An LED lamp including at least one LED is electrically connected to a utility input voltage. A driving apparatus located inside a lamp holder of the LED lamp includes an input rectifying/filtering unit to accept the utility input voltage; an isolated power inverter electrically connected to the input rectifying/filtering unit to generate an a buck A.C.; an output rectifying/filtering unit electrically connected to the isolated power inverter to generate an output D.C. voltage to drive the at least one LED. The components of the driving apparatus could be located inside the LED lamp, and the components can provide an isolation protection against the utility input voltage. The driving apparatus can more precisely control output D.C. voltage, current, and power as output D.C. voltage and current signals sent from the output rectifying/filtering unit are feedbacked to a photo coupler signal feedback unit.