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Charger for phone from cigarette lighter on MC34063. Homemade USB power source in the car Charging circuit for a smartphone from a car

The MC34063 is a popular IC for designing small transformerless voltage converter circuits. It is universal because it can be used to make step-up, step-down and inverting DC-DC voltage converters. The range of input and output voltages makes it easy to assemble a number of voltage converters based on this microcircuit at minimal cost, which are indispensable in everyday life.

Of course, all these designs can be bought in China, ready-made, but we won’t talk about that today; you can buy everything in China, but it’s more interesting to do it yourself.

We will consider the design of a step-down voltage converter, the input of which can be supplied with a voltage from 5/6 to 40 Volts, while the output voltage will always remain stable at 5 Volts. All mobile phones, tablets, some players and players are charged from 5 Volts.

The microcircuit is widely popular among radio amateurs precisely for the reason that it costs a penny and contains minimal wiring.

Inductor, rectifier diode (Schottky) and several passive components. The output voltage may be different; there are a lot of programs and formulas for calculating inverters on this chip. The output voltage depends on the ratio of resistors R3/R2.

The diode, in principle, is also not critical and you can take ordinary pulse ones, from the FR/UF/HER/SF line, etc.
A diode is needed with a current higher than 1.5 Amps, preferably 3, since the output current from the microcircuit can reach up to 1.5 Amps. The inductor itself is wound on a ferrite dumbbell, or a ring can be used, the winding is wound with 0.6-0.8 mm wire and consists of 15-20 turns. You can take a ready-made inductor from some computer power supplies.

Capacitor C1 is responsible for the operating frequency of the oscillator built into the chip; it is recommended to run the chip at frequencies of 40-60 kHz.

By the way, single-ended transformer voltage converters are also implemented on this microcircuit to obtain a wider range of output voltage and provide galvanic isolation. In this case, the power can also be increased, because in this case the output of the microcircuit is amplified by a powerful transistor.

In our technological age, it is difficult to imagine life without a phone. And what a disappointment it is when he sits down. If this happened at home or in the office, this is certainly not a problem, plug the charger into the outlet and that’s it. But when traveling in a car or when working in a job that involves constant travel, this will not be possible.

To do this, you need a charger in the car. Of course, you can buy it in the store, but we are not looking for easy ways, especially since assembling it is not a big problem.

The MC34063 chip will be taken as the basis; it is usually used in DC/DC voltage converters, i.e. from permanent to permanent.

Which is exactly what we need. As you know, the on-board power supply is 12 V, and the charger requires 5 V. Therefore, based on this microcircuit, we will assemble a voltage converter from 12 V to 5V. A schematic diagram of the future device is shown below.

The output voltage rating is set by the values of resistors R2 and R3. For the required value of 5 V, it is necessary to set R2=1 kOhm, R3=3 kOhm. The formula for determining the output voltage value is given below, so if you need to set the output voltage to a different voltage, you can use it to calculate.

In principle, you can make a universal adapter if you put a variable in place of R3 and unscrew the required value. The only thing is that before this you should do a calculation in order to understand in what range its values should be.

Resistor R1 plays the role of a current limiter, when setting R1 with a nominal value of 0.3 Ohm, exceeding the output current of more than 500 mA turns off the device, decreasing the resistance value will increase the shutdown current limit.

Capacitor C3 sets the operating frequency of the converter, the remaining capacitors are filtering ones. The inductor also acts as a filter, designed for a current of 1 A. 1N5819 was chosen as the diode, but the domestic analogue is quite suitable.

The adapter is assembled on the basis of the Z-43 case; its size is quite sufficient to compactly accommodate the entire element base. At the input we put the plug into the cigarette lighter and the output is a USB connector - you're done!

A car charger is a very primitive device, consisting of only a few elements and capable of performing only one function: recharging a smartphone from the cigarette lighter while the car engine is running. However, despite the simplicity of a car phone charger, the choice of this accessory must also be approached very responsibly. A motorist using a low-quality charger runs the risk of finding himself without means of communication at any time - if a charging failure occurs during a long trip, this will become a real problem for the driver.

How to choose a car charger for a smartphone: basic criteria

First of all, the motorist must decide what he needs: full car charger or USB adapter. An adapter is an adapter from a cigarette lighter to a USB cable.

The adapter has a significant drawback: it turns into a completely useless thing if the motorist forgot the USB cable at home. Therefore, when contacting a communication store, the driver is recommended to take a full-fledged charger - it costs only a little more in retail than a USB adapter.

