SLVSF62B November 2020 – September 2021 TPS25858-Q1 , TPS25859-Q1
PRODUCTION DATA
The TPS2585x-Q1 has two USB ports. Because the secondary current limit, IOS_HI, is 1.6x of the primary current limit, IOS_BUS, if the two USB ports pull out large current at the same time, then the DC-DC regulator is overloaded, and DC-DC regulator output voltage can be crashed. To avoid these potential issues, the TPS2585x-Q1 adopts the interlocking scheme to manage the current limits of the two USB ports.
For interlocking, if one USB port current is beyond the primary current limit threshold, IOS_BUS, then another USB port current limit threshold is overridden to the primary current limit, IOS_BUS, immediately. With this control scheme, the TPS2585x-Q1 only allows one USB port to output a large current, which can be as high as 1.6x of the primary current limit, IOS_BUS, at the same time. Ensure the DC-DC regulator has enough energy to sustain its output voltage. That means in MFi OCP testing, the DC-DC regulator will support up to 8.4-A output current during the tIOS_HI_DEG deglitch time, which is 4.8 A for the USB type-C port which under testing, 3 A for another USB type-C port, and maximum 0.6-A total for VCONN and OUT.