参数资料
| 型号： | ISL9111EH30Z-T |
| 厂商： | Intersil |
| 文件页数： | 8/15页 |
| 文件大小： | 0K |
| 描述： | IC VOLTAGE REGULATOR |
| 标准包装： | 3,000 |
| 系列： | * |
ISL9111, ISL9111A
Typical Application Circuits (Continued)
4.7μH
100
V IN = 4.2V
V IN
4.7μF
6
3
1
SW
VIN
EN
VOUT
FB
5
4
V OUT
5.25V
4.7μF
923k
90 V IN = 3.6V
80
70
60
V IN = 1.8V
V IN = 1.5V
GND
2
166k
50
V IN = 0.9V
ISL9111, ISL9111A - ADJ
40
0.1
1.0
10
I OUT (mA)
100
1000
FIGURE 5A. POWER SUPPLY SOLUTION FOR 5.25V OUTPUT VOLTAGE
Detailed Description
Current Mode PWM Operation
The control scheme of the device is based on the peak current
mode control, and the control loop is compensated internally.
The peak current of the N-channel MOSFET switch is sensed to
limit the maximum current flowing through the switch and the
inductor. The typical current limit is set to 1A.
The control circuit includes ramp generator, slope compensator,
and page 3). The ramp signal is derived from the inductor
current. This ramp signal is then compared to the error amplifier
output to generate the PWM gating signals for driving both
N-channel and P-channel MOSFETs. The PWM operation is
initialized by the clock from the internal oscillator (typical
1.2MHz). The N-channel MOSFET is turned on at the beginning of
a PWM cycle, the P-channel MOSFET remains off, and the current
starts ramping up. When the sum of the ramp and the slope
compensator output reaches the error amplifier output voltage,
the PWM comparator outputs a signal to turn off the N-channel
MOSFET. Here, both MOSFETs remain off during the dead-time
interval, and then the P-channel MOSFET is turned on and
remains on until the end of this PWM cycle. During this time, the
inductor current ramps down until the next clock. At this point,
following a short dead time, the N-channel MOSFET is again
turned on, repeating as previously described.
Skip Mode Operation
The device is capable of operating in two different modes. When
the inductor current is sensed to cross zero for eight consecutive
times, the converter enters skip mode. In skip mode, each pulse
cycle is still synchronized by the PWM clock. The N-channel
MOSFET is turned on at the rising edge of the clock and turned
off when the inductor peak current reaches typically 25% of the
current limit. Then the P-channel MOSFET is turned on, and it
stays on until its current goes to zero. Subsequently, both
N-channel and P-channel MOSFETs are turned off until the next
clock cycle starts, at which time the N-channel MOSFET is turned
on again. When V OUT is 1.5% typically higher than the nominal
output voltage, the N-channel MOSFET is immediately turned off
and the P-channel MOSFET is turned on until the inductor current
8
FIGURE 5B. EFFICIENCY AT V OUT = 5.25V
goes to zero. The N-channel MOSFET resumes operation when
V FB falls back to its nominal value, repeating the previous
operation. The converter returns to 1.2MHz PWM mode
operation when V FB drops 1.5% below its nominal voltage.
Given the skip mode algorithm incorporated in the ISL9111 and
ISL9111A, the average value of the output voltage is
approximately 0.75% higher than the nominal output voltage
under PWM operation. This positive offset improves the load
transient response when switching from skip mode to PWM
mode operation. The ripple on the output voltage is typically
1.5%*V OUT (nominal) when input voltage is sufficiently lower than
output voltage, and it increases as input voltage approaches
output voltage. Figure 9 shows the ripple voltage versus input
voltage.
Synchronous Rectifier
The ISL9111 and ISL9111A integrate one N-channel MOSFET
and one P-channel MOSFET to realize synchronous boost
converters. Because the commonly used discrete Schottky
rectifier is replaced with the low r DS(ON) P-channel MOSFET, the
power conversion efficiency reaches a value above 90%. Since a
typical step-up converter has a conduction path from the input to
the output via the body diode of the P-channel MOSFET, a special
circuit (see Block Diagrams on page 2 and page 3) is used to
reverse the polarity of the P-channel body diode when the part is
shut down. This configuration completely disconnects the load
from the input during shutdown of the converter. The benefit of
this feature is that the battery will not be completely depleted
during shutdown of the converter. No additional components are
needed to disconnect the battery from the output of the
converter.
Minimum Startup and Minimum Operating
Voltage
The ISL9111 and ISL9111A address applications with
rechargeable and non-rechargeable battery cells.
1. The ISL9111 has a UVLO feature. The part can start up with a
0.8V typical input voltage and internally shut off when the
battery drops below 0.7V to protect a rechargeable battery
from over-discharge.
FN7602.4
June 4, 2012
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相关代理商/技术参数 |
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| ISL9111EH30Z-T7A | 功能描述:IC REG BOOST SYNC 3V 1A 6SOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:1 系列:EZBuck™ 类型:降压（降压） 输出类型:可调式 输出数:1 输出电压:0.8 V ~ 22.1 V 输入电压:3 V ~ 26 V PWM 型:电流模式 频率 - 开关:1.5MHz 电流 - 输出:1.8A 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-WFDFN 裸露焊盘 包装:剪切带 (CT) 供应商设备封装:8-DFN（2x2） 其它名称:785-1276-1 |
| ISL9111EH33Z-T | 功能描述:IC VOLTAGE REGULATOR RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:* 标准包装:50 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:5 V ~ 25 V 输入电压:2.3 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:600kHz，1.2MHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 包装:管件 供应商设备封装:8-MSOP |
| ISL9111EH33Z-T7A | 功能描述:IC REG BST SYNC 3.3V 1A 6SOT23-6 RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:1 系列:EZBuck™ 类型:降压（降压） 输出类型:可调式 输出数:1 输出电压:0.8 V ~ 22.1 V 输入电压:3 V ~ 26 V PWM 型:电流模式 频率 - 开关:1.5MHz 电流 - 输出:1.8A 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-WFDFN 裸露焊盘 包装:剪切带 (CT) 供应商设备封装:8-DFN（2x2） 其它名称:785-1276-1 |
| ISL9111EH50Z-T | 功能描述:IC VOLTAGE REGULATOR RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:* 标准包装:50 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:5 V ~ 25 V 输入电压:2.3 V ~ 5.5 V PWM 型:电流模式 频率 - 开关:600kHz，1.2MHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 包装:管件 供应商设备封装:8-MSOP |
| ISL9111-EH50Z-T7A | 制造商:Intersil Corporation 功能描述: |
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