ETC MAX16832A/MAX16832C

19-4140; Rev 4; 8/10
估板
可提供评
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
___________________________________ 特性
MAX16832A/MAX16832C是降压型恒流高亮度LED (HB
LED)驱动器，为汽车内部/外部照明、建筑和环境照明、
LED灯及其它LED照明应用提供极具成效的解决方案。
♦ 高效解决方案
MAX16832A/MAX16832C工作在+6.5V至+65V输入电压
范围，最高工作温度达到+125°C时，输出电流最高可达
700mA；最高工作温度达到+105°C时，输出电流最高可达
1A。输出电流可由高边电流检测电阻调节，独特的脉宽
调制(PWM)输入可支持较宽的脉冲调节LED亮度范围。
这些器件非常适合宽输入电压范围的应用。高边电流检测
和内部电流设置减少了外部元件数量，并可提供精度为
±3%的平均输出电流。在负载瞬变和PWM亮度调节过程
中，滞回控制算法保证了优异的输入电源抑制和快速响应
特性。MAX16832A允许10%的电流纹波，而MAX16832C
允许30%的电流纹波。这两款器件的开关频率高达2MHz，
从而允许使用小尺寸元件。
MAX16832A/MAX16832C提供模拟亮度调节功能，可降低
输出电流，通过在TEMP_I和GND之间加载低于内部2V门
限电压的直流电压实现这种调节。TEMP_I还可向连接在
TEMP_I和GND之间的负温度系数(NTC)热敏电阻源出25µA
电流，提供折返式热管理功能，当LED串的温度超出指定
温度时能够降低LED电流。此外，器件还具有热关断保护
功能。
MAX16832A/MAX16832C工作在-40°C至+125°C汽车级温度
范围，采用增强散热型8引脚SO封装。
♦ 输入电压范围为6.5V至65V
♦ 输出电流最高可达1A
♦ 片上集成65V、0.45Ω功率MOSFET
♦ 滞回控制：开关频率高达2MHz
♦ LED电流精度：±3%
♦ 200mV检流基准
♦ 电阻可编程LED恒定电流
♦ 集成高边电流检测
♦ 折返式热保护/线性亮度调节
♦ 过热关断保护
♦ 采用增强散热型8引脚SO封装
♦ -40°C至+125°C工作温度范围
___________________________________ 定购信息
PART
TEMP RANGE
PIN-PACKAGE
MAX16832AASA+
-40°C to +125°C
8 SO-EP*
MAX16832CASA+
-40°C to +125°C
8 SO-EP*
+表示无铅(Pb)/符合RoHS标准的封装。
*EP = 裸焊盘。
___________________________ 典型应用电路
___________________________________ 应用
D1
建筑、工业及环境照明
汽车RCL、DRL和雾灯
HB LEDs
VIN
平面显示器
RSENSE
L1
指示灯和紧急事件灯
MR16和MR111 LED灯
C2
1
2
CS
TEMP_I
IN
DIM
C1
3
引脚配置在数据资料的最后给出。
4
GND
PGND
MAX16832A
MAX16832C
LX
LX
8
7
ON
NTC*
OFF
6
5
*OPTIONAL
________________________________________________________________ Maxim Integrated Products
1
本文是英文数据资料的译文，文中可能存在翻译上的不准确或错误。如需进一步确认，请在您的设计中参考英文资料。
有关价格、供货及订购信息，请联络Maxim亚洲销售中心：10800 852 1249 (北中国区)，10800 152 1249 (南中国区)，
或访问Maxim的中文网站：china.maxim-ic.com。
MAX16832A/MAX16832C
___________________________________ 概述
MAX16832A/MAX16832C
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
ABSOLUTE MAXIMUM RATINGS
IN, CS, LX, DIM to GND .........................................-0.3V to +70V
TEMP_I to GND .......................................................-0.3V to +6V
PGND to GND ......................................................-0.3V to +0.3V
CS to IN .................................................................-0.3V to +0.3V
Maximum Current into Any Pin
(except IN, LX, and PGND).............................................20mA
Continuous Power Dissipation (TA = +70°C)
8-Pin SO (derate 23.3mW/°C above +70°C)...........1860.5mW
Junction-to-Ambient Thermal Resistance (θJA) (Note 1) .....43°C/W
Operating Temperature Range
700mA (max) Output Current ........................-40°C to +125°C
1A (max) Output Current ...............................-40°C to +105°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Soldering (reflow).............................................................+260°C
Lead Temperature (soldering, 10s) .................................+300°C
Pin-to-Pin ESD Ratings......................................................±2.5kV
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to china.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +24V, VDIM = VIN, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
Input Voltage Range
CONDITIONS
VIN
MIN
TYP
6.5
MAX
65
UNITS
V
Ground Current
No switching
1.5
mA
Supply Current
VDIM < 0.6V, VIN = 12V
350
µA
VCS = VIN - 100mV, VIN rising until VLX <
0.5VIN
6.25
UNDERVOLTAGE LOCKOUT (UVLO)
Undervoltage Lockout
UVLO
6.5
V
VCS = VIN - 100mV, VIN falling until VLX >
0.5VIN
6.0
Undervoltage-Lockout Hysteresis
0.5
V
SENSE COMPARATOR
Sense Voltage Threshold High
Sense Voltage Threshold Low
VSNSHI
VSNSLO
MAX16832A, VIN - VCS rising from 140mV
until VLX > 0.5VIN, VDIM = 5V
201
210
216
MAX16832C, VIN - VCS rising from 140mV
until VLX > 0.5VIN, VDIM = 5V
218
230
236
MAX16832A, VIN - VCS falling from 260mV
until VLX < 0.5VIN , VDIM = 5V
185
190
198
MAX16832C, VIN - VCS falling from 260mV
until VLX < 0.5VIN, VDIM = 5V
166
170
180
mV
mV
Propagation Delay to Output High
tDPDH
Falling edge of VIN - VCS from 140mV to
260mV to VLX > 0.5VIN
50
