收藏本站
MAX16838
Integrated, 2-Channel, High-Brightness LED Driver
with High-Voltage Boost and SEPIC Controller
Detailed Description
The MAX16838 high-efficiency, HB LED driver inte-
grates all the necessary features to implement a high-
performance backlight driver to power LEDs in small-to-
medium-sized displays for automotive as well as general
applications. The device provides load-dump voltage
protection up to 40V in automotive applications. The
MAX16838 incorporates a DC-DC controller with peak
current-mode control to implement a boost, coupled
inductor boost-buck, or SEPIC-type switched-mode
power supply and a 2-channel LED driver with 20mA
to 150mA constant-current-sink capability per channel.
The MAX16838 can be combined with the MAX15054 to
achieve boost-buck topology without a coupled inductor
(see Figure 5).
The MAX16838 features a constant-frequency peak
current-mode control with internal slope compensation
to control the duty cycle of the PWM controller. The
DC-DC converter generates the required supply volt-
age for the LED strings from a wide input supply range.
Connect LED strings from the DC-DC converter output
to the 2-channel constant current sinks that control the
current through the LED strings. A single resistor
connected from ISET to ground sets the forward current
through both LED strings.
The MAX16838 features adaptive LED voltage control
that adjusts the converter output voltage depending
on the forward voltage of the LED strings. This feature
minimizes the voltage drops across the constant-current
sinks and reduces power dissipation in the device. The
MAX16838 provides a very wide PWM dimming range
where a dimming pulse as narrow as 1 F s is possible at
a 200Hz dimming frequency.
A logic input (EN) shuts down the device when pulled low.
The device includes an internal 5V LDO to power up the
internal circuitry and drive the internal switching MOSFET.
The MAX16838 includes output overvoltage protec-
tion that limits the converter output voltage to the pro-
grammed OV threshold in the event of an open-LED
condition. The device also features an overtemperature
protection that shuts down the controller if the die tem-
perature exceeds +165°C. In addition, the MAX16838
has a shorted LED string detection and an open-drain
FLT signal to indicate open LED, shorted LED, and over-
temperature conditions.
12
Current-Mode DC-DC Controller
The MAX16838 uses current-mode control to provide
the required supply voltage for the LED strings. The
internal MOSFET is turned on at the beginning of every
switching cycle. The inductor current ramps up linearly
until it is turned off at the peak current level set by the
feedback loop. The peak inductor current is sensedfrom
the voltage across the current-sense resistor (R CS )
connected from the source of the internal MOSFET to
PGND. A PWM comparator compares the current-sense
voltage plus the internal slope compensation signal with
the output of the transconductance error amplifier. The
controller turns off the internal MOSFET when the voltage
at CS exceeds the error amplifier’s output voltage. This
process repeats every switching cycle to achieve peak
current-mode control.
Error Amplifier
The internal error amplifier compares an internal feed-
back (FB) signal with an internal reference voltage
(V REF ) and regulates its output to adjust the inductor
current. An internal minimum string detector measures
the minimum LED string cathode voltage with respect
to SGND. During normal operation, this minimum V OUT_
voltage is regulated to 1V through feedback. The result-
ing DC-DC converter output voltage is 1V above the
maximum required total LED voltage.
The converter stops switching when LED strings are
turned off during PWM dimming. The error amplifier is
disconnected from the COMP output to retain the com-
pensation capacitor charge. This allows the converter to
settle to a steady-state level immediately when the LED
strings are turned on again. This unique feature provides
fast dimming response without having to use large out-
put capacitors. If the PWM dimming on-pulse is less than
five switching cycles, the feedback controls the voltage
on OV such that the converter output voltage is regu-
lated at 95% of the OV threshold. This mode ensures
that narrow PWM dimming pulses are not affected by
the response time of the converter. During this mode,
the error amplifier remains continuously connected to
the COMP output.
Adaptive LED Voltage Control
The MAX16838 reduces power dissipation using an
adaptive LED voltage control scheme. The adaptive LED
voltage control regulates the DC-DC converter output
based on the operating voltage of the LED strings.
Maxim Integrated
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MAX1698EUB IC LED DRVR WT/CLR BCKLGT 10MSOP
MAX17014EVKIT+ KIT EVAL FOR MAX17014
MAX17061AETI+T IC LED DRVR WHITE BCKLGT 28-TQFN
MAX17061ETI+T IC LED DRVR WHITE BCKLGT 28-TQFN
MAX17105ETG+T IC LED DRVR WHITE BCKLGT 24-TQFN
MAX17127ETP+ IC WLED DVR SIX STRING 20TQFN
MAX17149ETE+ IC LED DRVR 6CH STEP UP 16QFNEP
MAX17410EVKIT+ KIT EVAL FOR MAX17410 CTLR
相关代理商/技术参数
MAX16838AUP+T 功能描述:LED照明驱动器 HB w/High-Voltage DC/DC Controller RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX16838EVKIT+ 功能描述:LED 照明开发工具 MAX16838 evaluation kit RoHS:否 制造商:Fairchild Semiconductor 产品:Evaluation Kits 用于:FL7732 核心: 电源电压:120V 系列: 封装:
MAX16839ASA+ 功能描述:LED照明驱动器 High-Voltage Linear w/LED Open Detect RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX16839ASA+T 功能描述:LED照明驱动器 High-Voltage Linear w/LED Open Detect RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX16839ATT/V+ 制造商:Maxim Integrated Products 功能描述:
MAX16839ATT/V+T 功能描述:LED照明驱动器 High-Voltage Linear High-Brightness LED Driver with LED Fault Open Detect RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N
MAX16839ATT+ 制造商:Maxim Integrated Products 功能描述:HIGH-VOLTAGE LINEAR HIGH-BRIGHTNES - Bulk
MAX16839ATT+T 功能描述:LED照明驱动器 High-Voltage Linear w/LED Open Detect RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N