- 您现在的位置：买卖IC网 > Sheet目录968 > CAT3649AGEVB (ON Semiconductor)BOARD EVALUATION FOR CAT3649
CAT3649
Unused LED Channels
For applications with five LEDs or less, it is required to tie
the unused LED pin(s) directly to VOUT (see Figure 30).
SHORT LED Detection
If the LED forward voltage (V F = V OUT – LED pin
voltage) is less than 1 V, the channel is disabled and removed
1 m F
1 m F
from signaling charge pump mode changes. A 5 m A (typical)
test current is placed in the (shorted) channel. In case the
ADIM
LED4
LED5
2.4 V
to
5.5 V
VIN CIN
1 m F
CPWM
47 nF
C1+ C1 ? C2+ C2 ?
VIN VOUT
CAT3649
LED1
LED2
LED3
PWM
CPWM
GND LED6
COUT
1 m F
LED short goes away and V F is higher than 1 V, the channel
resumes normal operation.
Thermal Protection
If the die temperature exceeds +150 ° C, the driver will
enter a thermal protection shutdown mode. When the device
temperature drops by about 20 ° C, the device will resume
normal operation.
LED Selection
LEDs with forward voltages (V F ) ranging from 1.3 V to
3.8 V may be used. Selecting LEDs with lower V F is
recommended in order to keep the driver in 1x mode longer
Figure 30. Application with 5 LEDs
Protection Modes
As soon as the output voltage (V OUT ) exceeds about 6 V,
the driver resets itself and re ? evaluates the mode.
The driver supports automatic LED detection for both
Open LED and Short LED conditions. This feature disables
any unused channels (by connecting the LED pins to
VOUT) or during an LED Short condition. The LED
detection is always active, during power ? up and in normal
operation.
OPEN LED Detection
When an LED channel becomes open ? circuit, the device
will go into charge pump mode and drive the output (VOUT)
above 4.5 V. If that channel is still not working at VOUT
greater than 4.5 V, the channel is locked out from signaling
a charge pump mode change and the device returns to
normal operation like a 5 ? channel device. If an Open LED
condition is removed, the device will resume normal
operation.
as the battery voltage decreases. For example, if a white
LED with a 3.3 V V F is selected over one with 3.5 V V F , the
driver will stay in 1x mode for lower supply voltage of 0.2 V.
This extends battery life.
External Components
The driver requires four external 1 m F ceramic capacitors
for decoupling input, output, and for the charge pump. Both
capacitors type X5R and X7R are recommended for the
LED driver application. In all charge pump modes, the input
current ripple is kept very low by design and an input bypass
capacitor of 1 m F is sufficient.
In 1x mode, the device operates in linear mode and does
not introduce switching noise back onto the supply.
Recommended Layout
In charge pump mode, the driver switches internally at a
high frequency. It is recommended to minimize trace length
to all four capacitors. A ground plane should cover the area
under the driver IC as well as the bypass capacitors. Short
connection to ground on capacitors C IN and C OUT can be
implemented with the use of multiple via. A copper area
matching the TQFN exposed pad (TAB) must be connected
to the ground plane underneath. The use of multiple via
improves the package heat dissipation.
http://onsemi.com
12
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
CAT4139AEVB
BOARD EVALUATION DPP CAT4139A
CAT4201AEVB
BOARD EVALUATION DPP CAT4201A
CAT4238AEVB
BOARD EVALUATION DPP CAT4238A
CAT4240AEVB
BOARD EVALUATION DPP CAT4240A
CB1A-R-WM-12V
RELAY AUTOMOTIVE SPST 40A 12V
CB3127-000
D-1744-03-LF
CB5065-000
HEAT SHRINK TUBING
CB5143-000
HEAT SHRINK TUBING
相关代理商/技术参数
CAT3649HV3-GT2
功能描述:LED照明驱动器 6 channel quad mode LED Driver 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
CAT3661HV3-GT2
功能描述:LED照明驱动器 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
CAT37
制造商:TI 制造商全称:Texas Instruments 功能描述:CMOS White LED Driver Boost Converter
CAT37_05
制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:CMOS White LED Driver Boost Converter
CAT37_08
制造商:TI 制造商全称:Texas Instruments 功能描述:CMOS White LED Driver Boost Converter
CAT37EKK-TE7
制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:CMOS White LED Driver Boost Converter
CAT37RD4-TE13
制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:CMOS White LED Driver Boost Converter
CAT37TDI
制造商:CATALYST 制造商全称:Catalyst Semiconductor 功能描述:CMOS White LED Driver Boost Converter