Introduction

The LM2576 voltage regulator is a monolithic IC ideal for simple buck converter designs, also known as buck switching regulators. This series of regulators is used in all circuits to drive 3.0A loads with excellent line and load regulation. The LM2576 voltage regulator provides fixed or adjustable voltage

The LM2576 voltage regulator is mainly designed to reduce external components to simplify the design of the power supply. Compared to 3-terminal linear regulators, the LM256 regulator is much more efficient, especially regarding maximum input voltage.

Table of Content

LM2576 Description

The LM2576 is one of many voltage regulator models primarily used as a pre-regulator in linear voltage regulators. This voltage regulator is an improved version of a switching power supply that contains all the features needed to reduce the voltage of a circuit. This buck converter contains an IC designed to drive loads below 3A.

Figure1-LM2576 Description

The LM2576 voltage regulator is available with special load regulation and load lines. This regulator is available in two versions, the first with a permanent output voltage and the second with a variable o/p to select the desired output.

This regulator is a DC-to-DC converter used to step down the input supply voltage to its o/p load. When voltage regulation occurs, the flow of current is enhanced. This regulator is available with an oscillator with a fixed frequency of approximately 52kHz, or with an integral frequency compensation technique.

This regulator is a DC-to-DC converter used to step down the input supply voltage to its o/p load. When voltage regulation occurs, the flow of current is enhanced. This regulator is available with an oscillator with a fixed frequency of approximately 52kHz, or with an integral frequency compensation technique.

LM2576 Pinout

The LM2576 voltage regulator includes five pins. Each pin and its function will be discussed below.

Figure2-LM2576 Pinout

Pin Configuration

LM2576 Regulator features and specifications

• contains a fixed frequency voltage and an internal oscillator with a frequency of 52kHz.
• lAvailable packages are TO-220 and TO-263.
• lThis voltage regulator provides permanent o/p voltages such as 3.3V, 5V, 12V and 15V.
• built-in current limiting protection and thermal shutdown
• By connecting external components, the output voltage can be from 1.23V to 37V.
• The maximum input voltage is 40V.
• lSpecified output current up to 3A.
• It includes an undervoltage lockout circuit that keeps the i/p voltage within a certain range and keeps the regulator off until a fixed threshold level is reached.

Application Circuits

The circuit diagram of the LM2576 voltage stabilizing circuit is shown below. This IC is used to build a 5V 3A switching regulator. This circuit uses some basic electronic components such as LM2576IC.IN5822 diode, 100uF inductor, 1000uf and 100uf capacitors, etc.

Figure3-circuit diagram of the LM2576

The above circuit is simple to design for power digital circuits. It requires a 5V2A power supply because it is a digital circuit and uses a high power of 10 watts. The power required for this circuit is 5V 3A. When applied to a car, the circuit can be powered by the car's cigarette lighter. But it is suitable for 12V, so for circuit operation, you need to use 3A to step down the voltage to 5V.

LM2576 maintains stable voltage like 5V and current 3A so it can be easily compatible with any device. This circuit is simple to use as it uses four main components such as 100uF C1, 1N5822 D1, 100uH L1, and 1000uF C2. The input voltage range of this circuit is 7V~40V, and the operating frequency is high.

Due to the built-in cooler, the LM2576 does not generate heat and therefore can be used continuously for long periods. In addition, different integrated circuits can be changed. The voltage levels may vary for different ICs, for example, LM2576 has 3.3Vdc o/p, LM2576 has 5Vdc o/p, LM2576 has 12Vdc o/p, LM2576 has 15Vdc o/p, the output range of LM2576 is 1.23Vdc - 37Vdc.

LM2576 Applications

The LM2576 voltage regulator uses a buck converter to step down the voltage and change the voltage value from maximum to low range. Therefore, it is one of the non-synchronous regulators that uses a maximum input voltage of 40V and delivers a maximum current of 3A with a peak efficiency of 90%.

Same-LM2576 is available in different types of converters such as fixed voltage and variable voltage types. So, if you are looking for a voltage regulator with these characteristics to vary the voltage for your application, then the LM2576 voltage regulator is more suitable.

Additionally, the LM2576's use of easily accessible inductors makes it ideal for SMPS designs as it greatly simplifies design. If you want to drive a 3A load and provide an o/p in the 1.23V-37V range with 88% efficiency, the LM2576 is suitable. Some of its other applications include:

• Used in battery circuits because of their high efficiency.
• Used to change the +ve input voltage to offset the o/p voltage.
• Used in buck linear regulators and micro SMPS circuits.
• Efficient pre-regulator for designing linear regulators.
• For battery chargers, it provides power.
• For negative step upconverter.
• For use in buck-boost converters.
• Used in designing SMPS (switched-mode power supplies).

Where to use LM2576 Buck Converter IC?

The voltage regulator integrated circuit (LM2576) steps down and regulates higher-level voltage values to a lower level using the Buck-converter topology. It is a non-sync type device with a maximum input voltage of 40V and a maximum output current of 3A, and it has a peak efficiency of 90%.

With the same IC, converters with fixed and variable output voltage types are also available. Thus, this integrated circuit may be of interest to you if you're searching for a switching step-down regulator with these features to control a voltage for your circuit.

How to use LM2576 in Circuits?

5V/3A step-down switching regulator schematic

Figure4-5V/3A step-down switching regulator schematic

The given circuit, which generates 5V from a 7V–40V unregulated supply with a maximum output current of 3A, is straightforward, inexpensive, and simple to construct. Up to 70V can be used as the input voltage when utilizing the LM2576HVT-5V version.

Parts list:

• IC1: LM2576T-5V or LM2576HVT-5V (National Semiconductor)
• L1: 100µH (415-0930, 67127000, PE-92108, RL2444)
• D1: 1N5822 (Schottky Barrier Rectifier diode)
• C1: 100µF/75V (Aluminum electrolytic capacitor)
• C2: 100µF/75V (Aluminum electrolytic capacitor)

1.2-50V/3A variable output step-down switching regulator

Figure5-1.2-50V/3A variable output step-down switching regulator

From a 55V unregulated power source, we may construct a basic switching regulator with a 1.2-50V, 3A variable output by using the LM2576HVT-ADJ or LM2576HVS-ADJ adjustable version. Three amps are the maximum output current.

Parts list:

• IC1: LM2576HVT-ADJ or LM2576HVS-ADJ
• L1: 150µH (67127060, PE-53115 or RL2445)
• D1: 1N5822 (Schottky diode)
• C1: 100µF/75V (electrolytic capacitor)
• C2: 2200µF/75V (electrolytic capacitor)
• R1: 47K potentiometer
• R2: 1.2K resistor

Similar Parts Specs

Equivalents for LM2576

LM1117, CS51411, LM723, LM7912

2D-Model (TO-220)

Figure6-2D-Model (TO-220)

LM2576 Datasheet PDF

LM2576 Datasheet PDF