Phytec phyCORE-i.MX27, Hardware Manual

Page: 35 / 100

Power Requirements
©
PHYTEC Messtechnik GmbH 2011 L-710e_5
27
4 Power Requirements
The phyCORE-i.MX27 normally operates off two different voltage supplies denoted as VIN and
VCC_3V3 . The MC13783 primary on-board voltage regulator operates off VIN and generates all
on-board supply voltages except 3.3 V. The VCC_3V3 input supplies this required voltage.
Because of its wide input voltage range VIN is ideally suited for a battery. VCC_3V3, however, has a
very narrow input voltage range and must not be connected to a battery. A well regulated supply
should be used for VCC_3V3.
The phyCORE-i.MX Carrier Board generates VCC_3V3 from VIN with a 3.3 V voltage regulator on the
Carrier Board. VIN is sourced from either the wall socket input, or a battery. The Carrier Board also
controls charging the battery when the wall socket is used.
You should refer to this example circuitry
when designing your own Carrier Board.
If your system does not require a battery then you can connect VIN and VCC_3V3 together and
supply both inputs with a 3.3 V input voltage. This will simplify the design and reduce the component
count. In this case make sure that the X_CHARGER_INPUT_3-20V is connected to a power supply
>4.4V. You also have to design a 0.02R resistor between X_POWER_BATT and X_BATTISNS and a
22µF capacitor at X_POWER_BATT. Put both components as close as possible to the module
connector. (
see Figure 8 and Table 3 )
Figure 8: minimum circuit