参数资料
型号: ISL6569ACR-T
厂商: Intersil
文件页数: 12/22页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM 32-QFN
标准包装: 6,000
PWM 型: 电流/电压模式
输出数: 1
频率 - 最大: 2MHz
占空比: 75%
电源电压: 4.75 V ~ 5.25 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: 0°C ~ 85°C
封装/外壳: 32-VFQFN 裸露焊盘
包装: 带卷 (TR)
ISL6569A
TABLE 1. VOLTAGE IDENTIFICATION CODES (Continued)
DYNAMIC VID
VID4
1
1
1
1
1
1
VID3
1
1
1
1
1
1
VID2
0
0
1
1
1
1
VID1
1
1
0
0
1
1
VID0
0
1
0
1
0
1
DAC
0.900
0.875
0.850
0.825
0.800
Shutdown
Next generation microprocessors can change VID inputs at
any time while the regulator is in operation. The power
management solution is required to monitor the DAC inputs
and respond to VID voltage transitions, or ‘on-the-fly’ VID
changes, in a controlled manner. Supervising the safe output
voltage transition within the DAC range of the processor
without discontinuity or disruption.
The ISL6569A checks the five VID inputs at the beginning of
LOAD-LINE REGULATION
Microprocessor load current demands change from near no-
load to full load often during operation. The resulting sizable
transient current slew rate causes an output voltage spike
since the converter is not able to respond fast enough to the
rapidly changing current demands. The magnitude of the
spike is dictated by the ESR and ESL of the output
capacitors selected. In order to drive the cost of the output
capacitor solution down, one commonly accepted approach
is active voltage positioning. By adding a well controlled
output impedance, the output voltage can effectively be level
shifted in a direction which works against the voltage spike.
The average current of all the active channels, I AVG , flows out
IOUT, see Figure 6. IOUT is connected to FB through a load-
line regulation resistor, R FB . The resulting voltage drop across
R FB is proportional to the output current, effectively creating
an output voltage droop with a steady-state value defined as
each channel-1 switching cycle. If the VID code has
changed, the controller waits one complete switching cycle
to validate the new code. If the VID code is stable for this
entire switching cycle, then the controller will begin executing
the output voltage change. The controller begins
incrementing the reference voltage by making 25mV steps
every two switching cycles until it reaches the new VID code.
The total time required for a VID change, t DV , is dependent
on the switching frequency (f S ), the size of the change
( ? VID), and the time before the next switching cycle begins.
Since the ISL6569A recognizes VID-code changes only at
the beginning of switching cycles, up to one full cycle may
pass before a VID change registers. This is followed by a
one-cycle wait before the output voltage begins to change.
The one-cycle uncertainty in Equation 8 is due to the
possibility that the VID code change may occur up to one full
cycle before being recognized.
----- ? 2 ------------------ – 1 ? < t DV ≤ ----- ? 2 ------------------ ?
f S ? 0.025
f S ? 0.025 ?
V DROOP = I AVG R FB
(EQ. 5)
?
1 ? VID 1 ? VID
(EQ. 8)
In most cases, each channel uses the same R ISEN value to
sense current. A more complete expression for V DROOP is
derived by combining Equations 4 and 5.
The time required for a converter running with f S = 500kHz to
make a 1.2V to 1.4V reference-voltage change is between
30 μ s and 32 μ s as calculated using Equation 8. This example
V DROOP = ------------- ---------------------- R FB
R ISEN
I OUT r DS ( ON )
2
(EQ. 6)
is also illustrated in Figure 7.
Droop is an optional feature of the ISL6569A. If active voltage
positioning is not required, simply leave the IOUT pin open.
01110
00110
VID, 5V/DIV
VID CHANGE OCCURS
REFERENCE OFFSET
Typical microprocessor tolerance windows are centered
ANYWHERE HERE
around a nominal DAC set point. Implementing a load-line
requires offsetting the output voltage above this nominal
DAC set point; centering the load-line within the static
specification window. The ISL6569A features an internal
1.2V
V REF , 100mV/DIV
100 μ A current source which feeds out the OFS pin. Placing
a resistor from OFS and ground allows the user to set the
amount of positive offset desired directly to the reference
voltage. The voltage developed across the OFS resistor,
R OFS , is divided down internally by a factor of 10 and directly
counters the DAC voltage at the error amplifier non-inverting
input. Select the resistor value based on the voltage offset
desired, V OFS , using Equation 7
V OUT , 100mV/DIV
1.2V
5 μ s/DIV
FIGURE 7. DYNAMIC-VID WAVEFORMS FOR 500kHz ISL6569A
BASED MULTI-PHASE BUCK CONVERTER
V OFS ? 10
R OFS = ---------------------------
100 μ A
12
(EQ. 7)
FN9092.2
December 29, 2004
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ISL6569ACRZ-T 功能描述:IC REG CTRLR BUCK PWM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC(0.154",3.90mm 宽) 包装:带卷 (TR)
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ISL6569CB-T 功能描述:IC REG CTRLR DIVIDER PWM 24-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:100% 电源电压:8.2 V ~ 30 V 降压:无 升压:无 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:0°C ~ 70°C 封装/外壳:8-DIP(0.300",7.62mm) 包装:管件 产品目录页面:1316 (CN2011-ZH PDF)
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