A power source module for an LED lamp includes a filament-simulating circuit electrically connected to a first bi-pin terminal and a second bi-pin terminal of the LED lamp, each of the first bi-pin terminal and the second bi-pin terminal configured to allow a current to flow from one pin to the other pin via the filament-simulating circuit during a pre-heat process executed by a ballast; a current limiting circuit electrically connected to the filament-simulating circuit configured to limit a current from the filament-simulating circuit; a first rectifier electrically connected to the current limiting circuit configured to rectify the current from the current limiting circuit; and a filter electrically connected between the first rectifier and at least one LED of the LED lamp configured to smooth the current from the first rectifier.