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!
P.S.:
1. The text may contain punctuation, grammatical and semantic errors, please report them in a personal message.
2. Thoughts, ideas, technical corrections and control points from more experienced comrades are, on the contrary, welcome in the comments.
3. I apologize for any technical inaccuracies, because... Until recently, I was not involved in electronics and circuit design.
Thank you for your attention, good luck and inexhaustible optimism to everyone!
Problems when charging various devices via USB often arise when non-standard chargers are used. At the same time, charging occurs rather slowly and incompletely or completely absent.
It should also be said that charging via USB is not possible with all mobile devices. They have this port only for data transfer, and a separate round socket is used for charging.
The output current in computer USB is no more than half an ampere for USB 2.0, and for USB 3.0 – 0.9 A. For a number of devices, this may not be enough for a normal charge.
It happens that you have a charger at your disposal, but it does not charge your gadget (this may be indicated by a message on the display or there will be no charge indication). Such a charger is not supported by your device, and this may be due to the fact that a number of gadgets scan for the presence of a certain voltage on pins 2 and 3 before starting the charging process. For other devices, the presence of a jumper between these pins, as well as their potential, may be important.
Thus, if the device does not support the proposed type of charger, then the charging process will never begin.
In order for the device to start charging from the charger provided to it, it is necessary to provide the necessary voltages on the 2nd and 3rd USB pins. These voltages may also differ for different devices.
Many devices require that pins 2 and 3 have a jumper or resistance element whose value is no more than 200 ohms. Such changes can be made in the USB_AF socket, which is located in your memory. Then it will be possible to charge using a standard Data cable.
The Freelander Typhoon PD10 gadget requires the same connection circuit, but the charge voltage must be at 5.3 V.
If the charger does not have a USB_AF socket, and the cord comes out directly from the charger case, you can solder mini-USB or micro-USB plugs to the cable. Connections must be made as shown in the following picture:
Various Apple products have this connection option:
In the absence of a 200 kOhm resistance element on pins 4 and 5, Motorola devices cannot carry out a full charge.
To charge the Samsung Galaxy, you need a jumper on pins 2 and 3, as well as a 200 kOhm resistor element on pins 4 and 5.
It is recommended to fully charge the Samsung Galaxy Tab in gentle mode using two resistors with a nominal value of 33 kOhm and 10 kOhm, as shown in the picture below:
A device such as E-ten can be charged by any charger, but only on the condition that pins 4 and 5 are connected by a jumper.
This scheme is implemented in the USB-OTG cable. But in this case, you need to use an additional male-to-male USB adapter.
The Ginzzu GR-4415U universal charger and other similar devices have sockets with different resistor connections for charging iPhone/Apple and Samsung/HTC devices. The pinout of these ports looks like this:
To charge your Garmin navigator, you need the same cable with a jumper on pins 4 and 5. But in this case, the device cannot charge while in use. In order for the navigator to be recharged, it is necessary to replace the jumper with a resistor rated 18 kOhm.
Tablets usually require 1-1.5A to charge, but as mentioned earlier, USB ports will not be able to charge them properly as USB 3.0 will only output 900mA maximum.
Some tablet models have a round coaxial socket for charging. In this case, the positive pin of the mini-USB/micro-USB socket does not have a connection to the battery charge controller. According to some users of such tablets, if you connect the plus from the USB socket to the plus of the coaxial socket with a jumper, charging can be carried out via USB.
You can also make an adapter for connecting to a coaxial socket, as shown in the figure below:
Here are the jumper diagrams indicating the voltage and resistor values:
As a result, in order to charge various gadgets from non-native chargers, you need to make sure that the charging produces a voltage of 5 V and a current of at least 500 mA, and make changes to the USB socket or plug according to the requirements of your device.
Convenient storage of radio components
Many modern cars have modules with several USB outputs for power. By and large, several USB sockets are necessary in any car, because you often have to charge your phone, tablet, camera, and you also need to connect a navigator and recorder.
It's high time to make a neat panel with USB sockets in your car. And assembling it yourself is not at all difficult and not expensive, even for .
