UniLab
A switch-mode 0–30 V / 3 A bench supply
Materials
Gerber file
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Extra info / Update
* Output voltage 0–30 V (typical) (25 V minimum)
* Adjustable current limiting up to 3 A
* Maximum output power 90 W
* Compact PCB layout
* Switching frequency 52 kHz
* Parts kit available from the Elektor Shop
Component list
(default: 250 mW 1%)
R1,R2 = 820Ohm
R3 = 240Ohm
R4,R5 = 560Ohm 1W
R6 = 0.05Ohm 5W (Vishay Dale type LVR05R0500FE73 or 1.73Ohm/m resistance wire, see text)
R7,R8 = 12kOhm
R9 = 47kOhm
R10 = 39kOhm
R11 = 160kOhm
R12,R13 = 1kOhm
R14 = 100Ohm
R15 = 100kOhm
R16 = 10kOhm
P1 = 25kOhm potentiometer, linear
P2 = 250kOhm potentiometer, linear
P3 = 50Ohm trimpot, multiturn, vertical
P4 = 10kOhm trimpot, multiturn, vertical
P5 = 50kOhm trimpot, multiturn, vertical
P6 = 1kOhm trimpot, multiturn, vertical
P7 = 200Ohm trimpot, multiturn, vertical
Capacitors
C1 = 10,000µF 50V radial
C2,C3 = 220µF 63V radial
C4 = 100µF 63V radial
C5 = 2200µF 63V, radial
C6 = 680pF ceramic
C7 = 100nF ceramic
Inductors
L1 = 330µH 4.5A (muRata Power Solution type 1433445C) or 330 µH 3A (Würth type 744137)
Semiconductors
B1 = 800V 6A bridge rectifier (e.g. Vishay type GSIB680)
D1 = 1N5822 (Schottky diode, 40V 3A)
D2,D3 = 1N4007
D4 = zener diode 22V 1W
D5 = zener diode 18V 1W
D6 = 1N4148
D7 = LED, 3mm, red, low current (2mA)
IC1 = LM2576T-ADJ (National Semiconductor) (see text)
IC2 = LM337LZ
IC3 = LM358AN
Miscellaneous
TR1 = power transformer, secondary 25V 3.2 A (see text)
Heatsink for IC1 (T0-220 <9.9K/W, e.g. Fischer Elektronik type SK129 25,4 STS)
K1,K2 = 2-pin PCB terminal block, lead pitch 5mm
K3 = 6-pin DIL pinheader, lead pitch 2.54mm (0.1’’)
PCB, order code 090786-1
Kit of parts, contains all components except power transformer. Order code 090786-71
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