The only difference between the TPS40210 and the TPS40211 is the reference voltage that the error amplifier uses to regulate the output voltage. The TPS40211 uses a 260-mV reference and is intended for applications where the output is actually a current instead of a regulated voltage. A typical example of an application of this type is an LED driver. An example schematic is shown in Figure 29.
The current in the LED string is set by the choice of the resistor RISNS as shown in Equation 31.