LM2577 Boost Converter circuit | Step up | Datasheet | Pinout

Imagine you want to increase the DC voltage. For example, you have a voltage 5V to 12V, Or from 12V to 16V. We have many ways. In this article. Let’s try using the LM2577 IC.

It is easier than other methods. It can greatly reduce your time. Of course, using IC is surely reliable, suitable for the present.

LM2577 Boost Converter circuit | Step up | Datasheet | Pinout

LM2577 Datasheet

The LM2577 or LM1577 is a simple Step-Up(boost), flyback, forward converter Switching Voltage Regulator.

Included on the chip is a 3 amp NPN switch and they have protection circuits, consisting of current and thermal limiting, and under-voltage lockout.

Read also: Step up converter circuit using TDA2822

Other detail within a 52 kHz stable-frequency oscillator that
no external components, a soft start mode to reduce running current during start-up, and current mode control for rejection of input voltage and output load transients.

Features

  • Requires a few external components
  • NPN output switches 3.0A, can stand-off 65V
  • Wide input voltage range: 3.5V to 40V
  • The current-mode operation for the improved transient response, line regulation, and current limit
  • 52 kHz internal oscillator
  • Soft-start function reduces in-rush current during start-up
  • Output switch protected by current limit, under-voltage lockout, and thermal shutdown.
  • Automatic overheat shutdown, automatic over-voltage shutdown, etc.

Typical Application

  • Simple boost regulator
  • Flyback and forward regulators
  • Multiple-output regulator

Related: LM2596 circuit voltage regulator and datasheet

LM2577 pinout

Look at the LM2577 pinout on TO-220 (left) and TO-263 (right).

LM2577 pinout

The output voltage. It can be determined by the IC.

  • LM2577-12 for 12V output
  • LM2577-15 for 15V output
  • LM2577-ADJ for adjustable voltage 1.23VDC to 37VDC output.

Test Basic LM2577 ADJ boost Converter circuit

Look at the circuit below.

Basic using LM2577-ADJ Boost converter 5V to 12V 800mA

This circuit can increase the input voltage of 5VDC. It causes the output voltage to increase to 12V at 0.8A.

We use IC No: LM2577 ADJ. Therefore able to receive the input voltage 3.5V to 40V. And, The max output voltage of the circuit is 60VDC.

We can set the output voltage using R1 and R2.
Vout = 1.23 (1+R1/R2)

Recommended: USB 5V to 12V DC-DC Step-Up Converter circuit

Example LM2577 Circuits

These projects use a minimum number of external parts, these regulators are price reasonably good value., and made project easily.

5V to 12V DC Converter step up Voltage Regulator

If you are looking an ICs for a DC to DC converter circuit. I highly recommend the LM2577 supply all of the power and control functions for step-up (boost), flyback, and forward converter switching regulators.

LM2577 5V to 12V DC Converter step up Voltage Regulator

Look at the circuit diagram above. It is a simple 5V to 12V DC converter.

The output voltage typical: Wide input voltage 3.5Vdc to 40Vdc.

Component list

  • IC1: LM2577-12
  • 2.2k 0.5W resistor
  • 0.1uF capacitor
  • 0.33uF capacitor
  • 680uF 50V electrolytic capacitor
  • 1N5822 high-speed Schottky diode (3A)
  • Wire coil inductor, 100uH

Note: If use LM2577-ADJ. use 20k multi-turn variable resistor, set to ratio to R2=2k, R1=18k. And This setting for voltage output of 12V before soldering.

Read next: 5V to 12V boost converter circuit or higher using transistor

Adjustable Step-up Boost Converter using LM2577-ADJ

With this circuit below, you can set the output voltage of 1.23V to 60V.

1.23V to 60V Adjustable Regulated supply using LM2577-ADJ

Parts you will need

  • IC1: LM2577-ADJ
  • C1: 0.18uF 63V Ceramic or MKT capacitor
  • C2: 0.33uF 50V Ceramic
  • C3: 1,000uF 80V Electrolytic capacitor
  • R1: 1K 1W Resistor
  • R2,R3: 2.2K 0.5W Resistor
  • D1: 1N5821 high-speed Schottky diode (3A)
  • L1: Wire coil inductor, 100uH

12V to 16V Step-up DC to DC Converter using LM2577

It is similar to the circuit above. The circuit is a boost step-up regulator based around an LM2577-ADJ voltage regulator chip and a few other components.

12V to 16V DC/DC Converter using LM2577

Both Resistors R1 and R2 set the regulated output voltage.

A switch inside the voltage regulator closes between pins 4 and 3, causing current to flow through the inductor to ground.

When the switch is released a few microseconds later, a back-EMF ‘kick’ is produced by the inductor.

This result is a positive pulse with respect to the input voltage. This pulse charges the output capacitor via the Schottky diode-D1, which tends towards an equilibrium voltage.

The switch continues to oscillate, the diode preventing the switch from shorting the output capacitor during the ‘on’ phase.

The output voltage is monitored via the voltage divider R1/R2, causing the duty cycle of the switch oscillator to be continuously regulated in order to maintain a constant output voltage under varying loads.

3.7V 5V to +15V -15V DC-DC Converter Step-up Boost Dual Voltage

If you are building a large digital circuit You only provide 5V power supply. But by chance, you have to use a good quality preamplifier with the tone control circuit. It requires DC regulated power supply, 15V, -15V and GND.

Look at the circuit diagram below. It might be a good solution.

3.7V 5V to +15V -15V DC DC Converter Step up Boost Dual Voltage

This is the flyback Regulator Easily Provides Dual outputs.

A Flyback regulator can produce single or multiple outputs
voltages that are lower or greater than the input supply voltage.

In the circuit shows the LM1577/LM2577 used as a flyback regulator with positive and negative regulated outputs.

Its operation is similar to a step-up regulator, except the output switch controls the primary current of a flyback transformer.

Note that the primary and secondary windings are out of phase, so no current flows through secondary when current flows through the primary.

This allows the primary to charge up the transformer core when the switch is on.

When the switch turns off, the core discharges by sending current through the secondary, and this produces a voltage at the outputs.

The output voltages are controlled by adjusting the
peak primary current, as described in the step-up regulator
section.

Here are a few related posts you may find helpful, too:

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