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参数资料
| 型号： | ISL97652IRZ-TK |
| 厂商： | Intersil |
| 文件页数： | 13/25页 |
| 文件大小： | 0K |
| 描述： | IC LCD SUPPLY 4CH DUAL AMP 48QFN |
| 标准包装： | 1,000 |
| 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
Rectifier Diode (Boost Converter)
A high-speed diode is necessary due to the high switching
frequency. Schottky diodes are recommended because of
their fast recovery time and low forward voltage. The reverse
voltage rating of this diode should be higher than the
maximum output voltage. The rectifier diode must meet the
output current and peak inductor current requirements. The
following table is some recommendations for boost converter
diode.
TABLE 4. BOOST CONVERTER RECTIFIER DIODE
RECOMMENDATION
examined with an oscilloscope set to AC 100mV/div and the
amount of ringing observed when the load current changes.
Reduce excessive ringing by reducing the value of the
resistor in series with the VC pin capacitor.
A VDD Delay Switch
The ISL97652 integrates a PMOS disconnect switch for the
A VDD boost output to disconnect V IN from A VDD when the
EN2 input is not selected. When EN2 is taken high, the
PMOS FET is turned on to connect power to the display. The
CSUI capacitor provide soft-start control for the connection
of this switch.
DIODE
SS23
SL23
V R /I AVG
RATING
30V/2A
30V/2A
PACKAGE
SMB
SMB
VENDOR
Fairchild Semiconductor
Vishay Semiconductor
The operation of the AVDD delay switch is controlled by
internal VDSOK and VDSHYS control signals which operate
as follows:
During start-up (or during fault conditions):
VDSOK goes to 1 when V(SWI - SWO) becomes less than
Output Capacitor
The output capacitor supplies the load directly and reduces
the ripple voltage at the output. Output ripple voltage consists
of two components: the voltage drop due to the inductor ripple
current flowing through the ESR of output capacitor, and the
charging and discharging of the output capacitor.
~0.5V. This will turn-on the boost function.
VDSOK goes to 0 when VDS_pfet becomes greater than
~1.1V. This will turn-off the boost function.
The threshold voltages have a Vin dependence such that:
For Vin1 = 8V: VDSOK goes to 1 occurs at ~0.5V and
VDSOK goes to 0 occurs at ~1.1V.
V RIPPLE = I LPK × ESR + ------------------------ × -------------------- × ----
V C f
O AVDD s
V O – V IN I O 1
(EQ. 7)
For Vin1 =18.5V: VDSOK goes to1 occurs at ~1.13V and
VDSOK goes to 0 occurs at ~2.65V.
For low ESR ceramic capacitors, the output ripple is
dominated by the charging and discharging of the output
capacitor. The voltage rating of the output capacitor should
be greater than the maximum output voltage.
Note: Capacitors have a voltage coefficient that makes their
effective capacitance drop as the voltage across then
increases. C OUT in Equation 7 above assumes the effective
value of the capacitor at a particular voltage and not the
manufacturer's stated value, measured at zero volts.
The following table shows some selections of output
capacitors.
TABLE 5. BOOST OUTPUT CAPACITOR RECOMMENDATION
V(SWI - SWO) is the VDS voltage across the internal PFET
protection switch. If this voltage exceeds 1.1V for some
reason (e.g. under fault conditions or during start-up if
VMAIN rises faster than AVDD) the boost is turned-off to
allow the AVDD (SWO) potential to catch-up with VMAIN
(SWI).
VDSHYS is the VDS hysteresis level;
Once VDSOK goes to 1 the voltage V(SWI - SWO) then
needs to exceed 1.1V for VDSOK goes to 0.
During normal operation VDS will be ~Ron_PFET * Iload
(~ 0.18x2 = 0.36V for max AVDD load).
If a fault develops on AVDD, which causes VDS to exceed
1.1V, then the boost operation is interrupted by the internal
CAPACITOR
10μF/25V
10μF/25V
SIZE
1210
1210
VENDOR
TDK
Murata
PART NUMBER
C3225X7R1E106M
GRM32DR61E106K
VDSOK goes to 0 signal and fault timers will start to operate
while the rising/falling character of AVDD is monitored.
A VDD Delay Switch Fault Operation
When enabled, the gate of the PFET is pulled down with a
Loop Compensation (Boost Converter)
The boost converter of ISL97652 can be compensated by a
RC network connected from V C pin to ground. C C = 4.7nF
and R C = 10k RC network is used in the demo board. A
higher resistor value can be used to lower the transient load
change A VDD overshoot - however, this may be at the
expense of stability to the loop.
The stability can be examined by repeatedly changing the
load between 100mA and a max level that is likely to be
used in the system being used. The A VDD voltage should be
13
30μA current, turning on the FET switch. The speed of this
turn-on can be controlled by placing a capacitor from SWI to
SUI. In normal operation the gate (and SUI pin) are pulled
down to 5V below SWI. The A VDD delay switch circuitry
constantly monitors both the current in the switch and the
voltage at SWO. If the current exceeds the current limit of
2A, the gate of the FET (and also the SUI pin) will be pulled
up to the correct level to limit the current to 2A. In this mode
the switch acts like a 2A current source. this current cannot
be maintained indefinitely due to the power dissipation on
FN9287.1
November 2, 2007
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| 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: |
| ISL97656IRTZ | 功能描述:IC REG BOOST ADJ 4A 10TDFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:1 输出电压:5V，1 V ~ 10 V 输入电压:3.5 V ~ 28 V PWM 型:电流模式 频率 - 开关:220kHz ~ 1MHz 电流 - 输出:600mA 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:16-SSOP（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:16-QSOP |
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