I have been using the TPS61150 for an LCD with 2 Strands of 4 White LED's each. The voltage ends up around 14V with the current in each strand set by Vset/Rset * 920 or 1.229 / 54.9K * 920 = 20 mA each. I use the On/Off pins in I/O mode and not PWM mode. This has been working fine but I am confused by the following two statements in the datasheet which appear to state that I am exceeding the parts design limits:
Page 5
I(IFB_MAX) - Current sink max output current (IFB current = 330mV) = Minimum of 34 mA
and
Page 12
The maximum output current can also be limited by the current capability of the current sink circuitry. It is designed to provide maximum 35mA current regardless of the current capability of the boost converter.
and
Page 8
Graph Shows Io curves efficiency out above 50 mA
In my current design which has been working fine for many months, I am not sure if I am exceeding the Iout capacity or not (but could not find a limit on Iout in the Electrical Specifications Table.)
Thanks