LED driver with inherent current limiting and soft startup capability

[0023]Referring generally to FIGS. 1-3, various exemplary embodiments of the invention may now be described in detail. Where the various figures may describe embodiments sharing various common elements and features with other embodiments, similar elements and features are given the same reference numerals and redundant description thereof may be omitted below.

[0024]As represented in FIG. 1, an exemplary LED driver 10 includes an input end which may be connected to an input AC voltage source V_ac_IN. A voltage sensor 11 is coupled across the input terminals and may be formed by a voltage divider including resistors R1 and R2. In the example shown, a node between the resistors R1, R2, is coupled to feed back the sensed voltage (V_sense) to a controllable switch module 12. A current sensing resistor R5 is coupled to an output end of the switch module 12, with an output from the resistor being coupled back to the switch module 12 for current sensing feedback (I_sense). A current limiting c