Simple schematic above is a circuit of power supply that can operate at high current with very small ripple voltage. How it works similiar to the high power class AB amplifiers, with the same quality. T1,T2 ,and R2 can also be called a power NPN-Darlington transistor. ZD1 and R1 as a supplier of voltage on the transistor base and filtered by C2. ZD1 can be slected with formulated (Figure 1.0) . For the C2 can be selected in accordance with the degree of smoothness as its value is effectively combined with the multiplied gain of the Transistor T1 and T2, assumsing minimum hfe for T1 and T2 , C=100x15(T1) x 25 (T2) = 37,000uF, adjust the voltage C2 with the input voltage, but must be higher than input voltage.
Part List :R1 = 2K2R2 = 56RR3 = 10KC1 = 1500uFD1-D4 = Didode 6AT1 = 2N3054T2 = 2N3055