参数资料
型号: ISL97635AIRZ
厂商: Intersil
文件页数: 24/28页
文件大小: 0K
描述: IC LED DRVR WHT/RGB BCKLGT 24QFN
标准包装: 75
拓扑: PWM,升压(升压)
输出数: 6
内部驱动器:
类型 - 主要: 车载,背光
类型 - 次要: RGB,白色 LED
频率: 600kHz,1.2MHz
电源电压: 6 V ~ 24 V
输出电压: 34.5V
安装类型: 表面贴装
封装/外壳: 24-VFQFN 裸露焊盘
供应商设备封装: 24-QFN 裸露焊盘(4x4)
包装: 管件
工作温度: -40°C ~ 85°C
ISL97635A
REGISTER 0x09
OUTPUT CHANNEL REGISTER
RESERVED RESERVED
CH5
CH4
CH3
CH2
CH1
CH0
Bit 7 (R/W)
Bit 6 (R/W)
Bit 5 (R/W)
Bit 4 (R/W)
Bit 3 (R/W)
Bit 2 (R/W)
Bit 1 (R/W)
Bit 0 (R/W)
BIT ASSIGNMENT
CH[5..0]
BIT FIELD DEFINITIONS
CH5 = Channel 5, CH4 = Channel 4 and so on
FIGURE 29. OUTPUT CHANNEL REGISTER
Components Selections
According to the inductor Voltage-Second Balance principle,
the change of inductor current during the switching regulator
On-time is equal to the change of inductor current during the
switching regulator Off-time. Since the voltage across an
inductor is:
of the input capacitor is suitable to handle the full supply
range.
Inductor
The selection of the inductor should be based on its
maximum current (I SAT ) characteristics, power dissipation
(DCR), EMI susceptibility (shielded vs unshielded), and size.
V L = L × Δ I L ? Δ t
and Δ I L @ On = Δ I L @ Off, therefore:
( V I – 0 ) ? L × D × t S = ( V O – V D – V I ) ? L × ( 1 – D ) × t S
(EQ. 16)
(EQ. 17)
Inductor type and value influence many key parameters,
including ripple current, current limit, efficiency, transient
performance and stability.
Its maximum current capability must be adequate to handle
the peak current at the worst case condition. If an inductor
where D is the switching duty cycle defined by the turn-on
time over the switching period. V D is Schottky diode forward
voltage that can be neglected for approximation.
Rearranging the terms without accounting for V D gives the
boost ratio and duty cycle respectively as Equations 18
and 19:
core is chosen with too low a current rating, saturation in the
core will cause the effective inductor value to fall, leading to
an increase in peak to average current level, poor efficiency
and overheating in the core. The series resistance, DCR,
within the inductor causes conduction loss and heat
dissipation. A shielded inductor is usually more suitable for
EMI susceptible applications, such as LED backlighting.
V O ? V I = 1 ? ( 1 – D )
D = ( V O – V I ) ? V O
Input Capacitor
(EQ. 18)
(EQ. 19)
The peak current can be derived from the fact that the
voltage across the inductor during the Off-period can be
shown as Equation 20:
IL peak = ( V O × I O ) ? ( 85% × V I ) + 1 ? 2 [ V I × ( V O – V I ) ? ( L × V O × f S ) ]
(EQ. 20)
Switching regulators require input capacitors to deliver peak
charging current and to reduce the impedance of the input
supply. This reduces interaction between the regulator and
input supply, improving system stability. The high switching
frequency of the loop causes almost all ripple current to flow
in the input capacitor, which must be rated accordingly.
A capacitor with low internal series resistance should be
chosen to minimize heating effects and improve system
efficiency, such as X5R or X7R ceramic capacitors, which
offer small size and a lower value of temperature and voltage
coefficient compared to other ceramic capacitors.
In boost mode, input current flows continuously into the
inductor, with an AC ripple component proportional to the
rate of inductor charging only and smaller value input
capacitors may be used. It is recommended that an input
capacitor of at least 10μF be used. Ensure the voltage rating
24
The choice of 85% is just an average term for the efficiency
approximation. The first term is average current that is
inversely proportional to the input voltage. The second term
is inductor current change that is inversely proportional to L
and f S . As a result, for a given switching frequency and
minimum input voltage the system operates, the inductor
I SAT must be chosen carefully. At a given inductor size,
usually the larger the inductance, the higher the series
resistance because of the extra winding of the coil. Thus, the
higher the inductance, the lower the peak current capability.
The ISL97635A current limit may also have to be taken into
account.
Output Capacitors
The output capacitor acts to smooth the output voltage and
supplies load current directly during the conduction phase of
the power switch. Output ripple voltage consists of the
discharge of the output capacitor for I LPEAK during FET On
FN6564.2
December 22, 2008
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ISL97635AIRZ-T 功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压(升压),切换式电容器(充电泵) 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽) 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635AIRZ-TK 功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压(升压),切换式电容器(充电泵) 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽) 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635AIRZ-TKR5306 制造商:Intersil Corporation 功能描述:
ISL97635IRZ 功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压(升压),切换式电容器(充电泵) 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽) 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C
ISL97635IRZ-T 功能描述:IC LED DRVR WHT/RGB BCKLGT 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压(升压),切换式电容器(充电泵) 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽) 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C