Other criteria for choosing an ASU include the following:

Output current. To charge smartphones you need a current of at least 1 A, and given modern smartphones this may not be enough, so the best option is 2 or 2.4 A per port. If you choose a charger with a current strength from 2 A, then the motorist will be able to recharge both a smartphone and a tablet. Worry about the fact that the smartphone is dated 2 A If it burns out, it shouldn’t: modern gadgets are equipped with special charging controllers - devices that do not allow excess current to pass through. In addition, a similar controller is installed in high-quality chargers.

Output voltage. There is such a rule: the voltage specified in the technical specifications of a car phone charger should not exceed the value indicated on the gadget’s battery by more than 5%. Otherwise, the ASU will overheat and very soon fail.

Wire length and type. Experts unanimously recommend taking an ASU with a twisted wire. The likelihood that the twisted wire will break (which could lead to a fire) is extremely low. In addition, the twisted wire is adjustable in length - a very useful feature considering how varied the interior of modern cars is.

Wire fastening. It is worth making sure that there is a corrugated sheath at the place where the wire comes out of the adapter. Here's what we mean:

The corrugated sheath prevents the wire from breaking at bend points. The fastening of the wire to the plug must also be protected by it.

Number of ports. This criterion is relevant if the motorist chooses a USB adapter. Optimal number of ports – 2 : both must have a current of at least 2 A. You can consider an ASU with a 1 A port, but only if the device is old or from the budget category.

In addition, we should not forget that in 2019 the vast majority of smartphones have a Type-C connector, so you can consider a charging option that has one USB-A output and a second.

Buying adapters with a large number of ports is advisable only for those motorists who are the heads of large or simply large families. Otherwise, the driver will pointlessly overpay for the accessory, because some of the ports will be idle.

Design. The driver should pay attention to the fact that there is no metal ring around the central contact of the AZU.

Since the charging body is most often made of plastic, the metal ring will sooner or later break off the thread and remain in the car’s cigarette lighter. A stuck part can short-circuit the contacts inside the cigarette lighter, which can lead to a fire. To be fair, it should be noted that AZUs with metal rings are now on sale very rarely, although previously a significant part of the chargers had just such a design.

A useful advantage from a design point of view is the presence of an LED, thanks to which the driver can be sure that the charger is working correctly. And in the dark, finding a charger is easier than trying to connect the cable by touch.

Otherwise, as far as design is concerned, the motorist should rely on his own opinion. For example, he may prefer a charger with an LED display informing about the state of charge and voltage of the car’s battery.

However, such an accessory will cost approximately more than a regular adapter.

What to buy: original or Chinese copy?

Buyers of expensive gadgets, as a rule, do not spare money on the best accessories - as long as nothing threatens their new mobile device. Such clients insist that they be provided with original chargers, cables and USB adapters, because they believe that universal chargers can cause damage to the device’s battery. But are they right?

More likely no than yes. If an iPhone XS buyer asks to sell him an original memory device, the consultant will probably offer an accessory from the company Belkin- but not Apple. By visiting the online store of the official retailer of Apple equipment in Russia Re:Store the buyer will find the company's ASU accessories in the catalog Deppa, MOMAX, Juicies, Anker– but again there is no charging made by Apple.

You won’t be able to find the original on the Apple company’s website either. In fact, this means that Apple does not produce its own RAMs. Belkin and other famous ones, of course, produce excellent accessories, but in relation to the iPhone this company is still a third-party manufacturer.

Anker PowerDrive 2 PD/PIQ A2229H12 (Black)

Price: from 2,590 rubles.

This stylish and compact model from Anker has an excellent range of useful features. The device has two outputs - a classic USB connector and an additional Type-C output. For ease of use at night, a blue backlight is provided - it allows you to see the AZU in the dark and at the same time will not distract the driver from driving the car with bright light.

Both connectors support Power Delivery and Power IQ functions, which are responsible for selecting the right power for different gadgets. In addition, the ASU is equipped with protection against overheating, overload and short circuit. For those who are worried about their device, and this is especially true for owners of expensive phones from Apple, Samsung and other famous manufacturers, this charger will be the best choice - you don’t have to worry that the battery will be damaged in any way or the device will burn out due to a power surge. There is no cable included, so it is recommended to use a proprietary cable from the smartphone manufacturer.

Anker PowerDrive 2 Elite A2212011 (Black)

Price: from 1290 rubles.

