DLPS039F December 2015 – April 2019 TPS99000-Q1
In continuous mode the CMODE signal from the TPS99000-Q1 is set low so the FET controlling the big (~1 µF) capacitor is turned off leaving only a small (~ 0.1 µF) high frequency decoupling capacitance in parallel with the LEDs and shunt FET paths (refer to Figure 7). Using a lower capacitance in continuous mode allows the voltage across the capacitor and LED to charge up faster so that the current in the inductor does not overshoot the desired current level before the LED light emission threshold is reached. This prevents the light pulse from overshooting at the beginning of bit slices. (Discontinuous pulse mode requires a larger, ~1 µF capacitance as will be discussed later in this document. CMODE pin is set high in discontinuous mode to enable higher capacitance in parallel with LEDs).