ns
Propagation Delay to Output Low
tDPDL
Rising edge of VCS - VIN from 260mV to
140mV to VLX < 0.5VIN
50
ns
CS Input Current
ICSIN
VIN - VCS = 200mV, VIN = VCS
3.5
µA
INTERNAL MOSFET
Drain-to-Source Resistance
LX Leakage Current
2
RDSON
ILX_LEAK
VIN = VDIM = 24V, VCS = 23.9V,
ILX = 700mA
0.45
0.9
VIN = VDIM = 6.0V, VCS = 5.9V,
ILX = 700mA
1
2
Ω
VDIM = 0V, VLX = 65V
_______________________________________________________________________________________
10
µA
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
(VIN = +24V, VDIM = VIN, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIM INPUT
DIM Input-Voltage High
DIM Input-Voltage Low
DIM Turn-On Time
VIH
VIN - VCS = 100mV
VIL
VCS - VIN = 100mV
tDIM_ON
2.8
V
0.6
VDIM rising edge to VLX < 0.5VIN
DIM Input Leakage High
VDIM = VIN
DIM Input Leakage Low
VDIM = 0V
V
200
-3
ns
8
15
µA
-1.5
0
µA
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Temperature rising
+165
o
C
10
o
C
Thermal-Shutdown Threshold
Hysteresis
THERMAL FOLDBACK
Thermal-Foldback Enable
Threshold Voltage
VTFB_ON
VDIM = 5V
Thermal-Foldback Slope
FBSLOPE
VDIM = 5V
TEMP_I Output Bias Current
1.9
2.0
2.12
V
0.75
ITEMP_I
25
1/V
26.5
28
µA
_________________________________________________________________________ 典型工作特性
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
DUTY CYCLE
vs. INPUT VOLTAGE
90
85
1 LED
80
15 LEDs
90
13 LEDs
80
11 LEDs
70
9 LEDs
7 LEDs
60
5 LEDs
50
3 LEDs
40
30
75
5
15
25
35
VIN (V)
45
55
65
450
13 LEDs
15 LEDs
400
11 LEDs
9 LEDs
350
300
7 LEDs
5 LEDs
250
200
3 LEDs
150
1 LED
20
100
10
50
0
70
500
MAX16832A toc03
100
FREQUENCY (kHz)
11 LEDs 13 LEDs 15 LEDs
DUTY CYCLE (%)
EFFICIENCY (%)
95
9 LEDs
7 LEDs
5 LEDs
3 LEDs
MAX16832A toc01
100
FREQUENCY
vs. INPUT VOLTAGE
MAX16832A toc02
EFFICIENCY
vs. INPUT VOLTAGE
1 LED
16 LEDs
0
5
15
25
35
VIN (V)
45
55
65
5
15
25
35
45
55
65
VIN (V)
_______________________________________________________________________________________
3
MAX16832A/MAX16832C
ELECTRICAL CHARACTERISTICS (continued)
___________________________________________________________________ 典型工作特性(续)
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
NORMALIZED ILED CURRENT
vs. INPUT VOLTAGE
1.02
1.01
13 LEDs
11 LEDs 15 LEDs
7 LEDs 9 LEDs
1 LED 3 LEDs 5 LEDs
1.00
0.99
MAX16832A toc05
1.03
MAX16832A toc06
450
QUIESCENT CURRENT (µA)
NORMALIZED ILED CURRENT
1.04
PWM DIMMING
AT 200Hz (10% DUTY CYCLE)
500
MAX16832A toc04
1.05
0.98
400
VIN = 48V
8 LEDs
350
ILED
200mA/div
300
250
200
0
150
0.97
100
0.96
50
0.95
VDIM
5V/div
0
VDIM = 0V
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
VIN (V)
VIN (V)
PWM DIMMING
AT 200Hz (90% DUTY CYCLE )
1ms/div
PWM DIMMING
AT 20kHz (90% DUTY CYCLE)
MAX16822A toc07
MAX16832A toc08
ILED
200mA/div
ILED
200mA/div
0
VIN = 48V
8 LEDs
VIN = 48V
8 LEDs
1ms/div
10µs/div
LED CURRENT
vs. VTEMP_I
ILED
vs. TEMPERATURE
0
MAX16832A toc10
1.0
MAX16832A toc09
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
VIN = 48V
0
0
0.4
0.8
1.2
1.6
VTEMP_I (V)
4
0
VDIM
5V/div
VDIM
5V/div
0
ILED (A)
LED CURRENT (mA)
MAX16832A/MAX16832C
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
2.0
2.4
2.8
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
_______________________________________________________________________________________
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
ITEMP_I
vs. TEMPERATURE
LXRDSON
vs. TEMPERATURE
0.6
VIN = 48V
29.5
29.0
0.4
VIN = 6.5V
0.3
ITEMP_I (µA)
28.5
0.5
LXRDSON (Ω)
30.0
MAX16832A toc12
VIN = 65V
MAX16832A toc11
0.7
28.0
27.5
27.0
26.5
26.0
0.2
25.5
VIN = 48V
25.0
0.1
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
___________________________________________________________________________ 引脚说明
引脚
名称
1
CS
电流检测输入。在IN和CS之间连接一个电阻设置LED电流。
2
IN
正电源电压输入。通过一个1µF或更大电容旁路至GND。
3
GND
4
PGND
5, 6
LX
7
DIM
8
TEMP_I
—
EP
功能
地。
功率地。
开关节点。
逻辑电平亮度调节输入。拉低DIM关闭电流调节器；拉高DIM则使能电流调节器。
折返式热管理和线性亮度调节输入。如果使用折返式热管理或模拟亮度调节，则用一个0.01µF
电容旁路至GND，请参考折返式热管理 部分。
裸焊盘。将EP连接到一个较大的接地面，改善散热。请勿将其作为IC的唯一接地端。
_________________________________________ 详细说明
MAX16832A/MAX16832C是降压型、恒流、HB LED驱动
