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参数资料
| 型号： | ISL8118CRZ |
| 厂商： | Intersil |
| 文件页数： | 12/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 28-QFN |
| 标准包装： | 60 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 2MHz |
| 占空比： | 100% |
| 电源电压： | 2.97 V ~ 22 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 28-VFQFN 裸露焊盘 |
| 包装： | 管件 |
| 产品目录页面： | 1244 (CN2011-ZH PDF) |
ISL8118
R BSOC = ------------------------------------------------------------------------------------
? I
+ ----- ? ? r
? OC_SOURCE 2 ?
I BSOC ? N B
VDIFF
+15%
+9%
V REF_MARG
-9%
-15%
parallel with R BSOC to prevent on chip parasitics from
impacting the accuracy of the OCP measurement .
Simple Bottom Side OCP Equation
I OC_SOURCE ? r DS ( ON ) Botside
100 μ A
Detailed Bottom Side OCP Equations
Δ I
DS ( ON ) B
R BSOC = -------------------------------------------------------------------------------------
GOOD
GOOD
V IN - V OUT V OUT
UV
OV
UV
Δ I = -------------------------------- ? ----------------
F S L V IN
T PGDLY = C PGDLY ? ---------------
I OC_SINK = ---------------------------------------------------------- – -----
r DS ( ON ) B
R TSOC = --------------------------------------------------------------------
? I
+ ----- ? ? r
? OC_SOURCE 2 ?
I TSOC ? N T
FIGURE 3. UNDERVOLTAGE-OVERVOLTAGE WINDOW
1.5V
30 μ A
Undervoltage and Overvoltage Protection
The Undervoltage (UV) and Overvoltage (OV) protection
circuitry compares the voltage on the VDIFF pin with the
reference that tracks with the margining circuitry to prevent
accidental tripping. UV and OV functionality is not enabled
until the end of soft-start.
An OV event is detected asynchronously and causes the top
side MOSFET to turn off, the bottom side MOSFET to turn
on (effectively a 0% duty cycle), and PGOOD to pull low. The
regulator stays in this state and overrides sourcing and
sinking OCP protections until the OV event is cleared.
A UV event is detected asynchronously and results in the
PGOOD pulling low.
Overcurrent Protection
The ISL8118 monitors both the top side MOSFET and bottom
side MOSFET for overcurrent events. Dual sensing allows the
ISL8118 to detect overcurrent faults at the very low and very
high duty cycles that can result from the ISL8118’s wide input
range. The OCP function is enabled with the drivers at start-up
and detects the peak current during each sensing period. A
resistor and a capacitor between the BSOC pin and GND set
the bottom side source and sinking current limits. A 100μA
current source develops a voltage across the resistor which is
then compared with the voltage developed across the bottom
side MOSFET at conduction mode. The measurement
comparator uses offset correcting circuitry to provide precise
current measurements with roughly ±2mV of offset error. An
~120ns blanking period, implemented on the upper and lower
MOSFET current sensing circuitries, is used to reduce the
current sampling error due to the leading-edge switching noise.
An additional 120ns low pass filter is used to further reduce
measurement error due to noise. In sourcing current
applications, the BSOC voltage is inverted and compared with
the voltage across the MOSFET while on. When this voltage
exceeds the BSOC set voltage, a sourcing OCP fault is
triggered. A 1000pF or greater filter capacitor should be used in
12
I BSOC ? N B ? R BSOC Δ I
2
N B = Number of Bottom side MOSFETs
The ISL8118’s sinking current limit is set to the same voltage
as its sourcing limit. In sinking applications, when the voltage
across the MOSFET is greater than the voltage developed
across the resistor (RBSOC) a sinking OCP event is
triggered. To avoid non-synchronous operation at light load,
the peak-to-peak output inductor ripple current should not be
greater than twice of the sinking current limit.
The top side sourcing current limit is set by connecting the
TSOC pin with a resistor (R TSOC ) and a capacitor to the drain
of the top side MOSEFT. A 100μA current source develops a
voltage across the resistor which is then compared with the
voltage developed across the top side MOSFET while on.
When the voltage drop across the MOSFET exceeds the
voltage drop across the resistor, a sourcing OCP event
occurs. A 1000pF or greater filter capacitor should be used in
parallel with R TSOC to prevent on chip parasitics from
impacting the accuracy of the OCP measurement and to
smooth the voltage across R TSOC in the presence of
switching noise on the input bus.
Sourcing OCP faults cause the regulator to disable (TGATE
and BGATE drives pulled low, PGOOD pulled low, soft-start
capacitor discharged) itself for a fixed period of time after which
a normal soft-start sequence is initiated. The period of time the
regulator waits before attempting a soft-start sequence is set by
three charge and discharge cycles of the soft-start capacitor.
Simple Top Side OCP Equation
I OC_SOURCE ? r DS ( ON ) T
100 μ A
Detailed Top Side OCP Equation
Δ I
DS ( ON ) T
R TSOC = -------------------------------------------------------------------------------------
N T = Number of top side MOSFETs
FN6325.2
November 29, 2012
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| ISL8118CRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 28-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) |
| ISL8118EVAL1Z | 功能描述:EVALUATION BOARD FOR ISL8118 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ISL8118IRZ | 功能描述:IC REG CTRLR BUCK PWM VM 28-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:75 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.3 V ~ 13.5 V 降压:是 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:0°C ~ 70°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:管件 产品目录页面:1051 (CN2011-ZH PDF) 其它名称:296-2543-5 |
| ISL8118IRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 28-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) |
| ISL8120 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual/n-Phase Buck PWM Controller with Integrated Drivers |
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