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Original question:

TPS22910A Full time reverse current protection at Vin=0V condition

TPS22910A: INPUT C V OUTPUT C

Sara Caron1
Prodigy 115 points
Part Number: TPS22910A
Other Parts Discussed in Thread: TPS22916

In my circuit the Vout (1.2V for example) runs a plane to a device with several 1uF and 2.2uF capacitors on each pin (6 to be exact). I want the slowest rise time (> 100 usec) and  the output continuous  current is 120mA (est).The datasheet recommends a ratio of 10 to 1 (input capacitance to output capacitance. I estimate about 20 uF of capacitance required to supply and filter the device. I currently have a 10 uF capacitor on the output of my regulator a TPS62841. How do I determine what to put on the output of the load switch or is there a better device?

Thanks

  • 0
    TI__Mastermind 34935 points

    While we recommend a 10:1 input to output capacitor ratio on the device, the reality is that this is based on the power supply’s ability to handle the turn on transients of the device. The TPS22910A has a pretty controlled slew rate, and adding the CT capacitance slows that down even further. As long as the power supply can handle the turn on of the device, then the 10:1 ratio is not needed (even 1:1 is okay). If the output capacitance is larger than the input capacitance, then if the input drops very suddenly, the output voltage will drop slower than the input and reverse current may flow through the device.

    One thing to note in your example scenario is that your example voltage of 1.2V is below the device minimum of 1.4V. 

  • 0 in reply to Timothy Logan
    Prodigy 115 points

    You are correct - he min voltage input is 1.4V I will probably switch - no pun intended - to the TPS22916 or equivalent.

    Thanks