Справочник Пользователя для Itron MINI1
Riva Edge Mini HW Design and User Guide
Rev 1.01
ITRON PROPRIETARY & CONFIDENTIAL INFORMATION
For Reference Only, Printed: 3/6/2018
Page 14 of 49
I
TRON
R
IVA
D
EV
M
INI
P
OWER
H
ANDLING
P
OWER
I
NPUT
The Mini requires a single +5 VDC supply. The input voltage should be within 4.75 VDC and 5.25 VDC.
+5
VDC
SUPPLY
The Itron Riva Dev Mini requires an input power supply of +5 VDC. This can be supplied through the
mini-USB connector or through the expansion connector. The +5.0 VDC supply derives from one of
two sources: U57, the mini-USB connector or from the expansion header pins 1 and 2. In either case
this board can consume a peak of about 6 watts during full power transmissions.
mini-USB connector or through the expansion connector. The +5.0 VDC supply derives from one of
two sources: U57, the mini-USB connector or from the expansion header pins 1 and 2. In either case
this board can consume a peak of about 6 watts during full power transmissions.
+5 VDC from USB
When the Itron Riva Dev Mini is powered through the mini-usb connector it will provide +5 VDC
power to the expansion connector pins 1 and 2. There is a circuit to limit the inrush current to prevent
the host from triggering an over-current error. Once the initial period of current limiting ends the
the host from triggering an over-current error. Once the initial period of current limiting ends the
TPS2151 will allow up to 1.6 amps to flow from the USB Host. Note it is up the system firmware to
provide the configuration and protocol operations to request the maximum required current from
provide the configuration and protocol operations to request the maximum required current from
the host port. Careful attention to this detail must be followed for adding external circuitry.
+5 VDC from Expansion Header
If the mini-USB port is not used as a power source +5 VDC may be supplied through the expansion
connector pins 1 and 2. Currently, for the first prototype run, this will not provide power to the mini-
USB port. It should be possible to put a diode where R21 is to allow powering the mini-usb from the
expansion +5 VDC input.
connector pins 1 and 2. Currently, for the first prototype run, this will not provide power to the mini-
USB port. It should be possible to put a diode where R21 is to allow powering the mini-usb from the
expansion +5 VDC input.
P
OWER
O
UTPUT
+5 VDC to USB
When powered from the USB connector the current limited +5 VDC is routed to the Expansion header
to provide power for additional circuitry.
to provide power for additional circuitry.
+3.3
VDC
SUPPLY
T
O
E
XPANSION
C
ONNECTOR
(3V3_EXP)
There is a 3.3 VDC regulator connected to the +5 VDC signal to create an expansion power supply for
use by the user. This rail is gated by a signal from the iSOM which tells the system that the iSOM is
use by the user. This rail is gated by a signal from the iSOM which tells the system that the iSOM is
powered on and ready. This supply rail is limited to 250ma.
U
SER
P
OWER
S
UPPLY
W
ARNING
When adding hardware to the interface connector it may be required to create additional power
supply rails or higher current supplies. It is important to not connect any of these voltages to the
Itron Riva Dev Mini before the A8 has its power rails in place and steady. Having a voltage on an I/O
Pin on the A8 before it has its Vdd supply can cause permanent damage to the A8.
supply rails or higher current supplies. It is important to not connect any of these voltages to the
Itron Riva Dev Mini before the A8 has its power rails in place and steady. Having a voltage on an I/O
Pin on the A8 before it has its Vdd supply can cause permanent damage to the A8.
If you need to create your own power supplies make sure you gate them with 3V3_EXP because
3V3_EXP will not rise until the A8 supply rails are ready. This will prevent you from damaging the A8
processor or other circuitry.
3V3_EXP will not rise until the A8 supply rails are ready. This will prevent you from damaging the A8
processor or other circuitry.