- 您现在的位置：买卖IC网 > PDF目录15184 > ISL6315CRZ-TK (Intersil)IC REG CTRLR BUCK PWM VM 24-QFN PDF资料下载
参数资料
| 型号： | ISL6315CRZ-TK |
| 厂商： | Intersil |
| 文件页数： | 15/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24-QFN |
| 标准包装： | 1,000 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 255kHz |
| 占空比： | 67% |
| 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： | 0°C ~ 70°C |
| 封装/外壳： | 24-VFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
ISL6315
number of approximations and is generally not accurate at
frequencies approaching or exceeding half the switching
frequency. When designing compensation networks, select
target crossover frequencies in the range of 10% to 30% of
the per-channel switching frequency, F SW .
General Application Design Guide
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.
MOSFETs
UPPER MOSFET POWER CALCULATION
In addition to r DS(ON) losses, a large portion of the upper-
MOSFET losses are switching losses, due to currents
conducted through the device while the input voltage is
present as V DS . Upper MOSFET losses can be divided into
separate components, separating the upper-MOSFET
switching losses, the lower-MOSFET body diode reverse
recovery charge loss, and the upper MOSFET r DS(ON)
conduction loss.
In most typical circuits, when the upper MOSFET turns off, it
continues to conduct the inductor current until the voltage at
the phase node falls below ground. Once the lower MOSFET
begins conducting (via its body diode or enhancement
channel), the current in the upper MOSFET falls to zero. In the
following equation, the required time for this commutation is t 1
and the associated power loss is P UMOS,1 .
? I OUT I L , P-P ? ? ?
P UMOS , 1 ≈ V IN ? ------------- + --------------- ? ? ---- 1 ? f S
Given the fixed switching frequency of the ISL6315 and the
integrated output drives, the selection of MOSFETs revolves
closely around the current each MOSFET is required to
conduct, the capability of the devices to dissipate heat, as well
t
? N 2 ? ? 2 ?
(EQ. 17)
as the characteristics of available heat sinking. Since the
ISL6315 drives the MOSFETs with 5V, the selection of
appropriate MOSFETs should be done by comparing and
evaluating their characteristics at this specific V GS bias voltage.
LOWER MOSFET POWER CALCULATION
Since virtually all of the heat loss in the lower MOSFET is
Similarly, the upper MOSFET begins conducting as soon as
it begins turning on. Assuming the inductor current is in the
positive domain, the upper MOSFET sees approximately the
input voltage applied across its drain and source terminals,
while it turns on and starts conducting the inductor current.
This transition occurs over a time t 2 , and the approximate
the power loss is P UMOS,2 .
P UMOS , 2 ≈ V IN ? ------------- – --------------- ? ? ---- 2 ? f S
conduction loss (due to current conducted through the
channel resistance, r DS(ON) ), a quick approximation for heat
dissipated in the lower MOSFET can be found in the
? I OUT I L , P-P ? ? t ?
? N 2 ? ? 2 ?
(EQ. 18)
following equation:
A third component involves the lower MOSFET’s reverse-
I L , P-P ( 1 – D )
? I OUT ? 2
P LMOS1 = r DS ( ON ) ? ------------- ? ( 1 – D ) + ----------------------------------
? 2 ?
2
12
(EQ. 15)
recovery charge, Q RR . Since the lower MOSFET’s body
diode conducts the full inductor current before it has fully
switched to the upper MOSFET, the upper MOSFET has to
where: I M is the maximum continuous output current, I L,P-P
is the peak-to-peak inductor current, and D is the duty cycle
(approximately V OUT /V IN ).
provide the charge required to turn off the lower MOSFET’s
body diode. This charge is conducted through the upper
MOSFET across VIN, the power dissipated as a result,
P UMOS,3 can be approximated as:
An additional term can be added to the lower-MOSFET loss
equation to account for additional loss accrued during the
P UMOS , 3 = V IN Q rr f S
(EQ. 19)
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
Lastly, the conduction loss part of the upper MOSFET’s
power dissipation, P UMOS,4, can be calculated using the
following equation:
? I OUT ?
I P-P
P UMOS , 4 = r DS ( ON ) ? ------------- ? d + -----------
the beginning and the end of the lower-MOSFET conduction
interval, respectively.
? N ? 12
2 2
(EQ. 20)
? I OUT I P-P ?
P LMOS 2 = V D ( ON ) f S ? ------------- + ----------- ? t
? I OUT I P-P ?
+ ? ------------- – ----------- ? t d2
? 2 2 ? d1
? 2 2 ?
(EQ. 16)
In this case, of course, r DS(ON) is the ON resistance of the
upper MOSFET.
The above equation assumes the current through the lower
MOSFET is always positive; if so, the total power dissipated
in each lower MOSFET is approximated by the summation of
P LMOS1 and P LMOS2 .
15
The total power dissipated by the upper MOSFET at full load
can be approximated as the summation of these results.
Since the power equations depend on MOSFET parameters,
choosing the correct MOSFETs can be an iterative process
that involves repetitively solving the loss equations for
FN9222.1
July 18, 2007
相关PDF资料 |
PDF描述 |
|---|---|
| VI-2TM-EW-F4 | CONVERTER MOD DC/DC 10V 100W |
| VI-2TM-EW-F3 | CONVERTER MOD DC/DC 10V 100W |
| VI-2TM-EW-F2 | CONVERTER MOD DC/DC 10V 100W |
| VI-2TM-EW-F1 | CONVERTER MOD DC/DC 10V 100W |
| ISL6341AIRZ | IC REG CTRLR BUCK PWM VM 10-TDFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6315IRZ | 功能描述:IC REG CTRLR BUCK PWM VM 24-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) |
| ISL6315IRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 24-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) |
| ISL6316CRZ | 功能描述:软开关 PWM 控制器 W/ANNEAL 4-PHS VR11 CNTRLR COM RoHS:否 制造商:Fairchild Semiconductor 输出端数量: 输出电流: 开关频率: 工作电源电压:30 V 电源电流: 最大工作温度:+ 105 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel |
| ISL6316CRZ-T | 功能描述:软开关 PWM 控制器 W/ANNEAL ISL6306 4-PHS VR11 CNTRLRCOM RoHS:否 制造商:Fairchild Semiconductor 输出端数量: 输出电流: 开关频率: 工作电源电压:30 V 电源电流: 最大工作温度:+ 105 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel |
| ISL6316IRZ | 功能描述:软开关 PWM 控制器 W/ANNEAL 4-PHS VR11 CNTRLR INDUSTRIAL RoHS:否 制造商:Fairchild Semiconductor 输出端数量: 输出电流: 开关频率: 工作电源电压:30 V 电源电流: 最大工作温度:+ 105 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel |
发布紧急采购，3分钟左右您将得到回复。