A Ripple filter for the power supply of a modular Analog Computer in Eurorack format. The design goal is to be simple in part count and assembly while being cost effective and maintaining low ripple output.
The filter is designed for a +15V/-15V input power supply and a +12V/-12V output.
The filter is devided into two parts, for the positive and negative supply voltage. In a first step the voltage is filteres in a capacitance multiplier, supplied by a second order RC low-pass filter. The output is then put through a second stage a linear voltage regulator. In simulations in falstadts online circuit simulator and LTSpice, the resulting output voltage should have a voltage ripple in the lower mV range, depending on the input powwer supply.
For an explaination on how a capacitance multiplier works, see [1].
Schematic if the power supply filter.
As a first step the power is routed through a capacitance multiplier with a second order RC low pass filter. The corner frequency here is set to around 10 Hz.
Linear Regulators:
12V 3A:
MIC29300-12WT
-12V 1.5A:
LM7912CT/NOPB
-12V 1.8A:
LM2990T-12/NOPB
12V 1.5A:
LM340T-12/NOPB
TO-220 Heatsinks:
Boyd Laconia 513002B02500G
Boyd Laconia 530002B02500G
Boyd Laconia 529802B02500G
Isolator:
THERM PAD
Screws:
M3,5x0,6 Nylon
M3,5 Nut Nylon
Base Power supply:
PD-2515
Filter Capacitors:
UBY2A161MHL
0.22u CL31B224KBFNNNE
0.1u 1206B104K500CT
Output Linear Regulator Capacitors:
2.2u Typ1
1u Type1
2.2u Type2
1u Type2
Filter Resistor:
MFR50SFTE52-100R