Reaching the power circuit of this bulb required destroying the base, nothing you can't do with a screwdriver and a wire cutter. A screwdriver separated the bulb’s plastic 'glass' from the heat sink.
With the glass removed, you can see 14 LEDs. Note how 10 of them are vertical mounted; that's how the bulb's emitted light becomes 'omnidirectional.'
With the LED board removed, the PCB was visible but not accessible. Using a wire cutter, I nibbled away the plastic base, which revealed the power-supply board. Note the 250 V aluminum electrolytic capacitor across the output to the LEDs.
I measured the voltage at the output with a DMM. The bulb's base was still intact at this point so I inserted it into a lamp fixture. The output was a surprising 234 VDC unloaded. There's no transformer on the board, hence no isolation of AC mains.
Now, let's take a tour of the components. Circuit protection starts with a 2 A, 250 V fuse in series with the AC line hot and neutral lines. The mustard-colored component on the left is TVR1, a 7N721K 270 V varistor.
By bending the components, their markings became visible. C1 is a 22 µF capacitor. The black canister at the bottom of the photo is an unmarked inductor designated L1.
Capacitors CX1 and CX2 are 0.047 µF.
Q1 is a 4N60 N-channel MOSFET.
While inductor L1 has no markings, inductor L2 is marked 821, indicating a value of 820 µH.
The underside of the board contains three active components. BD1 is a full-wave rectifier marked ABS10 from Taiwan Semiconductor (Maximum voltage is 70 VRMS). Component D1 is an RB751V low-forward-voltage diode used to drive the LEDs and U1 is an AP1910 universal high brightness LED driver controller. Also present are an RB751 low-voltage drop diode, and an AP1910 LED driver controller.