Figure bellow shows the configuration using 4 diodes where the output voltage is two times the input voltage.
Formula 1
Voltage in the capacitors:
Vca = Vc2 = Vmax
Where:
Vc1 and Vc2 are the minimum working voltage dc (WVDC) of the capacitors in volts (V)
Vmax is the peak value of the applied input voltage in volts (V)
Note: minimum PIV of the diodes is 2 x Vmax.