ZHCSL08C October 2019 – August 2021 TPS8804
PRODUCTION DATA
Enough voltage must be provided to the LED such that the DINA voltage is at least the dropout voltage (VDINA,DROP) above the CSA voltage while the LED driver is enabled. Ensure the DINA voltage does not exceed 11.5 V. Because of the high LED drive currents, a large capacitor connected to the LED anode is required to provide pulsed power to the LED. Any of the internal regulators ( PLDO, LEDLDO) or external supply ( VDC) meeting the voltage requirements can be used to charge the LED capacitor. Connect the LED anode to LEDLDO when VCC > 11.5 V.
The LED LDO clamps the VSLC voltage and blocks reverse current with an integrated diode. It is current limited to prevent inrush current caused by charging the large capacitor. The regulation voltage is adjustable in the LEDLDO register. The LED LDO may be operated with VSLC below the regulation voltage. In this case, the LEDLDO voltage stabilizes to VSLC minus a diode voltage drop.
The LED driver current and rise time can vary by a few millivolts and microseconds across the LED anode supply and VCC voltages. It is recommended to use a consistent LED anode voltage whenever the LED driver is enabled.
Connect a capacitor with a value between 1 μF and 100 μF to the LEDLDO.