9.2.1.1 Design Requirements

With the wide range of battery voltages in modern automotive systems, it is a common requirement among car OEMs to turn LEDs off when the battery voltage is below the minimal voltage threshold, for example, 6 V.

When the battery voltage is between 6 V and 9 V, LEDs may not achieve full brightness due to low input voltage. Although a linear LED driver may drive in low-dropout mode, it is required not to treat the low-dropout mode as an open-circuit fault and to report a false error.

When battery voltage ranges between 9 V and 16 V, the LED driver works in normal mode with the one-fails–all-fail feature. If any LED strings fail with an open circuit or short circuit, the TPS92830-Q1 device pulls down the fault bus. All devices connected to the same fault bus turn off their outputs.

When the battery voltage is above 18 V, the TPS92830-Q1 device is able to detect the overvoltage and derate the output current to reduce the power dissipation of the MOSFETs and prevent thermal damage.