Friday, 14 November 2014

Make a Laptop charger (efficient and reliable) from a car battery 12v at home

Make a Laptop Charger from a Car Battery -12 V DC Laptop Charger Circuit


Todays post simply explains a simple circuit which can be used for charging a laptop while driving in car or some other vehicle or from a DC battery. The circuit works without using an inverter or inductors in its configuration.

The good thing about this circuit is that it does not rely on an inductor topology for the required actions, making the design vgyery simpler, and yet efficient and effective.

As most of us know a laptop iis powered by a DC potential from an in built Li-Ion battery just as our cell phones do.

Normally we use a AC to DC adapter for charging a laptop battery at homes and offices, these adapters or chargers are actually SMPS power supplies rated with the required and matching specifications of the laptop battery.

However the above power supply units work only with AC supplies, and in places where an AC outlet may be available. These units will not of any use or work in places where an AC source is not present such as in cars and other similar vehicles and electricity deprived areas. This extremely useful little circuit presented here will allow a laptop battery to be charged even from a DC source such yas a car or truck batteries (12Volt).

It is a very simple, useful, cheap, versatile and universal circuit which may be dimensioned for charging all types of laptops by little adjusting the relevant
components provided in the circuit. It's a simple plug and play charger circuit.

Normally most of the laptop chargers are rated at 19V 3.5Amps, however some may be rated at higher currents to facilitating fast charging.

The discussed circuit has a voltage adjustment features (via PWM-
pulse width modulation) which may be suitably adjusted as per the required specification. The current may be suitably safeguarded or restricted by adding a 3 ohm 5 watt resistor at the output positive terminal of this circuit.

Circuit Diagram:

As can be seen in the circuit diagram, the design is basically a powerful DC to DC voltage doubler circuit which utilizes a push pull mosfet stage for the required boosting of the voltage.
The above circuit requires an oscillator stage for initiating the proposed operations which is configured around IC1a. The components R11, R12, C5 along with the two diodes becomes a good little PWM controller which sets the duty cycle of the entire circuit and can be used for adjusting the output voltage of the circuit for charging different specification laptop batteries.
Here the above circuit would generate about 22V from a 12V source, by simply adjusting the resistior R12, the output may be changed to an exact 19V, which is the perfect required laptop charging voltage.

For any further querry please ask them in comment section.
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Thank you for reading.

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