器。这些器件的工作电压范围为+6.5V至+65V，最高工作
温度TA = +105°C时，最大输出电流为1A；最高工作温度
TA = +125°C时，最大输出电流为700mA。由一个高边电
流检测电阻设置输出电流，独特的PWM亮度调节输入能
够支持较宽的脉冲调节LED亮度范围。
高边电流检测设计以及内部电流设置大大减少了外部器
件数量，并且以1%的检流电阻即可获得±3%精度的LED
电流，功能框图请参考图1。
_______________________________________________________________________________________
5
MAX16832A/MAX16832C
___________________________________________________________________ 典型工作特性(续)
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
MAX16832A/MAX16832C
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
IN
VCC
REGULATOR
MAX16832A
MAX16832C
VCC _ANA
ISET
OPEN LED
COMPARATOR
LX
VCC _ANA
CS
CURRENT-SENSE
COMPARATOR
0.45Ω, 65V
nMOS SWITCH
PWM
DIMMING
1.23V
BANDGAP
REF
GATE
DRIVER
UVLO
COMPARATOR
DIM
DIM
BUFFER
VCC _ANA
25µA
TEMP_I
PGND
VTFB_ON
2V
THERMAL
FOLDBACK
COMPARATOR
GND
图1. 功能框图
6
_______________________________________________________________________________________
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
_______________________________ 应用信息
MAX16832A/MAX16832C包含带有500mV滞回的UVLO。
当VIN 下降至低于5.5V至6.0V时，内部MOSFET关闭。
DIM输入
通过在DIM引脚输入PWM信号实现LED亮度调节。低于
0.6V逻辑电平的DIM输入将MAX16832A/MAX16832C的输
出强制拉低，从而关闭LED电流。若需打开LED电流，DIM
上的逻辑电平必须高于2.8V。
热关断
MAX16832A/MAX16832C的热关断功能在结温超过+165°C
时关断LX驱动器，当结温降至关断温度门限以下10°C时，
LX驱动器重新打开。
模拟亮度控制
MAX16832A/MAX16832C提供了模拟亮度调节功能，当
TEMP_I的电压低于内部2V门限电压时，降低输出电流。
MAX16832A/MAX16832C通过TEMP_I和地之间连接的外
部直流电压源，或25µA内部电流源在TEMP_I和地之间连
接的电阻上的检测电压实现调光。当TEMP_I上的电压低
于内部2V门限电压时，MAX16832A/MAX16832C将降低
LED电流。模拟调光电流的设置公式如下：
⎡
⎤
⎛ 1⎞
ITF (A) = ILED (A) × ⎢1− FBSLOPE ⎜ ⎟ × VTFB _ ON − VAD (V)⎥
⎝
⎠
V
⎣
⎦
(
选择RSENSE 设置LED电流
LED电流由IN和CS之间连接的检流电阻设置。采用下式
计算电阻值：
RSENSE (Ω) =
其中，V SNSHI 为检测电压门限的上限，V SNSLO 为检测电
压门限的下限(请参见 Electrical Characteristics 表)。
电流调节器工作原理
MAX16832A/MAX16832C利用一个具有滞回的比较器调节
LED电流(参见图2)。当通过电感的电流上升，并且检测
电阻两端的电压达到上限时，内部MOSFET关断；当通过
续流二极管的电感电流下降，直到检测电阻上的电压等
于下限时，内部MOSFET再次打开。采用下式确定工作
频率：
fSW =
(VIN − nVLED ) × nVLED × RSENSE
VIN × ∆V × L
其中，n为LED的数量，VLED 为1个LED的导通压降，∆V =
(VSNSHI - VSNSLO)。
)
其 中 ， V TFB_ON = 2V， FB SLOPE = 0.75， 由Electrical
Characteristics 表获得，VAD 为TEMP_I上的电压。
折返式热管理
MAX16832A/MAX16832C具有折返式热管理，可在串联
LED灯的温度超过规定的温度门限时降低输出电流。当
NTC热敏电阻(热敏电阻与LED之间须提供好的导热通路，
电气连接置于TEMP_I和地之间)的压降低于内部2V门限
时，这些器件进入折返式热管理模式。
1 (VSNSHI + VSNSLO )(V)
2
ILED (A)
电感选择
MAX16832A/MAX16832C的开关频率可达2MHz。对于空
间受限的应用，采用高开关频率有利于降低电感尺寸。
采用下式计算电感值，选择最为接近的标准值：
L(approx.) =
(VIN − nVLED ) × nVLED × RSENSE
VIN × ∆V × fSW
可利用MAX16832A/C设计工具选择元件，网址为：china.
maxim-ic.com/MAX16832-software。
_______________________________________________________________________________________
7
MAX16832A/MAX16832C
欠压锁存(UVLO)
MAX16832A/MAX16832C
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
HYSTERETIC
MODE
fSW
ILED
∆I
AVG. LED
CURRENT
t
VDIM
t2
t1
t
图2. 电流调节器工作原理
续流二极管的选择
出于稳定性和最佳效率考虑，建议采用正向压降低、反向
恢复时间快的低电容二极管。肖特基二极管的击穿电压
足以承受最大工作电压，所以是个很好的选择。
PCB布局指南
合理的 PCB 布局是获得低开关损耗和稳定工作的关键。
正常工作时，有两个电源环路。当内部MOSFET打开时，
大电流通过地、输入电容、RSENSE、LED负载、电感、内
部MOSFET返回至地，形成了一个环路；当内部MOSFET
关闭时，大电流通过输入电容正端、RSENSE、LED负载、
电感和续流二极管返回至输入电容正端，形成了另一个环
路。需要注意的是，通过RSENSE、LED负载和电感的电流
是带有三角波纹波(低噪声)的直流电流。噪声较大、快速
8
切换的大电流信号仅通过续流二极管和输入电容正端或
通过MOSFET、地、输入电容正端。如果PCB布局不当，
这些方波开关电流信号会给带滞回的 LED 驱动器带来
问题。
电流控制仅依靠R SENSE 两端的电压实现。通过该节点拾
取的噪声会导致内部MOSFET的异常开关操作(IC将工作
在较高的开关频率)。为避免上述问题，将RSENSE 尽量靠
近CS和IN放置，并保持较短的检测连线。使续流二极管
中的方波开关电流信号远离R SENSE 十分重要。为减小干
扰，将续流二极管放置在IC和R SENSE 的背面，将输入电
容靠近二极管放置，使高频电流返回至地。可以参考图3
进行布局，虚线所示为可能干扰正常工作的高频元件通
路。为实现良好的散热，IC的裸焊盘应通过多个过孔焊
接到地平面背面的大面积焊盘。
_______________________________________________________________________________________
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
MAX16832A/MAX16832C
LED+
LED-
CFILTER
RSENSE
1
L
GND
LX
CIN
VIAS FOR THERMAL TRANSFER
TO BACKSIDE GROUND PLANE
VIN
D
tOFF AND tON CURRENT PATHS
KEEP THIS LOOP TIGHT.
图3. PCB布局
_______________________________ 引脚配置
_______________________________ 芯片信息
PROCESS: BiCMOS
TOP VIEW
+
CS
1
8
TEMP_I
IN
2
7
DIM
GND
3
6
LX
5
LX
MAX16832A
MAX16832C
PGND 4
SO-EP
_______________________________ 封装信息
如需最近的封装外形信息和焊盘布局，请查询 china.maxim-ic.
