MAX16832CEVKIT [MAXIM]
MAX16832C Evaluation Kit;
| 型号： | MAX16832CEVKIT |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | MAX16832C Evaluation Kit |
| 文件： | 总6页 (文件大小：98K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-4289; Rev 0; 9/08
MAX16832C Evaluation Kit
Evluates:C/MX16832A
General Description
Features
The MAX16832C evaluation kit (EV kit) demonstrates the
MAX16832C hysteretic current-mode high-brightness
LED (HB LED) driver IC. The MAX16832C EV kit is config-
ured as a step-down topology with a constant-current HB
LED driver circuit for external HB LEDs. The MAX16832C
EV kit operates from a DC supply voltage of 6.5V to 65V
and is configured to deliver 666mA of current to user-sup-
plied HB LEDs. The output voltage for the HB LED string
can go up to 64V and depends upon the EV kit’s input
voltage.
o 6.5V to 65V Wide Supply Voltage Range
o 666mA HB LED Current
o Digital PWM Dimming Control
o Analog Dimming Control
o Thermal-Foldback and Temperature-Simulation
Circuit
o Demonstrates a Thermally Optimized PCB Layout
Design
The MAX16832C EV kit can be configured for digital
pulse-width modulation (PWM) dimming operation
using a digital PWM input signal. The EV kit circuit also
features a thermal-foldback and temperature-simulation
circuit feature. The MAX16832C EV kit is a fully assem-
bled and tested surface-mount board. Additionally, the
PCB layout design has been maximized for optimum
thermal dissipation. The MAX16832C EV kit can also
evaluate a MAX16832A after replacing the IC, which
can be ordered from the number listed below.
o Evaluates MAX16832A (IC Replacement Required)
o Lead-Free and RoHS Compliant
o Fully Assembled and Tested
Ordering Information
PART
TYPE
MAX16832CEVKIT+
EV Kit
Warning: Voltages exceeding 42V could exist on the
LED+ and LED- output pads.
+Denotes lead-free and RoHS compliant.
Component List
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
0.300Ω 1ꢀ, 0.5W sense resistor
(1206)
1µF 10ꢀ, 100V XꢁR ceramic
capacitor (1210)
R1
1
C1
1
IRC LRC-LRF1206LF-01-R300-F
Murata GRM32CRꢁ2A105K
R2
R3
1
1
1
1
1
100kΩ 10ꢀ potentiometer
20kΩ 5ꢀ resistor (0805)
100kΩ 5ꢀ resistor (0805)
PC mini red test point
0.01µF 10ꢀ, 50V XꢁR ceramic
capacitor (0603)
Murata GRM188Rꢁ1H103K
C2
C3
D1
1
0
1
R4
Not installed, ceramic capacitor
(1210)
TP1
TP2
PC mini black test point
100V, 2A Schottky rectifier (SMA)
Central Semi CMSH2-100M
(Top Mark: CS2100M)
Step-down HB LED driver
(8 SO-EP*)
Maxim MAX16832CASA+
U1
1
JU1, JU2
L1
2
1
2-pin headers
—
2
1
Shunts (JU1, JU2)
220µH, 1.28A inductor
Coilcraft MSS1260-224KLB
—
PCB: MAX16832C Evaluation Kit+
*EP = Exposed pad.
Component Suppliers
SUPPLIER
PHONE
WEBSITE
Central Semiconductor Corp
Coilcraft, Inc.
631-435-1110
84ꢁ-639-6400
361-992-ꢁ900
ꢁꢁ0-436-1300
www.centralsemi.com
www.coilcraft.com
IRC, Inc
www.irctt.com
Murata Electronics North America, Inc.
www.murata-northamerica.com
Note: Indicate that you are using the MAX16832C when contacting these component suppliers.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX16832C Evaluation Kit
Quick Start
Required Equipment
Before beginning, the following equipment is needed:
Detailed Description of Hardware
The MAX16832C EV kit demonstrates the MAX16832C
hysteretic constant-current HB LED driver in an 8-pin SO
package with an exposed pad. The MAX16832C EV kit is
configured in a step-down topology with constant current
driving a string of user-supplied external HB LEDs. The
MAX16832C EV kit operates from a DC supply voltage of
6.5V to 65V and requires up to 1A. The MAX16832C IC’s
UVLO is configured from 6V to 6.5V internally.
