An LED driver is provided with input surge absorbing capacity. A surge protection circuit branch is coupled across output lines from a DC power source, in parallel with and between a filtering capacitor and a non-isolated buck-boost PFC circuit. A variable impedance device such as a spark gap is coupled to a first power line and having a breakdown voltage to operate as an open circuit during normal operating conditions with respect to a peak input voltage across the capacitor. Responsive to a surge condition with respect to excess energy across the capacitor, the spark gap operates as a closed circuit, and a second capacitor coupled between the spark gap and the second line absorbs the excess energy. Responsive to a return to normal operating conditions, the spark gap reverts to an open state and the accumulated surge energy is discharged from the second capacitor to circuit ground.