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| 型号： | MAX16802BEVKIT |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 8/16页 |
| 文件大小： | 0K |
| 描述： | EVAL KIT FOR MAX16802 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 电流 - 输出 / 通道： | 750mA |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 12V |
| 特点： | 可调光 |
| 输入电压： | 10.8 ~ 30V |
| 已供物品： | 板 |
| 已用 IC / 零件： | MAX16802B |
Offline and DC-DC PWM Controllers for
High-Brightness LED Drivers
VDC
VDC
R
R
Q
IN
IN
D
MAX16802A
D
C
MAX16802A
(a)
Figure 2. (a) Resistor-Zener and (b) Transistor-Zener-Resistor Bias Arrangements
(b)
in applications with higher input DC voltages by imple-
menting resistor-Zener bias (Figure 2a) or transistor-
Zener-resistor bias (Figure 2b).
MAX16801/MAX16802 Undervoltage
Lockout
The MAX16801/MAX16802 have an input voltage
UVLO/EN pin. The threshold of this UVLO is +1.28V.
Before any operation can commence, the voltage on
this pin has to exceed +1.28V. The UVLO circuit keeps
the CPWM comparator, ILIM comparator, oscillator,
and output driver in shutdown to reduce current con-
sumption (see the Functional Diagram ). Use this UVLO
function to program the input start voltage. Calculate
the divider resistor values, R2 and R3 (Figure 5), by
using the following formulas:
MAX16801 Bootstrap Undervoltage
Lockout
In addition to the externally programmable UVLO func-
tion offered in both the MAX16801/MAX16802, the
MAX16801 has an additional internal bootstrap UVLO
that is very useful when designing high-voltage LED
drivers (see the Functional Diagram ). This allows the
device to bootstrap itself during initial power-up. The
MAX16801 attempts to start when V IN exceeds the
bootstrap UVLO threshold of +23.6V. During startup,
the UVLO circuit keeps the CPWM comparator, ILIM
comparator, oscillator, and output driver shut down to
reduce current consumption. Once V IN reaches
+23.6V, the UVLO circuit turns on both the CPWM and
ILIM comparators, as well as the oscillator, and allows
the output driver to switch. If V IN drops below +9.7V,
R 3 ?
V ULR 2 × V IN
500 × I UVLO ( V IN ? V ULR 2 )
the UVLO circuit will shut down the CPWM comparator,
ILIM comparator, oscillator, and output driver thereby
returning the MAX16801 to the startup mode.
R 2 = × R 3
The value of R3 is calculated to minimize the voltage-
drop error across R2 as a result of the input bias cur-
rent of the UVLO/EN pin. V ULR2 = +1.28V, I UVLO =
50nA (max), V IN is the value of the input-supply voltage
where the power supply must start.
V IN ? V ULR2
V ULR 2
where I UVLO is the UVLO/EN pin input current, and
V ULR2 is the UVLO/EN wake-up threshold.
MAX16801 Startup Operation
In isolated LED driver applications, V IN can be derived
from a tertiary winding of a transformer. However, at
startup there is no energy delivered through the trans-
former. Therefore, a special bootstrap sequence is
required. Figure 3 shows the voltages on IN and V CC
during startup. Initially, both V IN and V CC are 0V. After
the line voltage is applied, C1 charges through the
startup resistor R1 to an intermediate voltage. At this
point, the internal regulator begins charging C2 (see
Figure 5). The MAX16801 uses only 45μA of the current
supplied by R1, and the remaining input current
charges C1 and C2. The charging of C2 stops when
the V CC voltage reaches approximately +9.5V, while
the voltage across C1 continues rising until it reaches
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX16803ATE/V+ | 功能描述:LED照明驱动器 350mA HB LED Drvr w/PWM Dim and 5V Reg 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 |
| MAX16803ATE/V+T | 功能描述:LED照明驱动器 350mA HB LED Drvr w/PWM Dim and 5V Reg 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 |
| MAX16803ATE+ | 功能描述:LED照明驱动器 350mA HB LED Drvr w/PWM Dim and 5V Reg 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 |
| MAX16803ATE+T | 功能描述:LED照明驱动器 350mA HB LED Drvr w/PWM Dim and 5V Reg 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 |
| MAX16803EVKIT | 制造商:Maxim Integrated Products 功能描述:HIGH-VOLTAGE, 350MA, HIGH-BRIGHTNES - Bulk |
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