•
•
•
6.5V to 65V, 1A power supply
Two digital voltmeters
A series-connected HB LED string rated no less
than 666mA
•
A current probe to measure HB LED current
The EV kit circuit is configured to deliver 666mA of
current into a series HB LED string with a maximum
64V forward voltage. The average series inductor cur-
rent is set to 666mA (typ) by resistor R1. The
MAX16832C thermal-foldback feature can be evaluat-
ed by connecting a negative temperature coefficient
(NTC) thermistor between the TEMP_I and PGND PCB
pads on the EV kit. Alternatively, a temperature-vary-
ing thermistor circuit can be simulated using poten-
tiometer R2 and resistor R3. The EV kit also features a
DIM PCB pad to evaluate digital PWM dimming opera-
tion of the external HB LEDs.
Procedures
The MAX16832C EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
Warning: Voltages exceeding 42V could exist on the
LED+ and LED- output pads.
1) Verify that a shunt is not installed across jumper
JU1 (enabled).
2) Verify that a shunt is installed across jumper JU2
(temperature simulation).
The MAX16832C EV kit uses a 1oz copper, 2-layer
PCB. It has been designed to provide an example of
good thermal dissipation, incorporating thermal vias
under U1’s exposed pad and additional thermal vias
adjacent to U1. These vias carry additional heat to the
bottom-layer ground plane for maximum thermal con-
ductivity when evaluating a MAX16832 IC.
3) Connect the power supply’s positive terminal to the
VIN PCB pad on the EV kit. Connect the power sup-
ply’s ground terminal to PGND PCB pad.
4) Connect digital voltmeters across the VIN and
PGND PCB pads and the LED+ and LED- PCB
pads.
5) Connect the anode of the HB LED string to the
LED+ pad.
Jumper Selection
The MAX16832C EV kit features several jumpers to
reconfigure the PWM dimming, thermal-foldback fea-
ture and for reconfiguring the external HB LED current.
6) Connect the cathode of the HB LED string to the
LED- pad.
ꢁ) Clip the current probe across the HB LED+ wire to
measure the HB LED current.
Enable and HB LED Dimming Control
(Digital and Analog)
Evluates:C/MX16832A
The MAX16832C EV kit features a jumper to enable
and disable U1. Installing jumper JU1 disables the
MAX16832C IC. Additionally, HB LED dimming can be
achieved on the MAX16832C EV kit by applying a digi-
tal PWM signal at the DIM PCB input pad. The signal
can be applied using an open-collector or open-drain
output rated for at least the VIN voltage. Alternatively,
resistor R4 can be removed and TTL logic can control
the DIM pin. Remove the shunt at jumper JU1 to enable
HB LED dimming using a digital PWM signal at the DIM
and PGND PCB pads. The applied signal should have
a 0.6V logic-low (or less) and a 2.8V logic-high (or
greater) level and frequencies from 200Hz to 20kHz. To
adjust the HB LED brightness, vary the signal duty
cycle from 0ꢀ to 100ꢀ. See Table 1 for jumper JU1
setting of the HB LED dimming operation.
8) Turn on the power supply and increase the power-
supply output voltage from 0V, slowly ramping it up
to 65V (HB LED dependant). Do not hot plug
> 30V DC voltage on the evaluation board! It will
generate over ꢁ0V high-voltage spark on the
MAX16832C and damage the IC due to the power
cable inductance-caused ringing with the input fil-
ter capacitor.
9) Using a voltmeter, verify that the voltage across
TP1 and TP2 is > 2V. If it is not, adjust potentiome-
ter R2 to obtain a reading > 2V.
