
My question is: Is it possible to apply a 5VDC to the output of the DCDC L7983PU50R (LX and VOUT pins) when there is no voltage at the VIN input? This is needed for debugging purposes. If this is not advisable due to potential overvoltage at the LX input, would it be valid to connect a reverse diode with a low voltage drop between VOUT and VIN? In this case, would the device attempt to start? I would use a small diode with a low current rating.
Alternatively, of course, I could place a pass-through diode at the output of the entire circuit between the output capacitor on the VOUT line and the system's 5V line. However, this would require the installation of a powerful diode, and some energy would be dissipated on it, along with a voltage drop, which is undesirable.
Could you advise on a possible method to supply 5V without turning on the voltage at VIN?
Thank you!
