参数资料
型号: ISL6554CB-T
厂商: Intersil
文件页数: 12/16页
文件大小: 0K
描述: IC PWM CORE VOLTAGE REG 20-SOIC
标准包装: 1,000
应用: 控制器,Intel Itanium?
输入电压: 4.75 V ~ 5.25 V
输出数: 4
输出电压: 0.95 V ~ 1.7 V
工作温度: 0°C ~ 70°C
安装类型: 表面贴装
封装/外壳: 20-SOIC(0.295",7.50mm 宽)
供应商设备封装: 20-SOIC W
包装: 带卷 (TR)
ISL6554
resistor R T . To avoid pickup by the FS/DIS pin, it is important
to place this resistor next to the pin.
25
20
15
10
5
0
FIGURE 8. TWO CHANNEL MULTI-PHASE SYSTEM WITH
CURRENT BALANCING DISABLED
25
Layout Considerations
MOSFETs switch very fast and efficiently. The speed with
which the current transitions from one device to another
causes voltage spikes across the interconnecting impedances
and parasitic circuit elements. These voltage spikes can
degrade efficiency, radiate noise into the circuit and lead to
device overvoltage stress. Careful component layout and
printed circuit design minimizes the voltage spikes in the
converter. Consider, as an example, the turnoff transition of
the upper PWM MOSFET. Prior to turnoff, the upper MOSFET
was carrying channel current. During the turnoff, current stops
flowing in the upper MOSFET and is picked up by the lower
MOSFET. Any inductance in the switched current path
generates a large voltage spike during the switching interval.
Careful component selection, tight layout of the critical
components, and short, wide circuit traces minimize the
magnitude of voltage spikes. Contact Intersil for evaluation
board drawings of the component placement and printed
circuit board.
20
where I LT
Then: R ISEN
15
10
5
0
FIGURE 9. TWO CHANNEL MULTI-PHASE SYSTEM WITH
CURRENT BALANCING ENABLED
As discussed previously, the voltage drop across each Q2
transistor at the point in time when current is sampled is r DSON
(Q2) x I SAMPLE . The voltage at Q2’s drain, the PHASE node,
is applied through the R ISEN resistor to the ISL6554 ISEN pin.
This pin is held at virtual ground, so the current into ISEN is:
I SENSE = I SAMPLE x r DS(ON) (Q2) / R ISEN .
R Isen = I SAMPLE x r DS(ON) (Q2) / 50 μ A
Example: From the previous conditions,
= 100A,
I SAMPLE = 25.49A,
r DS(ON) (Q2) = 4m ?
= 2.04K and
I CURRENT TRIP = 165%
There are two sets of critical components in a DC-DC
converter using a ISL6554 controller and a HIP6601 gate
driver. The power components are the most critical because
they switch large amounts of energy. Next are small signal
components that connect to sensitive nodes or supply critical
bypassing current and signal coupling.
The power components should be placed first. Locate the
input capacitors close to the power switches. Minimize the
length of the connections between the input capacitors, C IN ,
and the power switches. Locate the output inductors and
output capacitors between the MOSFETs and the load.
Locate the gate driver close to the MOSFETs.
The critical small components include the bypass capacitors for
VCC and PVCC on the gate driver ICs. Locate the bypass
capacitor, C BP , for the ISL6554 controller close to the device. It
is especially important to locate the resistors associated with
the input to the amplifiers close to their respective pins, since
they represent the input to feedback amplifiers. Resistor R T ,
that sets the oscillator frequency should also be located next to
the associated pin. It is especially important to place the R SEN
resistors at the respective terminals of the ISL6554.
A multi-layer printed circuit board is recommended. Figure 11
shows the connections of the critical components for one
output channel of the converter. Note that capacitors C IN and
C OUT could each represent numerous physical capacitors.
Dedicate one solid layer, usually the middle layer of the PC
Short circuit I LT
= 165A.
board, for a ground plane and make all critical component
Channel Frequency Oscillator
The channel oscillator frequency is set by placing a resistor,
R T , to ground from the FS/DIS pin. Figure 10 is a curve
showing the relationship between frequency, F SW , and
12
ground connections with vias to this layer. Dedicate another
solid layer as a power plane and break this plane into smaller
islands of common voltage levels. Keep the metal runs from
the PHASE terminal to output inductor short. The power plane
should support the input power and output power nodes. Use
FN9003.3
February 11, 2005
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ISL6554CBZA-T 功能描述:IC PWM CORE VOLTAGE REG 20-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源,ICERA E400,E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA,WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR)
ISL6554CBZ-T 功能描述:IC PWM CORE VOLTAGE REG 20-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源,ICERA E400,E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA,WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR)