This is a highly efficient and compact project that is capable of driving a 3A load with excellent line and load regulation and adjustable output of
1.2V to 35V DC. The project is built around the
LM2596-ADJ regulator which is ideally suited for easy and convenient design of step-down switching regulator using buck converter topology. The adjustable output version of
LM2596 is internally compensated to minimize the number of external components to simplify the power supply design.
LM2596 – 3.0 A, STEP-DOWN SWITCHING REGULATOR
The LM2596 regulator is a monolithic integrated circuit ideally suited for easy and convenient design of a step−down switching regulator (buck converter). It is capable of driving a 3.0 A load with excellent line and load regulation. This device is available in adjustable output version and it is internally compensated to minimize the number of external components to simplify the power supply design. Since
LM2596 converter is a switch−mode power supply, its efficiency is significantly higher in comparison with popular three−terminal linear regulators, especially with higher input voltages. The LM2596 operates at a switching frequency of
150 kHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Available in a standard5−lead TO−220 package with several different lead bend options, and
D2PAK surface-mount package. The other features include a guaranteed 4% tolerance on output voltage within specified input voltages and output load conditions, and
+/-15% on the oscillator frequency. External shutdown is included, featuring
80 uA (typical) standby current. Self-protection features include switch cycle−by−cycle current limit for the output switch, as well as
thermal shutdown for complete protection under fault conditions.
FEATURES
- Adjustable Output Voltage Range 1.23 V to 35 V
- Guaranteed 3 A Output Load Current
- Wide Input Voltage Range 3.2V to 40 V
- Input must be >1.5V higher than the output
- High Efficiency Up to 92%
- 150 kHz Fixed Frequency Internal Oscillator
- Thermal Shutdown and Current Limit Protection
- Internal Loop Compensation
- Precise potentiometer for voltage adjustment
- Output Ripple: ≤100mV
- PCB dimensions 57.15 x 44.34 mm
SCHEMATIC
PARTS LIST
| | | |
|---|
| R1 | 50k ±10% Precision Pot | TH | C118911 |
| R2 | 1.21K 1% | SMD 0805 | C228373 |
| R3 | 4k7 | SMD 0805 | C229219 |
| L1 | 33uH/5A | SMD 12MM INDUCTOR | C439422 |
| C2 C3 | 220uF/50V | SMD ELECTROLYTIC | C3358 |
| C1 | 100uF/50V | SMD ELECTROLYTIC | C249588 |
| IC1 | LM2596-ADJ | TO263 SMD | C29781 |
| D1 | MBRS340T3 | SMC | C40326 |
| D2 | RED LED | SMD 0805 | C192318 |
| CN1 CN2 | 2 PIN SCREW TERMINALS | TH | C409161 |
