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DC Electronic Load – 1A
- Rajkumar Sharma
- 104 Views
- moderate
- Tested
- SKU: EL138799
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- 2 Likes
This is a very precise Electronic Load project built using the ultra-Precision, Low-Noise OPAMP MAX44251 from Analog Devices. The project can sink current from a power source. It can be used as test gear for power supplies, chargers, solar panels, batteries, and DC-DC converters. The resistor R11 acts as a shunt, OPAMPs convert current into voltage, 2nd op-amp, and Q1 MOSFET are used to control the load current. A Multi-turn potentiometer helps to adjust the load current in the range of 0 to 1A. The supply voltage is up to 60V DC. The board works with dual supply +/-15V DC and draws a few milli amps. LM317 regulator provides 12V DC top op-amp and LM337 provides regulated -7V supply to op-amp. At full load, MOSFET Q1 produces lots of heat, and a fan and large heatsink on MOSFET will help cool it down. Users may use a current meter in series to load to display the current. Optional onboard Trimmer potentiometer provided in case external potentiometer is not required.
Features
- Operating Power Supply Dual 15V DC (+/-15V DC)
- Load Current 1Amp, Power Supply Up to 60V DC
- Highly Efficient and Ultra-Precision Current Control
- On-Board Power LED
- Barrier Block Connector for Load connection
- External Or On-Board Trimmer Potentiometer Option for Current Control
- PCB dimensions: 66.52 x 33.66 mm
Connections and other details
- CN1: Pin 1 = +Load, Pin 2 = GND
- CN2: Pin 1 = +15V DC Power Supply, Pin 2 = GND, Pin 3 = +15V Power Supply
- D1: Power LED
- PR1: Optional Trimmer Potentiometer (Do Not Use CN3 Potentiometer If this is used)
- CN3: External Potentiometer Pin 1 = Reference Voltage, Pin 2 = Input, Pin 3 = GND
Schematic
Parts List
| NO | QNYTY | REF | DESC | MANUFACTURER | SUPPLIER | SUPPLIER PART NO |
|---|---|---|---|---|---|---|
| 1 | 1 | CN1 | 2 PIN BARRIER BLOCK CONNECTOR PITCH 9.53MM | TE COONECTIVITY | DIGIKEY | A98495-ND |
| 2 | 1 | CN2 | 3 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5316-ND |
| 3 | 1 | CN3 | 3 PIN MALE HEADER PITCH 2.54MM 5K POT | WURTH | DIGIKEY | 732-5316-ND |
| 4 | 2 | C1,C8 | 1uF/25V CERAMUC SMD SIZE 1206 | YAGEO/MURATA | DIGIKEY | |
| 5 | 2 | C2,C9 | 100nF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 6 | 1 | C3 | 10uF/25V CERAMIC SMD SIZE 1210 | YAGEO/MURATA | DIGIKEY | |
| 7 | 1 | C4 | 1uF/80V CERAMIC SMD SIZE 1210 | YAGEO/MURATA | DIGIKEY | |
| 8 | 2 | C5,C7 | 4.7nF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 9 | 2 | C6,C10 | 100PF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 10 | 1 | D1 | LED RED SMD SIZE 0805 | OSRAM | DIGIKEY | 475-1278-1-ND |
| 11 | 4 | PR1,U2,R9,R10 | DNP | |||
| 12 | 1 | Q1 | IRFP250 TO247 MOSFET | VISHAY | DIGIKEY | IRFP250PBF-ND |
| 13 | 2 | R1,R13 | 240E 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 14 | 1 | R2 | 36K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 15 | 1 | R3 | 2.1K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 16 | 1 | R4 | 100E 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 17 | 1 | R5 | 1M 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 18 | 4 | R6,R12,R14,R16 | 1K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 19 | 3 | R7,R8,R18 | 10K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 20 | 1 | R11 | 0.025E/1W 1% SMD SZIE 2512 | YAGEO/MURATA | DIGIKEY | |
| 21 | 1 | R15 | 3.3K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 22 | 1 | R17 | 680E 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 23 | 1 | U1 | LM317 DPAK | TI | DIGIKEY | 497-1574-1-ND |
| 24 | 1 | U3 | MAX44251 | ANALOG DEVICE | DIGIKEY | MAX44251AUA+TTR-ND |
| 25 | 1 | U4 | LM337 DPAK | TI | DIGIKEY | 296-21578-1-ND |
| 26 | A | POT | MULTI-TURN POTENTIOMETER 5K OHM | BOURNS | DIGIKEY | 3590S-1-502L-ND |
Connections
Gerber View
Photos
Video
MAX44251 Datasheet
PCB
