This is a very simple 400V DC power supply circuit diagram, or, it may called as 230VAC to 400VDC converter. The working principle of this circuit diagram is very simple. You already knew the working principle of a bridge rectifier. This circuit is same as bridge rectifier and the working principle is also same. The fuse is used to protect the circuit, if the current is greater than 1 A.
Components List:
F1 = 1 A
B1 = IN4007
C1 = 470uF/450V
V1 = 230 V AC
How to add current limiting upto 10 micro ampere for such high voltage