参数资料
| 型号： | ISL6265CHRTZ |
| 厂商： | Intersil |
| 文件页数： | 22/27页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR MULTI-OUTPUT 48TQFN |
| 标准包装： | 50 |
| 应用： | 控制器，AMD SVI 兼容移动式 CPU |
| 输入电压： | 5 V ~ 24 V |
| 输出数： | 3 |
| 输出电压： | 0.5 V ~ 1.55 V |
| 工作温度： | -10°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-WFQFN 裸露焊盘 |
| 供应商设备封装： | 48-TQFN-EP（6x6） |
| 包装： | 管件 |
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ISL6265C
R OCSET V OCSET
R OCSET + R BIAS
I OC ? r DS ( ON )
R OCSETNB = -------------------------------------
V O
V O ? ( 1 – D )
I P-P = ------------------------------
The resistor divider ratio used to determine the R BIAS and R OCSET
values is shown in Equation 15.
------------------------------------------------ = ----------------------- (EQ. 15)
1.17V
The resistor values must also meet the R BIAS requirement that
the total series resistance to ground equal 117k ? . An OC
condition must be sustained for 100μs before action is taken by
the controller in response to the OC fault.
A short-circuit OC loop is also active based on the same sense
elements outlined above with a threshold set to 2.25x the OCSET
threshold set. The controller takes immediate action when this
fast OC fault is detected.
NORTHBRIDGE OC DETECTION
Northbridge OC sensing is achieved via r DS(ON) sensing across the
lower MOSFET. An internal 10μA current source develops a
voltage across R OCSET_NB , which is compared with the voltage
developed across the low-side MOSFET as measured at the
PHASE pin. When the voltage drop across the MOSFET exceeds
the voltage drop across the resistor, an OC event occurs. The
OCSET_NB resistor is selected based on the relationship in
Equation 16.
(EQ. 16)
10 μ A
Where I OC is the OC trip level selected for the Northbridge
application and r DS(ON) is the drain-source ON-resistance of the
lower MOSFET.
OC FAULT RESPONSE
When an OC fault occurs on any combination of outputs, both
Core and Northbridge regulators shutdown and the driver outputs
are tri-stated. The PGOOD signal transitions low indicating a fault
condition. The controller will not attempt to restart the regulators
and the user must toggle either EN or VCC to clear the fault
condition.
Overvoltage Protection
The ISL6265C monitors the individual Core and Northbridge
value by a nominal 295mV for 205μs. The PWM outputs turn off
both Core and Northbridge internal drivers and PGOOD goes low.
General Application Design
Guide
This design guide is intended to provide a high-level explanation of
the steps necessary to design a single-phase power converter. It is
assumed that the reader is familiar with many of the basic skills
and techniques referenced in the following section. In addition to
this guide, Intersil provides complete reference designs that
include schematics, bills of materials, and example board layouts.
Selecting the LC Output Filter
The output inductor and output capacitor bank form a low-pass
filter responsible for smoothing the pulsating voltage at the
phase node. The output filter also must support the transient
energy required by the load until the controller can respond.
Because it has a low bandwidth compared to the switching
frequency, the output filter limits the system transient response.
The output capacitors must supply or sink load current while the
current in the output inductors increases or decreases to meet
the demand.
The duty cycle of an ideal buck converter is a function of the
input and the output voltage. This relationship is written as
Equation 17:
D = --------- (EQ. 17)
V IN
The output inductor peak-to-peak ripple current is written as
Equation 18:
(EQ. 18)
f SW ? L
For this type of application, a typical step-down DC/DC converter
has an I P-P of 20% to 40% of the maximum DC output load
current. The value of I P-P is selected based upon several criteria
such as MOSFET switching loss, inductor core loss, and the
resistive loss of the inductor winding. The DC copper loss of the
inductor can be estimated by Equation 19:
output voltages using differential remote sense amplifiers. The
ISL6265C features a severe overvoltage (OV) threshold of 1.8V. If
P COPPER = I LOAD
2
?
DCR
(EQ. 19)
any of the outputs exceed this voltage, an OV fault is immediately
triggered. PGOOD is latched low and the low-side MOSFETs of the
offending output(s) are turned on. The low-side MOSFETs will
remain on until the output voltage is pulled below 0.85V at which
time all MOSFETs are turned off. If the output again rises above
1.8V, the protection process repeats. This offers protection
against a shorted high-side MOSFET while preventing output
voltage from ringing below ground. The OV is reset by toggling EN
low. OV detection is active at all times that the controller is
enabled including after one of the other faults occurs so that the
processor is protected against high-side MOSFET leakage while
the MOSFETs are commanded off.
Undervoltage Protection
Where I LOAD is the converter output DC current.
The copper loss can be significant so attention must be given to
the DCR selection. Another factor to consider when choosing the
inductor is its saturation characteristics at elevated temperature.
A saturated inductor could cause destruction of circuit
components as well as nuisance OCP faults.
A DC/DC buck regulator must have output capacitance C O into
which ripple current I P-P can flow. Current I P-P develops a
corresponding ripple voltage V P-P across C O, which is the sum of
the voltage drop across the capacitor ESR and of the voltage
change stemming from charge moved in and out of the
capacitor. These two voltages are written as shown in
Equation 20:
Undervoltage protection is independent of the OC limit. A fault
latches if any of the sensed output voltages are less than the VID set
22
Δ V ESR = I PP ? E SR
(EQ. 20)
FN6976.2
January 11, 2013
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| ISL6267HRZ | IC PWM CTRLR MULTIPHASE 48TQFN |
| ISL6268CAZ | IC REG CTRLR BUCK PWM 16-QSOP |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6265CHRTZ-T | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLRS PHS W/EMBEDDED GATE 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 |
| ISL6265CIRTZ | 制造商:Intersil Corporation 功能描述:MULTI-OUTPUT CONTROLLER (SINGLE PHASE) WITH EMBEDDED GATE DR - Rail/Tube |
| ISL6265EVAL1Z | 制造商:Intersil Corporation 功能描述: |
| ISL6265HRTZ | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLRS PHS W/EMBEDDED GATE 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 |
| ISL6265HRTZ-T | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLRS PHS W/EMBEDDED GATE 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 |
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