参数资料
| 型号： | ISL6334CIRZ-T |
| 厂商： | Intersil |
| 文件页数： | 15/30页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM SYNC BUCK 40-QFN |
| 标准包装： | 4,000 |
| 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： | -40°C ~ 85°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： | 带卷 (TR) |
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ISL6334B, ISL6334C
INDUCTOR DCR SENSING
An inductor ’s winding is characteristic of a distributed
resistance, as measured by the DCR (Direct Current
Resistance) parameter. Consider the inductor DCR as a
separate lumped quantity, as shown in Figure 4. The
ISEN+ signals. Select the proper C T to keep the time
constant of R ISEN and C T (R ISEN x C T ) close to 27ns.
Equation 6 shows that the ratio of the channel current to the
sensed current, I SEN , is driven by the value of the sense
resistor and the DCR of the inductor.
I SEN = I L ? ------------------
R
channel current I L , flowing through the inductor, will also
pass through the DCR. Equation 4 shows the s-domain
equivalent voltage across the inductor V L .
DCR
ISEN
(EQ. 6)
V L ( s ) = I L ? ( s ? L + DCR )
(EQ. 4)
RESISTIVE SENSING
For accurate current sense, a dedicated current-sense resistor
A simple R-C network across the inductor extracts the DCR
voltage, as shown in Figure 4.
R SENSE in series with each output inductor can serve as the
current sense element (see Figure 5). This technique is more
accurate, but reduces overall converter efficiency due to the
I ( s )
V IN
L
additional power loss on the current sense element R SENSE .
ISL6596
L
DCR
INDUCTOR
V L
V C (s)
V OUT
C OUT
The same capacitor C T is needed to match the time delay
between ISEN- and ISEN+ signals. Select the proper C T to
keep the time constant of R ISEN and C T (R ISEN x C T ) close to
27ns.
Equation 7 shows the ratio of the channel current to the
I SEN = I L ? -----------------------
R
PWM(n)
ISL6334B, ISL6334C
R
C
sensed current I SEN .
R SENSE
ISEN
(EQ. 7)
I n
R ISEN(n)
The inductor DCR value will increase as the temperature
increases. Therefore, the sensed current will increase as the
temperature of the current sense element increases. In order
to compensate the temperature effect on the sensed current
CURRENT
SENSE
+
-
ISEN-(n)
ISEN+(n)
C T
signal, a Positive Temperature Coefficient (PTC) resistor can
be selected for the sense resistor R ISEN , or the integrated
temperature compensation function of ISL6334B, ISL6334C
should be utilized. The integrated temperature compensation
I SEN = I ------------------
L R
DCR
ISEN
L
IL
R SENSE V OUT
FIGURE 4. DCR SENSING CONFIGURATION
The voltage on the capacitor V C , can be shown to be
proportional to the channel current I L . See Equation 5.
ISL6334B, ISL6334C
C OUT
? s ? ------------- + 1 ? ? ( DCR ? I )
V C ( s ) = ---------------------------------------------------------------------
L
? DCR ? L
( s ? RC + 1 )
(EQ. 5)
I n
R ISEN(n)
CURRENT
If the R-C network components are selected such that the
RC time constant (= R*C) matches the inductor time
constant (= L/DCR), the voltage across the capacitor V C is
SENSE
+
-
ISEN-(n)
equal to the voltage drop across the DCR, i.e., proportional
ISEN+(n)
C T
I SEN = I --------------------------
L R
to the channel current.
With the internal low-offset current amplifier, the capacitor
voltage V C is replicated across the sense resistor R ISEN .
Therefore, the current out of ISEN+ pin, I SEN , is proportional
to the inductor current.
Because of the internal filter at ISEN- pin, one capacitor, C T ,
is needed to match the time delay between the ISEN- and
15
R SENSE
ISEN
FIGURE 5. SENSE RESISTOR IN SERIES WITH INDUCTORS
Channel-Current Balance
The sensed current I n from each active channel is summed
together and divided by the number of active channels. The
resulting average current I AVG provides a measure of the
FN6689.2
August 31, 2010
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| ISL6334CRZ | 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 |
| ISL6334CRZ-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 |
| ISL6334DCRZ | 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 |
| 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 |
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