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Looking for an efficient USB charger that can operate from a 12V car battery? This unit functions at up to 89% efficiency and can charge USB devices at currents up to 525mA. Best of all, it won’t flatten the battery if it's left permanently connected, as long as you remember to unplug the USB device. There are lots of USB chargers on the market but this device has two stand-out features: high efficiency and low standby current. In fact, its standby current is just 160µA, a figure that’s well below the self-discharge current of most lead-acid batteries. This means that you can leave the device permanently connected and it will not cause that battery to go flat (or at least, not much faster than it would of its own accord). Picture of the project: Why is this useful? Well, in September 2009’s “Ask SILICON CHIP” section, D. E. of Ainslie, ACT asked if it was possible to connect a 12V-to-5V USB charger directly to the battery on a motorbike. His reason for wanting to do this is that ...

Description This is a portable battery powered USB charger circuit. This circuit is able to charge your PDAs, Ipods, Mp3 players and any device that plug in to a computer USB to charge. If you fit this circuit in a small box with a 9V battery then it will become a portable emergency USB charger. The schematic is so simple using only few components so you can make this circuit in some minutes if all parts available with you. The circuit is using low dropout regulator IC LM7805 which is easily available in the market and it is also very cheap. The circuit takes voltage from 9V battery and step down the voltage in to a DC 5V output.  Circuit Diagram  Source- http://circuitdiagram.org/usb-charger.html

This circuit is a simple test of USB ports, it is a circuit very useful for anyone working in the field of computer science. To be "stuck" in the PC USB port or an information display Notebook USB device not recognized, just after the yellow LED flashes 3 times, and since it is not a normal USB device, the connection is not established, and micro displays an error message. Tester for USB communication ports Circuit Diagram List of Components 1 Red LED 1 Led Yellow 1 Green LED 3 per 1k 1/8W Resistors 1 USB connector male Simple Test for USB communication ports Indications of LEDs when lit: Red - Polarization USB port was mounted inverted Yellow - Wire USB port data were linked inverted All Deleted - No power to the USB port Green and yellow lights flashing 3 times when turned on - Normal Operation

Create USB PowerInjector for GSM Modem Maximizing and stabilization USB voltage . Sometimes we need also to extend the USB cable connection. Usually cable so the store is no more or less than one meter. If the cable is good quality automatic reduction of voltage and current remain so flash media or a modem to function remained normal. Sometimes the two media are not readable because of a decline in flow due to cable resistance is very large, so that lost power wasted. USB injector circuit If this happens often flash or USB modem off often error-disconnected. To overcome this decrease in voltage performance. The principle is quite very simple. You simply "inject" is indeed voltage VCC 5VDC needed a modem or a flash. Finishing USB inject After using the USB power injector is expected regardless of the length of external cable fixed voltage maximum. The principle works is simple enough original 5VDC voltage of the CPU / your computer off and then injected...

Does this sound familiar: you buy a small piece of equipment, such as a programming & debugging interface for a microcontroller, and you have to use a clunky AC wall adapter to supply it with power? It’s even worse when you’re travelling and there’s no mains socket anywhere in sight. Of course, you can use the USB bus directly as a power source if the supply voltage is 5 V. If you need a higher voltage, you can use the USB converter described here. This small switch-mode step-up converter can generate an output voltage of up to 15 V with a maximum output current of 150 mA. The LM3578 is a general-purpose switchmode voltage converter. Figure 1 shows its internal block diagram. Here we use it as a step-up converter. The circuit diagram in Figure 2 shows the necessary components. Voltage conversion is achieved by switching on the internal transistor until it is switched off by the comparator or the current-limiting circuit. The collector current flows through coil L1, which stores ...

One tool that I’ve been missing at my lab at home is function generator. They tend to be a bit expensive, so I haven’t bought one. I thought this might be a good opportunity to try and make one myself. I found a pretty common DDS (direct digital synthesis) chip, called AD9833. Then just strap a USB-enabled AVR micro there and maybe some analog electronics.   This board doesn’t do any of the special analog magic to allow for variable amplitude or offset for the signal. The output is fixed to 0-4v. I’m planning to make another completely analog board for adjusting amplitude and offset.

