参数资料
| 型号： | ISL6327AIRZ |
| 厂商： | Intersil |
| 文件页数： | 23/29页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 48-QFN |
| 标准包装： | 43 |
| PWM 型： | 控制器 |
| 输出数： | 6 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 4.75 V ~ 5.25 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 48-VFQFN 裸露焊盘 |
| 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页当前第23页第24页第25页第26页第27页第28页第29页
ISL6327A
.
ISL6327A
require heat sinks and forced air to cool the MOSFETs,
inductors, and heat-dissipating surfaces.
°C
COMP
IDROOP
INTERNAL
CIRCUIT
MOSFETS
The choice of MOSFETs depends on the current each
MOSFET will be required to conduct; the switching
frequency; the capability of the MOSFETs to dissipate heat;
and the availability and nature of heat sinking and air flow.
FB
LOWER MOSFET POWER CALCULATION
The calculation for heat dissipated in the lower MOSFET is
VDIFF
FIGURE 16. EXTERNAL TEMPERATURE COMPENSATION
The sensed current will flow out of IDROOP pin and develop
the droop voltage across the resistor (R FB ) between FB and
VDIFF pins. If R FB resistance reduces as the temperature
simple, since virtually all of the heat loss in the lower
MOSFET is due to current conducted through the channel
resistance (r DS(ON) ). In Equation 22, I M is the maximum
continuous output current; I P-P is the peak-to-peak inductor
current (see Equation 1); d is the duty cycle (V OUT /V IN ); and
L is the per-channel inductance.
? I M ? 2 I L ( P-P ) 2 ( 1 – d )
P LOW , 1 = r DS ( ON ) ? ------ ? ( 1 – d ) + ------------------------------------
increases, the temperature impact on the droop can be
compensated. An NTC resistor can be placed close to the
power stage and used to form R FB . Due to the non-linear
temperature characteristics of the NTC, a resistor network is
? N ? 12
(EQ. 22)
needed to make the equivalent resistance between FB and
VDIFF pin reverse proportional to the temperature.
The external temperature compensation network can only
compensate the temperature impact on the droop, while it
has no impact to the sensed current inside ISL6327A.
Therefore, this network cannot compensate for the
An additional term can be added to the lower-MOSFET loss
equation to account for additional loss accrued during the dead
time when inductor current is flowing through the lower
MOSFET body diode. This term is dependent on the diode
forward voltage at I M , V D(ON) ; the switching frequency, f S ; and
the length of dead times, t d1 and t d2 , at the beginning and the
end of the lower-MOSFET conduction interval respectively.
temperature impact on the overcurrent protection function.
.
I P-P ?
? I
P LOW , 2 = V D ( ON ) f S ? ------ + I ---------- ? t
? d1 + ? ? ------ – ---------- ? ? d2
I M P-P M
? N
General Design Guide
2 N 2
t
(EQ. 23)
This design guide is intended to provide a high-level
explanation of the steps necessary to create a multiphase
power converter. It is assumed that the reader is familiar with
many of the basic skills and techniques referenced below. In
addition to this guide, Intersil provides complete reference
designs that include schematics, bills of materials, and
example board layouts for all common microprocessor
applications.
Power Stages
The first step in designing a multiphase converter is to
determine the number of phases. This determination
depends heavily on the cost analysis which in turn depends
on system constraints that differ from one design to the next.
Principally, the designer will be concerned with whether
components can be mounted on both sides of the circuit
board; whether through-hole components are permitted; and
the total board space available for power-supply circuitry.
Generally speaking, the most economical solutions are
those in which each phase handles between 15A and 20A.
All surface-mount designs will tend toward the lower end of
this current range. If through-hole MOSFETs and inductors
can be used, higher per-phase currents are possible. In
Thus, the total maximum power dissipated in each lower
MOSFET is approximated by the summation of P LOW,1 and
P LOW,2 .
UPPER MOSFET POWER CALCULATION
In addition to r DS(ON) losses, a large portion of the upper
MOSFET losses are due to currents conducted across the
input voltage (V IN ) during switching. Since a substantially
higher portion of the upper-MOSFET losses are dependent on
switching frequency, the power calculation is more complex.
Upper MOSFET losses can be divided into separate
components involving the upper-MOSFET switching times;
the lower-MOSFET body-diode reverse-recovery charge, Q rr ,
and the upper MOSFET r DS(ON) conduction loss.
When the upper MOSFET turns off, the lower MOSFET does
not conduct any portion of the inductor current until the
voltage at the phase node falls below ground. Once the
lower MOSFET begins conducting, the current in the upper
MOSFET falls to zero as the current in the lower MOSFET
ramps up to assume the full inductor current. In Equation 24,
the required time for this commutation is t 1 and the
approximated associated power loss is P UP,1 .
P UP , 1 ≈ V IN ? ------ + ---------- ? ? ---- 1 ? f S
cases where board space is the limiting constraint, current
can be pushed as high as 40A per phase, but these designs
23
? N 2 ? ? 2 ?
I M I P-P ? t ?
(EQ. 24)
FN6833.0
February 17, 2009
相关PDF资料 |
PDF描述 |
|---|---|
| ISL6327IRZ | IC REG CTRLR BUCK PWM 48-QFN |
| ISL6328AIRZ | IC VOLTAGE REGULATOR |
| ISL6328IRZ | IC CTRLR PWM SYNC BUCK DL 48QFN |
| ISL6329IRZ-T | IC CTRLR PWM SYNC BUCK DL 60QFN |
| ISL6333IRZ | IC CTRLR PWM 3PHASE BUCK 48-QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6327AIRZ-T | 功能描述:IC REG CTRLR BUCK PWM 48-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6327CRZ | 功能描述:IC REG CTRLR BUCK PWM 48-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6327CRZ-T | 功能描述:IC REG CTRLR BUCK PWM 48-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6327IRZ | 功能描述:IC REG CTRLR BUCK PWM 48-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6327IRZ-T | 功能描述:IC REG CTRLR BUCK PWM 48-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。