• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 32 subscribers
  • Views 650 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS2044B: Higher current than the limit (500mA) when USB device plugged

Nicolas Schmidt
Prodigy 70 points
Part Number: TPS2044B

I'm using the TUSB4041 with the TPS2044B for a USB hub. When I plug a USB device, the output current is around 730mA which is higher than the 500mA current limit of the TPS2044B. If I create a short-circuit at the output (by connecting the ground to the output) and then removing it, the output current falls to 500mA (475mA). If I disconnect the USB cable and replug it, the output current goes back to around 730mA. 

I was using the TPS2044B with the TUSB2077 and it was working great (always around 500mA). I didn't change the "TPS2044B to the USB output connector" circuit.

Any ideas? Thanks in advance.

  • 0
    Prodigy 70 points
    NOTE: If the device's battery is almost full, it's okay (around 500mA or less). If the device's battery is almost empty, it's worse. In every case, after the short-circuit, the current goes to around 500mA.
  • 0 in reply to Nicolas Schmidt
    TI__Mastermind 42795 points

    Hi Nicolas,

    Note that 500mA is the operating current for this switch. The current limit (Ios) is 1A typical.

    While the Ios current limit for this device is 1A, the current must hit the Ioc trip point first before the switch will regulate at Ios. If the load current slowly approach's Ioc, you can see DC currents between Ioc and Ios. Notice the high current spike in FIgure 25/26 before the device regulates at Ios (1A typical).