I am quite sure that many of us have attended our fair share of trade shows and conferences over the years that we have amassed quite a collection of USB flash drives in our homes, so much so that these have become not valuable at all compared to the early days when a 32MB USB flash drive was all the rage, and hitting 1GB was like, “Whoa!”. Well, we just love the way that technology progresses over time, and here we are with the Kingston HyperX PREDATOR which offers a whopping 1TB of storage space, and fret not about spending huge amounts of time whenever you transfer data to and from it, as it will feature USB 3.0 connectivity to get the job done as fast as possible. Having the Kingston HyperX PREDATOR around is definitely a boon, especially for those of you who do plenty of traveling and yet need to carry a portable hard drive around. The physical dimension of it is extremely small compared to even the smallest 2.5” portable hard drive around, although the latter has now achieved the...

Want to comfortably enjoy your favorite coffee beside your computer? Take a look at the cookie shaped USB mug warmer, it may be able to catch your eyes. This is an interesting and practical USB mug warmer that measures 4 inches in length and 1 inch in width. As we can see from the images, the USB mug warmer is shaped as a chocolate sandwich cookie, and features delicious details and colors. Of course, you can put it into your mouths, but using integrated USB cable you can connect the cookie shaped USB cup warmer to your computer in order to keep your favorite beverage piping hot – up to 140 degrees. Apart from that, the mug warmer is compatible with all Mac and PCs. The cookie shaped USB mug warmer is priced at $14 USD. If you’re interested, jump to Urban Outfitters for more details.

This is a 5V to 12V DC-DC step-up (boost) converter circuitry that is especially ideal for the USB powered applications. First of all a USB port has two current supply modes. Before detecting the connected device, it supplies maximum 100mA to the load. After recognizing the device, it increases the output current up to 500mA. In this circuit, controller (LT1618) also provides two input current modes. 100mA and 500mA input modes can be selected by the user. USB 5V to 12V DC-DC Step-Up Converter by LT1618  Output currents are limited due to the increased potential difference at the output. When the demand of the load increases, output voltage will start to decrease. For example, if the circuit operates in the 100 mA input mode, when the load is 35 mA, the output voltage will be kept at 12V. But if the load increases to 50 mA, output voltage will reduce to 8V to maintain the constant 100 mA input current.

A very simple USB power supply electronic project Using the ISL6185 USB power controller family can be designed that provides fully independent overcurrent (OC) fault protection for two or more USB ports. Dual USB Power Supply Controller Circuit Diagram: This product family consists of sixteen individual functional product variants and three package options and is operation rated for a nominal +2.5V to +5V range and specified over the full commercial and industrial temperature ranges. Each ISL6185 type incorporates in a single package two 71mΩ P-channel MOSFET power switches for power control and features internal current monitoring, accurate current limiting and current limited delay to turn-off for system supply protection along with control and communication I/O. The ISL6185 family offers product variants with specified continuous output current levels of 0.6A, 1.1A, 1.5A or 1.8A. Due to all integrated features this power supply circuit is very easy to be designed and require few el...

Procyon is a general purpose development board with special features for Ethernet, USB, and audio applications. It is based on Luminary Micro/Texas Instruments LM3S9x9x series of parts. The initial MCU is LM3S9B90. The board contains the following features: 80 MHz, 100 Pin Cortex M3 Processor 16 MB SDRAM accessed on a 50 MHz EPI bus USB Host/Device/OTG port microSD card slot (Attached to SSI1/SPI1) 10/100 Ethernet I2S header for DAC output interface Up to 24 GPIOs available 3 UART, 2 I2C, 1 CAN, 2 SPI/SSI (one shared with microSD card) 10-bit ADCs General purpose timers: four 32-bit or eight 16-bit FTDI/Basic UART debug/program interface, on 16 pin GPIO/configuration header Three 10 pin headers for daughter boards 20 Pin JTAG Header User LED and User switch [ ]