Atmel STK526, Руководство пользователя, Страница: 7 / 38

Using the STK526
STK526 rev. B Hardware User Guide 2-7
7709B–AVR–05/07
EXT (JACK)
VBUS
STK500
5V
3V3
AT90USBxx2
Vsource
(VCC SOURCE)
Internal
3V3 100mA
Regulator
(1) (2)
UVcc
Vcc
Ucap
NOREG INTREG
REG5V
REG3V3
VBUS
STK
(3V3 REG)
2.2 Power Supply
The on-board power supply circuitry allows various power supply configurations.
Because the AT90USB82/162 contains an internal 3V3 regulator that can be used to
power an external circuitry, several power configurations are handled by the STK526.
The power path is represented by the figure below :
Figure 2-2 . STK526 Power Configuration
First, the board allows to drain power from three external sources, leading to four
different solutions. The selected voltage is applied to the regulator input of the
AT90USB82/162. Then user can choose to power the MCU I/O either directly with the
primary power source (external 5V/3V3), or from the internal regulator itself (MCU auto-
power).
2.2.1 Power Supply Sources
The power supply can come from three different
(3)
sources:
USB connector,
JACK PWR connector (J5, See Figure 2-3),
STK500
USB powered: When used as a USB device bus powered application, the STK526 can be powered via
the USB VBUS power supply line.
JACK PWR connector: – Need of a male JACK outlet,
– Input supply from 9 up to 15V
(1)
DC,
– No specific polarization
(2)
is required.