参数资料
| 型号： | ISL62883IRTZ-T |
| 厂商： | Intersil |
| 文件页数： | 19/37页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM 3PHASE BUCK 40TQFN |
| 标准包装： | 6,000 |
| 应用： | 控制器，Intel IMVP-6.5? |
| 输入电压： | 5 V ~ 21 V |
| 输出数： | 1 |
| 输出电压： | 0.013 V ~ 1.5 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 供应商设备封装： | 40-TQFN-EP（5x5） |
| 包装： | 带卷 (TR) |
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ISL62883, ISL62883B
comparator threshold voltage accordingly in iterative steps such
that the low-side MOSFET body diode conducts for approximately
40ns to minimize the body diode-related loss.
Overshoot Reduction Function
droop amplifier. The preferred values are R is = 82.5 Ω and
C is = 0.01μF. Slight deviations from the recommended values are
acceptable. Large deviations may result in instability.
Inductor DCR Current-Sensing Network
The ISL62883 has an optional overshoot reduction function.
Using R BIAS = 47k Ω enables this function and using
R BIAS = 147k Ω disables this function.
When a load release occurs, the energy stored in the inductors
will dump to the output capacitor, causing output voltage
Phase1
Phase2
Phase3
Rsum
Rsum
Rsum
ISUM+
overshoot. The inductor current freewheels through the low-side
MOSFET during this period of time. The overshoot reduction
function turns off the low-side MOSFET during the output voltage
overshoot, forcing the inductor current to freewheel through the
L
L
L
Rntcs
Rp
Cn Vcn
low-side MOSFET body diode. Since the body diode voltage drop
is much higher than MOSFET R dson voltage drop, more energy is
dissipated on the low-side MOSFET therefore the output voltage
DCR
DCR
DCR
Rntc
Ro
Ri
ISUM-
V Cn ( s ) = ? ----------------------------------------- × ------------ ? × I o ( s ) × A cs ( s )
N
R sum
? ?
R ntcnet = --------------------------------------------------- (EQ. 20)
1 + ------
A cs ( s ) = ----------------------
ω L
s
ω sns
overshoot is lower.
If the overshoot reduction function is enabled, the ISL62883
monitors the COMP pin voltage to determine the output voltage
overshoot condition. The COMP voltage will fall and hit the clamp
voltage when the output voltage overshoots. The ISL62883 will
turn off LGATE1 and LGATE2, and tri-state PWM3 when COMP is
being clamped. All the low-side MOSFETs in the power stage will
be turned off. When the output voltage has reached its peak and
starts to come down, the COMP voltage starts to rise and is no
longer clamped. The ISL62883 will resume normal PWM
operation.
When PSI# is low, indicating a low power state of the CPU, the
controller will disable the overshoot reduction function as large
magnitude transient event is not expected and overshoot is not a
concern.
While the overshoot reduction function reduces the output voltage
overshoot, energy is dissipated on the low-side MOSFET, causing
additional power loss. The more frequent transient event, the more
power loss dissipated on the low-side MOSFET. The MOSFET may
face severe thermal stress when transient events happen at a high
repetitive rate. User discretion is advised when this function is
enabled.
Key Component Selection
R BIAS
The ISL62883 uses a resistor (1% or better tolerance is
recommended) from the RBIAS pin to GND to establish highly
accurate reference current sources inside the IC. Using
R BIAS = 47k Ω enables the overshoot reduction function and using
R BIAS = 147k Ω disables this function. Do not connect any other
components to this pin. Do not connect any capacitor to the RBIAS
pin as it will create instability.
Care should be taken in layout that the resistor is placed very close
to the RBIAS pin and that a good quality signal ground is
connected to the opposite side of the R BIAS resistor.
R is and C is
As Figures 1 and 2, show, the ISL62883 needs the R is - C is
network across the ISUM+ and the ISUM- pins to stabilize the
19
Ro
Ro
Io
FIGURE 14. DCR CURRENT-SENSING NETWORK
Figure 14 shows the inductor DCR current-sensing network for a
3-phase solution. An inductor current flows through the DCR and
creates a voltage drop. Each inductor has two resistors in R sum
and R o connected to the pads to accurately sense the inductor
current by sensing the DCR voltage drop. The R sum and R o
resistors are connected in a summing network as shown, and feed
the total current information to the NTC network (consisting of
R ntcs , R ntc and R p ) and capacitor C n . R ntc is a negative
temperature coefficient (NTC) thermistor, used to
temperature-compensate the inductor DCR change.
The inductor output side pads are electrically shorted in the
schematic, but have some parasitic impedance in actual board
layout, which is why one cannot simply short them together for the
current-sensing summing network. It is recommended to use
1 Ω ~10 Ω R o to create quality signals. Since R o value is much
smaller than the rest of the current sensing circuit, the following
analysis will ignore it for simplicity.
The summed inductor current information is presented to the
capacitor C n . Equations 19 thru 23 describe the
frequency-domain relationship between inductor total current
I o (s) and C n voltage V Cn (s):
? ?
? R ntcnet DCR ?
(EQ. 19)
N
? R ntcnet + -------------- ?
( R ntcs + R ntc ) × R p
R ntcs + R ntc + R p
s
(EQ. 21)
1 + ------------
where N is the number of phases.
FN6891.4
June 21, 2011
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL62884C | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Single-Phase PWM Regulator for IMVP-6a?￠ Mobile CPUs |
| ISL62884CEVAL2Z | 功能描述:EVAL BOARD FOR ISL62884C RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL62884CHRTZ | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY 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 |
| ISL62884CHRTZ-T | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY 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 |
| ISL62884CIRTZ | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY 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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