Having to use a Raspberry Pi and other USB Devices in an electronics production environment where 5V isn't standard, I have noticed a lack of power supplies capable of fitting in. A unit had to be designed to fit into systems where 12V & 24V are the norm or where batteries / solar panels etc are the only supply method available.
Using only high performance parts, a solution was prototyped to meet this criteria. Only a few tweaks are needed to improve spacings, add mounting holes and to make the board completely production ready. The unit has a tiny form factor, only 56x21.5mm, meaning it is small enough to travel around with you.
Battery powered robots, adapting an old 9 or 12V wall charger, powering your Arduino / Raspberry pi in-car project, a simple and easy solution is here.
The power supply has been designed to power/charge the following devices:
- Raspberry Pi
- Arduino Boards
- Mobile Phones
- Other 5V USB Devices up to 2A constant draw
The power supply is constructed using high quality parts, to ensure long life and great stability in your application:
- Aluminium based PCB for exceptional heat dissipation
- Panasonic Polymer Hybrid Aluminium Capacitor for high stability and endurance
- X7R Dielectric Ceramic Capacitors
- Push button terminal block for easy and fast wire connection
- Texas Instruments regulator
- Low DCR Coilcraft Inductor
The unit features push-fit connectors so that it can be wired into your project in seconds whilst the status LED tells you that the output voltage is within regulation and the load is powered.
The power supply is designed with efficiency and stability in mind, bringing together high quality parts to create a quality solution. It uses switching regulator technology to maintain high efficiency and a small size. Operating parameters and features:
- 7-42V DC Input Voltage
- 2A Current limited and short circuit protected
- Use at-least a 12W PSU input for full (2A) output current
- Reverse input polarity protection
- Minimum 80% efficient across the input voltage range for 1A output
- 6V Input under voltage protection
- Output good, status LED
- 2.5ms controlled soft start to prevent input current spikes
Cheap Supply Comparison
As many of you are aware, less expensive alternatives on the market. However those converters use low cost, low quality parts. You know there is something wrong when you can buy one for less than £3.50 including VAT & Delivery in the UK. These supplies are usually not reverse input protected or over current/over temperature protected. They use slow, inefficient switching regulators and low quality capacitors. Over time they will degrade and eventually fail.
Switching converters get hot, the cheap supplies use regular FR4 PCB material which has a high thermal resistance, meaning they do not effectively sink heat away from the critical components. The life of components such as electrolytic capacitors degrade with use at high temperature, as they start to dry up. Eventually they become unstable for power supply operation.
This supply uses Aluminium PCB material to sink the heat away from components more effectively. Even with the output shorted the supply only rising 25°C above ambient, and then rapidly cool after the fact. This ability can be improved even more by mounting the unit on/in a metal enclosure, as it will use it efficiently as a heat-sink.
You will be protected if you wire it backwards. Instead of blowing up in your face, the unit's 'status good' indicator won't light until the unit is plugged in correctly. It will also current limit if the output load exceeds 2A, protecting your expensive device/circuit.
Update #2: 500mA Model
Whilst updating the PCB to V2 I realised there may be a need for a cut down version of the Supply, hence there will now be a 500mA version.
The 500mA version uses the same high quality power circuitry and layout as the 2A but with a lower current limit. There is also no Status LED circuitry and it uses an FR4 PCB instead of Aluminium, as the power dissipation requirement is much lower. It will also be offered less than retail price.
The Basic Model will be the exact same dimensions as the 2A version allowing mounting compatibility. The unit can be used where status indication isn't necessary, and where 500mA output current is sufficient. 500mA is a standard charging current for mobile phones and is usually plenty of power for user circuitry, however it is not suitable for the Raspberry Pi or Beaglebone.
The project funding will go towards bringing this unit into manufacture, buying components in bulk and delivering them to you at a fraction of the one-off cost.
1) Part purchasing - the components will be purchased on bulk reels from reputable distributors and manufacturers. Est. Completion: June 2014
2) PCB ordering - the PCBs will be made from a reputable and trusted manufacturer. The boards are aluminium based for exceptional thermal dissipation and ENIG (Electroless Nickel Immersion Gold) plated for great solder-ability and robustness. Est. Completion: June 2014
3) Assembly - the boards will be populated using the parts and PCBs purchased. This will be an entirely Lead-Free operation. Est. Completion: July 2014
4) Testing - the assembled units will be individually tested against strict tolerances under several loads to ensure quality in every one. Est. Completion: July 2014
5) Packing & Shipping - each tested unit will be packed into an anti-static bag along with an instruction card and shipped to you, along with my thanks. Est. Completion: August 2014
Risks and challenges
The unit has been designed to use multiple suppliers for components. Should it be that a certain component is unavailable at the time this project ends then the shipment date will be pushed back until it is in stock. However many distributors to seem to keep good stock of the required components at this time.
If all goes well the products will be sent to you on or before the estimated shipment dates.
- (30 days)