DEMO CIRCUIT1039
QUICK START GUIDE
LTC3207/LTC3207-1
LTC3207/LTC3207-1
600mA Universal Multi-
Output LED/CAM Driver
DESCRIPTION
WARNING!
Do not look directly at operating LED.
This circuit produces light that can damage eyes.
Demonstration circuit 1039 is a 600mA Universal Multi-
Output LED/CAM Driver with six white LEDs, two RGB
LEDs, and a camera flash featuring the
LTC3207/LTC3207-1.
The LTC3207/LTC3207-1 is a low noise charge pump
designed to drive 12 universal LED (ULED) current
sources and one high current camera flash. The
LTC3207/LTC3207-1 requires only five small ceramic
capacitors to form a complete LED power supply and
current controller.
The maximum display currents are set with an internal
precision current reference. On/Off blinking, gradation,
and intensity are achieved via an I
2
C serial interface. See
the LTC3207/LTC3207-1 data sheet for more information
on this process. There are 64 dimming states available
for the universal LEDs and 16 dimming states for the
camera LED.
The charge pump optimizes efficiency based on the volt-
age across the LED current sources. The part powers up
in 1x mode and will automatically switch to boost mode
whenever any enabled LED current source begins to drop
out. The first dropout switches the part to 1.5x mode and
a subsequent dropout switches the part into 2x mode.
The part resets to 1x mode whenever a data byte is up-
dated via the I
2
C port.
Design files for this circuit board are available. Call
the LTC factory.
L
, LTC, LTM, LT are registered trademarks of Linear Technology Corporation. Other product
names may be trademarks of the companies that manufacture the products.
QUICK START PROCEDURE
Demonstration circuit 1039 is easy to set up to evaluate
the performance of the LTC3207/LTC3207-1. Refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below:
NOTE.
When measuring the input or output voltage ripple, care
must be taken to avoid a long ground lead on the oscilloscope
probe. Measure the input or output voltage ripple by touching the
probe tip directly across the VBAT and GND terminals. See
Figure 2 for proper scope probe technique.
3.
Connect DC1039 to the DC590 USB Serial Controller
using the supplied 14-conductor ribbon cable as
shown in Figure 1.
4.
With power off, connect the input power supply to
VBAT and GND with a series ammeter and a voltmeter
as shown in Figure 1.
5.
Turn on and set the input power supply between 2.9 –
5.5V. The DC1039 has an extra 4.7uF de-coupling ca-
pacitor between VBAT and GND to help accommodate
long VBAT source lead lengths. The DC590 board gets
its power from the USB cable.
NOTE.
Make sure that the input voltage does not exceed 6V.
1.
Refer to the DC590 Quick Start Guide for QuikEval
TM
setup and software installation details.
2.
Make sure the USB cable is connected between the
computer and the DC590 controller board.
NOTE.
If using the DC590B board, a specific DVCC voltage level
may be selected. This is done by setting the VCCIO jumper on the
DC590 board to one of the following settings: 3.3V, 5V, removed
for 2.7V or set to external if use of an external supply is desired.
6.
Run the QuikEval program. The program detects the
DC1039 and displays the LTC3207 control window
(shown in Figure 3).
1
LTC3207/LTC3207-1
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
VIN
GND
2
LTC3207/LTC3207-1
USING THE LTC3207 QUIKEVAL SOFTWARE
The LTC3207 program provides brightness controls for
the universal and camera LEDs. It also allows the user to
gradate the universal LEDs up or down and blink at a
selected on-time and period. The LTC3207/LTC3207-1
also controls the LEDs from an external enable pin, and
may flash the camera LED using the I
2
C port or an exter-
nal switch. The intensity of the universal LEDs may be
set by 1) Selecting the desired ULED select button.
2) Setting the intensity in the associated vertical slider.
3) Selecting the SET ULEDs button.
LTC3207/LTC3207-1
select button selects between the
LTC3207 and the LTC3207-1 I
2
C address to drive demo
boards with either the LTC3207 or the LTC3207-1.
VIEW LTC3207 PRODUCT PAGE
button opens an inter-
net browser and searches the Linear Technology Corpo-
ration web site for information on the LTC3207 when an
internet connection is available.
REG 0
through
REG 15
text box windows display the
hexadecimal value that has been written to the corre-
sponding registers.
SELECT ALL
selects all universal LEDs to change when
the SET ULEDs, CLEAR ULEDs, or other ULED control
buttons are selected.