2
_______________________________________________________________________________________
MAX16832C Evaluation Kit
Evluates:C/MX16832A
To evaluate the MAX16832C IC thermal-foldback fea-
ture, remove jumper JU2 and connect an NTC thermistor
to the TEMP_I and PGND PCB pads. Refer to the
Thermal Foldback section in the MAX16832A/
MAX16832C IC data sheet for information on using the
thermal-foldback feature. See Table 2 for configuring
jumper JU2 for the desired mode of operation.
Table 1. Enable and HB LED Dimming
(Jumper JU1)
SHUNT
POSITION
EV KIT ENABLE OR
DIMMING OPERATION
DIM PIN
Not
Connected to
Enabled or analog dimming*
installed
VIN through R4 (see Table 2)
Table 2. Temperature Simulation and
Thermal Foldback (Jumper JU2)
Not
installed
Connected to
PWM signal
Enabled, PWM signal applied
at DIM PCB pad
Connected to
PGND
SHUNT
Installed
Disabled
TEMP_I PIN
EV KIT OPERATION
POSITION
*Analog dimming can be achieved by placing a resistor
(RDIM) across the TEMP_I and PGND PCB pads. Remove the
Connected to
R2 and R3
Installed
Temperature simulation
shunt across jumpers JU1 and JU2, and then use the ILED
DIM
equation to calculate the current for the TEMP_I PCB pad
resistor, necessary to reduce the HB LED driving current. Refer
to the Analog Dimming section in the MAX16832A/MAX16832C
IC data sheet for information on the analog-dimming feature.
Connected to
external NTC
thermistor
Not
installed
Thermal foldback*
*Also analog dimming (see Table 1).
Setting External HB LED Current
Resistor R1 sets the MAX16832C EV kit average HB
LED current up to 666mA. However, the HB LED aver-
age current can be set up to ꢁ00mA after replacing
resistor R1. Use the following equation to calculate R1
when reconfiguring the HB LED current:
ILED
= ILED [1 - 0.ꢁ5 x (2 - (RDIM x 26.5µA))]
DIM
where RDIM is the TEMP_I pad resistor, ILED
is the
DIM
required current for the desired HB LED current, and
ILED is configured for 666mA.
Alternatively, installing jumper JU2 and adjusting
potentiometer R2 can simulate analog dimming. Or, for
DC-control analog dimming, install jumper JU2 and
apply a DC voltage in the range of 0.ꢁV to 2V at the
TP1 (positive) and TP2 (PGND) test points.
0.2V
R1=
I
LED
where I
is the desired HB LED average current.
LED
Thermal Foldback and Temperature
Simulation
Refer to the Selecting R
to Set LED Current sec-
SENSE
tion in the MAX16832A/MAX16832C IC data sheet for
information on setting the HB LED current.
The MAX16832C EV kit features a thermal-foldback
and temperature-simulation circuit available at the
TEMP_I PCB pads and jumper JU2. Jumper JU2 sets
the mode of operation, temperature simulation, or ther-
mal foldback. Potentiometer R2 and resistor R3 form
the adjustable temperature-simulation circuit. Test
points TP1 and TP2 (PGND) provide access to the sig-
nal for adjusting the voltage.
_______________________________________________________________________________________
3
MAX16832C Evaluation Kit
Evluates:C/MX16832A
Figure 1. MAX16832C EV Kit Schematic
4
_______________________________________________________________________________________
MAX16832C Evaluation Kit
Evluates:C/MX16832A
Figure 2. MAX16832C EV Kit Component Placement Guide—
Component Side
Figure 3. MAX16832C EV Kit PCB Layout—Component Side
_______________________________________________________________________________________
5
MAX16832C Evaluation Kit
Figure 4. MAX16832C EV KIT PCB Layout—Solder Side
Evluates:C/MX16832A
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
相关型号：
©2020 ICPDF网 联系我们和版权申明