com/packages。请注意，封装编码中的“+”、“#”或“-”仅表示
RoHS状态。封装图中可能包含不同的尾缀字符，但封装图只与封
装有关，与RoHS状态无关。
封装类型
封装编码
外形编号
焊盘布局编号
8 SO-EP
S8E-12
21-0111
90-0150
_______________________________________________________________________________________
9
MAX16832A/MAX16832C
2MHz、高亮度LED驱动器，
集成MOSFET和高边电流检测
____________________________________________________________________________ 修订历史
修改页
修订号
修订日期
说明
0
5/08
最初版本。
—
1
9/08
发布MAX16832C。
1
2
5/09
修改了概述、特性、Absolute Maximum Ratings 和详细说明。
3
2/10
更新了 PCB布局指南，增加了图3。
4
8/10
修正了功能框图，并在 Absolute Maximum Ratings中增加焊接(回流焊)温度信息。
1, 2, 5
8, 9
2, 5, 6
Maxim 北京办事处
北京 8328信箱 邮政编码 100083
免费电话：800 810 0310
电话：010-6211 5199
传真：010-6211 5299
Maxim不对Maxim产品以外的任何电路使用负责，也不提供其专利许可。Maxim保留在任何时间、没有任何通报的前提下修改产品资料和规格的权利。
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2010 Maxim Integrated Products
Maxim 是 Maxim Integrated Products, Inc. 的注册商标。
MAX16832A, MAX16832C 2MHz、高亮度LED驱动器，集成MOSFET和高边电流检测 - 概述
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Maxim > 产品 > 汽车电子 > MAX16832A, MAX16832C
Maxim > 产品 > 电源和电池管理 > MAX16832A, MAX16832C
MAX16832A, MAX16832C
2MHz、高亮度LED驱动器，集成MOSFET和高边电流检测
高压、高效LED驱动器，集成MOSFET有效节省电路板空间和成本
概述 技术文档 定购信息 相关产品 用户说明 (0) 所有内容 状况
状况：生产中。
数据资料
提供更新的英文版数据资料
下
英文
Rev. 6 (PDF, 247.8kB)
载
概述
MAX16832A/MAX16832C是降压恒流高亮度LED (HB LED)驱动器，为汽车内部/外部照明、建筑和环境照
明、LED灯泡和其它LED照明应用提供具有成本效益的解决方案。
中文
MAX16832A/MAX16832C工作于+6.5V至+65V输入电压范围，在最高+125°C温度范围内可提供最大700mA的输
出电流，而在最高+105°C的温度范围内可提供1A的输出电流。高边检流电阻调节输出电流，而专用的脉宽调
制(PWM)输入可实现宽亮度范围的脉冲式LED亮度调节。
这些器件非常适合需要宽输入电压范围的应用。高边电流检测和内置电流设置电路减少了外部元件数量，并可提
供±3%精度的平均输出电流。在负载瞬变和PWM亮度调节过程中，滞回控制算法保证了优异的输入电源抑制和快
速响应性能。MAX16832A允许10%的电流纹波，而MAX16832C允许30%的电流纹波。这两款器件的开关频率高
达2MHz，从而允许使用小尺寸元件。
MAX16832A/MAX16832C提供模拟亮度调节功能，可降低输出电流，通过在TEMP_I至GND之间加载一路低于内
部2V门限电压的外部直流电压来实现这种调节。TEMP_I还可向连接在TEMP_I和GND之间的负温度系数(NTC)热
敏电阻源出25µA电流，提供模拟热折返功能，当LED串的温度超出指定温度值时可降低LED电流。此外，器件还
具有热关断保护功能。
MAX16832A/MAX16832C工作于-40°C至+125°C汽车级温度范围，采用增强散热型8引脚SO封装。
现备有评估板：MAX16832CEVKIT
关键特性
高效解决方案
输入电压范围为6.5V至65V
输出电流高达1A
http://china.maxim-ic.com/datasheet/index.mvp/id/5851[2012-08-17 8:02:07]
E-Mail
应用/使用
建筑、工业及环境照明
汽车RCL、DRL和雾灯
平面显示器
下
载
Rev. 4 (PDF, 676kB)
E-Mail
MAX16832A, MAX16832C 2MHz、高亮度LED驱动器，集成MOSFET和高边电流检测 - 概述
片上集成65V、0.45Ω功率MOSFET
滞回控制：开关频率高达2MHz
LED电流精度：±3%
200mV检流基准
电阻可编程的恒定LED电流
集成的高边电流检测
热折返保护/线性亮度调节
过热关断保护
采用增强散热型8引脚SO封装
-40°C至+125°C工作温度范围
指示灯和紧急事件灯
MR16和MR111 LED灯
关键特性:
High Brightness LED Drivers
Part
Number
Topology
Device
V IN
(V)
max
min
MAX16832 Buck
65
6.5
Device
V IN
(V)
LED
String
Volt.
(V)
LED
Channels
I LED per
Channel
(A)
max
max
1
0.7
63
Internal
Pwr.
MOSFETs
Freq.
(kHz)
PWM
Dimming
Freq.
(kHz)
max
max
max
Yes
2000
20
200
查看所有High Brightness LED Drivers (29)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may
differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized
distributor.
图表
http://china.maxim-ic.com/datasheet/index.mvp/id/5851[2012-08-17 8:02:07]
PWM
Dimming
Ratio
EV
Kit
Budgetary Price
Yes
$1.95 @1k
See Notes
19-4140; Rev 6; 7/12
KIT
ATION
EVALU
LE
B
A
IL
A
AV
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
The MAX16832A/MAX16832C step-down constant-current high-brightness LED (HB LED) drivers provide a
cost-effective design solution for automotive
interior/exterior lighting, architectural and ambient lighting, LED bulbs, and other LED illumination applications.
The MAX16832A/MAX16832C operate from a +6.5V to
+65V input voltage range and can provide an output
current up to 700mA, if operated up to a temperature of
+125°C, or up to a 1A if operated up to a temperature
of +105°C. A high-side current-sense resistor adjusts
the output current, and a dedicated pulse-width modulation (PWM) input enables pulsed LED dimming over a
wide range of brightness levels.
These devices are well suited for applications requiring
a wide input voltage range. The high-side current sensing and an integrated current-setting circuitry minimize
the number of external components while delivering an
average output current with ±3% accuracy. A hysteretic
control method ensures excellent input supply rejection
and fast response during load transients and PWM dimming. The MAX16832A allows 10% current ripple, and
the MAX16832C allows 30% current ripple. Both
devices operate up to a 2MHz switching frequency,
thus allowing the use of small-sized components.
The MAX16832A/MAX16832C offer an analog dimming
feature that reduces the output current by applying an
external DC voltage below the internal 2V threshold voltage from TEMP_I to GND. TEMP_I also sources 25µA to
a negative temperature coefficient (NTC) thermistor connected between TEMP_I and GND, thus providing an
analog thermal-foldback feature that reduces the LED
current when the temperature of the LED string exceeds
a specified temperature point. Additional features
include thermal-shutdown protection.
The MAX16832A/MAX16832C operate over the -40°C to
+125°C automotive temperature range and are available
in a thermally enhanced 8-pin SO package.
Features
o High-Efficiency Solution
o 6.5V to 65V Input Voltage Range
o Output Current Up to 1A
o On-Board 65V, 0.45Ω Power MOSFET
o Hysteretic Control: Up to 2MHz Switching
Frequency
o ±3% LED Current Accuracy
o
o
o
o
o
200mV Current-Sense Reference
Resistor-Programmable Constant LED Current
Integrated High-Side Current Sense
Thermal-Foldback Protection/Linear Dimming
Thermal-Shutdown Protection
o Available in a Thermally Enhanced 8-Pin SO
Package
o -40°C to +125°C Operating Temperature Range
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX16832AASA+
-40°C to +125°C
8 SO-EP*
MAX16832AASA/V+
-40°C to +125°C
8 SO-EP*
MAX16832CASA+
-40°C to +125°C
8 SO-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
/V denotes an automotive qualified part.
