参数资料
| 型号： | ISL6334DCRZ |
| 厂商： | Intersil |
| 文件页数： | 23/28页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM 4PHASE VR11.1 40QFN |
| 标准包装： | 50 |
| 应用： | 控制器，Intel VR11.1 |
| 输入电压： | 3 V ~ 12 V |
| 输出数： | 1 |
| 输出电压： | 0.5 V ~ 1.6 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
ISL6334D
MOSFETs
The choice of MOSFETs depends on the current each
MOSFET will be required to conduct; the switching
At turn-on, the upper MOSFET begins to conduct and this
transition occurs over a time t 2 . In Equation 24, the
approximate power loss is P UP,2 .
P UP , 2 ≈ V IN ? ------ – ---------- ? ? ---- 2 ? f S
frequency; 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 P-P ? ? t ?
? N 2 ? ? 2 ?
(EQ. 24)
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 21, 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.
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 V IN . The power
dissipated as a result is P UP,3 and is approximated in
Equation 25:
? I M ? 2 I L ( P-P ) 2 ( 1 – d )
P LOW , 1 = r DS ( ON ) ? ------ ? ( 1 – d ) + ------------------------------------
P UP , 3 = V IN Q rr f S
? N ? 12
(EQ. 21)
(EQ. 25)
Finally, the resistive part of the upper MOSFET’s is given in
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 sw ; and the length of dead times, t d1 and t d2 , at
the beginning and the end of the lower-MOSFET conduction
interval respectively.
Equation 26 as P UP,4 .
The total power dissipated by the upper MOSFET at full load
can now be approximated as the summation of the results
from Equations 23, 24, and 25. Since the power equations
depend on MOSFET parameters, choosing the correct
MOSFETs can be an iterative process involving repetitive
solutions to the loss equations for different MOSFETs and
different switching frequencies, as shown in Equation 26.
I P-P ?
? I
P LOW , 2 = V D ( ON ) F sw ? ------ + I ---------- ? t
? d1 + ? ? ------ – ---------- ? ? d2
I M P-P M
? N
I P-P2
? I M ?
P UP , 4 ≈ r DS ( ON ) ? ------ ? d + ---------- d
2 N 2
t
(EQ. 22)
? N ? 12
2
(EQ. 26)
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
Current Sensing Resistor
The resistors connected to the ISEN+ pins determine the
gain in the channel-current balance loop and set the
overcurrent trip point. Select values for these resistors by
using Equation 27:
R ISEN = --------------------------- --------------
105 × 10
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
R X I OCP
N
(EQ. 27)
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 23,
the required time for this commutation is t 1 and the
approximated associated power loss is P UP,1 .
where R ISEN is the sense resistor connected to the ISEN+
pin, N is the active channel number, R X is the resistance of
the current sense element, either the DCR of the inductor or
R SENSE depending on the sensing method, and I OCP is the
desired overcurrent trip point. Typically, I OCP can be chosen
to be 1.2x the maximum load current of the specific
application.
With integrated temperature compensation, the sensed
current signal is independent on the operational temperature
of the power stage, i.e. the temperature effect on the current
sense element R X is cancelled by the integrated
temperature compensation function. R X in Equation 27
should be the resistance of the current sense element at the
I P-P ? ?
I M
P UP , 1 ≈ V IN ? ------ + ---------- ? ? ---- 1 ? f S
? N 2 ? ? 2 ?
t
23
(EQ. 23)
room temperature.
When the integrated temperature compensation function is
disabled by pulling the TCOMP pin to GND, the sensed
current will be dependent on the operational temperature of
FN6802.3
November 22, 2013
相关PDF资料 |
PDF描述 |
|---|---|
| GSC35DRTN-S93 | CONN EDGECARD 70POS DIP .100 SLD |
| ISL6536IB | IC SUPERVISOR 4-CHAN 8-SOIC |
| ISL6334DCRZ-T | IC CTRLR PWM 4PHASE VR11.1 40QFN |
| MIC5330-PGYML TR | IC REG LDO 3V/1.8V .3A 8-MLF |
| ISL6334AIRZ-T | IC CTRLR PWM 4PHASE BUCK 40-QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6334DCRZ-T | 功能描述:IC CTRLR PWM 4PHASE VR11.1 40QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| ISL6334DIRZ | 功能描述:IC CTRLR PWM 4PHASE VR11.1 40QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| ISL6334DIRZ-T | 功能描述:IC CTRLR PWM 4PHASE VR11.1 40QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| ISL6334IRZ | 功能描述:IC CTRLR PWM 4PHASE BUCK 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| ISL6334IRZ-T | 功能描述:IC CTRLR PWM 4PHASE BUCK 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
发布紧急采购，3分钟左右您将得到回复。