7.3.5.4 Short-to-GND Detection

The TPS92611-Q1 device has LED short-to-GND detection. Short-to-GND detection monitors the output voltage when the channel is in the ON state. Once a short-to-GND LED failure is detected, the device turns off the output channel and retries automatically, ignoring the PWM input. If the retry mechanism detects removal of the LED short-to-GND fault, the device resumes normal operation.

The device monitors the V_(OUT) voltage and compares it with the internal reference voltage to detect a short-to-GND failure. If V_(OUT) falls below V_{(SG_th_rising)} longer than the deglitch time of t_{(SG_deg)}, the device asserts the short-to-GND fault and pulls FAULT low. During the deglitching time period, if V_(OUT) rises above V_{(SG_th_falling)}, the timer is reset.

Once the device has detected a short-to-GND fault, the device turns off the output channel and retries automatically with a small current. When retrying, the device sources a small current I_(retry) from IN to OUT to pull up the LED loads continuously. Once auto-retry detects output voltage rising above V_{(SG_th_falling)}, it clears the short-to-GND fault and resumes normal operation.