参数资料
| 型号： | ISL6262CRZ-T |
| 厂商： | Intersil |
| 文件页数： | 25/27页 |
| 文件大小： | 0K |
| 描述： | IC CORE REG 2PHASE 48-QFN |
| 标准包装： | 4,000 |
| 应用： | 转换器，Intel IMVP-6 |
| 输入电压： | 5 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.3 V ~ 1.5 V |
| 工作温度： | -10°C ~ 100°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： | 带卷 (TR) |
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ISL6262
In the above example, the two errors add to 4A. For the two
phase DC/DC, the currents would be 22A in one phase and
18A in the other phase. In the above analysis, the current
Now, the input to the droop amplifier is essentially the
Vrsense voltage. This voltage is given by the following
equation:
Vrsense EQV = -------------------- ? I OUT
balance can be calculated with 2A/20A = 10%. This is the
worst case calculation, for example, the actual tolerance of
two 10% DCRs is 10%*sqrt(2) = 7%.
R sense
2
(EQ. 26)
There are provisions to correct the current imbalance due to
layout or to purposely divert current to certain phase for
better thermal management. Customer can put a resistor in
The gain of the droop amplifier, K droopamp , must be adjusted
for the ratio of the Rsense to droop impedance, Rdroop. We
use the following equation:
K droopamp = -------------------- ? I OUT
parallel with the current sensing capacitor on the phase of
interest in order to purposely increase the current in that
phase.
R droop
R sense
(EQ. 27)
In the case the pc board trace resistance from the inductor to
the microprocessor are not the same on two phases, the
current will not be balanced. On the phase that have too
Solving for the Rdrp2 value, Rdroop = 0.0021(V/A) as per
the Intel IMVP-6 specification, Rsense = 0.001 Ω and
Rdrp1 = 1k Ω , we obtain the following:
much trace resistance a resistor can be added in parallel
with the ISEN capacitor that will correct for the poor layout.
Rdrp2 = ( K droopamp – 1 ) ? R drp1 = 3.2k Ω
(EQ. 28)
An estimate of the value of the resistor is:
Rtweak = Risen * Rdcr/(Rtrace-Rmin)
where Risen is the resistance from the phase node to the
ISEN pin; usually 10k Ω . Rdcr is the DCR resistance of the
inductor. Rtrace is the trace resistance from the inductor to
the microprocessor on the phase that needs to be tweaked.
It should be measured with a good microOhm meter. Rmin is
the trace resistance from the inductor to the microprocessor
on the phase with the least resistance.
For example, if the pc board trace on one phase is 0.5m Ω
and on another trace is 0.3m Ω ; and if the DCR is 1.2m Ω ;
then the tweaking resistor is
Rtweak = 10k Ω * 1.2/(0.5 - 0.3) = 60k Ω .
When choosing current sense resistor, not only the tolerance
of the resistance is important, but also the TCR. And its
combined tolerance at a wide temperature range should be
calculated.
Droop Using Discrete Resistor Sensing - Static/
Dynamic Mode of Operation
Figure 36 shows the equivalent circuit of a discrete current
sense approach. Figure 27 shows a more detailed
These values are extremely sensitive to layout. Once the
board has been laid out, some tweaking may be required to
adjust the full load droop. This is fairly easy and can be
accomplished by allowing the system to achieve thermal
equilibrium at full load, and then adjusting Rdrp2 to obtain
the desired droop value.
Fault Protection - Overcurrent Fault Setting
As previously described, the overcurrent protection of the
ISL6262 is related to the droop voltage. Previously we have
calculated that the droop voltage = ILoad * Rdroop, where
Rdroop is the load line slope specified as 0.0021 (V/A) in the
Intel IMVP-6 specification. Knowing this relationship, the
overcurrent protection threshold can be set up as a voltage
droop level. Knowing this voltage droop level, one can
program in the appropriate drop across the Roc resistor.
This voltage drop will be referred to as Voc. Once the droop
voltage is greater than Voc, the PWM drives will turn off and
PGOOD will go low.
The selection of Roc is given in equation. Assuming we
desire an overcurrent trip level, Ioc, of 55A, and knowing
from the Intel Specification that the load line slope, Rdroop is
0.0021 (V/A), we can then calculate for Roc as shown in
equation.
R OC = ----------------------------------- = ------------------------------ = 11.5k Ω
10 ? 10
schematic of this approach. Droop is solved the same way
as the DCR sensing approach with a few slight
modifications.
I OC ? R droop 55 ? 0.0021
10 μ A – 6
(EQ. 29)
First, there is no NTC required for thermal compensation,
therefore, the Rn resistor network in the previous section is
not required. Secondly, there is no time constant matching
required, therefore, the Cn component is not matched to the
L/DCR time constant. This component does indeed provide
noise immunity and therefore is populated with a 39pF
capacitor.
The RS values in the previous section, RS = 1.5k_1% are
sufficient for this approach.
25
Note, if the droop load line slope is not -0.0021 (V/A) in the
application, the overcurrent setpoint will differ from
predicted.
FN9199.2
May 15, 2006
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6262CRZ-TK | 功能描述:直流/直流开关调节器 TWO-PHS DC/DC BUCK CNTRLR IMVP-6 4 8LD 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 |
| ISL6262CRZ-TR5242 | 制造商:Intersil Corporation 功能描述:53350B01 MASK ONLY AND DOT ON BRAND - Tape and Reel |
| ISL6262IRZ | 功能描述:直流/直流开关调节器 TWO-PHS DC/DC BUCK CNTRLR IMVP-6 4 8LD 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 |
| ISL6262IRZ-T | 功能描述:直流/直流开关调节器 TWO-PHS DC/DC BUCK CNTRLR IMVP-6 4 8LD 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 |
| ISL6263 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:5-Bit VID Single-Phase Voltage Regulator for IMVP-6 Santa Rosa GPU Core |
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