DC1039A-A - ANALOG DEVICES

LTC3207/LTC3207-1

DESCRIPTION

DEMO CIRCUIT1039

QUICK START GUIDE

LTC3207/LTC3207-1

600mA Universal Multi-

Out

ut LED/CAM Driver

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

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

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.

Refer to the DC590 Quick Start Guide for QuikEval

setup and software installation details.

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.

Connect DC1039 to the DC590 USB Serial Controller

using the supplied 14-conductor ribbon cable as

shown in Figure 1.

With power off, connect the input power supply to

VBAT

and GND with a series ammeter and a voltmeter

as shown in Figure 1.

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.

Run the QuikEval program. The program detects the

DC1039 and displays the LTC3207 control window

(shown in Figure 3).

LTC3207/LTC3207-1

Figure 1.

Proper Measurement Equipment Setup

VIN

GND

Figure 2.

Measuring Input or Output Ripple

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

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

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

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

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.

LTC3207/LTC3207-1

Figure 3.

LTC3207 Control Window

LTC3207/LTC3207-1