Typical Application Circuit
D1
HB LEDs
VIN
RSENSE
L1
Applications
C2
Architectural, Industrial, and Ambient Lighting
Automotive RCL, DRL, and Fog Lights
1
Heads-Up Displays
2
Indicator and Emergency Lighting
MR16 and MR111 LED Lights
IN
C1
3
4
Pin Configuration appears at end of data sheet.
CS
GND
PGND
TEMP_I
MAX16832A
MAX16832C
DIM
LX
LX
8
7
NTC*
ON
OFF
6
5
*OPTIONAL
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.
1
MAX16832A/MAX16832C
General Description
MAX16832A/MAX16832C
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
ABSOLUTE MAXIMUM RATINGS
IN, CS, LX, DIM to GND .........................................-0.3V to +70V
TEMP_I to GND .......................................................-0.3V to +6V
PGND to GND ......................................................-0.3V to +0.3V
CS to IN .................................................................-0.3V to +0.3V
Maximum Current into Any Pin
(except IN, LX, and PGND).............................................20mA
Continuous Power Dissipation (TA = +70°C)
8-Pin SO (derate 18.9mW/°C above +70°C)...........1509.4mW
Operating Temperature Range
700mA (max) Output Current ........................-40°C to +125°C
1A (max) Output Current ...............................-40°C to +105°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Soldering (reflow).............................................................+260°C
Lead Temperature (soldering, 10s) .................................+300°C
Pin-to-Pin ESD Ratings......................................................±2.5kV
PACKAGE THERMAL CHARACTERISTICS (Note 1)
SO-EP
Junction-to-Ambient Thermal Resistance (θJA)...............+53°C/W
Junction-to-Case Thermal Resistance (θJC)......................+5°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = +24V, VDIM = VIN, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
Input Voltage Range
CONDITIONS
VIN
MIN
TYP
6.5
MAX
65
UNITS
V
Ground Current
No switching
1.5
mA
Supply Current
VDIM < 0.6V, VIN = 12V
350
µA
VCS = VIN - 100mV, VIN rising until VLX <
0.5VIN
6.25
UNDERVOLTAGE LOCKOUT (UVLO)
Undervoltage Lockout
UVLO
6.5
V
VCS = VIN - 100mV, VIN falling until VLX >
0.5VIN
6.0
Undervoltage-Lockout Hysteresis
0.5
V
SENSE COMPARATOR
Sense Voltage Threshold High
Sense Voltage Threshold Low
2
VSNSHI
VSNSLO
MAX16832A, VIN - VCS rising from 140mV
until VLX > 0.5VIN, VDIM = 5V
197
205
213
MAX16832C, VIN - VCS rising from 140mV
until VLX > 0.5VIN, VDIM = 5V
218
230
236
MAX16832A, VIN - VCS falling from 260mV
until VLX < 0.5VIN , VDIM = 5V
185
190
198
MAX16832C, VIN - VCS falling from 260mV
until VLX < 0.5VIN, VDIM = 5V
166
170
180
mV
mV
Propagation Delay to Output High
tDPDH
Falling edge of VIN - VCS from 140mV to
260mV to VLX > 0.5VIN
50
ns
Propagation Delay to Output Low
tDPDL
Rising edge of VCS - VIN from 260mV to
140mV to VLX < 0.5VIN
50
ns
CS Input Current
ICSIN
VIN - VCS = 200mV, VIN = VCS
3.5
µA
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
(VIN = +24V, VDIM = VIN, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
VIN = VDIM = 24V, VCS = 23.9V,
ILX = 700mA
0.45
0.9
VIN = VDIM = 6.0V, VCS = 5.9V,
ILX = 700mA
1
UNITS
INTERNAL MOSFET
Drain-to-Source Resistance
RDSON
LX Leakage Current
ILX_LEAK
Ω
2
VDIM = 0V, VLX = 65V
10
µA
DIM INPUT
DIM Input-Voltage High
DIM Input-Voltage Low
DIM Turn-On Time
VIH
VIN - VCS = 100mV
VIL
VCS - VIN = 100mV
tDIM_ON
2.8
V
0.6
V
VDIM rising edge to VLX < 0.5VIN
60
DIM Input Leakage High
VDIM = VIN
8
15
µA
DIM Input Leakage Low
VDIM = 0V
-1.5
0
µA
-3
ns
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Temperature rising
+165
o
C
10
o
C
Thermal-Shutdown Threshold
Hysteresis
THERMAL FOLDBACK
Thermal-Foldback Enable
Threshold Voltage
VTFB_ON
VDIM = 5V
Thermal-Foldback Slope
FBSLOPE
VDIM = 5V
TEMP_I Output Bias Current
ITEMP_I
1.9
2.0
25
26.5
2.12
V
0.75
TA = +25 oC
1/V
28
µA
Typical Operating Characteristics
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
1 LED
80
13 LEDs
80
11 LEDs
70
9 LEDs
7 LEDs
60
5 LEDs
50
3 LEDs
40
30
75
70
5
15
25
35
VIN (V)
45
55
65
500
450
300
200
10
50
0
0
25
7 LEDs
5 LEDs
250
100
15
11 LEDs
9 LEDs
350
3 LEDs
150
1 LED
35
VIN (V)
45
55
65
15 LEDs
400
20
5
13 LEDs
MAX16832A toc03
15 LEDs
90
FREQUENCY (kHz)
90
85
100
MAX16832A toc02
11 LEDs 13 LEDs 15 LEDs
DUTY CYCLE (%)
EFFICIENCY (%)
95
9 LEDs
7 LEDs
5 LEDs
3 LEDs
MAX16832A toc01
100
FREQUENCY
vs. INPUT VOLTAGE
DUTY CYCLE
vs. INPUT VOLTAGE
EFFICIENCY
vs. INPUT VOLTAGE
1 LED
16 LEDs
5
15
25
35
45
55
65
VIN (V)
3
MAX16832A/MAX16832C
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
1.02
13 LEDs
11 LEDs 15 LEDs
7 LEDs 9 LEDs
1 LED 3 LEDs 5 LEDs
1.00
0.99
MAX16832A toc05
450
QUIESCENT CURRENT (µA)
1.03
MAX16832A toc06
500
MAX16832A toc04
NORMALIZED ILED CURRENT
1.04
1.01
PWM DIMMING
AT 200Hz (10% DUTY CYCLE)
QUIESCENT CURRENT
vs. INPUT VOLTAGE
NORMALIZED ILED CURRENT
vs. INPUT VOLTAGE
1.05
0.98
400
VIN = 48V
8 LEDs
350
ILED
200mA/div
300
250
200
0
150
0.97
100
0.96
50
0.95
VDIM
5V/div
0
VDIM = 0V
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65
0 5 10 15 20 25 30 35 40 45 50 55 60 65
VIN (V)
VIN (V)
PWM DIMMING
AT 200Hz (90% DUTY CYCLE )
1ms/div
PWM DIMMING
AT 20kHz (90% DUTY CYCLE)
MAX16822A toc07
MAX16832A toc08
ILED
200mA/div
ILED
200mA/div
0
0
VIN = 48V
8 LEDs
VDIM
5V/div
0
VIN = 48V
8 LEDs
1ms/div
10µs/div
LED CURRENT
vs. VTEMP_I
ILED
vs. TEMPERATURE
0
MAX16832A toc10
1.0
MAX16832A toc09
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
VIN = 48V
0
0
0.4
0.8
1.2
1.6
VTEMP_I (V)
4
VDIM
5V/div
ILED (A)
LED CURRENT (mA)
MAX16832A/MAX16832C
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
2.0
2.4
2.8
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
ITEMP_I
vs. TEMPERATURE
LXRDSON
vs. TEMPERATURE
0.6
29.5
29.0
28.5
0.5
0.4
VIN = 6.5V
0.3
ITEMP_I (µA)
LXRDSON (Ω)
VIN = 48V
30.0
MAX16832A toc12
VIN = 65V
MAX16832A toc11
0.7
28.0
27.5
27.0
26.5
26.0
0.2
25.5
25.0
0.1
VIN = 48V
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
Pin Description
PIN
NAME
1
CS
Current-Sense Input. Connect a resistor between IN and CS to program the LED current.