DESELECT ALL
deselects all selected universal LEDs and
prevents the universal LEDs from changing intensity or
modes.
ULED1
through
ULED12
select buttons are used to indi-
vidually select or deselect the universal LEDs.
ULED (1/4)
vertical slide control adjusts the intensity for
selected universal LEDs U1 and U4 from 0 to 27.5mA in
64 steps. The SET ULEDs, BLINK ULEDs, or other LED
control buttons need to be selected to illuminate the se-
lected LEDs. The LED intensity slider may be adjusted by
clicking on the up or down arrows to increment by one
LSB or by clicking and dragging the slide pointer. The
hex code is displayed in the box below the slider.
ULED (2/5)
vertical slide control adjusts the intensity for
selected universal LEDs U2 and U5 from 0 to 27.5mA in
64 steps. The SET ULEDs, BLINK ULEDs, or other LED
control buttons need to be selected to illuminate the se-
lected LEDs. The LED intensity slider may be adjusted by
clicking on the up or down arrows to increment by one
LSB or by clicking and dragging the slide pointer. The
hex code is displayed in the box below the slider.
ULED (3/6)
vertical slide control adjusts the intensity for
selected universal LEDs U3 and U6 from 0 to 27.5mA in
64 steps. The SET ULEDs, BLINK ULEDs, or other LED
control buttons need to be selected to illuminate the se-
lected LEDs. The LED intensity slider may be adjusted by
clicking on the up or down arrows to increment by one
LSB or by clicking and dragging the slide pointer. The
hex code is displayed in the box below the slider.
RED (7/10)
vertical slide control adjusts the intensity for
selected universal LEDs U7 and U10 from 0 to 27.5mA in
64 steps. The SET ULEDs, BLINK ULEDs, or other LED
control buttons need to be selected to illuminate the se-
lected LEDs. The LED intensity slider may be adjusted by
clicking on the up or down arrows to increment by one
LSB or by clicking and dragging the slide pointer. The
hex code is displayed in the box below the slider.
GREEN (8/11)
vertical slide control adjusts the intensity
for selected universal LEDs U8 and U11 from 0 to
27.5mA in 64 steps. The SET ULEDs, BLINK ULEDs, or
other LED control buttons need to be selected to illumi-
nate the selected LEDs. The LED intensity slider may be
adjusted by clicking on the up or down arrows to incre-
ment by one LSB or by clicking and dragging the slide
pointer. The hex code is displayed in the box below the
slider.
BLUE (9/12)
vertical slide control adjusts the intensity for
selected universal LEDs U9 and U12 from 0 to 27.5mA in
64 steps. The SET ULEDs, BLINK ULEDs, or other LED
control buttons need to be selected to illuminate the se-
lected LEDs. The LED intensity slider may be adjusted by
clicking on the up or down arrows to increment by one
LSB or by clicking and dragging the slide pointer. The
hex code is displayed in the box below the slider.
SET ULEDs
button sets all selected LEDs to the selected
intensity settings.
QUICK WRITE
button sets all LEDs to the intensity and
mode of ULED1 using the LTC3207/LTC3207-1 Quick
3
LTC3207/LTC3207-1
Write feature. The intensity of ULED1 is updated to the
value indicated on the ULED (1/4) vertical slider. All ver-
tical sliders and register text boxes on the LTC3207 Con-
trol Window are updated to match the IC settings. The
ULED1 select button does not need to be selected for
this button to work.
CLEAR ULEDs
button turns off and clears the register for
all selected LEDs.
ENU OUTPUT SELECT
button sets or unsets the ENU
control for the selected LEDs. When an LED ENU output
is selected, the ULED register label below the ULED reg-
ister text box is highlighted in blue. If gradation with ENU
control is desired, use the START GRADATION WITH
ENU control button.
SET ENU PIN HI/LO
button sets the ENU pin high or low
and turns on or off the LEDs under ENU control. If the
LED is set for gradation or blinking with ENU control, the
LED will gradate up/down, or start/stop blinking at the
selected intensity.
GRADATION TIME
option buttons set the desired time to
gradate up to or down from the selected LED intensity
when the GRADATE UP, GRADATE DOWN, START
GRADATION WITH ENU or Demo 1 button is selected. If
the DISABLED option button is selected, the universal
LEDs will not gradate when any of the GRADATION con-
trol buttons are selected.
GRADATE UP
button gradates the selected LEDs up to
the desired intensity and disables gradation when done.
The ULED select button is highlighted purple to indicate
that gradation mode has been enabled.
