![\"\"](\"http:\/\/embedded-lab.com\/blog\/wp-content\/uploads\/2012\/05\/PowerSupplyTitle.jpg\" "\\"PowerSupplyTitle\\"")
<\/a>Dual power supply regulator board<\/p><\/div>\n
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The regulator circuit uses two AMS1117 series fixed voltage regulators, AMS117 5.0 and AMS1117 3.3, to derive constant 5.0V and 3.3V outputs from an unregulated DC input voltage. The circuit diagram of the board is shown below.<\/p>\n
<\/a>Dual power supply regulator circuit<\/p><\/div>\n
Note that both AMS1117-3.3 and\u00a0AMS1117-5.0 derive input power directly from the unregulated supply voltage, which means each of them can deliver up to 0.8A of current. However, for this particular board it is recommended to limit the output current up to 500 mA maximum. For the safety of the AMS1117-3.3 regulator IC, the unregulated input voltage is also recommended to be within 6.5 to 10.0 V. This board is best to use in a project that is designed tobe powered with a 9V DC from either a PP3 battery or a wall adapter. The PCB is only 1.9″ x 1.4″, and occupies a small area inside the project box.<\/p>\n
<\/a>Assembled regulator board<\/p><\/div>\n
The board doesn’t have any ON\/OFF switch, because it may not be useful if this board is enclosed inside the project box. But through-hole pads are provided on the board if you want to add one externally. There are two surface mount pads which are shorted together by default with solder to close the circuit permanently. These must be disconnected if an external ON\/OFF switch has to be added.<\/p>\n
<\/a>Shorted pads for continuous power supply<\/p><\/div>\n
The regulated output voltages (5V and 3.3V) are accessed through screw terminal blocks. This power supply board can also be used to power breadboard circuits (see the picture below).<\/p>\n
<\/a>Power supply for breadboarding<\/p><\/div>\n
I have made few PCBs of this using iTeadStudio’s PCB service. If anybody need one, contact admin(at)embedded-lab(dot)com. It will be $5.50 for one PCB, $10.25 for kit (one PCB along with the components shown in the circuit diagram), and $11.99 for assembled board. Shipping (regular USPS) within the United States is included in the price<\/strong>.<\/p>\n Update (02\/26\/2013)<\/strong><\/span><\/p>\n This board has been revised a little bit. The new board can have maximum DC input of +15V, but I would recommend to use below +12V to prevent overheating of the regulators. In the new board, the input to AMS1117-3.3 is derived from the output of AMS1117-5.0, so maximum recommended output current is 600 mA combined (5.0V and 3.3V). The price of the new assembled board is $10.50 plus shipping and can be purchased on Tindie<\/a><\/strong>. You will get a free 9V battery connector with the board. Following are the pictures of the new board.<\/span><\/p>\n Revised version of dual power supply regulator board<\/p><\/div>\n Input voltage from a 9V battery or a wall adapter<\/p><\/div>\n Update (08\/12\/2013)<\/strong><\/p>\n A new version of this board is released with a further reduction in the PCB size.<\/p>\n<\/a><\/a>