The Exigo USB Charger
The fastest, most powerful & intelligent charger.
The Exigo USB charger is designed from the ground up to be the best USB charger period. Boasting 3A current capability on all 4 ports and simultaneous compatibility with all existing charge standards, it is easily the most sophisticated high-power, 4 port USB charger available. The electronics are housed inside a CNC machined aircraft aluminum case and rests on an anti-slip neoprene pad. Dedicated RGB color LED lights indicate the status of each port and a graphic OLED display provides detailed information so you know if your devices are still nearly empty, nearly full or finished charging at a glance.
- 3000mA Current Capacity on All 4 Ports (12A Total)
- Automatic Negotiation of Device Charge Protocol
- Multi-Phase Voltage Regulation
- Charger Port Status Indication
- Billet Aluminum Housing
- Graphic OLED Display
- 5.00V +/- 10mV RMS Output Voltage (5.50V Turbo Mode)
- 3000mA Capacity (all 4 ports simultaneously)
- <0.1uV/sqrt(Hz) Spectral Noise (no load)
- Independent final stage voltage trim on all 4 ports via. 40MHz microprocessor control
- Independent current monitoring and limiting on all 4 ports w/1ms response
- All Major Charging Device Protocols Supported
The Exigo contains power delivery technology unlike any other charger. We’ve taken a page from the ultra-demanding requirements of modern aviation and medical reliability as well as high current demands from Intel i7 motherboards and integrated that multi-phase power technology into our charger. That means patent pending high current capability, low noise and robust components designed to handle dozens of amps of current. On top of that we added dedicated 3.0A microprocessor-controlled voltage regulators on every port. They provide active current and voltage monitoring, charge status analysis, over-current protection and extremely low noise output for every connected device.
Automatic Negotiation of Device Charge Protocol
The Exigo USB charger integrates dedicated intelligence to identify and provide native charger handshakes for 4 connection profiles and 7 families of devices – covering basically every mobile device ever made.
- Apple (2.5W) : D+ 2.0V / D- 2.0V (earliest iPods – 4th gen and older)
- Apple (5.0W) : D+ 2.0V / D- 2.8V (all iPhones & iPods, iPad Mini, etc.)
- Apple (10W) : D+ 2.8V / D- 2.0V (iPad 1, 2 & 3, iPad mini w/Retina, etc.)
- Apple (12.5W) : D+ 2.8V / D- 2.8V (iPad Air, iPad 4, etc.)
- Samsung (10W) : D+ 1.2V / D- 1.2V
- USB Charging Spec 2007 (7.5W) : D+ & D- shorted together
- Chinese Telecom Standard YD/T 1591-2009 : D+ & D- shorted together
Why does that matter?
When USB was first widely adopted by the market after the introduction of the USB 1.1 standard in 1998, the original specification for power only provided 150mA (0.75W). As time went on, additional specifications for 500mA (2.5W), 900mA (4.5W) and eventually 2A (10W) were established to supply bigger devices. If a device draws too much current the results could be as simple as the charger shutting down, or as disastrous as the charger overheating and self destructing. Because the same connector (USB) is used for all devices, there needed to be a way to indicate to the connected device whether or not it can safely draw higher current. That critical “high power OK” signal is provided through the data lines of the USB cable.
Unfortunately the need for higher power evolved quicker than the standards, so manufacturers developed different techniques to communicate the capacity of the charger to the device and they’re neither compatible with each other nor with the current USB power and charging specifications. This is the fragmented situation we’re in now – if you want to charge at the maximum rate a device supports you need an Apple-compatible charger to power an Apple device, or a Samsung-compatible charger for a Samsung device, etc. Most chargers either support one proprietary standard or one common standard and nothing else. So even if you do have a high-power charger, it probably only works best with one breed of devices. Many manufacturers side-step this issue by simply calling them “Universal,” but all that really means is it will charge anything at the lowest rate the device perceives as safe (usually 2.5W). A tablet that’s capable of recharging a dead battery at 12.5W in a couple hours could actually take 10 hours if it doesn’t recognize it’s connected to compatible charger.
To make sure the Exigo was the best possible charger we could offer, we performed in-depth testing of several existing chargers. We learned a lot about what makes a good charger and what doesn’t. We were surprised by the unpredictable way many devices reacted, but found at least one universal truth among them: devices prefer higher voltage. Provide less than 5 volts *at the device* and nearly everything starts drawing less power. Provide less than 4 volts and most devices won’t charge at all. This universal truth means performance is almost always degraded because of two common issues: low quality cables and chargers that can’t maintain 5 volts (or more) at full output. Armed with that knowledge and a host of other technology advantages, the Exigo outperforms all other chargers by addressing not just one device, but all devices, all cables and their mix of unique demands and preferences.
Quality & Noise
It doesn’t take very much voltage noise from a charger to affect the entire device, interfering with other systems and especially sensitive analog I/O like audio. Higher levels of noise will result in even more stress on your device. If you’ve ever tried to listen to music while charging your device – you’ve probably heard some of this yourself.
Some of the most common quality issues we’ve encountered with existing chargers include electrical noise, poor voltage accuracy and – in extreme examples – poor protection circuitry which can even lead to electrocution. Electrical noise is an issue common to all switching power supplies, but the level of noise found in some USB power supplies can be immense. We’ve measured more than 1000 mV of noise on some with several suffering from at least 200-300 mV. Most modern devices will survive even extreme levels of electrical noise, but long term affects are largely unknown. By contrast the combination of multi-phase technology and dedicated linear regulators in the Exigo provides the cleanest, most accurate power delivery in the industry.
