Overview: 3.7V to 5V Boost Converter for Lithium-Ion Battery
The post explains how we can make DIY 3.7V to 5V Boost Converter Module for 3.7V Lithium-Ion Batteries. A single cell Lithium-Ion Battery Voltage range from a minimum of 3.2V to 4.2V. It’s not sufficient to power those circuits which require 5V or more. Thus we need to step-up the voltages up to 5V. Thus DC-to-DC Step-up converter circuit is required which is also called as Boost Converter.
Not only Lithium-Ion or Lithium Polymer Battery but the circuit can also be used for Samsung 18650 Battery. The important element of the circuit is Boost Converter IC. So we can use MC34063 IC which is the most popular switching regulator in such applications. MC34063A is ideal for small projects which need DC-to-DC Converters. The circuit that I am gonna show here will step up the voltage into 3 different level like 5V, 5.3V & 6V.
In one of my previous post I explained about Buck Converter using XL4015. You can follow the post if you want to learn more about the Buck Converter. Similarly, I also explained how you can design Simple Lithium-Ion Battery Charger Circuit using MCP73831 IC.
Bill of Materials
Following are the components required for making the 3.7V to 5V Boost Converter project. All the components can be easily purchased from Amazon.
| S.N. | Components | Description | Quantity |
|---|---|---|---|
| 1 | MC34063 | Boost Converter IC | 1 |
| 2 | Resistor | 0.47 Ω | 1 |
| 3 | Resistor | 180 Ω | 1 |
| 4 | Resistor | 2.2 K Ω | 3 |
| 5 | Resistor | 2.7 K Ω | 1 |
| 6 | Resistor | 10 K Ω | 1 |
| 7 | Resistor | 470 Ω | 1 |
| 8 | Capacitor | 470 µF, 16V (Electrolytic Capacitor) | 1 |
| 9 | Capacitor | 100 µF, 16V (Electrolytic Capacitor) | 3 |
| 10 | Capacitor | 100 nF, Ceramic Disk | 4 |
| 11 | Capacitor | 470 pF, Ceramic Disk | 1 |
| 12 | 1N5819 | Schottky diode | 2 |
| 13 | 1N4007 | Rectifier diode | 1 |
| 14 | LED | 5mm Any Color | 3 |
| 15 | Inductor | 100uH | 1 |
| 16 | Power Supply | 3.7V Lithium Ion Battery | 1 |
MC34063 IC
The MC34063A Buck-Boost Converter IC is a monolithic control circuit containing the primary functions required for DC−to−DC converters. The IC consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver, and high current output switch. The IC was specifically designed to be incorporated in Step−Down and Step−Up and Voltage−Inverting applications with a minimum number of external components.
Features of MC34063 IC
1. Operation from 3.0 V to 40 V Input
2. Low Standby Current
3. Current Limiting
4. Output Switch Current to 1.5 A
5. Output Voltage Adjustable
6. Frequency Operation to 100 kHz
7. Precision 2%
Circuit: 3.7V to 5V Boost Converter for Lithium-Ion Battery
The heart of the circuit is the switching regulator IC MC34063A. Two different diodes like 1N5819 & 1N4007 are used to drop down the voltage. The Schottky diode 1N5819 has a drop down voltage of 0.3V and Diode 1N4007 has 0.7V.
As MC34063A works up to 40V, thus The circuit works with DC voltage in the range of 3.0V to 40.0V. We are using 3.7V as input from Lithium-Ion Battery. The output of the circuit is designed to give fix 6V. The diode 1N4007 reduces the 6V output voltage to around 5.3V. The Schottky diode further reduces 5.3V to around 5.0V.
The total maximal output current from all outputs terminal is around 100mA. The current can be adjusted with the help resistor R1 in the circuit. For the fix 5V output, a load always needs to be connected as between 220ohm to 470ohm. Thus a single circuit can be used as 3.7 to 5V Voltage Booster Circuit or 5.3V or 6V Booster.
The MC34063 can also be used as DC-to-DC Boost Converter to boost 3.7V to 9V. You can use this Circuit in this project: Power Supply for NodeMCU
