| RSS Web Feed for Renewable Energy UK |  | REUK Shop | Directory | Bookmark Site | About Us  

DC Voltage Multiplier Circuit Plans



DC Voltage Multiplier Circuit Plans

Build a circuit to boost the voltage of a DC power source using a MAX756 IC Chip

electric circuit | electronics | education
Printer Friendly Version Print Article     

A DC voltage booster, DC voltage multiplier, or DC-DC Step-Up Converter is a very useful tool which enables a low source DC voltage to be boosted (stepped up) to a higher output DC voltage which is more useful.

For example, ultrabright LEDs need a 2.5-3.5 Volts to light: even two AA rechargeable batteries in series (1.2 + 1.2 = 2.4V) would not provide sufficient voltage to light up LEDs. Using a voltage boost circuit an LED can be powered by just one AA battery or any other power source - sometimes down 0.7 Volts!

This circuit can be used with low voltage solar panels to make a small battery charger or to power a 5 Volt device directly. It is also particularly good for getting useable voltages from small DIY stepper motor wind turbines - again to charge batteries or light LEDs.

The MintyBoost


MintyBoost Small USB Battery Powered Charger

The origin of the booster circuit described in this article is the Original MintyBoost - a DIY device to power / recharge any USB device (e.g. an iPod) using just two rechargeable AA batteries. MintyBoost kits are available for sale ($19.50 in USA), however the circuit can be made with easy to find electronic components together with a MAX756 integrated circuit chip and put to alternative uses.

There is a useful forum where you can ask questions regarding the MintyBoost.

MAX756 3.3V/5V Step-Up DC-DC Converter

MAX756 Step-Up DC-DC Converter
The key component in this voltage booster is the MAX756 - an integrated circuit from MAXIM . This tiny chip boosts input supply voltages as low as 0.7 Volts to an ouput of 3.3 or 5 Volts (user selectable) at up to 87% efficiency. The maximum output current is 200mA which is sufficient for a wide range of applications including LED lighting, and the low minimum voltage input enables the full capacity of batteries to be used up.

The full MAX756 Specification Sheet (PDF 120K) is available for download here.

Making the DC-DC Converter

The following parts are necessary to make this 0.7 to 5 Volt DC boost converter together with leads and either prototyping breadboard or soldering equipment and a board:

1 x MAX756
2 x 100uF Capacitors
2 x 0.1uF Capactitors
1 x 1N5817 Schottky Diode
1 x 22uH Power Inductor

The MAX756 is available direct from MAXIM with prices ranging from $3.02 (ordering 1-24) down to $1.95 (ordering 1000+). We can supply the rest of the components through the REUK Shop if required - email us to request a quote listing the components and quantities you require.

Circuit Diagram


Circuit diagram for 0.7 to 5V DC-DC converter

Pictured below is the (not very photogenic) finshed prototype circuit.

Completed MAX756 DC-DC Voltage Converter Circuit

The above circuit was tested using two 'flat' AA rechargeable batteries. The total voltage of the batteries was measured at 2.21 Volts, and the output voltage from the circuit was measured at exactly 5.00 Volts with a digital multimeter. The output voltage was used to power an ultrabright LED for 24 hours (through a 270 Ohm current limiting resistor) without any sign of dimming during that time.

3.3V Output from MAXC756

The circuit above is used to boost DC voltages from 0.7+ Volts up to 5.0 Volts. By changing the input to pin 2 of the MAX756 from ground to positive, the output is switched to 3.3 Volts. This enables some LEDs to be lit without needing a series resistor or with a smaller resistor, so there is less power wasted as heat.
The 3.3 Volt DC output can also be used to slowly charge a couple of AA batteries (in series) with the sub-200mA current output from the MAX756.

Alternative Circuit


Alternative DC-DC Converter using LT1073

Details of an alternative, but similar, USB Battery Pack circuit are available by clicking here. As with the MintyBoost, it is designed to power USB devices with the output from a couple of AA batteries however the circuit can be put to many other uses.

Instead of the MAX756, an LT1073 (specification sheet (1.4MB) here) integrated circuit is used. This chip is designed to be used in single-cell to 5V converters.
Article Last Modified: 09:06, 10th Jul 2008

Comment on this Article

If you have any comments on this article, please email them to neil@reuk.co.uk.


