参数资料
| 型号： | ISL62881DHRTZ-T |
| 厂商： | Intersil |
| 文件页数： | 20/37页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM SGL PHASE 32TQFN |
| 标准包装： | 6,000 |
| 应用： | 控制器，Intel IMVP-6.5? |
| 输入电压： | 4.5 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.013 V ~ 1.5 V |
| 工作温度： | -10°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN（5x5） |
| 包装： | 带卷 (TR) |
| 配用： | ISL62881CCPUEVAL2Z-ND - EVAL BOARD ISL62881CCPU 28QFN |
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ISL62881C, ISL62881D
i O
i L
C n is the capacitor used to match the inductor time
constant. It usually takes the parallel of two (or more)
capacitors to get the desired value. Figure 18 shows
Cn.1
Rntc
V O
RING
BACK
FIGURE 17. OUTPUT VOLTAGE RING BACK PROBLEM
ISUM+
Rntcs
+
Rp Cn.2 Vcn
-
Rn
that two capacitors C n.1 and C n.2 are in parallel.
Resistor R n is an optional component to reduce the V o
ring back. At steady state, C n.1 + C n.2 provides the
desired C n capacitance. At the beginning of i o change,
the effective capacitance is less because R n increases
the impedance of the C n.1 branch. As Figure 15
explains, V o tends to dip when C n is too small, and this
effect will reduce the V o ring back. This effect is more
pronounced when C n.1 is much larger than C n.2 . It is
also more pronounced when R n is bigger. However, the
presence of R n increases the ripple of the V n signal if
C n.2 is too small. It is recommended to keep C n.2
greater than 2200pF. R n value usually is a few ohms.
C n.1 , C n.2 and R n values should be determined
through tuning the load transient response waveforms
on an actual board.
OPTIONAL
Ri
ISUM-
Resistor Current-Sensing Network
PHASE
Rip Cip
OPTIONAL
L
FIGURE 18. OPTIONAL CIRCUITS FOR RING BACK
REDUCTION
Figure 17 shows the output voltage ring back problem
during load transient response. The load current i o has a
fast step change, but the inductor current i L cannot
accurately follow. Instead, i L responds in first order
system fashion due to the nature of current loop. The
ESR and ESL effect of the output capacitors makes the
DCR
RSEN
RSUM
Vcn
Cn
Ri
ISUM+
ISUM-
V Cn ( s ) = R sen × I o ( s ) × A Rsen ( s )
output voltage V o dip quickly upon load current change.
However, the controller regulates V o according to the
droop current i droop , which is a real-time representation
of i L ; therefore it pulls V o back to the level dictated by i L ,
causing the ring back problem. This phenomenon is not
observed when the output capacitors have very low ESR
and ESL, such as all ceramic capacitors.
Figure 18 shows two optional circuits for reduction of the
ring back. R ip and C ip form an R-C branch in parallel
with R i , providing a lower impedance path than R i at
the beginning of i o change. R ip and C ip do not have
any effect at steady state. Through proper selection of
R ip and C ip values, i droop can resemble i o rather than
i L , and V o will not ring back. The recommended value
for R ip is 100 Ω . C ip should be determined through
tuning the load transient response waveforms on an
Io
FIGURE 19. RESISTOR CURRENT-SENSING NETWORK
Figure 19 shows the resistor current-sensing network.
The inductor has a series current-sensing resistor R sen .
R sum and is connected to the R sen pad to accurately
capture the inductor current information. The R sum feeds
the sensed information to capacitor C n . R sum and C n
form a a filter for noise attenuation. Equations 13
through 15 gives V Cn (s) expressions:
(EQ. 13)
A Rsen ( s ) = -----------------------
1 + -------------
ω Rsen = -----------------------------
actual board. The recommended range for C ip is
100pF~2000pF. However, it should be noted that the
R ip -C ip branch may distort the i droop waveform.
Instead of being triangular as the real inductor current,
i droop may have sharp spikes, which may adversely
affect i droop average value detection and therefore
may affect OCP accuracy. User discretion is advised.
20
1
s
ω sns
1
R sum × C n
(EQ. 14)
(EQ. 15)
FN7596.0
March 8, 2010
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL62881HRTZ | 功能描述:直流/直流开关调节器 1 PHS PWM BUCKG FOR MICROPROCESR PWR SUP RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881HRTZ-T | 功能描述:直流/直流开关调节器 1 PHS PWM BUCKG FOR MICROPROCESR PWR SUP RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62882 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Multiphase PWM Regulator for IMVP-6.5 Mobile CPUs and GPUs |
| ISL62882B | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Multiphase PWM Regulator for IMVP-6.5 Mobile CPUs and GPUs |
| ISL62882BHRTZ | 功能描述:直流/直流开关调节器 2 PHS PWM BUCKG FOR MICROPROC PWR SUP RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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