A simplified version of the previous model, which differs in the material used. Carbon fiber makes the body ergonomic and visually interesting. The model has illuminated ports, there are two of them, type - USB A. Both outputs support PowerIQ technologies (automatic power selection depending on the smartphone model) and VoltageBoost (speeds up the process of increasing battery capacity). In addition, there is protection against overheating, short circuit and overload. An excellent option for those who are looking for not the most expensive, but stylish and safe car charger for their mobile phone.

Conclusion

A driver choosing a car charger for a gadget should not pay attention to the price of the accessory and not look for the original charger, since in most cases they do not exist. It is much more important to look at the characteristics, as well as the level of safety, which comes down not only to the build quality, but to the materials used and the presence of protective controllers. Of course, a good charger costs a decent amount, but at the very least it is stupid to buy a car charger for 300-500 rubles for an iPhone for 100 thousand rubles.

Hello Habra gentlemen and Habra ladies!
I think some of you are familiar with the situation:
“Car, traffic jam, Nth hour behind the wheel. The communicator with the navigator running has been beeping for the third time about the end of the charge, despite the fact that it is always connected to charging. And you, as luck would have it, have absolutely no bearings in this part of the city.”
Next, I will talk about how, with moderately straight hands, a small set of tools and a little money, you can build a universal (suitable for charging with the rated current of both Apple and all other devices) car USB charger for your gadgets.

CAUTION: Under the cut there are a lot of photos, a little work, no LUT and no happy ending (not yet).

Author, why all this?

Some time ago, the story described in the prologue happened to me, a Chinese USB twin absolutely shamelessly let my smart device run out of charge while navigating; out of the declared 500mA, it produced about 350 on both sockets. I must say I was very angry. Well, okay - I’m a fool, I decided, and on the same day, in the evening, I ordered a 2A car charger on eBay, which rested in the depths of the Chinese-Israeli post office. By luck, I had a handkerchief DC-DC step down converter with an output current of up to 3 A lying around and I decided to use it to build myself a reliable and universal car charger.

A little about chargers.
I would divide most chargers that are on the market into four types:
1. Apple - tailored for Apple devices, equipped with a little charging trick.
2. Conventional - aimed at most gadgets, for which shorted DATA+ and DATA- are sufficient to consume the rated charging current (the one stated on the charger of your gadget).
3. Clueless - for whom DATA+ and DATA- are hanging in the air. In this regard, your device decides that it is a USB hub or a computer and does not consume more than 500 mA, which negatively affects the charging speed or even the absence of it under load.
4. Cunning%!$&e - since they have a microcontroller installed inside, which tells the device something like what Kipling’s well-known hero told animals - “You and I are of the same blood, you and I”, checks the originality of the charge. For all other devices they are memory devices of the third type.

For obvious reasons, I consider the last two options uninteresting and even harmful, so let’s focus on the first two. Since our charger must be able to charge both Apple and all other gadgets, we use two USB outputs, one will be focused on Apple devices, the second on all others. I will only note that if you mistakenly connect the gadget to a USB socket that is not intended for it, nothing bad will happen, it will just take the same notorious 500mA.
So, the goal: “With a little work with your hands, get a universal charger for the car.”

What do we need

1. First, let’s look at the charging current, usually it’s 1A for smartphones and about 2 Amps for tablets (by the way, my Nexus 7, for some reason it doesn’t take more than 1.2A from its own charge). In total, to simultaneously charge a medium-sized tablet and smartphone, we need a current of 3A. So the DC-DC converter that I have in stock is quite suitable. I must admit that a 4A or 5A converter would be better suited for these purposes, so that the current would be enough for 2 tablets, but I never found compact and inexpensive solutions, and besides, time was running out.
So I used what I had:
Input voltage: 4-35V.
Output voltage: 1.23-30V (adjustable by potentiometer).
Maximum output current: 3A.
Type: Step Down Buck converter.

2. USB socket, I used a double one, which I unsoldered from an old USB hub.

You can also use regular sockets from a USB extension cable.

3. Development board. In order to solder a USB socket to something and assemble a simple charging circuit for Apple.

4. Resistors or resistors, whichever you prefer, and one LED. There are 5 pieces in total, 75 kOhm, 43 kOhm, 2 rated 50 kOhm and one rated at 70 Ohm. The first 4 are exactly where the Apple charging circuit is built; I used 70 Ohms to limit the current on the LED.

5. Body. I found a case for a Mag-Lite flashlight in the bins of my homeland. In general, a black toothbrush case would be ideal, but I couldn’t find one.

6. Soldering iron, rosin, solder, wire cutters, drill and an hour of free time.

Assembling the charger

1. First of all, I short-circuited the DATA+ and DATA- pins on one of the sockets:

*I apologize for the harshness, I got up early and my body wanted to sleep, but my brain wanted to continue the experiment.