Recommended Related Articles

People who read this article also enjoyed the following articles:

Making Voltage Doublers and Multipliers
Find out how to construct an AC voltage doubler circuit. Extend it to a tripler circuit and more.
Article Last Modified: 14:29, 26th Apr 2007
electric circuit | education

Voltage Doubler for Solar Battery Charger
Boost the voltage of a solar panel to power higher voltage devices or charge batteries
Article Last Modified: 13:15, 16th May 2007
solar | electronics | education

Adjustable Step Up Voltage Regulator
Find out more about a step up voltage regulator used to output a voltage higher than the input voltage
Article Last Modified: 11:42, 15th Dec 2007
electronics | electric circuit | general

Power Inverters
Find out about the uses of power inverters in renewable energy generation
Article Last Modified: 16:41, 21st Jul 2008
storage | general | electronics

Wind Turbine Charge Controller
Buy a charge controller for a wind turbine generator
Article Last Modified: 15:46, 3rd Dec 2008
wind | electronics | shopping

Basic 4 AA Solar Battery Charger Plans
Make a simple solar charger for 4 AA rechargeable batteries
Article Last Modified: 09:43, 30th Jul 2007
solar | education

Pure Sine Wave Power Inverters
Find out more about pure sine wave inverters and their use
Article Last Modified: 16:52, 21st Jul 2008
storage | general

Solar Battery Charging
Make a solar charger for NiCd and NiMH rechargeable AA, AAA etc batteries
Article Last Modified: 09:43, 30th Jul 2007
solar | education

DIY 2kW Wind Turbine
Read about a home built 2kW wind turbine constructed from scrap
Article Last Modified: 08:46, 4th Oct 2007
wind | recycling

Low Voltage Battery Disconnect Circuits
Find out more about low voltage battery disconnect (LVD) circuits - used to protect batteries
Article Last Modified: 15:04, 28th May 2009
electric circuit | electronics | storage

© 2006-2009 REUK - All Rights Reserved
Page Last Updated on 10th July 2009 at 09:47:17am

Latest
Articles


OWL Micro
OWL Micro (CM130) - a leaner and cheaper version of the Owl wireless energy monitor now available
shopping
09:44, 10th Jul 2009

OWL CM119 Wireless Energy Monitor
Find out more about the new OWL CM119 wireless electricity monitor
shopping
09:44, 10th Jul 2009

Freeloader Pro
Introduction to the new Freeloader Pro - the ultimate professional solar charger
solar
16:56, 9th Jul 2009

Solar Roof Tiles
Find out about solar cells built into roof tiles / shingles
solar
12:03, 29th Jun 2009

Automatic Hen House Door Closer Opener
Find out how to put together a DIY automatic hen house door opener and closer
electric circuit
11:47, 27th Jun 2009

Freeloader Solar Charger
Find out more about the Freeloader solar charger for mobile phones, iPods, PDAs, and GPS
solar
12:01, 25th Jun 2009

SolarMate Solar Shed Light Review
A review of the SolarMate 0.5 remote control utility light
solar
10:35, 25th Jun 2009

Immersion Heaters to help Renewable Energy
Find out how the electric immersion heater could enable almost full renewable electricity supply in the UK
general
14:34, 18th Jun 2009



REUK Shop

Popular Items


12 VOLT 5 WATT SOLAR PANEL
Waterproof 12 Volt 5 Watt Solar Panel with aluminium frame - 290mm x 205mm x 17mm with fitted 5m leads
£33.99 each.
Solar Power



300 WATT POWER INVERTER
Convert 12V DC battery power into 230 AC to power portable televisions, computers, video recorders etc. 300 Watt power rating - peak power 600 Watts
£29.99 each.
Renewable Energy System Parts



SOLAR PUMP CONTROLLER WITH RELAY
Solar water heating system microprocessor controlled circuit with fitted 10A relay
£25.99 each.
Complete Circuits



CONVERTED PROGRAMMABLE DIGITAL TIMER RELAY
Mains powered programmable timer converted to low voltage with relay board
£21.99 each.
Renewable Energy System Parts



12 VOLT REGULATOR
Supply a fixed 12.0 Volt DC to your devices (up to 1 Amp output)
£4.99 each.
Complete Circuits



MR16 CERAMIC BULB HOLDER
Bulb holder for 12 Volt LED spotlight bulbs
£1.39 each.
Energy Efficient Lighting