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Electronic Design
Build A Smart Battery Charger, And More

Build A Smart Battery Charger, And More

Build A Smart Battery Charger Using A Single-Transistor Circuit by Ejaz ur Rehman is one of the most popular articles on It is just one of thousands of Ideas for Design (IFD) articles that we have published over the years. IFDs are short articles designed to deliver a basic idea in a compact and concise format. We have at least two in every print version of Electronic Design and more online. Often they include a single circuit diagram like the one for the single transistor circuit (Fig. 1).

I cover the Digital and Embedded technology areas for Electronic Design but I've always been interested in the power and analog IFDs because they are often handy adjuncts to digital projects that need power or analog interfaces. In many cases, a project needs power or has an analog requirement. IFDs often come in handy because the provide the answers in a short and simple fashion.

There are literally hundreds of IFDs for battery chargers or power supplies on our website. Finding them all can be a challenge but I have collected a few here. The Build A Smart Battery Charger Using A Single-Transistor Circuit article is one of the simplest although it requires a relay. The transistor in the circuit actually controls the relay. It is one way to charge a battery but not necessarily the lowest cost or most reliable. It does work.

The Battery-Charger Load Switch Approximates An Ideal Diode article uses an alternative technique (Fig. 2). It is more complex using a battery-charging IC with a Power OK (POK) output, like Maxim's MAX8814. There are more parts but eliminates the relay and uses power transistors instead. The charging characteristics are also more complex because of the battery-charging chip.

Of course, sometimes you might be looking an in depth article. Something like Battery ICs Charge, Gauge, And Authenticate might be more useful. Our feature articles are often written by our editors or a contributing editor.

Here are a couple more battery charger articles I found useful:

Using our search engine to search for Battery Charger comes up with a list that starts with these articles:

Not bad for a short list but this is just the start of the list. Of course, you will find a few articles that are not exactly a good fit. Energizer USB Battery Charger Introduces Backdoor is one I wrote but it has to do with spyware. It is a fun read though.

If you have ideas that might improve existing IFDs or brand new ones then check out our article submission guidelines. We are always interested in new technical articles.

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