参数资料
| 型号： | ISL6308CRZ |
| 厂商： | Intersil |
| 文件页数： | 9/28页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM 3PHASE BUCK 40-QFN |
| 标准包装： | 500 |
| 应用： | 控制器，DDR |
| 输入电压： | 5 V ~ 12 V |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 2.3 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-VFQFN 裸露焊盘 |
| 供应商设备封装： | 40-QFN（6x6） |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页当前第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页
ISL6308
PHASE1, PHASE2, and PHASE3 (Pins 29, 28, 22)
Connect these pins to the sources of the upper MOSFETs.
These pins are the return path for the upper MOSFETs’
drives.
LGATE1, LGATE2, and LGATE3 (Pins 34, 23, 17)
These pins are used to control the lower MOSFETs and are
monitored for shoot-through prevention purposes. Connect
these pins to the lower MOSFETs’ gates. Do not use external
series gate resistors as this might lead to shoot-through.
PGOOD (Pin 35)
PGOOD is used as an indication of the end of soft-start. It is
an open-drain logic output that is low impedance until the
soft-start is completed and VOUT is equal to the VID setting.
Once in normal operation, PGOOD indicates whether the
output voltage is within specified overvoltage and
undervoltage limits. If the output voltage exceeds these limits
or a reset event occurs (such as an overcurrent event),
PGOOD becomes high impedance again. The potential at
this pin should not exceed that of the potential at VCC pin by
more than a typical forward diode drop at any time.
OVP (Pin 38)
Overvoltage protection pin. This pin pulls to VCC when an
overvoltage condition is detected. Connect this pin to the
gate of an SCR or MOSFET tied across V IN and ground to
prevent damage to a load device.
can use less per-channel inductance and lower total output
capacitance for any performance specification.
Figure 1 illustrates the multiplicative effect on output ripple
frequency. The three channel currents (I L1 , I L2 , and I L3 )
combine to form the AC ripple current and the DC load
current. The ripple component has three times the ripple
frequency of each individual channel current. Each PWM
pulse is terminated one third of a cycle after the PWM pulse of
the previous phase. The peak-to-peak current for each phase
is about 7A, and the DC components of the inductor currents
combine to feed the load.
I L1 + I L2 + I L3 , 7A/DIV
I L3 , 7A/DIV
PWM3, 5V/DIV
I L2 , 7A/DIV
PWM2, 5V/DIV
I L1 , 7A/DIV
PWM1, 5V/DIV
FIGURE 1. PWM AND INDUCTOR-CURRENT WAVEFORMS
FOR 3-PHASE CONVERTER
Operation
Multi-Phase Power Conversion
Modern low voltage DC/DC converter load current profiles
To understand the reduction of ripple current amplitude in the
multi-phase circuit, examine Equation 1, which represents
an individual channel peak-to-peak inductor current.
( V IN – V OUT ) ? V OUT
L ? F SW ? V IN
have changed to the point that the advantages of multi-phase
power conversion are impossible to ignore. The technical
challenges associated with producing a single-phase
I PP = ----------------------------------------------------------
(EQ. 1)
converter that is both cost-effective and thermally viable have
forced a change to the cost-saving approach of multi-phase.
The ISL6308 controller helps simplify implementation by
integrating vital functions and requiring minimal output
components. The “Block Diagram” on page 3 provides a top
level view of multi-phase power conversion using the ISL6308
controller.
Interleaving
The switching of each channel in a multi-phase converter is
timed to be symmetrically out-of-phase with each of the
other channels. In a 3-phase converter, each channel
switches one third cycle after the previous channel and one
third cycle before the following channel. As a result, the
three-phase converter has a combined ripple frequency
three times greater than the ripple frequency of any one
In Equation 1, V IN and V OUT are the input and output
voltages respectively, L is the single-channel inductor value,
and F SW is the switching frequency.
The output capacitors conduct the ripple component of the
inductor current. In the case of multi-phase converters, the
capacitor current is the sum of the ripple currents from each
of the individual channels. Compare Equation 1 to the
expression for the peak-to-peak current after the summation
of N symmetrically phase-shifted inductor currents in
Equation 2. Peak-to-peak ripple current decreases by an
amount proportional to the number of channels. Output
voltage ripple is a function of capacitance, capacitor
equivalent series resistance (ESR), and inductor ripple
current. Reducing the inductor ripple current allows the
designer to use fewer or less costly output capacitors.
L ? F SW ? V
phase. In addition, the peak-to-peak amplitude of the
combined inductor currents is reduced in proportion to the
number of phases (Equations 1 and 2). Increased ripple
frequency and lower ripple amplitude mean that the designer
9
( V IN – N ? V OUT ) ? V OUT
I C , PP = --------------------------------------------------------------------
IN
(EQ. 2)
FN9208.4
September 30, 2008
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相关代理商/技术参数 |
参数描述 |
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| ISL6308CRZR5374 | 制造商:Intersil Corporation 功能描述:ISL6308CRZ W/ 24HR BURN-IN - Rail/Tube 制造商:Intersil Corporation 功能描述:IC CTRLR PWM 3PHASE BUCK 40-QFN 制造商:Intersil 功能描述:ISL6308CRZ W/24HRU RN-IN |
| ISL6308CRZ-T | 功能描述:电压模式 PWM 控制器 DAC-LESS MULTI-PHS PWM CNTRLR W/3-DRVRS RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| ISL6308CRZ-TR5374 | 制造商:Intersil Corporation 功能描述:ISL6308CRZ W/ 24HR BURN-IN - Tape and Reel 制造商:Intersil Corporation 功能描述:IC CTRLR PWM 3PHASE BUCK 40-QFN 制造商:Intersil 功能描述:ISL6308CRZ W/24HRU RN-IN |
| ISL6308CRZ-TR5453 | 制造商:Intersil Corporation 功能描述:STD. ISL6308CRZ-T W/GOLD BOND WIRE ONLY - Tape and Reel |
| ISL6308EVAL1Z | 制造商:Intersil Corporation 功能描述:ISL6308 EVALUATION BOARD 1 - ROHS COMPLIANT - QFN - Bulk |
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