To assemble a USB power supply you will need at a minimum:
- microcircuit voltage stabilizer 5 V;
- two capacitors: both 25 V or only one and the other 10 V (the capacitance values of the capacitors depend on the selected stabilizer and will be determined later);
- 1 A semiconductor diode;
- socket types: 1USB-A or 2USB-A;
- connecting wires of small cross-section - no more than 0.5 mm2.
Microcircuit stabilizers voltages for assembling a USB power supply are preferable because they:
- capable of operating within a wide range of input voltages 7 – 20 V;
- have an overcurrent protection system;
- equipped with an overheating protection system, which limits the output current when the microcircuit crystal heats up.
One USB connector can be powered from a 78L05 stabilizer: Imax =0.1 A, Pmax =0.5 W, TO-92 housing.
Two or more USB connectors must be connected to power from 78M05 or 7805 stabilizers.
The 78M05 microcircuit has the following characteristics: Imax = 0.5 A, Pmax = 7.5 W, housing TO-202 or TO-220.
Chip 7805: Imax =1.5 A, Pmax =10 W, TO-220 package.
Series 78 stabilizers are manufactured in a package that makes them look like transistors.
The pinout for microcircuits 78M05 and 7805 is as follows:
- the first pin on the left is the input (if you look at the body from the marking side);
- average – general;
- the third is the exit.
The 78L05 chips have the opposite pinout than the 78M05 and 7805 chips.
When assembling the circuit, you need to take into account that the common pin of microcircuits 78M05 and 7805 is connected to their metal heat sink, so when installing the stabilizer on a radiator, do not short-circuit the remaining elements of the circuit. But it is still advisable to screw the microcircuit to the radiator, because the stabilizer in this case will work better (remember that microcircuit stabilizers limit the current on the load when overheated).
Semiconductor diode needed to limit current surges when switches or relay contacts are turned on, through which a stabilization circuit can be connected.
Capacitors you need to put 10 μF each, and not 47 μF, if you use a less powerful 78L05 stabilizer in the circuit, and not the 78M05 and 7805 microcircuits. In terms of voltage, the capacitors, as mentioned earlier, should be selected for 25 V each, or the output capacitor can be set to 10 V.
Light-emitting diode It is not required as a power indicator, but it helps to visually determine the presence of voltage at the output and the serviceability of the stabilization circuit.
Resistor It is not necessary to set it to 160 Ohms, because with such a damping resistance the LED may shine too brightly. The quenching resistor can be selected with resistances: 270 Ohm, 300 Ohm, 470 Ohm.
Having assembled the voltage stabilization circuit, you need to connect it to the USB socket: output plus 5 V - to the plus contact of the USB supply voltage; common output to – common contact of the connector.
The pinout of the USB sockets is as follows:
- the first contact on the left is common (if you look at the connector contacts from above);
- the second is a plus data bus;
- the third is a plus data bus;
- the fourth is the plus supply voltage.
Of course, you will not transfer any data using the USB socket as a power source, so do not pay attention to the second and third pins of the connector.
Where to install USB power sockets in a car is a personal decision for each master. But as a recommendation, we can say that it is convenient to place several connectors along with the assembled circuit on a separate panel cut out of a plastic or aluminum plate. You can also install a small switch on this small console that will turn off the voltage at the input of the stabilization circuit. The ready-made socket with USB connectors is very easy to install in a convenient place inside the car.
Simple monoblock car amplifier based on TDA1560Q 
Automotive throttleless power supply based on IRS2153 for laptops and mobile phones
Probably some of us have had trouble in the form of a flash drive with a lot of useful information breaking down. Moreover, most often the flash drive dies for a mechanical reason - it is simply damaged in the USB connector due to accidental exposure to a break. Some flash drives die due to hardware reasons. Unfortunately, not all attempts to repair the storage medium are successful. However, the design of a flash drive, especially older types, contains a full-fledged male USB connector. Instead of throwing away an already useless gadget, we use it to make a USB charger. Most advanced cell phones charge when connected to a USB port. To enhance the motivation for making a USB charger with your own hands, let’s imagine a case where a cell phone is discharged at work, but there is no charger, or there is a charger, but there is no free socket and, as luck would have it, there is no cable connecting the phone to the computer. This is where USB charging comes in handy.
