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TPS63002: en pin not turning off output

Prodigy 90 points

Replies: 6

Views: 89

Part Number: TPS63002

I am about to give up on this Product I've replaced the part several times watched my soldering heat and still cant get it to turn off using en pin. I take the pin to GND level and the output goes to 3.5v and wont turn off. Any Idea's

  • Hi Kevin,

    Just so I know the operating conditions, could you please go through this sequence and confirm the following:

    1. Vin = 4.5 V (3 x AA battery?). You have some load on the output (could you specify what type of the load and what is the load current?).
    2. Set EN to low.
    3. Turn on the input power supply while EN is low. VOUT should be 0 V.
    4. Set EN to high, and VOUT should quickly go to 5 V.
    5. Set EN low and the output should go to 0, with a slope depending on the load. There is no active discharge in the TPS63002, so if the load current is very low, the output will slowly go down. Also if there is something pulling up the output to another supply voltage, the output will stay at that voltage.

    A scope plot of VIN, VOUT and EN pins during startup and including EN pulse would also be very helpful.

    Best regards,
    Milos

    ti.com/buckboost

  • In reply to Milos:

    Yes 4.5v from 3 AA Batteries, Load current is @ 30ma (Pic microchip, and 6 4067 cmos switches) I will work on scope plots

  • In reply to Kevin Pingel:

    plot shows output not shutting off with en pulled low. output goes correctly to 5v when en goes high.

    ch1 and ch 2 markers ar at gnd level. both channels are 1v per division.

      

    plot below  yellow is output blue is input and en is held at gnd through 1k resister. Output stabilizes at @3.3v  with en at 0v.

    ch1 and ch 2 markers ar at gnd level. both channels are 1v per division.

  • In reply to Kevin Pingel:

    Yellow trace on both plots is the output voltage. 

  • In reply to Kevin Pingel:

    Hi Kevin,

    I am sorry for the delay.

    On both plots the output voltage does not look right. On the first plot, the output voltage is almost 6 V, and on the second one is around 4 V and oscillating, and should be 5 V.

    1. Can you check if the FB pin is properly connected to the output?
    2. Can you isolate the circuit from the rest of the board and then run it (without any load and tying EN to VIN)? 
    3. Do you have another board to try?
    4. Please check if R7 is 100 Ω or smaller. 

    Best regards,
    Milos



    ti.com/buckboost

  • In reply to Kevin Pingel:

    Hi Kevin,

    We haven’t heard back so we're assuming this resolves your issue. If not, just post a reply below, or create a new thread if the thread has locked due to time-out.

    Thanks and regards,
    Milos

    ti.com/buckboost