FUNCTION
2
IN
Positive Supply Voltage Input. Bypass with a 1µF or higher value capacitor to GND.
3
GND
4
PGND
5, 6
LX
Ground
Power Ground
Switching Node
7
DIM
8
TEMP_I
—
EP
Logic-Level Dimming Input. Drive DIM low to turn off the current regulator. Drive DIM high to
enable the current regulator.
Thermal Foldback Control and Linear Dimming Input. Bypass with a 0.01µF capacitor to GND if
thermal foldback or analog dimming is used. See the Thermal Foldback section.
Exposed Pad. Connect EP to a large-area ground plane for effective power dissipation. Do not use
as the IC ground connection.
Detailed Description
The MAX16832A/MAX16832C are step-down, constantcurrent, HB LED drivers. These devices operate from a
+6.5V to +65V input voltage range. The maximum output
is 1A, if the part is used at temperatures up to TA =
+105°C, or 700mA, if it is used up to TA = +125°C. A
high-side current-sense resistor sets the output current
and a dedicated PWM dimming input enables pulsed
LED dimming over a wide range of brightness levels.
A high-side current-sensing scheme and an on-board
current-setting circuitry minimize the number of external components while delivering LED current with ±3%
accuracy, using a 1% sense resistor. See Figure 1 for a
functional diagram.
5
MAX16832A/MAX16832C
Typical Operating Characteristics (continued)
(VIN = VDIM = 48V, RSENSE = 0.3Ω, L = 220µH (connected between IN and CS). Typical values are at TA = +25°C, unless otherwise
noted.)
MAX16832A/MAX16832C
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
IN
VCC
REGULATOR
MAX16832A
MAX16832C
VCC _ANA
ISET
OPEN LED
COMPARATOR
LX
VCC _ANA
CS
CURRENT-SENSE
COMPARATOR
0.45Ω, 65V
nMOS SWITCH
PWM
DIMMING
1.23V
BANDGAP
REF
GATE
DRIVER
UVLO
COMPARATOR
DIM
DIM
BUFFER
VCC _ANA
25µA
TEMP_I
PGND
VTFB_ON
2V
GND
Figure 1. Functional Diagram
6
THERMAL
FOLDBACK
COMPARATOR
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
DIM Input
LED dimming is achieved by applying a PWM signal at
DIM. A logic level below 0.6V at DIM forces the
MAX16832A/MAX16832Cs’ output low, thus turning off
the LED current. To turn the LED current on, the logic
level at DIM must be greater than 2.8V.
Thermal Shutdown
The MAX16832A/MAX16832C thermal-shutdown feature
turns off the LX driver when the junction temperature
exceeds +165°C. The LX driver turns back on when the
junction temperature drops 10°C below the shutdown
temperature threshold.
Analog Dimming
The MAX16832A/MAX16832C offer an analog-dimming
feature that reduces the output current when the voltage at TEMP_I is below the internal 2V threshold voltage. The MAX16832A/MAX16832C achieve analog
dimming by either an external DC voltage source connected between TEMP_I and ground or by a voltage on
a resistor connected across TEMP_I and ground
induced by an internal current source of 25µA. When
the voltage at TEMP_I is below the internal 2V threshold
limit, the MAX16832A/MAX16832C reduce the LED current. Use the following formula to set the analog dimming current:
⎡
⎤
⎛ 1⎞
ITF (A) = ILED (A) × ⎢1− FBSLOPE ⎜ ⎟ × VTFB _ ON − VAD (V)⎥
⎝
⎠
V
⎣
⎦
(
)
where VTFB_ON = 2V and FBSLOPE = 0.75 are obtained
from the Electrical Characteristics table and VAD is the
voltage at TEMP_I.
Thermal Foldback
The MAX16832A/MAX16832C include a thermal-foldback feature that reduces the output current when the
temperature of the LED string exceeds a specified temperature point. These devices enter thermal-foldback
mode when the voltage drop on the NTC thermistor,
thermally attached to the LEDs and electrically connected between TEMP_I and ground, drops below the
internal 2V threshold limit.
Selecting RSENSE to Set LED Current
The LED current is programmed with a current-sense
resistor connected between IN and CS. Use the following equation to calculate the value of this resistor:
RSENSE (Ω) =
1 (VSNSHI + VSNSLO )(V)
ILED (A)
2
where VSNSHI is the sense voltage threshold high and
VSNSLO is the sense voltage threshold low (see the
Electrical Characteristics table for values).
Current-Regulator Operation
The MAX16832A/MAX16832C regulate the LED current
using a comparator with hysteresis (see Figure 2). As
the current through the inductor ramps up and the voltage across the sense resistor reaches the upper
threshold, the internal MOSFET turns off. The internal
MOSFET turns on again when the inductor current
ramps down through the freewheeling diode until the
voltage across the sense resistor equals the lower
threshold. Use the following equation to determine the
operating frequency:
fSW =
(VIN − nVLED ) × nVLED × RSENSE
VIN × ∆V × L
where n is the number of LEDs, VLED is the forward
voltage drop of 1 LED, and ∆V = (VSNSHI - VSNSLO).
