LT3760
APPLICATIONS INFORMATION
1 -
?
? V IN
V IN
L =
0.5 ? OUT ? I LEDx ? 8
(1 -
) ?
? 12V
3.2 10 6
INTV CC RegulatorBypassingandOperation
The INTV CC pin is the output of an internal linear regula-
tor driven from V IN and is the supply for the LT3760 gate
driver. The INTV CC pin should be bypassed with a 10V
rated 4.7μF low ESR, X7R or X5R ceramic capacitor to
ensure stability and to provide enough charge for the gate
driver. For high enough V IN levels the INTV CC pin provides
a regulated 7V supply. Make sure INTV CC voltage does
not exceed the V GS rating of the external MOSFET driven
by the GATE pin. For low V IN levels the INTV CC level will
depend on V IN and the voltage drop of the regulator. The
INTV CC regulator has an undervoltage lockout which
prevents gate driver switching until INTV CC reaches 3.8V
and maintains switching until INTV CC falls below 3.4V.
This feature prevents excessive power dissipation in the
external MOSFET by ensuring a minimum gate drive level
to keep R DS(ON) low. The INTV CC regulator has a current
limit of 40mA to limit power dissipation inside the I.C.
This current limit should be considered when choosing the
N-channel power MOSFET and the switching frequency.
The average current load on the INTV CC pin due to the
LT3760 gate driver can be calculated as:
I INTVCC = Q g ? f OSC
where Q g is the gate charge (at V GS = INTV CC ) specified
for the MOSFET and fosc is the switching frequency of the
LT3760 boost converter. It is possible to drive the INTV CC
pin from a variety of external sources in order to remove
power dissipation from the LT3760 and/or to remove the
INTV CC current limitation of 40mA. An external supply for
INTV CC should never exceed the V IN pin voltage or the
maximum INTV CC pin rating of 13V. If INTV CC is shorted
to the V IN pin, V IN operational range is 4.5V to 13V.
Inductor
A list of inductor manufacturers is given in Table 1. How-
ever, there are many other manufacturers and inductors
that can be used. Consult each manufacturer for more
detailed information and their entire range of parts. Ferrite
cores should be used to obtain the best efficiency. Choose
an inductor that can handle the necessary peak current
without saturating. Also ensure that the inductor has a
low DCR (copper-wire resistance) to minimize I 2 R power
losses. Values between 2.2μH and 33μH will suffice for
most applications. The typical inductor value required for
a given application (assuming 50% inductor ripple current
for example) can be calculated as:
1 1
V OUT f OSC
V
V IN
where:
V OUT = (N ? V F ) + 1V
(N = number of LEDs per string),
V F = LED forward voltage drop,
I LEDx = LED current per string
Example: For a 12W LED driver application requiring 8
strings of 10 LEDs each driven with 40mA, and choos-
ing V IN = 12V, V OUT = (3.75V ? 10) + 1V = 38.5V, I LEDx =
40mA and f OSC = 1MHz the value for L is calculated as
1 1
L = = 16.5μH
0.5 ? 3.2 ? 40mA ? 8
3760fc
11
相关PDF资料
LT3799IMSE#PBF IC LED DRIVER TRIAC DIM 16-MSOP
LT3956EUHE#PBF IC LED DVR BUCK BOOST 36-VQFN
LTC3201EMS#TRPBF IC LED DRVR WHITE BCKLGT 10-MSOP
LTC3202EDD#PBF IC LED DRIVR WHITE BCKLGT 10-DFN
LTC3205EUF#TRPBF IC LED DRVR WT/RGB BCKLGT 24-QFN
LTC3206EUF#TRPBF IC LED DRVR WT/RGB BCKLGT 24-QFN
LTC3207EUF-1#TRPBF IC LED DRIVR QVGA DISPLAY 24-QFN
LTC3208EUH#TRPBF IC LED DRIVR QVGA DISPLAY 32-QFN
相关代理商/技术参数
LT3760EFE#TRPBF 功能描述:IC LED DVR 100MA 8CHAN 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LT3760EFEPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:8-Channel × 100mA LED Driver
LT3760EFETRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:8-Channel × 100mA LED Driver
LT3760IFE 制造商:LINER 制造商全称:Linear Technology 功能描述:8-Channel × 100mA LED Driver
LT3760IFE#PBF 功能描述:IC LED DVR 8CHAN 100MA 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LT3760IFE#TRPBF 功能描述:IC LED DVR 100MA 8CHAN 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极,PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND
LT3760IFEPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:8-Channel × 100mA LED Driver
LT3760IFETRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:8-Channel × 100mA LED Driver