The design is designed for charging advanced NOKIA phones with a “thin” plug. There is nothing complicated in making a charger. The power supply voltage of the USB port is supplied to the charging plug via two wires without the presence of any intermediate electronic elements. The manufacturing sequence is simple:
1. We disassemble the flash card and carefully use a soldering iron to unsolder the electronic part from the connector.
2. Solder two wires to the USB connector. I cut a piece of the two-wire cable from the old charger. The connector pinout is shown in the table. We are only interested in contacts No. 1 and No. 4. One conductor (I had it red) was soldered to contact No. 1, and the other to contact No. 4.
| Pin no. | Designation | Description |
|---|---|---|
| 1 | V BUS | Power supply, +5 V |
| 2 | D– | Data |
| 3 | D+ | Data |
| 4 | GND | Ground (body) |
3. Depending on the design of the donor flash drive case, we secure the connector with wires. In my case, the connector with wires was filled with hot glue on the movable platform of the case.
5. A “thin” plug was soldered to the stripped wires of the other end of the cable. Do not forget Before soldering, place the plastic connector cap on the cable. The wire from pin No. 1 must be soldered to central charging connector plug. Soldering must be done carefully and carefully insulate at least one conductor to prevent short closures.
6. We use a tester to check the correctness of the soldering, for example, the presence of a connection between contact No. 4 and the charging connector (external cylindrical contact) and the absence of a short circuit between contacts No. 1 and No. 4.
7. We finally assemble the charger and test it on a live phone.
This homemade product is successfully used on business trips. A homemade cell phone charger takes up little space in your luggage and if it is forgotten or lost, the damages are minimal.
In modern times, we have more and more electronic devices. Smartphones, tablets, smart watches, MP-3 players. Charging them at the same time sometimes becomes a task. You can, of course, take an extension cord for a certain number of sockets and organize your own charging corner. I usually don’t use my smartphone when charging.
I decided to make my own charging station for charging. It takes up one outlet and is not difficult to make.
Will need
The basis is an old power supply from a computer. I received the board without a case. There is no standby source on the board and there are no 3.3 volt elements. It feels like it wasn't there. Everything looks neat.
In the bins I took the case from the computer power supply. You can use any suitable one. But the board has the right place in this case.
USB sockets were ordered from China. I decided to install 7 pieces. I didn't want to put it too closely. Of course, you can arrange it differently, then more will fit. I am satisfied with this quantity.
My mains switch is the T3 toggle switch. Any one can be used. My toggle switch breaks both network wires.
The indicator is a domestic LED. I connect it through a 1 kOhm current-limiting resistor to a 12-volt line.
I will install the USB on PVC plastic. I really like this plastic, it is very easy to work with.
We make a charging station for USB gadgets
I mark the holes for the sockets. Also under the power switch and LED. I mark it on the protective film.
I cut out all the windows and drill holes. I remove the protective film.
I duplicate the holes on the power supply housing panel. I paint their PVC panels. I also paint the lower part of the power supply housing.
I also painted the housing cover. I paint everything with matte paint, I had this in stock.
I unsolder the original power supply wires. Instead of soldered wires, I solder in a couple of others. Green minus, red plus. The twisted wire will go to the LED.
I screw the panel on. I'm installing a switch. I also reinstall the network connectors (I removed them when painting).
I install the nests in the windows and secure them with thermal glue. The LED was also secured with glue.
I connect the positive contacts to each other, and the negative contacts too. I soldered a resistor to the LED, and hid the resistor in a heat-shrinkable tube. Soldered the power to the LED.
I soldered the positive and negative wires from the board to the jumpers of the USB sockets. There was a piece of plastic left from the old project, which was used to fix the USB. The nests are firmly seated. The main thing is not to overdo it with hot glue; you can fill the springs in the sockets. I had to soften the glue a little; the connectors did not fit into the socket.
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