Other Parts Discussed in Thread: TPS2419
Not sure if it is a design or assembly issue!
The device will properly shutdown when a short is connected across the output, but multiple boards are not recovering from shutdown. The device will recover however if the output power is cycled.
Design criteria for TPS2419:
- Vcc=EN=28VDC,
- PROG=VREF=4V,
- Rsense=0.062 Ohm,
- Ct=1nF,
- Cout =11uF,
- Cbypass=0.1uF,
- Cin=10uF.
- Load=140Ohm resistor (0.2A),
- Q=STL70N10F with 10 Ohm in series gate resistor.
- Circuit tested @ +25C.
The controller implemented at the output of a 28VDC DC-DC SEPIC converter, current limit to 0.3A.
The first 50+ circuits worked flawlessly, The latest batch of 10 units has 60% failure rate.
Increased Ct to 10nF+1nF=11nF in all failed units, at least two units still do not recover after short to ground were removed.
Question:
1) Does Ct has a minimum capacitance value?
2) Is there a minimum restart time or fault timer for this controller?
Thank you,
Ryan