This paper proposes a quantitative design method for a linear AC LED driver with a multi-level structure and a variable current regulator. The currently proposed circuit with a variable current regulator was found to drastically reduce the number of required circuit components by realizing a sinusoidal input current with only a single row of LEDs. However, it is necessary to adjust the parameters of the circuit components through simulations to properly design the circuit and realize its stable operation. In this paper, the operation of the currently proposed circuit is first described. Second, the losses of the circuit are calculated. The quantitative design of the circuit parameters is then suggested. Third, an experimental efficiency of 92.3% was confirmed, and the calculated and simulated efficiencies were 93.1% and 93.4% under the same design conditions. The experimental efficiency of 92.3% is 5.6% higher than that of the previous design. Next, a thermally designed circuit board was designed using a simulation for practical installation. Finally, conduction noise was experimentally measured.