The maximum output current of the buck-boost is a function of input voltage (VIN) and output voltage (VLED). The relationship between VIN, VLED, and MAX ILED is shown in Figure 3. Note that VLED is the output of the buck-boost regulator, which includes the voltage drop across the sense resistor RLIM (100 mΩ typical), internal strobe control switch
(75 mΩ max), and the forward voltage of the LED.
2.3 V < VLED< 4.8 V
Figure 3. Maximum LED Output Current as a Function of
Input Voltage (VIN) and Buck-Boost Output Voltage (VLED)