- 您现在的位置：买卖IC网 > Sheet目录310 > AOZ1977AI (Alpha & Omega Semiconductor Inc)IC LED DRVR BCKLGT 16SOIC
AOZ1977
Detailed Description
T AUTORESTART = ---------------------------
The AOZ1977 is a boost DC/DC controller designed to
power a series of LEDs by regulating the current into the
LED string. The LED current information is provided to
the system through the sense resistor RFB at the bottom
of the LED string, between FB pin and GND pin.
Protection Features
Over-Current Protection at Boost Switch
The current limit is a function of RS resistor value at
CS pin and the voltage setting at ILIM pin. The voltage at
ILIM is directly compared to the sense voltage at CS pin.
When CS voltage reaches ILIM set voltage, current limit
protection triggers and the boost switch will be turned off
immediately until the next clock cycle. To make sure that
current limit protection does not affect the normal
operation, the current limit should be set at least 30 %
higher than the inductor peak current. However, the
voltage at ILIM must be less than 0.4 V. When CS voltage
is higher than 0.4V, fault detection is active and that may
affect normal operation. ILIM voltage is generated by
connecting a resistor divider (RL1 and RL2 in the Typical
Application diagram on page 1) from 1.2 V VREF pin to
ILIM and GND pins. To minimize power consumption, it is
recommended that the total resistance for the divider is
approximately 20 k ? .
For example,
- If peak current is 0.55 A.
- 30% higher is 0.72 A.
- CS voltage is 0.72 V x 0.55 ? = 0.4 V.
Over-Voltage Protection at Output
Over-voltage protection is monitoring the LED output
voltage through a resistor divider (Rov1 and Rov2 on
page 1) from VOUT to OVP and GND pins. When the
voltage at this pin is higher than 1 V, the controller will
stop switching immediately until the voltage at this pin is
below 0.8 V.
LED Short Protection
When FB voltage is higher than 1 V when LED current
control switch is ON, the system will consider some LEDs
are shorted instantaneously. Under this condition, the
controller will enter the fault state.
LED Open Protection
When all LEDs are open, the system will respond by
boosting the output voltage. Once the output voltage
reaches the OVP threshold, OVP protection will trigger.
Latch Off or Auto Restart Mode
AOZ1977 can select either auto restart mode or latch-off
mode under fault condition. Typical fault conditions are
excessive current at boost switch, or LED short. For
latch-off mode, the AUTO pin can be connected directly
to ground. For auto restart mode, the AUTO pin should
connect a capacitor to ground. The auto restart period
will be determined by the following equation:
C ? AUTO ?
1.25 uA
Thermal Protection
An internal temperature sensor monitors the junction
temperature. It shuts down the internal control circuit and
all drivers if the junction temperature exceeds 145 oC.
Rev. 2.1 May 2012
www.aosmd.com
Page 10 of 16
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
AP-104-NT
12V PLUG TRANSFORMER EMPTY CASE
AP-120
PLUG AUTO LOCKING BLACK
AP-121
PLUG AUTO LOCKING BLACK W/LED
AP-124
12V AUTO PLUG STD EURO CE
AP-129
PLUG 12V AUTO EURO CE
AP-130
PLUG 12V AUTO LED SW FUSE CE
AP-131
PLUG 12V AUTO MINI FUSE CE
AP-132
12V AUTO PLUG ADPT-AIRCRAFT PLUG
相关代理商/技术参数
AOZ1978
制造商:AOSMD 制造商全称:Alpha & Omega Semiconductors 功能描述:Dual Channel High Voltage LED Driver IC
AOZ1995MI
制造商:Alpha & Omega Semiconductor 功能描述:IC DISPLAY DRIVER
AOZ2002PI
功能描述:Linear Voltage Regulator IC Positive Adjustable 1 Output Adj to 0.8V 2A 8-SO Exposed Pad 制造商:alpha & omega semiconductor inc. 系列:- 包装:带卷（TR） 零件状态:有效 稳压器拓扑:正，可调式 电压 - 输出:可调至 0.8V 电流 - 输出:2A 电压 - 跌落（典型值）:0.18V @ 2A 稳压器数:1 电压 - 输入:1.3 V ~ 5.5 V 电流 - 限制（最小值）:2.2A 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 供应商器件封装:8-SO 裸露焊盘 标准包装:3,000
AOZ2003
制造商:AOSMD 制造商全称:Alpha & Omega Semiconductors 功能描述:3A Ultra Low Dropout Linear Regulator
AOZ2003PI
制造商:Alpha & Omega Semiconductor 功能描述:IC REG LDO ADJ 3A 8SO
AOZ2013PI
制造商:Alpha & Omega Semiconductor 功能描述:IC REGULATOR
AOZ2023PI
功能描述:Linear Voltage Regulator IC Positive Adjustable 1 Output 0.8 V ~ 6 V 3A 8-SO Exposed Pad 制造商:alpha & omega semiconductor inc. 系列:- 包装:带卷（TR） 零件状态:有效 稳压器拓扑:正，可调式 电压 - 输出:0.8 V ~ 6 V 电流 - 输出:3A 电压 - 跌落（典型值）:0.18V @ 2A 稳压器数:1 电压 - 输入:1.3 V ~ 5.5 V 电流 - 限制（最小值）:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽）裸焊盘 供应商器件封装:8-SO 裸露焊盘 标准包装:3,000