SBVS343 March 2019 TPS7A78
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The device has an internal current limit circuit that protects the LDO output during transient high-load current faults or short circuit events. The current limit circuit has a brick-wall scheme. In a high load current fault, as the output voltage drops below its targeted value till it reaches GND, the brick-wall scheme limits the output current to the current limit (ICL) specified in the Typical Characteristics section.
The output voltage is not regulated when the device is in current limit and the device begins to heat up because of the increase in power dissipation. While the device is in current limit, the pass transistor dissipates power equals to VDO × ICL, where VDO is increased to a worse case of VLDO_IN. The heat generated within the device while operating at the current limit in conjunction with the ambient temperature might trigger the device thermal shutdown and turn off the output voltage of the device. After the device cools down, the internal thermal shutdown circuit turns the output voltage back on. If the output current fault condition continues, the device cycles by continually soft-starting into current limit and then thermal shutdown.