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| 型号： | ISL6443IRZ-T |
| 厂商： | Intersil |
| 文件页数： | 13/18页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM DUAL 300KHZ 28-QFN |
| 产品培训模块： | Solutions for Industrial Control Applications |
| 标准包装： | 6,000 |
| 应用： | 电源 |
| 电流 - 电源： | 50µA |
| 电源电压： | 5.6 V ~ 24 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-VFQFN 裸露焊盘 |
| 供应商设备封装： | 28-QFN 裸露焊盘（5x5） |
| 包装： | 带卷 (TR) |
ISL6443
( I MAX ) ( R DS ( ON ) )
F PO = ---------------------------------
where, I OC is the desired overcurrent protection threshold,
and R CS is a value of the current sense resistor connected
to the ISENx pin. If an overcurrent is detected for 2
consecutive clock cycles then the IC enters a hiccup mode
by turning off the gate drivers and entering into soft-start.
The IC will cycle 2 times through soft-start before trying to
restart. The IC will continue to cycle through soft-start until
the overcurrent condition is removed. Hiccup mode is active
during soft-start so care must be taken to ensure that the
peak inductor current does not exceed the overcurrent
threshold during soft-start.
Because of the nature of this current sensing technique, and
to accommodate a wide range of r DS(ON) variations, the
value of the overcurrent threshold should represent an
overload current about 150% to 180% of the maximum
operating current. If more accurate current protection is
desired place a current sense resistor in series with the
lower MOSFET source.
Over-Temperature Protection
The IC incorporates an over-temperature protection circuit
that shuts the IC down when a die temperature of 150°C is
reached. Normal operation resumes when the die
temperatures drops below 130°C through the initiation of a
full soft-start cycle.
Implementing Synchronization
The SYNC pin may be used to synchronize two or more
controllers. When the SYNC pins of two controllers are
connected together, one controller becomes the master and
the other controller synchronizes to the master. A pull-down
resistor is required and must be sized to provide a low
enough time constant to pass the SYNC pulse. Connect this
pin to VCC_5V if not used. Figure 16 shows the SYNC pin
waveform operating at 16 times the switching frequency.
Feedback Loop Compensation
To reduce the number of external components and to simplify
the process of determining compensation components, both
PWM controllers have internally compensated error
amplifiers. To make internal compensation possible several
design measures were taken.
First, the ramp signal applied to the PWM comparator is
proportional to the input voltage provided via the VIN pin.
This keeps the modulator gain constant with variation in the
input voltage. Second, the load current proportional signal is
derived from the voltage drop across the lower MOSFET
during the PWM time interval and is subtracted from the
amplified error signal on the comparator input. This creates
an internal current control loop. The resistor connected to
the ISEN pin sets the gain in the current feedback loop. The
following expression estimates the required value of the
current sense resistor depending on the maximum operating
load current and the value of the MOSFET’s r DS(ON) .
32 μ A
R CS ≥ -------------------------------------------------
Choosing R CS to provide 32μA of current to the current
sample and hold circuitry is recommended but values down
to 2μA and up to 100μA can be used.
Due to the current loop feedback, the modulator has a single
pole response with -20dB slope at a frequency determined
by the load.
1
2 π ? R O ? C O
where R O is load resistance and C O is load capacitance. For
this type of modulator, a Type 2 compensation circuit is
usually sufficient.
F Z = ------------------------------- = 6kHz
F P = ------------------------------- = 600kHz
Figure 17 shows a Type 2 amplifier and its response along
with the responses of the current mode modulator and the
converter. The Type 2 amplifier, in addition to the pole at
origin, has a zero-pole pair that causes a flat gain region at
frequencies in between the zero and the pole.
1
2 π ? R 2 ? C 1
1
2 π ? R 1 ? C 2
FIGURE 16. SYNC WAVEFORM
13
FN9044.2
August 9, 2006
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相关代理商/技术参数 |
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| ISL6443IRZ-TK | 功能描述:IC CTRLR PWM DUAL 300KHZ 28-QFN 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 |
| ISL6443IRZ-TKS2698 | 制造商:Intersil Corporation 功能描述:LEAD-FREE DUAL PWM CONTROLLER + LINEAR CONT., 300KHZ, QFN, 5 - Tape and Reel 制造商:Rochester Electronics LLC 功能描述: |
| ISL6443IRZ-TS2698 | 制造商:Intersil Corporation 功能描述:LEAD-FREE DUAL PWM CONTROLLER + LINEAR CONTROLLER, 300KHZ, Q - Tape and Reel |
| ISL6444CA | 功能描述:电流型 PWM 控制器 Dual with DDR Memory 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 |
| ISL6444CA-T | 功能描述:IC CONTROLLER DDR 28-QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
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