SLVSFS4A December 2021 – June 2022 TPS92623-Q1
The TPS92623-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 faulty 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 TPS92623-Q1 monitors both V(OUTx) voltage and V(RESx) voltage of each channel and compares it with the internal reference voltage to detect a short-to-GND failure. If V(OUTx) or V(RESx) voltage 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(OUTx) and V(RESx) rises above V(SG_th_rising), the timer is reset.
Once the TPS92623-Q1 has asserted a short-to-GND fault, the device turns off the faulty output channel and retries automatically with a small current. During retrying, the device sources a small current I(Retry) from SUPPLY to OUT and RES to pull up the LED loads continuously. After auto-retry detects output voltage rising above V(SG_th_rising), it clears the short-to-GND fault and resumes to normal operation. Figure 7-3 illustrates the timing for LED short-circuit detection, protection, retry and recovery.