There is a trick to using lower voltage electrolytics after a bridge rectifier that is illustrated in the PT4207 LED driver IC data sheet, schematic below, which ...
- uses two electrolytics in series to reduce their voltage requirements
- automatically balances their voltages without extra components
- improves the input power factor in several ways
As the AC input rises to the peak as the capacitors charge, D3 puts C1 and C2 in series, which halves the capacitance seen by the mains input, reducing the large current spike at the crest of the input voltage that you would normally get with a capacitor filter, improving the power factor and harmonics.
After the crest as the voltage falls, D3 reverse biasses. The load continues to be supplied by the rectified mains input voltage. Normally a capacitor filter would supply the load immediately after the crest for the rest of the half cycle. Here while the input voltage is high, the load still draws input current, improving the power factor, and the capacitors don't supply the load, reducing their required value.
Once the mains voltage has dropped to below half of the crest voltage, D2 and D4 turn on, putting the capacitors in parallel to supply the load, doubling the capacitance.
As the capacitors are put in parallel, their voltages are equalised.
The SMPS load has to have sufficient voltage input range capability to handle the more than 2:1 swing in input voltage.
It's of course possible to extend this scheme to three capacitors in series, as long as the SMPS load can handle the more than 3:1 swing input voltage.