参数资料
| 型号： | EL7586AILZ-T13 |
| 厂商： | Intersil |
| 文件页数： | 16/21页 |
| 文件大小： | 0K |
| 描述： | IC POWER SUPPLY TFT-LCD 20-QFN |
| 标准包装： | 2,500 |
| 应用： | 转换器，TFT，LCD |
| 输入电压： | 3 V ~ 5 V |
| 输出数： | 4 |
| 输出电压： | 5.5 V ~ 20 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-VFQFN 裸露焊盘 |
| 供应商设备封装： | 20-QFN 裸露焊盘（4x4） |
| 包装： | 带卷 (TR) |
EL7586, EL7586A
C OUT ≥ ------------------------------------------------------
The following equation gives the boundary between
discontinuous and continuous boost operation. For
continuous operation (LX switching every clock cycle) we
require that:
I(A VDD _load) > D*(1-D)*V IN /(2*L*F OSC )
where the duty cycle, D = (A VDD - V IN )/A VDD
For example, with V IN = 5V, F OSC = 1.0MHz and A VDD =
12V we find continuous operation of the boost converter can
be guaranteed for:
L = 10μH and I(A VDD ) > 61mA
L = 6.8μH and I(A VDD ) > 89mA
L = 3.3μH and I(A VDD ) > 184mA
Charge Pump Output Capacitors
Ceramic capacitors with low ESR are recommended. With
ceramic capacitors, the output ripple voltage is dominated by
the capacitance value. The capacitance value can be
chosen by the following equation:
I OUT
2 × V RIPPLE × f OSC
where f OSC is the switching frequency.
Start-Up Sequence
Figure 33 and 34 show a detailed start-up sequence
waveform. For a successful power up, there should be six
peaks at V CDLY . When a fault is detected, the device will
latch off until either EN is toggled or the input supply is
recycled.
When the input voltage is higher than 2.5V, an internal
current source starts to charge C CDLY to an upper threshold
using a fast ramp followed by a slow ramp. During the initial
slow ramp, the device checks whether there is a fault
condition. If no fault is found, C CDLY is discharged after the
first peak and V REF turns on.
During the second ramp, the device checks the status of
V REF and over temperature. At the peak of the second
ramp, PG output goes low and enables the input protection
PMOS Q1. Q1 is a controlled FET used to prevent in-rush
current into V BOOST before V BOOST is enabled internally.
Its rate of turn on is controlled by C o . When a fault is
detected, M1 will turn off and disconnect the inductor from
V IN .
With the input protection FET on, NODE1 (See Typical
Application Diagram) will rise to ~V IN . Initially the boost is
not enabled so V BOOST rises to V IN -V DIODE through the
output diode. Hence, there is a step at V BOOST during this
part of the start-up sequence. If this step is not desirable, an
external PMOS FET can be used to delay the output until the
boost is enabled internally. The delayed output appears at
A VDD .
16
For the EL7586, V BOOST and V LOGIC soft-start at the
beginning of the third ramp. The soft-start ramp depends on
the value of the C DLY capacitor. For C DLY of 220nF, the
soft-start time is ~2ms.
The EL7586A is the same as the EL7586 except V REF and
V LOGIC turn on when input voltage (V DD ) exceeds 2.5V.
When a fault is detected, the outputs and the input protection
will turn off but V REF will stay on.
V OFF turns on at the start of the fourth peak. At the fifth
peak, the open drain o/p DELB goes low to turn on the
external PMOS Q4 to generate a delayed V BOOST output.
V ON is enabled at the beginning of the sixth ramp. A VDD ,
PG, V OFF , DELB and V ON are checked at end of this ramp.
Fault Protection
Once the start-up sequence is complete, the voltage on the
C DLY capacitor remains at 1.15V until either a fault is
detected or the EN pin is disabled. If a fault is detected, the
voltage on C DLY rises to 2.4V at which point the chip is
disabled until the power is recycled or enable is toggled.
Component Selection for Start-Up Sequencing and
Fault Protection
The C REF capacitor is typically set at 220nF and is required
to stabilize the V REF output. The range of C REF is from
22nF to 1μF and should not be more than five times the
capacitor on C DEL to ensure correct start-up operation.
The C DEL capacitor is typically 220nF and has a usable
range from 47nF minimum to several microfarads - only
limited by the leakage in the capacitor reaching μA levels.
C DEL should be at least 1/5 of the value of C REF (See
above). Note with 220nF on C DEL the fault time-out will be
typically 50ms and the use of a larger/smaller value will vary
this time proportionally (e.g. 1μF will give a fault time-out
period of typically 230ms).
Fault Sequencing
The EL7586 and EL7586A have advanced fault detection
systems which protects the IC from both adjacent pin shorts
during operation and shorts on the output supplies.
A high quality layout/design of the PCB, in respect of
grounding quality and decoupling is necessary to avoid
falsely triggering the fault detection scheme - especially
during start-up. The user is directed to the layout guidelines
and component selection sections to avoid problems during
initial evaluation and prototype PCB generation.
FN9210.2
January 17, 2006
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相关代理商/技术参数 |
参数描述 |
|---|---|
| EL7586AILZ-T7 | 功能描述:直流/直流开关调节器 EL7586AILZ TFT-LCD PWR SUPY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| EL7586ILZ | 功能描述:直流/直流开关调节器 EL7586ILZ TFT-LCD PWR SUPY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| EL7586ILZ-T13 | 功能描述:直流/直流开关调节器 EL7586ILZ TFT-LCD PWR SUPY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| EL7586ILZ-T7 | 功能描述:直流/直流开关调节器 EL7586ILZ TFT-LCD PWR SUPY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| EL7630 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:White LED Boost Regulator |
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