This will be our outlet for non-Apple gadgets.

2. We cut off the size of the breadboard we need and mark and drill holes in it for the mounting legs of the USB socket, while simultaneously checking that the contact legs coincide with the holes in the board.

3. Insert the socket, fix it and solder it to the breadboard. We connect the +5V contacts of the first (1) and second (5) sockets to each other, and do the same with the GND contacts (4 and 8).

The photo is for clarification only, the contacts are soldered already on the breadboard

4. Solder the following circuit to the remaining two contacts DATA+ and DATA-:

To maintain polarity, we use the USB pinout:

I got it like this:

Don’t forget to adjust the output voltage; use a screwdriver and a voltmeter to set it to 5 - 5.1V.

I also decided to add an indication to the USB power circuit; in parallel to +5V and GND, I soldered yellow ice with a 70-Ohm resistor to limit the current.

A convincing request to people with a fine mental organization and other lovers of beauty: “Do not look at the following picture, because the soldering is crooked.”

I'm brave!

5. We fix the converter board on our breadboard. I did this using the legs from the same resistors, soldering them into the contact holes on the converter board and on the breadboard.

6. Solder the outputs of the converter to the corresponding inputs on the USB socket. Maintain polarity!

7. Take the case, mark and drill holes for mounting our board, mark and cut out a place for a USB socket and add holes for ventilation opposite the converter chip.

We fasten the breadboard with bolts to the case and get a box like this:

In the Machine it looks like this:

Tests

Next, I decided to check whether my devices would actually consider that they were being charged from their original charger. And at the same time measure the currents.
Power is provided by a power supply from an old 24V 3.3A printer.
I measured the current before outputting to USB.

Looking ahead, I’ll say that all the devices I have recognized charging.
I connected to USB socket number one (which is intended for various gadgets):
HTC Sensation, HTC Wildfire S, Nokia E72, Nexus 7, Samsung Galaxy ACE2.
For the Sensation and Nexus 7, I checked the charging time, starting at 1% and charging up to 100%.
The smartphone charged in 1 hour 43 minutes (Anker 1900 mAh battery), I should note that it takes about 2 hours to charge on a standard charge.
The tablet charged in 3 hours 33 minutes, which is half an hour longer than charging from the mains (I only charged one device at a time).

In order for both Android devices to get the maximum from their charge, I had to solder a small adapter (which connected to apple USB), the HTC Sensation was connected to it.

I connected the following to USB socket number two: Ipod Nano, Ipod Touch 4G, Iphone 4S, Ipad 2. Since it’s ridiculous to charge the Nano with such a thing, it took a maximum of 200 mA from me, I checked the Touch 4g and iPad. The iPod was charged in 1 hour and 17 minutes from zero to 100% (albeit together with the IPAD 2). The iPad 2 took 4 hours and 46 minutes to charge (one).

As you can see, the iPhone 4S happily consumes its rated current.

By the way, Ipad 2 surprised me; it absolutely did not shy away from a circuit with short-circuited data contacts and consumed exactly the same currents as from the socket intended for it.

Charging process and conclusions

To begin with, let me remind you that all devices that use lithium batteries have a charge controller. It works according to the following scheme:

The graph is average and may vary for different devices.

As can be seen from the graph, at the beginning of the charging cycle, the controller allows you to charge with the maximum permissible current for your device and gradually reduces the current. The charge level is determined by voltage; the controllers also monitor the temperature and turn off charging at high temperatures. Charge controllers can be located in the device itself, in the battery or in the charger (very rarely).
You can read more about charging lithium cells.

Actually, here we come to the point why this topic is called: “Attempt number one.” The fact is that the maximum that I was able to squeeze out of charging is: 1.77A

Well, the reason, in my opinion, is not the optimally selected inductor, which in turn does not allow the Buck converter to produce its maximum current. I thought about replacing it, but I don’t have a tool for SMD soldering and don’t have any plans to do so in the near future. This is not a mistake of the designers of the board from ebay, it is simply a feature of this circuit since it is oriented to different incoming and outgoing voltages. Under such conditions, it is simply impossible to produce the maximum current over the entire voltage range.

As a result, I got a device that is capable of charging two smartphones at the same time or one tablet in a car in a reasonable amount of time.

In connection with the above, it was decided to leave this charger as is and assemble a new one, entirely with our own hands, based on a more powerful LM2678 converter,
which in the future will be able to “feed” two tablets and a smartphone at the same time (5A output). But more on that next time!

Android.

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