The project presented here is a wide input voltage range non-isolated DC-DC Converter, that provides a regulated, adjustable output voltage. The operating input supply is 55V DC and output regulated from 1.2V to 50V DC. The project built using LM2576HVT-ADJ IC. Screw terminals provided for easy input and output connections, onboard power LED at the input, bridge rectifier for AC/DC Input, an onboard potentiometer to adjust the output voltage, etc. This is a low-profile board with a thermal area on PCB that acts as a heatsink. An additional LC filter using C5 and L2 that reduces the output ripple by a factor of 10 or more is included in this circuit. The device has a current limiting feature to prevent the switching current from exceeding a safe value during an accidental overload on output.
LM2576 DESCRIPTION
The LM2576 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving 3-A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, 15 V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include fault protection and a fixed-frequency oscillator. The LM2576 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in some cases, no heat sink is required. A standard series of inductors optimized for use with the LM2576 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies. Other features include a ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50-µA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.Note: The board works with DC input and due to the onboard rectifier the input polarity is not a problem. This project can also work with AC input, use appropriate filter capacitor for AC input needed, CX capacitor provision helps you to use THT capacitor at input DC line.
FEATURES
- Input voltage 55V (it can work with Lower Input DC Supply, but the output will be lower)
- Bridge Rectifier at the input so No polarity issue in DC input
- Adjustable version output voltage range: 1.23 V to 50 V ±4% maximum over line and load conditions
- 3A output current (Maximum)
- Cycle-by-Cycle Peak Current Limit for Overload Protection
- Power LED at input
- Onboard Potentiometer for Output Voltage Adjust
- Screw Terminal for Inputs and Output Connection
- Additional Inductor and Capacitor to reduce the Ripple
- 52-kHz Fixed-frequency internal oscillator
- Thermal shutdown and current limit protection
- PCB Dimensions 85 x 71.60 mm
SCHEMATIC
PARTS LIST
| NO | QNTY. | REF | DESC | MANUFACTURER | SUPPLIER | SUPPLIER PART NO |
|---|
| 1 | 1 | CN1 | 2 PIN SCREW TERMENAL 5.08MM PITCH | WIEDMULLER | DIGIKEY | 281-2888-ND |
| 2 | 1 | CN2 | 2 PIN SCREW TERMENAL 5.08MM PITCH | WIEDMULLER | DIGIKEY | 281-2888-ND |
| 3 | 1 | C1 | 1uF/100V SMD SIZE 1206 | MURATA/YAGEO | DIGIKEY | |
| 4 | 3 | C2,C5,C8 | 100uF/63V SMD | NICHICON | DIGIKEY | 493-6185-1-ND |
| 5 | 2 | C3 | 2200uF/63V THT | NICHICON | DIGIKEY | 493-1360-ND |
| 6 | 5 | R1,J1,C4,C6,C7 | DNP | |||
| 7 | 4 | D1,D2,D3,D4 | 1N5408 | ON SEMI | DIGIKEY | 1N5408FSTR-ND |
| 8 | 1 | D5 | RED LED SMD SIZE 0805 | OSRAM | DIGIKEY | 475-1415-1-ND |
| 9 | 1 | D6 | MBRS360 | ON SEMI | DIGIKEY | MBRS360T3GOSCT-ND |
| 10 | 1 | L1 | 150uH/5A 30MM DIA | BOURNS | MOUSER | 652-2200LL-151-H-RC |
| 11 | 1 | L2 | 20uH OR 12uH/4.5A 12MMX12MM | BOURNS | DIGIKEY | SRR1260-120MTR-ND |
| 12 | 1 | P1 | 50K POT 16MM | BOURNS | DIGIKEY | PDB181-K415K-503B-ND |
| 13 | 1 | R2 | 4.7K 5% SMD 2512 OR 1210 | MURATA/YAGEO | ||
| 14 | 1 | R3 | 1.21K 1% SMD SIZE0805 | MURATA/YAGEO | ||
| 15 | 1 | U1 | LM2576HVT-ADJ TO220 | TEXAS | DIGIKEY | LM2576HVT-ADJ/NOPB-ND |