Inductor Selection
The MAX16832A/MAX16832C operate up to a switching frequency of 2MHz. For space-sensitive applications, the high switching frequency allows the size of
the inductor to be reduced. Use the following formula to
calculate an approximate inductor value and use the
closest standard value:
L(approx.) =
(VIN − nVLED ) × nVLED × RSENSE
VIN × ∆V × fSW
For component selection, use the MAX16832A/C Design
Tool available at: www.maxim-ic.com/MAX16832software.
7
MAX16832A/MAX16832C
Applications Information
Undervoltage Lockout (UVLO)
The MAX16832A/MAX16832C include a UVLO with
500mV hysteresis. The internal MOSFET turns off when
VIN falls below 5.5V to 6.0V.
MAX16832A/MAX16832C
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
HYSTERETIC
MODE
fSW
ILED
∆I
AVG. LED
CURRENT
t
VDIM
t2
t1
t
Figure 2. Current-Regulator Operation
Freewheeling-Diode Selection
For stability and best efficiency, a low forward-voltage
drop diode with fast reverse-recovery time and low
capacitance is recommended. A Schottky diode is a
good choice as long as its breakdown voltage is high
enough to withstand the maximum operating voltage.
PCB Layout Guidelines
Careful PCB layout is critical to achieve low switching
losses and stable operation. In normal operation, there
are two power loops. One is formed when the internal
MOSFET is on and the high current flows from ground
through the input cap, R SENSE , the LED load, the
inductor, and the internal MOSFET back to ground. The
second loop is formed when the internal MOSFET is off
and the high current circulates from the input cap positive terminal through RSENSE, the LED load, the inductor, and the freewheeling diode and back to the input
cap positive terminal. Note that the current through
RSENSE, the LED load, and the inductor is basically DC
with some triangular ripple (low noise). The high-noise,
large signal, fast transition switching currents only flow
through the freewheeling diode to the input cap positive
8
terminal, or through the MOSFET to ground and then to
the input cap positive terminal. Without a proper PCB
layout, these square-wave switching currents can create problems in a hysteretic LED driver.
The current control depends solely on the voltage
across RSENSE. Any noise pickup on this node induces
erratic switching of the internal MOSFET (the IC will
operate at a much higher frequency). To help prevent
this, place RSENSE as close as possible to CS and IN
and keep the sense traces short. It is especially important to keep the square-wave switching currents in the
freewheeling diode away from RSENSE. To minimize
interference, place the freewheeling diode on the opposite side of the IC as RSENSE and position the input
capacitor near the diode so it can return the high frequency currents to ground. The layout in Figure 3
should be used as a guideline. The dashed line shows
the path of the high frequency components that cause
disruption in operation. For a good thermal design, the
exposed pad on the IC should solder to a large pad
with many vias to the backside ground plane.
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
MAX16832A/MAX16832C
LED+
LED-
CFILTER
RSENSE
1
L
GND
LX
CIN
VIAS FOR THERMAL TRANSFER
TO BACKSIDE GROUND PLANE
VIN
D
tOFF AND tON CURRENT PATHS
KEEP THIS LOOP TIGHT.
Figure 3. PCB Layout
Pin Configuration
Chip Information
PROCESS: BiCMOS
TOP VIEW
Package Information
+
CS
1
IN
2
GND
3
MAX16832A
MAX16832C
PGND 4
SO-EP
8
TEMP_I
7
DIM
6
LX
5
LX
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE NO.
LAND
PATTERN NO.
8 SO-EP
S8E-12
21-0111
90-0150
9
2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
MAX16832A/MAX16832C
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
0
5/08
Initial release
—
1
9/08
Introduced the MAX16832C
1
2
5/09
Revised General Description, Features, Absolute Maximum Ratings, and
Detailed Description
3
2/10
Updated PCB Layout Guidelines and added Figure 3
4
8/10
Corrected Functional Diagram and added Soldering (reflow) to Absolute
Maximum Ratings
5
3/12
Updated Sense Voltage Threshold High and DIM Turn-On Time in Electrical
Characteristics
6
7/12
Added automotive qualified part to Ordering Information
1, 2, 5
8, 9
2, 5, 6
2, 3
1
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. The parametric values (min and max limits) shown in
the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
10
_______________Maxim Integrated Products, Inc. 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2012 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX16832CEVKIT MAX16823C和MAX16832A评估板 - 概述
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Maxim > 产品 > 电源和电池管理 > MAX16832CEVKIT
MAX16832CEVKIT
MAX16823C和MAX16832A评估板
概述 技术文档 定购信息 相关产品 用户说明 (0) 所有内容 状况
数据资料
状况：生产中。
英文
概述
中文
MAX16832C评估板(EV kit)用于演示滞回、电流模式高亮度LED (HB LED)驱动器MAX16832C的功
能。MAX16832C评估板配置为降压拓扑，恒流HB LED驱动电路用于驱动外部HB LED。MAX16832C评估板采
用6.5V至65V直流电源供电，最高可向HB LED提供666mA电流。用于驱动串联HB LED的输出电压可达64V，具
体取决于评估板的输入电压。
下载 Rev. 0 (PDF, 100kB)
E-Mail
下载 Rev. 0 (PDF, 556kB)
E-Mail
MAX16832C评估板可配置为数字脉宽调制(PWM)亮度控制模式，用数字PWM输入信号调节亮度。该评估板电路
还具有折返式热保护保护和温度仿真电路。MAX16832C评估板是完全组装并经过测试的表面贴装PCB。另
外，PCB布局经过优化能够提供最佳散热。通过替换IC，通过替换IC，MAX16832C评估板也可以用来评
估MAX16832A，根据完整数据资料中所列出的的编码定购。
警告：LED+及LED-输出焊盘上的电压有可能大于42V。
关键特性
应用/使用
建筑、工业及环境照明
汽车RCL、DRL和雾灯
平面显示器
指示灯和紧急事件灯
MR16和MR111 LED灯
6.5V至65V宽电源电压范围
666mA HB LED电流
数字PWM调光控制
模拟调光控制
折返式热保护及温度仿真电路
可用来评估MAX16832A (需替换IC)
无铅并符合RoHS标准
完全组装并经过测试
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概述
关键特性
应用/使用
关键指标
图表
注释、注解
数据资料
技术文档
评估板
可靠性报告
软件/模型
价格与供货
样品
在线订购
封装信息
无铅信息
类似功能器件
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配合该器件使用的产品
参考文献： 19- 4289 Rev. 0; 2008- 10- 30
本页最后一次更新: 2009- 03- 11
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© 2012 Maxim Integrated Products版权所有
http://china.maxim-ic.com/datasheet/index.mvp/id/6054[2012-08-17 8:12:03]
19-4289; Rev 0; 9/08
MAX16832C Evaluation Kit
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 configured 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-supplied HB LEDs. The output voltage for the HB LED string
can go up to 64V and depends upon the EV kit’s input
voltage.