The trend towards small cube chargers that plug directly into the wall outlets have shrunk power electronics to their physical limits. This means the isolation between dangerous household voltages and the low voltages used to charge your portable devices is also very slim. Everything is crammed into that little cube very close together. When corners are cut and substandard designs are used to lower cost, that close proximity can become dangerous and even fatal. Fires and electrocutions from sub-standard chargers have been documented all over the world. While not a common occurrence, it’s a real danger that consumers should be aware of and provides good reason to avoid cheap imitation chargers. We’d like to think that everything we buy is tested by UL or certified to rigorous CE standards but unfortunately these days many manufacturers rubber stamp their products, sneak through the safety and quality systems and deliver the cheapest possible product to your door.
Over the course of our own testing, we also experienced a dangerous failure when one of the prongs came out of the charger and stayed in the outlet – still energized at 120VAC.
Our 66W charger has 5x the total capacity of even the largest Apple USB charger so we need to take a rather different approach to the cheap cube chargers. We utilize an external power adapter that’s CE & UL listed to convert household voltage to 24VDC. Then the Exigo’s patent pending internal multi-phase converter and individual regulators fine tune and filter the final supply voltage to a current limited, precision output for each and every port. This combination increases safety and quality and reduces time to market. It also means the Exigo can run directly on 12 to 24V vehicle or battery power – making it the perfect travel companion. (It would also provide high utility by accepting a flexible range of power sources in the event of a zombie apocalypse…just sayin’…)
Apart from the negotiation issue, many chargers are also rated at specifications they can’t really provide. A charger may claim 2.1A current capability, but many lower the output voltage to 4.0, 3.0 or even 2.0 volts to achieve that current. Standards like the USB battery charging spec allow a deterioration to a dismal 3.6V at full current output. That’s nearly a 30% reduction in power. Even if your device manages to continue charging at such low voltages (most will not), it will be considerably slower. Our robust multi-phase converter and microprocessor controlled regulators ensure maximum power is delivered whether your device is sipping only 0.1A or drawing the full 3.0A capacity with zero voltage drop.
Development / Prototypes
First Stage: Multiphase Power Converter
We’ve already built and tested the multi-phase power subsystem. Its robust high current design easily handles the full load of 66W and will be integrated into the final product without any significant modifications.
The term “multi-phase” means pretty much what it sounds like – you have more than one phase of synchronized power conversion. This provides several advantages over single phase converters. First – you get to divide and conquer. Each circuit is only handling a fraction of the total power, so components can be smaller, transient load handling adjustments are smaller, ripple currents and switching noise are also reduced. Second – you effectively multiply your conversion frequency – allowing you to get all the benefits of higher frequencies (faster transient response, smaller loads, smaller components). And you get that without actually increasing your switching speed which can cause decreased efficiency through higher switching losses, reduced current limit accuracy and higher dropout voltage.
Second Stage: Output Regulators
Supplied by the multi-phase power converter, our USB output subsystem prototype utilizes dedicated 3.0A voltage regulators on every port. In the prototype they are adjusted via trim-pots, but in the final product they will be actively monitored and controlled with a 70MHz 16-bit PIC micro-controller. That combination provides active current and voltage monitoring, charge status analysis, over-current protection and extremely low noise output for every connected device. The data lines on each port are separately controlled by a dedicated auto-negotiation chip that identifies the connected device and sets up the connection to always enable maximum performance (included in this prototype and successfully demonstrated in our Kickstarter video).
The Exigo’s graphical OLED display eliminates any question as to how fast your device is charging by telling you exactly what’s happening in real time. Detailed charge current, voltage and elapsed time are displayed simultaneously for all four ports. Each port also includes a multi-color RGB LED to give you color-coded status information at a glance.
We’ve machined a prototype case out of aluminum to verify it has the look and feel we’re after. Since building this, we’ve added the OLED display above and will integrate that in a final prototype assembly soon. The exterior will have a satin finish similar to the prototype, anodized in clear, black, blue and red colors. The special edition offered only during the Kickstarter will be nickel plated for a one-of-a-kind, luxurious finish.
Who We Are
Patrick Marcus, PhD
Dr. Patrick Marcus is the President of Marcus Engineering, LLC and a principal of Apparently Connected, LLC. Dr. Marcus has a bachelors of science in Electrical Engineering, cum laude, and a PhD in Biomedical Engineering with a minor in Neuroscience from the University of Arizona. Dr. Marcus is also a graduate of the McGuire Entrepreneurship Program at the Eller College of Management. Dr. Marcus has extensive background in electronics design, industrial automation, and design for manufacturing. Dr. Marcus has founded and run several successful companies in technology and high reliability industrial manufacturing.
Nathan Crum is a principal of Apparently Connected, LLC. Nathan has a bachelors of science in Mechanical Engineering from Montana State University. Nathan has extensive background in mechanical engineering, machine design, material handling and thin film vacuum coating systems. Nathan has independently designed and delivered millions of dollars of innovative new products and custom machinery in the material handling and vacuum coating industries.
Back our Project
Help us complete the Exigo and be one of the first to own the most sophisticated high power, multi-port USB charger on the planet. The link to our project on Kickstarter will be coming very soon…