Other Parts Discussed in Thread: TPS5410
Q1) What is the approximate open load ENA voltage when VIN is 13.5V?
Q2) Do I need a diode from ENA to VIN to protect ENA pin (from 100uF cap on the pin) if VIN drops suddenly?
Q3) Is slow slope (<1V/s) ENA voltage OK (I assume yes due to large hysteresis)
Q4) Can I charge cap (ENA pin) with a voltage plus series resistance? Limits for Vth, Rth? Is 4V at 1kohms OK?
The plan is to add a 100uF capacitor on ENA pin to ground. I'm also adding a 3 state current sink to ENA pin.
In normal run mode, ENA sink current is 0uA, VIN is 13.5V and TPS5410 will make 5V (when and if cap is charged). I like to add energy to ENA pin/CAP (to 4V,1kohms for a short time).
In ENA decay mode, ENA sink current is 15uA, VIN is 12.6V, TPS5410 5V output is still live and ENA voltage will drop (-10uA sum on 100uF cap) until TPS5410 shuts down
In off mode, ENA sink load is 13.3k to ground for low ENA voltage, VIN is 12.6V, 5V is shut down. My low power mode.
When VIN goes back to 13.5V (the fourth mode), I want to help build up the ENA pin capacitor voltage quicker than the typical 5uA TPS5410 will provide on it own. So 4V at 1k ohms is OK? Once the TPS5410 5V is live again, I'll shut off this quick cap charge source.