GRADATE DOWN
button gradates the selected LEDs
down from the set intensity and disables gradation when
done. The ULED select button is highlighted purple to
indicate that gradation mode has been enabled.
START GRADATION WITH ENU
button gradates the se-
lected LEDs up to the set intensity when the ENU pin is
high (SET ENU PIN HI button is selected) and down
when the ENU pin is low. Note: the gradation time must
be set to something other than DISABLED to gradate the
LEDs. Selecting this button when GRADATION WITH
ENU is enabled and the ENU PIN is high, gradation and
ENU control will be disabled with the LEDs set. Selecting
this button when GRADATION WITH ENU is enabled and
the ENU PIN is low, gradation and ENU control will be
disabled with the LEDs off. During gradation with ENU
control, all other ULEDs and the flash LED must remain
off and the charge pump must remain in Auto mode (not
forced to any mode). The ULED select button is high-
lighted purple to indicate that gradation mode has been
enabled.
BLINK ONt/PERIOD
option buttons set the desired blink-
ing on-time and period to blink after the BLINK ULEDs
button has been selected.
BLINK ULEDs
button blinks or stops blinking the se-
lected LEDs at the on-time and period selected by the
BLINK ONt/PERIOD option buttons and at the selected
LED intensity. The ULED select button is highlighted
green to indicate that blink mode has been enabled.
CHARGE PUMP MODE
option buttons allow the user to
select between Auto switching (not forced to any mode),
Force 1x, Force 1.5x, and Force 2x charge pump modes.
GPO MODE
button disables or enables dropout for the
selected LEDs. When dropout is disabled the LED will not
cause the charge pump to switch into 1.5x or 2x modes
and the pin may be used as a general-purpose output
(GPO). The ULED select button is highlighted orange to
indicate that GPO MODE has been selected.
UPDATE ALL REG
button updates the data registers to
the data displayed in the register text boxes.
LEDs OFF
button turns off and resets all LEDs and LED
modes, plus stops and resets all demos.
CAML
intensity vertical slide control adjusts the CAM
display from 0 to 170mA in 7 steps. The current is lim-
ited in software because some LEDs can not handle large
continuous currents for long periods. The LED intensity
may be adjusted by clicking on the up or down arrows to
increment by one LSB or by clicking and dragging the
slide pointer. The hex code is displayed in the box below
the slider.
CAMH
intensity vertical slide control sets the CAMH reg-
ister from 0 to 425mA in 16 steps. When the CAM
FLASH button is selected, the CAM LED illuminates at the
intensity set by the CAMH register on the release of the
mouse button for the length of time selected in the
FLASH Time drop-down window up to two seconds. The
4
LTC3207/LTC3207-1
LED intensity may be adjusted by clicking on the up or
down arrows to increment by one LSB or by clicking and
dragging the slide pointer. The hex code is displayed in
the box below the slider.
FLASH Time
drop-down window allows the user to se-
lect a flash time from 50ms to 5000ms in various incre-
ments. The flash time is the time the program selects the
CAMH register and starts on the release of the mouse
button after the CAM FLASH button was selected.
CAM FLASH
button will flash the CAM LED at the inten-
sity selected in the CAMH register after the CAM FLASH
button has been released. The flash will last for the pe-
riod selected in the FLASH Time drop-down window or
until the LTC3207’s two second safety timer has elapsed.
This is accomplished by setting the CAMHL bit in register
0. Once the CAM flash begins, the program will not flash
the CAM LED again until double the selected flash time
has elapsed to prevent any damage to the LED.
FLASH
push button is located next to J1 on the DC1039
demo board. This button sets the CAMHL pin while de-
pressed and will flash the CAM LED at the intensity se-
lected in the CAMH register up to two seconds or until
the FLASH button is released.
DEMO 1-Rainbow
button may be selected to start or
stop Demo 1. Demo 1 cycles through the different colors
that the two RGB LEDs can produce using the
LTC3207/LTC3207-1’s gradation feature. The default
gradation time for this demo is 0.96s, however the 0.48s
or 0.24s gradation times may be used by selecting the
desired gradation time prior to starting the demo.
DEMO 2-Light Cycle
button gradates up and blinks all
universal LEDs starting with ULED1 to ULED12. After all
LEDs are up and blinking, the LEDs are gradated off
starting with ULED1 to ULED12. This is accomplished
using the LTC3207/LTC3207-1’s gradation and blinking
modes.
5
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
