参数资料
| 型号： | ISL6559CBZ-T |
| 厂商： | Intersil |
| 文件页数： | 14/21页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 28-SOIC |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 4MHz |
| 占空比： | 75% |
| 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： | 28-SOIC（0.295"，7.50mm 宽） |
| 包装： | 标准包装 |
| 产品目录页面： | 1243 (CN2011-ZH PDF) |
| 其它名称： | ISL6559CBZ-TDKR |
ISL6559
Power Stages
The first step in designing a multi-phase 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 where each phase handles between 15 and 20A. All
surface-mount designs will tend toward the lower end of this
current range and, if through-hole MOSFETs can be used,
higher per-phase currents are possible. In cases where
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 15,
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
board space is the limiting constraint, current can be pushed
as high as 30A per phase, but these designs require heat
sinks and forced air to cool the MOSFETs.
? N 2 ? ? 2 ?
I M I PP ? t ?
(EQ. 15)
MOSFETS
The choice of MOSFETs depends on the current each
MOSFET will be required to conduct; the switching frequency;
The upper MOSFET begins to conduct and this transition
occurs over a time t 2 . In Equation 16, the approximate power
loss is P UP,2 .
P UP , 2 ≈ V IN ? ------ – --------- ? ? ---- 2 ? f S
the capability of the MOSFETs to dissipate heat; and the
availability and nature of heat sinking and air flow.
LOWER MOSFET POWER CALCULATION
? I M I PP ? ? t ?
? N 2 ? ? 2 ?
(EQ. 16)
The calculation for heat dissipated in the lower MOSFET is
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 13, I M is the maximum
continuous output current; I PP is the peak-to-peak inductor
current (see Equation 1); d is the duty cycle (V OUT /V IN ); and
A third component involves the lower MOSFET’s reverse-
recovery charge, Q rr . Since the inductor current has fully
commutated to the upper MOSFET before the lower-
MOSFET’s body diode can draw all of Q rr , it is conducted
through the upper MOSFET across VIN. The power
dissipated as a result is P UP,3 and is approximately
L is the per-channel inductance.
P UP , 3 = V IN Q rr f S
(EQ. 17)
? I M ? 2 I L , PP ( 1 – d )
? ?
P L = r DS ( ON )
? ------ ? ( 1 – d ) + --------------------------------
N 12
(EQ. 13)
Finally, the resistive part of the upper MOSFET’s is given in
Equation 18 as P UP,4 .
I PP2
? I M ?
P UP , 4 ≈ r DS ( ON ) ? ------ ? d + ----------
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
? N ? 12
2
(EQ. 18)
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.
In this case, of course, r DS(ON) is the on resistance of the
upper MOSFET.
The total power dissipated by the upper MOSFET at full load
can now be approximated as the summation of the results
I PP ?
? I
P D = V D ( ON ) f S ? ------ + I --------- ? t
? d1 + ? ? ------ – --------- ? ? d2
I M PP M
? N
2 N 2
t
(EQ. 14)
from Equations 15, 16, 17 and 18. Since the power
equations depend on MOSFET parameters, choosing the
correct MOSFETs can be an iterative process that involves
Thus the total maximum power dissipated in each lower
MOSFET is approximated by the summation of P L and P D .
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
14
repetitively solving the loss equations for different MOSFETs
and different switching frequencies until converging upon the
best solution.
Current Sensing
The ISEN pins are denoted ISEN1, ISEN2, ISEN3 and
ISEN4. The resistors connected between these pins and
their respective phase nodes determine the gains in the
load-line regulation loop and the channel-current balance
FN9084.8
December 29, 2004
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相关代理商/技术参数 |
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| ISL6559CR | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 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:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| ISL6559CR-T | 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 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:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
| ISL6559CRZ | 功能描述:电流型 PWM 控制器 2 TO 4 PHS BUCK CNTRLR 32L 5X5 MLFP 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 |
| ISL6559CRZR5265 | 功能描述:IC REG CTRLR BUCK PWM VM 32-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) |
| ISL6559CRZ-T | 功能描述:电流型 PWM 控制器 2 TO 4 PHS BUCK CNTRLR 32L 5X5 MLFP 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 |
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