Other Parts Discussed in Thread: TPS5450
The question is, what are the factors that would cause the SMPS not to regulate.
We have a SMPS based on the TPS54560 designed to regulate 26 to 46 VDC to 24 VDC. The system is generally supplied by a 35 VDC wall wart. Recently we have seen a random, but frequent occurrence of what appears to be the SMPS passing the 35 VDC thru with no regulation. We are suspecting the change in level on the 24 VDC bus due to the motors randomly running at 40% faster than normal. We are in the process of setting up systems to monitor the 24 VDC bus to confirm the suspected situation.
Notes:
The 24 VDC bus feeds a 2nd SMPS with a 5 VDC output and is the main driving power for a bank of 24 VDC motors. The 5 VDC SMPS feeds a 3rd 3.3 VDC and supplies charging current to up to 2 smart devices.
Current Draw on the 3.3 VDC: < 100 mA
Current Draw on 5.0 VDC: Generally < 500 mA, max is 3 A
Current Draw on 24 VDC: Generally <150 mA, worst case (motor running/5 VDC max'ed) 1 A
Schematic attached
Any insights are welcome
