DLPS202A October 2020 – August 2024 TPS99000S-Q1
PRODUCTION DATA
The TPS99000S-Q1 includes a dedicated ADC channel for LED current measurement. The blanking current management process in system software described in the Section 6.3.1.3 section relies on this measurement to coordinate the blanking current to the photo feedback current. The software measures the actual LED current in photo feedback (per color) and measures the blanking current. The blanking current setting is fine-trimmed during system operation to a level ideal for optimizing the initial current of each light pulse. As such, it is critical to system performance that this LED current measurement is as noise-free as practical. Using a Kelvin connection to the low-side sense resistor, and an RC filter is recommended to filter switching ripple, as illustrated in Figure 7-3. The Kelvin resistors should be < 100Ω each and should have a tolerance of less than 0.5% matched resistors.