1.2V to 50V @ 3A – Adjustable Power Supply with 55Vdc Input

  • Rajkumar Sharma
  • 1.475 Views
  • easy
  • Tested

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

NOQNTY.REFDESCMANUFACTURERSUPPLIERSUPPLIER PART NO
11CN12 PIN SCREW TERMENAL 5.08MM PITCHWIEDMULLERDIGIKEY281-2888-ND
21CN22 PIN SCREW TERMENAL 5.08MM PITCHWIEDMULLERDIGIKEY281-2888-ND
31C11uF/100V SMD SIZE 1206MURATA/YAGEODIGIKEY
43C2,C5,C8100uF/63V SMD NICHICONDIGIKEY493-6185-1-ND
52C32200uF/63V THT NICHICONDIGIKEY493-1360-ND
65R1,J1,C4,C6,C7DNP
74D1,D2,D3,D41N5408ON SEMIDIGIKEY1N5408FSTR-ND
81D5RED LED SMD SIZE 0805OSRAMDIGIKEY475-1415-1-ND
91D6MBRS360ON SEMIDIGIKEYMBRS360T3GOSCT-ND
101L1150uH/5A 30MM DIABOURNSMOUSER652-2200LL-151-H-RC
111L220uH OR 12uH/4.5A 12MMX12MMBOURNSDIGIKEYSRR1260-120MTR-ND
121P150K POT 16MMBOURNSDIGIKEYPDB181-K415K-503B-ND
131R24.7K 5% SMD 2512 OR 1210MURATA/YAGEO
141R31.21K 1% SMD SIZE0805MURATA/YAGEO
151U1LM2576HVT-ADJ TO220TEXASDIGIKEYLM2576HVT-ADJ/NOPB-ND

Connections

Gerber View

Photos

Video

LM2576 Datasheet

lm2576

PCB

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