参数资料
| 型号： | ISL62882IRTZ |
| 厂商： | Intersil |
| 文件页数： | 24/42页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM 2PHASE BUCK 40TQFN |
| 标准包装： | 60 |
| 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： | -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： | 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页第23页当前第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页
ISL62882, ISL62882B
3I o × LL
V droop 2R droop R ntcnet DCR
LL = ------------------ = ---------------------- × ----------------------------------------- × ------------ (EQ. 31)
I o
R i
R sum
V droop 2R sen × R droop
Z out (s) = LL
o
where I omax is the full load current, I droopmax is the
corresponding droop current. For example, given N = 2,
R sen = 1m Ω , I omax = 51A and I droopmax = 34.3μA, Equation 30
gives R i = 1.487k Ω .
A resistor from COMP to GND can adjust the internal OCP
threshold, providing another dimension of fine-tune flexibility.
Table 4 shows the detail. It is recommended to scale I droop such
that the default OCP threshold gives approximately the desired
OCP level, then use R comp to fine tune the OCP level if necessary.
Load Line Slope
Refer to Figure 12.
For inductor DCR sensing, substitution of Equation 24 into
Equation 2 gives the load line slope expression:
N
N
R ntcnet + --------------
For resistor sensing, substitution of Equation 28 into Equation 2
gives the load line slope expression :
LL = ------------------ = ----------------------------------------- (EQ. 32)
I o N × R i
Substitution of Equation 25 and rewriting Equation 31, or
Rewriting Equation 36 and application of full load condition gives
Equation 37:
V Rimon × R droop
R imon = -------------------------------------------- (EQ. 37)
For example, given LL = 1.9m Ω , R droop = 2.825k Ω ,
V Rimon = 963mV at I omax = 51A, Equation 37 gives
R imon = 9.358k Ω .
A capacitor C imon can be paralleled with R imon to filter the IMON
pin voltage. The R imon C imon time constant is the user’s choice. It
is recommended to have a time constant long enough such that
switching frequency ripples are removed.
Compensator
Figure 18 shows the desired load transient response waveforms.
Figure 24 shows the equivalent circuit of a voltage regulator (VR)
with the droop function. A VR is equivalent to a voltage source
(= VID) and output impedance Z out (s). If Z out (s) is equal to the
load line slope LL, i.e., constant output impedance, in the entire
frequency range, V o will have square response when I o has a
square change.
i
substitution of Equation 29 and rewriting Equation 32 give the
same result in Equation 33:
VID
VR
LOAD
V
o
R droop = ---------------- × LL
I o
I droop
(EQ. 33)
V Rimon = 3 × I droop × R imon
One can use the full load condition to calculate R droop . For
example, given I omax = 51A, I droopmax = 34.3μA and
LL = 1.9m Ω , Equation 33 gives R droop = 2.825k Ω .
It is recommended to start with the R droop value calculated by
Equation 33, and fine tune it on the actual board to get accurate
load line slope. One should record the output voltage readings at
no load and at full load for load line slope calculation. Reading
the output voltage at lighter load instead of full load will increase
the measurement error.
Current Monitor
Refer to Equation 13 for the IMON pin current expression.
Refer to Figures 1 and 2, the IMON pin current flows through
R imon . The voltage across R imon is expressed in Equation 34:
(EQ. 34)
Rewriting Equation 33 gives Equation 35:
FIGURE 24. VOLTAGE REGULATOR EQUIVALENT CIRCUIT
Intersil provides a Microsoft Excel-based spreadsheet to help
design the compensator and the current sensing network, so the
VR achieves constant output impedance as a stable system.
Figure 27 shows a screenshot of the spreadsheet.
A VR with active droop function is a dual-loop system consisting of
a voltage loop and a droop loop which is a current loop. However,
neither loop alone is sufficient to describe the entire system. The
spreadsheet shows two loop gain transfer functions, T1(s) and
T2(s), that describe the entire system. Figure 25 conceptually
shows T1(s) measurement set-up and Figure 26 conceptually
shows T2(s) measurement set-up. The VR senses the inductor
current, multiplies it by a gain of the load line slope, then adds it
on top of the sensed output voltage and feeds it to the
compensator. T(1) is measured after the summing node, and T2(s)
is measured in the voltage loop before the summing node. The
spreadsheet gives both T1(s) and T2(s) plots. However, only T2(s)
I droop = ------------------ × LL
I o
R droop
(EQ. 35)
can be actually measured on an ISL62882 regulator.
T1(s) is the total loop gain of the voltage loop and the droop loop.
V Rimon = --------------------- × R imon
3I o × LL
R droop
Substitution of Equation 35 into Equation 34 gives Equation 36:
(EQ. 36)
24
It always has a higher crossover frequency than T2(s) and has
more meaning of system stability.
T2(s) is the voltage loop gain with closed droop loop. It has more
meaning of output voltage response.
Design the compensator to get stable T1(s) and T2(s) with
sufficient phase margin, and output impedance equal or smaller
than the load line slope.
FN6890.4
June 21, 2011
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| ISL62882IRTZ-T | 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 |
| ISL62883 | 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 |
| ISL62883BHRTZ | 功能描述:直流/直流开关调节器 3 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 |
| ISL62883BHRTZ-T | 功能描述:直流/直流开关调节器 3 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 |
| ISL62883C | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Multiphase PWM Regulator for IMVP-6.5a?￠ Mobile CPUs and GPUs |
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