JAJSCH0D August 2016 – January 2018 TPS25741 , TPS25741A
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
The gate-driver disable pin provides a method of overriding the internal control of GDNG and GDNS. A falling edge on GD disables the gate driver within tGDoff. If GD is held low after a sink is attached for 600 ms then a hard reset will be generated and the device sends a hard reset and goes through its startup process again.
The GD input can be controlled by a voltage or current source. An internal voltage clamp is provided to limit the input voltage in current source applications. The clamp can safely conduct up to 80 µA and will remain high impedance up to VGDC before clamping.
If the VPWR pin remains below its falling UVLO threshold (VPWR_TH) for more than 600 ms after a sink is attached then the devices consider it a fault and will not enable GDNG. If the VPWR pin is between the rising and falling UVLO threshold, the TPS25741/TPS25741A may enable GDNG and proceed with normal operations. However, after GDNG is enabled, if the VBUS pin does not rise above its UVLO within 190 ms the devices consider it a fast-shutdown fault and disables GDNG. Therefore, in order to ensure USB Type-C compliance and normal operation, the VPWR pin must be above its rising UVLO threshold (VPWR_TH) within 275 ms of when UFP is pulled low and the VBUS pin must be above VBUS_RTH within 190 ms of GDNG being enabled.