7.3.5.2 Short-to-GND Detection

The TPS92613-Q1 device has LED short-to-GND detection. The LED short-to-GND detection monitors the output voltage when the output current is enabled. Once a short-to-GND LED failure is detected, the device turns off the output channel and retries automatically, regardless of the state of the PWM input. If the retry mechanism detects the removal of the LED short-to-GND fault, the device resumes to normal operation.

The TPS92613-Q1 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_falling)} longer than the deglitch time of t_{(SG_deg)}, the device asserts the short-to-GND fault and pulls low the FAULT pin. During the deglitching time period, if V_(OUT) rises above V_{(SG_th_rising)}, the timer is reset.

Once the TPS92613-Q1 has asserted a short-to-GND fault, the device turns off the output channel and retries automatically with a small current. During 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 to normal operation.