ZHCSJM3B April 2019 – January 2020 TPS92613-Q1
PRODUCTION DATA.
The TPS92613-Q1 device has LED open-circuit detection. The LED open-circuit detection monitors the output voltage when the current output is enabled. The LED open-circuit detection is only enabled when DIAGEN is HIGH. A short-to-battery fault is also detected and recognized as an LED open-circuit fault.
The TPS92613-Q1 monitors dropout-voltage differences between the IN and OUT pins when PWM is HIGH. The voltage difference V(IN) – V(OUT) is compared with the internal reference voltage V(OPEN_th_falling) to detect an LED open-circuit incident. If V(IN) – V(OUT) falls below the V(OPEN_th_falling) voltage longer than the deglitch time of t(OPEN_deg), the device asserts an open-circuit fault. Once an LED open-circuit failure is detected, the internal constant-current sink pulls down the FAULT pin voltage. During the deglitch time period, if V(IN) – V(OUT) rises above V(OPEN_th_rising), the deglitch timer is reset.
The TPS92613-Q1 keeps the current output enabled to retry after LED open-circuit fault is detected if the PWM input is HIGH; the device sources a small current I(retry) from IN to OUT when PWM input is LOW. In either scenario, once the fault condition is removed, the device resumes normal operation and releases the FAULT pin.