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| 型号： | ISL97652IRZ-T |
| 厂商： | Intersil |
| 文件页数： | 14/25页 |
| 文件大小： | 0K |
| 描述： | IC LCD SUPPLY 4CH DUAL AMP 48QFN |
| 标准包装： | 4,000 |
| 应用： | LCD 电视机/监控器 |
| 电流 - 电源： | 500µA |
| 电源电压： | 8 V ~ 15 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-VFQFN 裸露焊盘 |
| 供应商设备封装： | 48-QFN（7x7） |
| 包装： | 带卷 (TR) |
ISL97652
chip. Therefore, three separate fault mechanisms are
operated.
1. The SWO output range is constantly monitored and
Feedback Resistors
The buck converter output voltage is determined by the
following equation:
V LOGIC = --------------------------- × V FBB
expected to rise if the PFET is in current limit. The rate of
rise at SWO can be calculated from the current limit and
the capacitance on SWO by using the equation
R 11 + R 12
R 12
(EQ. 11)
dV/dt = Ilimit/Cavdd. The SWO voltage range is split into
sections of approximately 0.7V such that every time the
output rises by this amount the circuit detects that the
voltage is rising. Should the circuit remain in current limit
for more than 100μs with no such rise taking place the
circuit will fault out. In this scenario, the PFET will
immediately switch itself off and the rest of the ISL97652
will later fault out due to the boost voltage at A VDD falling
away.
2. As well as monitoring any rise in the voltage at SWO, the
circuit also monitors any falls in this level. If the output
falls by more than a certain amount while it is in current
limit the circuit will fault out immediately. This amount
Where R11 and R12 are the feedback resistors of buck
converter to set the output voltage. Current drawn by the
resistor network should be limited to maintain the overall
converter efficiency. The maximum value of the resistor
network is limited by the feedback input bias current and the
potential for noise being coupled into the feedback pin. A
resistor network in the order of 1k Ω is recommended.
Buck Converter Input Capacitor
The capacitor should support the maximum AC RMS current
which happens when D = 0.5 and maximum output current.
varies from about 1V to about 1.4V depending on the
output level before the fall. In this scenario, the PFET will
I ACRMS ( C IN ) =
D ? ( 1 – D ) ? I O
(EQ. 12)
immediately switch itself off and the rest of the ISL97652
will later fault out due to the boost voltage falling away.
3. Once the ISL97652 has successfully sequenced the
boost on and the boost soft-start capacitor has charged
up, a third fault check is also added. After this point if the
Where I o is the output current of the buck converter. The
following table shows some recommendations for input
capacitor.
TABLE 6. INPUT CAPACITOR (BUCK) RECOMMENDATION
PFET enters current limit for greater than the global
timeout of 40μs then the chip will fault out. In this scenario
the whole chip will be disabled with the PFET
immediately switched off.
Buck Converter
CAPACITOR
10μF/16V
10μF/10V
22μF/16V
SIZE
1206
0805
1210
VENDOR
TDK
Murata
Murata
PART NUMBER
C3216X7R1C106M
GRM21BR61A106K
C3225X7R1C226M
The buck converter is the step down converter, which
supplies the current to the logic circuit of the LCD system.
The ISL97652 integrates an 20V N-Channel MOSFET to
save cost and reduce external component count. In the
continuous current mode, the relationship between input
voltage and output voltage is as follows:
Buck Inductor
A 3.3μH to 10μH inductor is the good choice for the buck
converter. Besides the inductance, the DC resistance and
the saturation current are also the factor needed to be
considered when choosing buck inductor. Low DC
V LOGIC
---------------------- = D
V IN
(EQ. 8)
resistance can help maintain high efficiency, and the
saturation current rating should be 2.5A. Here are some
Where D is the duty cycle of the switching MOSFET.
Because D is always less than 1, the output voltage of buck
converter is lower than input voltage.
recommendations for buck inductor.
TABLE 7. BUCK INDUCTOR RECOMMENDATION
DIMENSIONS
The peak current limit of buck converter is set to 2.5A, which
restricts the maximum output current (average) based on the
INDUCTOR
4.7μH/
(mm)
5.7x5.0x4.7
VENDOR
Murata
PART NUMBER
LQH55DN4R7M01K
following equation:
2.7A PEAK
I OMAX = 2.5A – Δ I PP
(EQ. 9)
6.8μH/
3A PEAK
7.3x6.8x3.2
TDK
RLF7030T-6R8M2R8
Where Δ I PP is the ripple current in the buck inductor as the
following equation:
10μH/
2.4A PEAK
12.95x9.4x3.0 Coilcraft
DO3308P-103
Δ I PP = ---------------------- ? ( 1 – D )
V LOGIC
L ? f s
(EQ. 10)
Rectifier Diode (Buck Converter)
Where L is the buck inductor, f s is the switching frequency.
14
A Schottky diode is recommended due to fast recovery and low
forward voltage. The reverse voltage rating should be higher
FN9287.1
November 2, 2007
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL97652IRZ-TK | 功能描述:IC LCD SUPPLY 4CH DUAL AMP 48QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:- 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像，声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP（8x8） 包装:管件 |
| ISL97653AIRZ | 功能描述:电流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL97653AIRZ-T | 功能描述:电流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL97653AIRZ-TK | 功能描述:电流型 PWM 控制器 5-CH INTEGRTD LCD SUPPLY W/TEMP SENSOR RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL97653IRZ | 制造商:Intersil Corporation 功能描述: |
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