参数资料
| 型号： | ISL6260CCRZ-T |
| 厂商： | Intersil |
| 文件页数： | 26/28页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM MULTI-PHASE 40-QFN |
| 标准包装： | 4,000 |
| 应用： | 转换器，Intel IMVP-6 |
| 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： | 40-VFQFN 裸露焊盘 |
| 供应商设备封装： | 40-QFN（6x6） |
| 包装： | 带卷 (TR) |
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ISL6260C
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%* √ (2) = 7%.
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 parallel
with the current sensing capacitor on the phase of interest in
order to purposely increase the current in that phase. It is
highly recommended to use symmetrical layout in order to
achieve natural current balance.
not required. Secondly, there is no time constant matching
required, therefore, the Cn component is not needed to
match the L/DCR time constant, but this component does
indeed provide noise immunity, especially to noise voltage
caused by the ESL of the current sensing resistors. A 47pF
capacitor can be used for such purposes.
The Rs values in the previous section, Rs = 7.68k_1% are
sufficient for this approach.
Now, the input to the Droop amplifier is the Vrsense voltage.
This voltage is given by Equation 21:
Vrsense = ---------------------- × I OUT
In the case the PC board trace resistance from the inductor
to the microprocessor are not the same on all three phases,
the current will not be balanced. On the phases that have too
Rsense
N
(EQ. 21)
much trace resistance a resistor can be added in parallel
with the ISEN capacitor that will correct for the poor layout.
The gain of the Droop amplifier, G2, must be adjusted equal
to the load line impedance. We use Equation 22:
G2 = ---------------------- × N
An estimate of the value of the resistor is as shown in
Equation 19:
Rdroop
Rsense
(EQ. 22)
Risen ? [ 2 ? Rdcr – Rtrace – Rmin ) ]
[ 2 ( ( Rtrace ) – Rmin ) ]
Rtweak = ------------------------------------------------------------------------------------------------
(EQ. 19)
Assuming N = 3, Rdroop = 0.0021(V/A) as per the Intel
IMVP-6+ specification, Rsense = 0.001 Ω , we obtain
G2 = 6.3.
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 micro Ω meter. Rmin is
the trace resistance from the inductor to the microproccessor
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 as shown in Equation 20:
The values of Rdrp1 and Rdrp2 are selected to satisfy two
requirements. First, the ratio of Rdrp2 and Rdrp1 determine
the gain G2 = (Rdrp2/Rdrp1)+1. Second, the parallel
combination of Rdrp1 and Rdrp2 should equal the parallel
combination of the Rs resistors. Combining these
requirements gives:
Rdrp1 = G2/(G2-1) * Rs/N
Rdrp2 = (G2-1) * Rdrp1
In the example above, Rs = 7.68k, N = 3, and G2 = 6.3 so
10k Ω? [ 2 ? 1.2 – ( 0.5 – 0.3 ) ]
[ 2 ? ( 0.5 – 0.3 ) ]
Rtweak = ------------------------------------------------------------------------ = 55k Ω
(EQ. 20)
Rdrp 3k and Rdrp2 is 15.8k Ω .
These values are extremely sensitive to layout. Once the
board has been laid out, some tweaking may be required to
For extremely unsymmetrical layout causing phase current
unbalance, ISL6260C applications schematics can be
modified to correct the problem.
Droop using Discrete Resistor Sensing - Static/
Dynamic Mode of Operation
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.
Figure 48 shows the equivalent circuit of a discrete current
sense approach. Figure 40 shows the simplified schematic
of this approach.
For discrete resistor current sensing circuit, the droop circuit
parameters can be solved the same way as the DCR
sensing approach with a few slight modifications.
First, there is no NTC required for thermal compensation,
therefore, the Rn resistor network in the previous section is
26
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.
Power Monitor
The power monitor signal tracks the inductor current. Due to
the dynamic operation of the CPU, the inductor current is
pulsating and the power monitor signal needs to be filtered.
If the RC filter is followed by an A/D converter, the input
impedance of the A/D converter needs to be much larger
than the resistor used for the RC filter. Otherwise, the input
impedance of the A/D converter and the RC filter resistor will
construct a resistor divider causing the A/D converter
reading incorrect information. It is desirable to choose a
small RC filter resistor in order to reduce the resistor divider
effect. The ISL6260C comes with a very strong current
sinking capability, users can use k Ω resistors for the RC
filter. Some A/D converters might have 100k Ω input
impedance, 1k Ω resistor will cause 1% error. As shown in
FN9259.3
June 21, 2010
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6260CIRZ | 功能描述:电流型 PWM 控制器 MULTI-PHS(3 PHS EXT DC/DC BUCK CONT RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL6260CIRZ-T | 功能描述:电流型 PWM 控制器 MULTI-PHS(3 PHS EXT DC/DC BUCK CONT RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL6260CRZ | 功能描述:直流/直流开关调节器 MULTI-PHS3 PHS EXT DC/DC BUCK CNTRLR 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 |
| ISL6260CRZR5242 | 制造商:Intersil Corporation 功能描述:53289C01 MASK ONLY WITH DOT ON BRAND - Rail/Tube |
| ISL6260CRZ-T | 功能描述:直流/直流开关调节器 MULTI-PHS3 PHS EXT BUCK CONT IMVP-6 4 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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