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 assembled 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 6.5V to 65V Wide Supply Voltage Range
Warning: Voltages exceeding 42V could exist on the
LED+ and LED- output pads.
+Denotes lead-free and RoHS compliant.
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
o Evaluates MAX16832A (IC Replacement Required)
o Lead-Free and RoHS Compliant
o Fully Assembled and Tested
Ordering Information
PART
TYPE
MAX16832CEVKIT+
EV Kit
Component List
DESIGNATION
QTY
QTY
DESCRIPTION
R1
1
0.300Ω ±1%, 0.5W sense resistor
(1206)
IRC LRC-LRF1206LF-01-R300-F
0.01µF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H103K
R2
1
100kΩ ±10% potentiometer
R3
1
20kΩ ±5% resistor (0805)
R4
1
100kΩ ±5% resistor (0805)
Not installed, ceramic capacitor
(1210)
TP1
1
PC mini red test point
TP2
1
PC mini black test point
U1
1
Step-down HB LED driver
(8 SO-EP*)
Maxim MAX16832CASA+
—
2
Shunts (JU1, JU2)
—
1
PCB: MAX16832C Evaluation Kit+
C1
1
C2
1
C3
0
D1
1
100V, 2A Schottky rectifier (SMA)
Central Semi CMSH2-100M
(Top Mark: CS2100M)
JU1, JU2
2
2-pin headers
1
220µH, 1.28A inductor
Coilcraft MSS1260-224KLB
L1
DESIGNATION
DESCRIPTION
1µF ±10%, 100V X7R ceramic
capacitor (1210)
Murata GRM32CR72A105K
*EP = Exposed pad.
Component Suppliers
SUPPLIER
PHONE
WEBSITE
Central Semiconductor Corp
631-435-1110
www.centralsemi.com
Coilcraft, Inc.
847-639-6400
www.coilcraft.com
IRC, Inc
361-992-7900
www.irctt.com
Murata Electronics North America, Inc.
770-436-1300
www.murata-northamerica.com
Note: Indicate that you are using the MAX16832C when contacting these component suppliers.
________________________________________________________________ Maxim Integrated Products
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.
1
Evaluates: MAX16832C/MAX16832A
General Description
Evaluates: MAX16832C/MAX16832A
MAX16832C Evaluation Kit
Quick Start
Detailed Description of Hardware
Required Equipment
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.
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 current is set to 666mA (typ) by resistor R1. The
MAX16832C thermal-foldback feature can be evaluated by connecting a negative temperature coefficient
(NTC) thermistor between the TEMP_I and PGND PCB
pads on the EV kit. Alternatively, a temperature-varying thermistor circuit can be simulated using potentiometer R2 and resistor R3. The EV kit also features a
DIM PCB pad to evaluate digital PWM dimming operation of the external HB LEDs.
Before beginning, the following equipment is needed:
• 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
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).
3) Connect the power supply’s positive terminal to the
VIN PCB pad on the EV kit. Connect the power supply’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.
6) Connect the cathode of the HB LED string to the
LED- pad.
7) Clip the current probe across the HB LED+ wire to
measure the HB LED current.
8) Turn on the power supply and increase the powersupply 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 70V high-voltage spark on the
MAX16832C and damage the IC due to the power
cable inductance-caused ringing with the input filter capacitor.
9) Using a voltmeter, verify that the voltage across
TP1 and TP2 is > 2V. If it is not, adjust potentiometer R2 to obtain a reading > 2V.
2
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 conductivity when evaluating a MAX16832 IC.
Jumper Selection
The MAX16832C EV kit features several jumpers to
reconfigure the PWM dimming, thermal-foldback feature and for reconfiguring the external HB LED current.
Enable and HB LED Dimming Control
(Digital and Analog)
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 digital 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 0% to 100%. See Table 1 for jumper JU1
setting of the HB LED dimming operation.
_______________________________________________________________________________________
MAX16832C Evaluation Kit
EV KIT ENABLE OR
DIMMING OPERATION
SHUNT
POSITION
DIM PIN
Not
installed
Connected to
VIN through R4
Enabled or analog dimming*
(see Table 2)
Not
installed
Connected to
PWM signal
Enabled, PWM signal applied
at DIM PCB pad
Installed
Connected to
PGND
Disabled
* Analog dimming can be achieved by placing a resistor
(RDIM) across the TEMP_I and PGND PCB pads. Remove the
shunt across jumpers JU1 and JU2, and then use the ILEDDIM
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.
To evaluate the MAX16832C IC thermal-foldback feature, 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 2. Temperature Simulation and
Thermal Foldback (Jumper JU2)
SHUNT
POSITION
TEMP_I PIN
EV KIT OPERATION
Installed
Connected to
R2 and R3
Temperature simulation
Not
installed
Connected to
external NTC
thermistor
Thermal foldback*
*Also analog dimming (see Table 1).
ILEDDIM = ILED [1 - 0.75 x (2 - (RDIM x 26.5µA))]
where RDIM is the TEMP_I pad resistor, ILEDDIM is the
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 0.7V to 2V at the
TP1 (positive) and TP2 (PGND) test points.
Thermal Foldback and Temperature
Simulation
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 thermal foldback. Potentiometer R2 and resistor R3 form
the adjustable temperature-simulation circuit. Test
points TP1 and TP2 (PGND) provide access to the signal for adjusting the voltage.
Setting External HB LED Current
Resistor R1 sets the MAX16832C EV kit average HB
LED current up to 666mA. However, the HB LED average current can be set up to 700mA after replacing
resistor R1. Use the following equation to calculate R1
when reconfiguring the HB LED current:
R1 =
0.2V
ILED
where ILED is the desired HB LED average current.
Refer to the Selecting RSENSE to Set LED Current section in the MAX16832A/MAX16832C IC data sheet for
information on setting the HB LED current.
_______________________________________________________________________________________
3
Evaluates: MAX16832C/MAX16832A
Table 1. Enable and HB LED Dimming
(Jumper JU1)
Evaluates: MAX16832C/MAX16832A
MAX16832C Evaluation Kit
Figure 1. MAX16832C EV Kit Schematic
4
_______________________________________________________________________________________
MAX16832C Evaluation Kit
Evaluates: MAX16832C/MAX16832A
Figure 2. MAX16832C EV Kit Component Placement Guide—
Component Side
Figure 3. MAX16832C EV Kit PCB Layout—Component Side
_______________________________________________________________________________________
5
Evaluates: MAX16832C/MAX16832A
MAX16832C Evaluation Kit
Figure 4. MAX16832C EV KIT PCB Layout—Solder Side
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.