+
+
+
Vin-12v
Boost
V-boost1
V-boost2
V-boost6
1A
1B
3B
I-Led6
I-Led2
I-Led1
F28027
3V3
Comms
CPU
32 bit
DSP core
60 MHz
I C
SPI
UART
2
ADC
12 bit
4.6 MSPS
I-Led1
I-Led2
I-Led8
V-boost1
V-boost6
V-sepic1
V-sepic2
1A / 1B
2A / 2B
3A / 3B
4A / 4B
PWM1
(HR)
PWM2
(HR)
PWM3
(HR)
PWM4
(HR)
Vref
Hardware Overview
Figure 3. LED BoosterPack Circuit Diagram
3.1
Subsystems
The LED BoosterPack board is divided into functional groups referred to as subsystems. The following is a
list of the subsystems present on the board and brief descriptions of each:
•
Power Supplies
– Power is supplied to the board via a 12 V AC/DC wall adapter. This power is
stepped down using the Buck regulator to generate 5 V. The 5 V is used to power a 3.3 V LDO that
supplies power to the 3.3 V device present on the BoosterPack. Both the 3.3 V and 5 V power
domains can be selectively jumpered (via J2 and J8, respectively) to supply power to the
LaunchPadXL headers.
•
Boost Converters
– Boost converters are used to step up the 12 V input voltage to a voltage high
enough to forward bias the LEDs. The boost converters are driven by the EPWM peripheral present on
the F28027 device on the C2000 LaunchPad™.
•
Current Feedback
– Shunt resistors at the base of each LED string are used to convert the LED
current into a voltage that can be measured. The voltage from the sense resistors is passed to a set of
op-amps to amplify and filter the current feedback signal. They also serve the purpose of driving the
analog-to-digital converter (ADC) inputs.
•
MSP430 Capacitive Touch
– The LED BoosterPack includes an MSP430 device and headers such
that a Capacitive Touch BoosterPack can be plugged into the LED BoosterPack and used to control
the LEDs. Switch S1 can be used to connect or disconnect the MSP430’s serial peripheral to the
F28027 device’s serial peripheral present on the C2000 LaunchPad. If the user wishes to use the
capacitive touch demo, ensure S1 is in the up position while S4 on the LaunchPad is in the down
position.
–
Advanced users can reprogram the MSP430 present on the LED BoosterPack by using J5.
6
C2000 LED BoosterPack
SPRUHH9 – July 2012
Copyright © 2012, Texas Instruments Incorporated
