Dialog DA9026 Manual do utilizador - Página 4

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User Guide - Preliminary

Hardware

The DA9026 Lightshow Processor Evaluation Board
comprises the DA9026 device, a USB-I2C bridge for
communication with the device, a 2.5V core voltage
regulator, a 4.0V regulator to power the device from the
USB 5V supply, and a set of six full color LEDs.
The DA9026 device contains a 5V DCDC converter, but it
has not been used in the simple evaluation module.
There are only four connections from the USB interface to
the PCB; +5V, GND, I2C Clock, I2C Data.
Figure 1. The DA9026 lightshow processor evaluation board

Power supplies

The Evaluation Board is designed to operate from an
external power source in the range 2.7V to 4.0V. The
current taken from the supply will depend upon the number
of LEDs energized.
In the standby state, the USB interface module will
consume about 120mA. A typical pattern will consume
about 150mA form the USB bus.
Vcore regulator
The DA9026 device uses a digital power supply voltage of
2.5V supplied externally.
The LED currents are relative to this supply.
The Evaluation Board includes a fixed 2.5V linear regulator.
© Dialog Semiconductor 2005. All rights reserved.
DA9026 Evaluation Board

LED supplies

In order to minimize power dissipation, it is desirable to
operate the LEDs with as low a cathode voltage as
possible. The current sink outputs IB1-6 require a voltage of
approximately 0.6V to maintain accurate current.
Any voltage above this represents wasted power.
The minimum voltage at the cathode of the colored LEDs is
therefore VF(max)+0.6V.
CONFIDENTIAL
DA9026-UG04-0705
DA9026
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