参数资料
| 型号： | ISL62881CIRTZ |
| 厂商： | Intersil |
| 文件页数： | 17/37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： | 4.5 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： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 管件 |
| 配用： | ISL62881CCPUEVAL2Z-ND - EVAL BOARD ISL62881CCPU 28QFN |
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ISL62881C, ISL62881D
ISL62881C monitors the VSEN pin voltage and compares
it to 100ns filtered version. When the unfiltered version is
20mV below the filtered version, the controller knows
there is a fast voltage dip due to load insertion, hence
issues an additional master clock signal to deliver a PWM
pulse immediately.
The R 3? modulator intrinsically has voltage feed
forward. The output voltage is insensitive to a fast slew
rate input voltage change.
Protections
The ISL62881C provides overcurrent, undervoltage,
and overvoltage protections.
The ISL62881C 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 ISL62881C 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.
TABLE 3. ISL62881C OCP THRESHOLD AND
OVERSHOOT REDUCTION FUNCTION
referred to as PGOOD overvoltage protection. If the
output voltage exceeds the VID set value by +200mV for
1ms, the ISL62881C will declare a fault and de-assert
PGOOD.
The ISL62881C takes the same actions for all of the
above fault protections: de-assertion of PGOOD and
turn-off of the high-side and low-side power MOSFETs.
Any residual inductor current will decay through the
MOSFET body diodes. These fault conditions can be reset
by bringing VR_ON low or by bringing V DD below the
POR threshold. When VR_ON and V DD return to their
high operating levels, a soft-start will occur.
The second level of overvoltage protection is different. If
the output voltage exceeds 1.55V, the ISL62881C will
immediately declare an OV fault, de-assert PGOOD, and
turn on the low-side power MOSFETs. The low-side power
MOSFETs remain on until the output voltage is pulled
down below 0.85V when all power MOSFETs are turned
off. If the output voltage rises above 1.55V again, the
protection process is repeated. This behavior provides
the maximum amount of protection against shorted
high-side power MOSFETs while preventing output
ringing below ground. Resetting VR_ON cannot clear the
1.55V OVP. Only resetting V DD will clear it. The 1.55V
OVP is active all the time when the controller is enabled,
even if one of the other faults have been declared. This
ensures that the processor is protected against high-side
power MOSFET leakage while the MOSFETs are
MIN
(k Ω )
305
R comp
NOMINAL
(k Ω )
none
400
MAX
(k Ω )
none
410
OCP
THRESHOLD
(μA)
60
68
OVERSHOOT
REDUCTION
FUNCTION
Disabled
commanded off.
Table 4 summarizes the fault protections.
TABLE 4. FAULT PROTECTION SUMMARY
FAULT
DURATION
205
155
235
165
240
170
62
54
FAULT TYPE
BEFORE
PROTECTION
PROTECTION
ACTION
FAULT
RESET
104
78
62
45
120
85
66
50
130
90
68
55
60
68
62
54
Enabled
Overcurrent
Way-Overcurrent
(2.5xOC)
Overvoltage
+200mV
120μs
<2μs
1ms
PWM tri-state, VR_ON
PGOOD latched toggle or
low VDD
toggle
The default OCP threshold is the value when R comp is
not populated. It is recommended to scale the droop
Undervoltage -
300mV
current 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.
For overcurrent condition above 2.5x the OCP level, the
PWM output will immediately shut off and PGOOD will go
low to maximize protection. This protection is also
referred to as way-overcurrent protection or
Overvoltage 1.55V Immediately
Low-side
MOSFET on
until V core
<0.85V, then
PWM tri-state,
PGOOD latched
low.
VDD
toggle
fast-overcurrent protection, for short-circuit protections.
The ISL62881C will declare undervoltage (UV) fault and
latch off if the output voltage is less than the VID set
value by 300mV or more for 1ms. It’ll turn off the PWM
output and de-assert PGOOD.
Current Monitor
The ISL62881C provides the current monitor function.
The IMON pin outputs a high-speed analog current
source that is 3 times of the droop current flowing out of
the FB pin. Thus as shown by Equation 6.
The ISL62881C has two levels of overvoltage
protections. The first level of overvoltage protection is
17
I IMON = 3 × I droop
(EQ. 6)
FN7596.0
March 8, 2010
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相关代理商/技术参数 |
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|---|---|
| ISL62881CIRTZ-T | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY 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 |
| ISL62881D | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Single-Phase PWM Regulator for IMVP-6.5a?￠ Mobile CPUs and GPUs |
| ISL62881DHRTZ | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 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 |
| ISL62881DHRTZ-T | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 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 |
| ISL62881HRTZ | 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 |
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