Adjustable Current Source – 0 to 1A

Rajkumar Sharma
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moderate
Tested
SKU: EL143488
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This voltage-to-current (V-I) converter delivers a well-regulated current to a load. The circuit accepts an adjustable input voltage from Trimmer potentiometer PR1 and converts it to an output current from 0A to 1A. The current is regulated by feeding the voltage across a low-side, current-sense resistor R9 back to the OPAMP. The output Darlington pair allows for higher current gain. Feedback components R8 and C6 provide frequency compensation to ensure the stability of the circuit during transients. They also help reduce noise. R8 provides a DC feedback path directly at the current setting resistor, R9, and C1 provide a high-frequency feedback path that bypasses the NPN pair.

Note: The project can support higher current and voltage ranges by changing the sense resistor, BJT transistor, and Input voltage. It is important to use an appropriate heatsink for Q1 to take care of overheating.

Features

Supply 24V
Output Current 0 to 1A (Adjustable)
PCB Dimensions 41.59 x 30.48 mm
4 x 2.5 mm Mounting Holes

Connections

CN1: Pin 1 = GND, Pin + Load Supply 24V DC
CN2: Pin 1 = + Load Supply, Pin 2 GND
D1: Power LED
PR1: Current Adjust 0 to 1A

Schematic

Parts List

NO	QNTY	REF	DESC	MANUFACTURER	SUPPLIER	SUPPLIER PART NO
1	1	CN1	2 PIN SCREW TERMINAL PITCH 5.08MM	PHOENIX	DIGIKEY	277-1247-ND
2	4	U2,CN2,C5,R10	DNP
3	2	C1,C3	100nF/50V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
4	1	C2	220uF/50V ELECTROLYTIC SMD	PANASONIC	DIGIKEY	PCE3921CT-ND
5	1	C4	10uF/35V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
6	1	C6	10PF/50V CERAMIC SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
7	1	D1	LED RED SMD SIZE 0805	OSRAM	DIGIKEY	475-1278-1-ND
8	1	PR1	100K MULTITURN TRIMMER POT	BOURNS	DIGIKEY	3296Y-104LF-ND
9	1	Q1	TIP142 TO247	ON SEMI	DIGIKEY	TIP142GOS-ND
10	3	R1,R6,R7	0E SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
11	1	R2	330K 1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
12	1	R3	3.3K 5% SMD SIZD SIZE 0805	MURATA/YAGEO	DIGIKEY
13	1	R4	49.9K 1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
14	1	R5	249E 1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
15	1	R8	10K 1% SMD SIZE 0805	MURATA/YAGEO	DIGIKEY
16	1	R9	0.01E 1% SMD SIZDE 2512	MURATA/YAGEO	DIGIKEY
17	1	U1	OPA197 SOT23	TI	DIGIKEY	296-47813-1-ND
18	1	Z1	2 PIN SCREW TERMINAL PITCH 5.08MM	PHOENIX	DIGIKEY	277-1247-ND