参数资料
型号: ISL6522ACR
厂商: Intersil
文件页数: 7/13页
文件大小: 0K
描述: IC REG CTRLR BST PWM VM 16-QFN
标准包装: 60
PWM 型: 电压模式
输出数: 1
频率 - 最大: 1MHz
占空比: 100%
电源电压: 10.8 V ~ 13.2 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: 25°C ~ 70°C
封装/外壳: 16-VQFN 裸露焊盘
包装: 管件
ISL6522A
I OCSET ? R OCSET
I PEAK = ---------------------------------------------------
is reference to V IN . When the voltage across the upper
MOSFET (also referenced to V IN ) exceeds the voltage
across R OCSET , the overcurrent function initiates a soft-start
sequence. The soft-start function discharges C SS with a
10 μ A current sink and inhibits PWM operation. The soft-start
function recharges C SS , and PWM operation resumes with
the error amplifier clamped to the SS voltage. Should an
overload occur while recharging C SS , the soft-start function
inhibits PWM operation while fully charging C SS to 4V to
complete its cycle. Figure 4 shows this operation with an
overload condition. Note that the inductor current increases
to over 15A during the C SS charging interval and causes an
overcurrent trip. The converter dissipates very little power
with this method. The measured input power for the
conditions of Figure 4 is 2.5W.
The overcurrent function will trip at a peak inductor current
(I PEAK) determined by:
r DS ( ON )
where I OCSET is the internal OCSET current source (200 μ A
is typical). The OC trip point varies mainly due to the
MOSFETs r DS(ON) variations. To avoid overcurrent tripping
in the normal operating load range, find the R OCSET resistor
from the equation above with:
The maximum r DS(ON) at the highest junction temperature.
1. The minimum I OCSET from the specification table.
2. Determine I PEAK for I PEAK > I OUT ( MAX ) + ( ? I ) ? 2 ,
where ? I is the output inductor ripple current.
capacitors, damage may occur to these parts. If the bias
voltage for the ISL6522A comes from the V IN rail, then the
maximum voltage rating of the ISL6522A may be exceeded
and the IC will experience a catastrophic failure and the
converter will no longer be operational. Ensuring that there is a
path for the current to follow other than the capacitance on the
rail will prevent these failure modes.
Application Guidelines
Layout Considerations
As in any high frequency switching converter, layout is very
important. Switching current from one power device to
another can generate voltage transients across the
impedances of the interconnecting bond wires and circuit
traces. These interconnecting impedances should be
minimized by using wide, short printed circuit traces. The
critical components should be located as close together as
possible using ground plane construction or single point
grounding.
Figure 5 shows the critical power components of the
converter. To minimize the voltage overshoot the
interconnecting wires indicated by heavy lines should be part
of ground or power plane in a printed circuit board. The
components shown in Figure 6 should be located as close
together as possible. Please note that the capacitors C IN
and C O each represent numerous physical capacitors.
Locate the ISL6522A within three inches of the MOSFETs,
Q1 and Q2. The circuit traces for the MOSFETs’ gate and
source connections from the ISL6522A must be sized to
handle up to 1A peak current.
For an equation for the ripple current see the section under
component guidelines titled Output Inductor Selection .
ISL6522A
V IN
A small ceramic capacitor should be placed in parallel with
R OCSET to smooth the voltage across R OCSET in the
presence of switching noise on the input voltage.
Current Sinking
The ISL6522A incorporates a MOSFET shoot-through
UGATE
PHASE
LGATE
PGND
Q1
Q2
D2
C IN
L O
C O
V OUT
protection method which allows a converter to sink current
as well as source current. Care should be exercised when
designing a converter with the ISL6522A when it is known
that the converter may sink current.
When the converter is sinking current, it is behaving as a boost
converter that is regulating its input voltage. This means that
the converter is boosting current into the V IN rail, the voltage
that is being down-converted. If there is nowhere for this current
to go, such as to other distributed loads on the V IN rail, through
a voltage limiting protection device, or other methods, the
capacitance on the V IN bus will absorb the current. This
situation will cause the voltage level of the V IN rail to increase. If
the voltage level of the rail is boosted to a level that exceeds the
maximum voltage rating of the MOSFETs or the input
7
RETURN
FIGURE 5. PRINTED CIRCUIT BOARD POWER AND
GROUND PLANES OR ISLANDS
Figure 6 shows the circuit traces that require additional
layout consideration. Use single point and ground plane
construction for the circuits shown. Minimize any leakage
current paths on the SS PIN and locate the capacitor, C SS
close to the SS pin because the internal current source is
only 10 μ A. Provide local V CC decoupling between VCC and
GND pins. Locate the capacitor, C BOOT as close as practical
to the BOOT and PHASE pins.
FN9122.2
April 13, 2005
相关PDF资料
PDF描述
ISL6522ACB-T IC REG CTRLR BST PWM VM 14-SOIC
ISL6522ACB IC REG CTRLR BST PWM VM 14-SOIC
VI-J4T-EY-F4 CONVERTER MOD DC/DC 6.5V 50W
X4043PZ-2.7 IC SUPERVISOR CPU 4K EE 8-DIP
RBM28DRKN-S13 CONN EDGECARD 56POS .156 EXTEND
相关代理商/技术参数
参数描述
ISL6522ACR-T 功能描述:IC REG CTRLR BST PWM VM 16-QFN 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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522BCB 功能描述:IC REG CTRLR BST PWM VM 14-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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522BCB-T 功能描述:IC REG CTRLR BST PWM VM 14-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:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6522BCBZ 功能描述:IC REG CTRLR BST PWM VM 14-SOIC 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
ISL6522BCBZ-T 功能描述:IC REG CTRLR BST PWM VM 14-SOIC 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)