参数资料
| 型号： | ISL62881HRTZ |
| 厂商： | Intersil |
| 文件页数： | 16/35页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM SGL PHASE 28TQFN |
| 标准包装： | 75 |
| 应用： | 控制器，Intel IMVP-6.5? |
| 输入电压： | 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： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 管件 |
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ISL62881, ISL62881B
V droop is the droop voltage required to implement load line.
Changing R droop or scaling I droop can both change the load line
slope. Since I droop also sets the overcurrent protection level, it is
recommended to first scale I droop based on OCP requirement,
then select an appropriate R droop value to obtain the desired
load line slope.
Modes of Operation
TABLE 2. ISL62881 MODES OF OPERATION
OPERATIONAL
CONFIGURATION DPRSLPVR MODE
CPU VR Application 0 1-phase CCM
VOLTAGE
SLEW RATE
5mV/μs
Differential Sensing
1
1-phase DE
Figure 12 also shows the differential voltage sensing scheme.
VCC SENSE and VSS SENSE are the remote voltage sensing signals
from the processor die. A unity gain differential amplifier senses
GPU VR Application
0
1
1-phase CCM
1-phase DE
5mV/μs
10mV/μs
the VSS SENSE voltage and adds it to the DAC output. The error
amplifier regulates the inverting and the non-inverting input
voltages to be equal, therefore:
Table 2 shows the ISL62881 operational modes, programmed by
the logic status of the DPRSLPVR pin. The ISL62881 enters
1-phase DE mode when there is DPRSLPVR = 1.
VCC SENSE + V
droop
= V DAC + VSS SENSE
(EQ. 3)
When the ISL62881 is configured for GPU VR application,
DPRSLPVR logic status also controls the output voltage slew
Rewriting Equation 3 and substituting Equation 2 gives:
VCC SENSE – VSS SENSE = V DAC – R droop × I droop
(EQ. 4)
rate. The slew rate is 5mV/μs for DPRSLPVR = 0 and is 10mV/μs
for DPRSLPVR = 1.
Dynamic Operation
Equation 4 is the exact equation required for load line
implementation.
The VCC SENSE and VSS SENSE signals come from the processor
die. The feedback will be open circuit in the absence of the
processor. As shown in Figure 12, it is recommended to add a
“catch” resistor to feed the VR local output voltage back to the
compensator, and add another “catch” resistor to connect the VR
local output ground to the RTN pin. These resistors, typically
10 Ω ~100 Ω , will provide voltage feedback if the system is
powered up without a processor installed.
CCM Switching Frequency
The R FSET resistor between the COMP and the VW pins sets the
VW windows size, which therefore sets the switching frequency.
When the ISL62881 is in continuous conduction mode (CCM), the
switching frequency is not absolutely constant due to the nature
of the R 3? modulator. As explained in “Multiphase R3?
increase during load insertion and will decrease during load
release to achieve fast response. On the other hand, the
switching frequency is relatively constant at steady state.
Variation is expected when the power stage condition, such as
input voltage, output voltage, load, etc. changes. The variation is
usually less than 15% and doesn’t have any significant effect on
output voltage ripple magnitude. Equation 5 gives an estimate of
the frequency-setting resistor R fset value. 8k Ω R FSET gives
approximately 300kHz switching frequency. Lower resistance
gives higher switching frequency.
When the ISL62881 is configured for CPU VR application, it
responds to VID changes by slewing to the new voltage at
5mV/μs slew rate. As the output approaches the VID command
voltage, the dv/dt moderates to prevent overshoot. Geyserville-III
transitions commands one LSB VID step (12.5mV) every 2.5μs,
controlling the effective dv/dt at 5mv/μs. The ISL62881 is
capable of 5mV/μs slew rate.
When the ISL62881 is configured for GPU VR application, it
responds to VID changes by slewing to the new voltage at a slew
rate set by the logic status on the DPRSLPVR pin. The slew rate is
5mV/μs when DPRSLPVR = 0 and is 10mV/μs when
DPRSLPVR = 1.
When the ISL62881 is in DE mode, it will actively drive the output
voltage up when the VID changes to a higher value. It’ll resume
DE mode operation after reaching the new voltage level. If the
load is light enough to warrant DCM, it will enter DCM after the
inductor current has crossed zero for four consecutive cycles. The
ISL62881 will remain in DE mode when the VID changes to a
lower value. The output voltage will decay to the new value and
the load will determine the slew rate.
The R 3? modulator intrinsically has voltage feed forward. The
output voltage is insensitive to a fast slew rate input voltage change.
Protections
The ISL62881 provides overcurrent, undervoltage, and overvoltage
protections.
R FSET ( k Ω ) = ( Period ( μ s ) – 0.29 ) × 2.65
16
(EQ. 5)
The ISL62881 determines overcurrent protection (OCP) by
comparing the average value of the droop current I droop with an
internal current source threshold. It declares OCP when I droop is
above the threshold for 120μs. A resistor R comp from the COMP
pin to GND programs the OCP current source threshold, as well as
the overshoot reduction function (to be discussed in later sections),
as Table 3 shows. It is recommended to use the nominal R comp
value. The ISL62881 detects the R comp value at the beginning of
start-up, and sets the internal OCP threshold accordingly. It
remembers the R comp value until the VR_ON signal drops below
the POR threshold.
FN6924.3
June 16, 2011
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
| ISL62882BHRTZR5411 | 制造商:Intersil Corporation 功能描述: |
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