Ublox EVK BMD-345, Руководство пользователя

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EVK BMD-345 - User guide
UBX-19051533 - R01 Hardware description Page 6 of 27
2 Hardware description
Design files for the BMD-345 evaluation board may be requested from the u-blox support team .
Figure 2: Features (Top view)
2.1 Power
The BMD-345 evaluation board has four possible power sources:
•
USB from the debug interface
•
USB from the BMD-345 interface
•
2.54 mm through-hole connector for connecting 3.3 V
•
Lithium Polymer (LiPo) battery input
These power sources use protection diodes to prevent reverse voltage to any supply. This allows them
to be used simultaneously. Solder jumpers are provided to allow by-passing any of the protection
diodes eliminating the voltage drop across them.
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Care should be taken to not damage the supplies when the protection is by-passed.
2.1.1 Powering the board
During typical debugging, power will be provided by VBUS on the USB debug interface to supply 5 V to
the 3.3 V LDO regulator and to the shield connector. The 3.3 V LDO regulator will then power VIO,
VSHLD, and VBMD.
When powering the board from the external power header or the LiPo header, USB can be left
disconnected. In this configuration, the interface IC is held in reset to conserve power.
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Only if the power protection diodes are left intact can the USB be safely connected at the same
time as the external power is still applied, which allows for easy programming of the module.