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| 型号： | MAX16834ATP+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 16/23页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVR HIGH BRIGHT 20-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 特色产品： | MAX16834 High-Power LED Driver |
| 标准包装： | 75 |
| 拓扑： | PWM，SEPIC，降压（降压），升压（升压） |
| 输出数： | 1 |
| 内部驱动器： | 无 |
| 类型 - 主要： | 车载，背光 |
| 类型 - 次要： | 高亮度 LED（HBLED），RGB |
| 频率： | 100kHz ~ 1MHz |
| 电源电压： | 4.75 V ~ 28 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-WFQFN 裸露焊盘 |
| 供应商设备封装： | 20-TQFN-EP |
| 包装： | 管件 |
| 工作温度： | -40°C ~ 125°C |
MAX16834
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
( R LED + R 10 ) × V LED
R OUT =
Boost configuration:
( R LED + R 10 ) × I LED + V LED
C 7 =
1
2 π × R 7 × f P 2
where C7 is in farads, f P2 is in hertz, and R7 is in ohms.
Boost-buck configuration:
To minimize switching frequency noise, an additional
R OUT =
( R LED + R 10 ) × V LED
( R LED + R 10 ) × I LED × D MAX + V L ED
capacitor can be added in parallel with the series com-
bination of R7 and C7. The pole from this capacitor and
R7 must be a decade higher than the loop crossover
where R LED is the dynamic impedance (rate of change
of voltage with current) of the LED string at the operat-
ing current, R10 is the LED current-sense resistor in
ohms, V LED is in volts, and I LED is in amperes.
The output pole frequency for both boost and boost-
buck configurations is calculated as follows:
frequency.
Short-Circuit Protection
Boost Configuration
In the boost configuration (Figure 2), if the LED string is
shorted then the excess current flowing in the LED cur-
rent-sense resistor will cause NDRV to stop switching.
f P 2 =
1
2 π × C OUT × R OUT
The input voltage will appear on the output capacitor,
and this causes very high peak currents to flow in the
LED current-sense resistor R10 because the dimming
MOSFET (Q2) is on. Once the voltage across the LED
where f P2 is in hertz, C OUT is the output filter capaci-
tance in farads, R OUT is the effective output impedance
in ohms calculated above.
Compensation components R7 and C7 perform two
functions. C7 introduces a low-frequency pole that
introduces a -20dB/decade slope into the loop gain. R7
flattens the gain of the error amplifier for frequencies
above the zero formed by R7 and C7. For compensa-
tion, this zero is placed at the output pole frequency f P2
such that it provides a -20dB/decade slope for frequen-
cies above f P2 for the complete loop gain.
The value of R7 needed to fix the total loop gain at f P2
such that the total loop gain crosses 0dB at
-20dB/decade at one-fifth of the RHP zero can be cal-
culated as follows:
current-sense resistor exceeds 300mV for more than
5μs, then the dimming MOSFET Q2 turns off and stays
off for 4096 switching clock cycles. At the same time,
NDRV is also off. The MAX16834 goes into the hiccup
mode and recovers from hiccup once the short has
been removed. The power dissipation in the dimming
MOSFET (Q2) is minimized during a short across the
LED string. During the same period, FLT only goes high
when the dimming MOSFET is on.
Boost-Buck Configuration
In the case of the boost-buck configuration (Figure 3),
once an LED string short occurs then the behavior is
different. A short across the LED string causes a high
current spike due to the external capacitors at the out-
put. The regulation loop will cause NDRV to stop
switching. This causes the voltage on HV to drop if its
R 7 =
f ZRHP × R 8
5 × f P 2 × ( 1 ? D MAX ) × R 10 × 9 . 9 × GM COMP
voltage is derived from LED+. The voltage on CLV will
drop, and this drop is detected after 128 clock cycles.
The dimming MOSFET and the switching MOSFET will
where R7 is the compensation resistor in ohms, f ZRHP
and f P2 are in hertz, R8 is the switch current-sense
resistor in ohms, R10 is the LED current-sense resistor
in ohms, factor 9.9 is the gain of the LED current ampli-
fier, and GM COMP is the transconductance of the error
amplifier in Siemens.
The value of C7 can be calculated as:
16
stop switching. It stays off for 4096 clock cycles, and
the cycle repeats itself. The short across the LED string
will cause the MAX16834 to go into a hiccup mode. At
the same time the FLT signal asserts itself for 4096
clock cycles every hiccup cycle. In the case where the
HV voltage is derived from a source different than
LED+, then the LED current will stay in regulation even
during a short across the LED string. In this case, FLT
does not assert itself during the short.
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX16834ATP/V+ | 功能描述:LED照明驱动器 w/Int Hside Crnt Sns & PWM Dim MOSFET 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 |
| MAX16834ATP/V+CEU | 制造商:Maxim Integrated Products 功能描述:HIGH-POWER LED DRIVER WITH INTEGRATED HIGH-SIDE LED CURRENT - Rail/Tube |
| MAX16834ATP/V+T | 功能描述:LED照明驱动器 w/Int Hside Crnt Sns & PWM Dim MOSFET 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 |
| MAX16834ATP/V+TCEU | 制造商:Maxim Integrated Products 功能描述:HIGH-POWER LED DRIVER WITH INTEGRATED HIGH-SIDE LED CURRENT - Tape and Reel |
| MAX16834ATP+ | 功能描述:LED照明驱动器 w/Int Hside Crnt Sns & PWM Dim MOSFET 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 |
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