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参数资料
| 型号： | ISL9104AIRUFEVAL1Z |
| 厂商： | Intersil |
| 文件页数： | 10/14页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD 1 FOR ISL9104AIRUF |
| 标准包装： | 1 |
| 系列： | * |
ISL9104, ISL9104A
The PWM operation is initialized by the clock from the oscillator.
The P-Channel MOSFET is turned on at the beginning of a PWM
cycle and the current in the P-Channel MOSFET starts ramping
up. When the sum of the CSA output and the compensation
slope reaches the control reference of the current loop, the PWM
comparator COMP sends a signal to the PWM logic to turn off the
P-Channel MOSFET and to turn on the N-Channel MOSFET. The
N-MOSFET remains on till the end of the PWM cycle. Figure 24
shows the typical operating waveforms during the normal PWM
operation. The dotted lines illustrate the sum of the slope
compensation ramp and the CSA output.
v EAMP
v CSA
d
i L
v OUT
FIGURE 24. PWM OPERATION WAVEFORMS
The output voltage is regulated by controlling the reference
voltage to the current loop. The bandgap circuit outputs a 0.8V
reference voltage to the voltage control loop. The feedback signal
comes from the FB pin. The soft-start block only affects the
operation during the start-up and will be discussed separately in
amplifier, which converts the voltage error signal to a current
output. The voltage loop is internally compensated by a RC
network. The maximum EAMP voltage output is precisely
clamped to the bandgap voltage.
Skip Mode (PFM Mode)
Under light load condition, ISL9104, ISL9104A automatically
enters a pulse-skipping mode to minimize the switching loss by
reducing the switching frequency. Figure 25 illustrates the skip
mode operation. A zero-cross sensing circuit (as shown in Figure
23) monitors the current flowing through SW node for zero
crossing. When it is detected to cross zero for 16-consecutive
cycles, the regulator enters the skip mode. During the 16-
consecutive cycles, the inductor current could be negative. The
counter is reset to zero when the sensed current flowing through
SW node does not cross zero during any cycle within the 16-
consecutive cycles. Once ISL9104, ISL9104A enters the skip
mode, the pulse modulation starts being controlled by the SKIP
comparator shown in Figure 23. Each pulse cycle is still
synchronized by the PWM clock. The P-Channel MOSFET is turned
on at the rising edge of clock and turned off when its current
reaches ~20% of the peak current limit. As the average inductor
current in each cycle is higher than the average current of the
load, the output voltage rises cycle over cycle. When the output
voltage is sensed to reach 1.5% above its nominal voltage, the
P-Channel MOSFET is turned off immediately and the inductor
current is fully discharged to zero and stays at zero. The output
voltage reduces gradually due to the load current discharging the
output capacitor. When the output voltage drops to the nominal
voltage, the P-Channel MOSFET will be turned on again,
repeating the previous operations.
The regulator resumes normal PWM mode operation when the
output voltage is sensed to drop below 1.5% of its nominal
voltage value.
Enable
The enable (EN) pin allows user to enable or disable the converter
for purposes such as power-up sequencing. With EN pin pulled to
high, the converter is enabled and the internal reference circuit
wakes up first and then the soft start-up begins. When EN pin is
pulled to logic low, the converter is disabled, both P-Channel
MOSFET and N-Channel MOSFETS are turned off, and the output
capacitor is discharged through internal discharge path.
16 CYCLES
CLOCK
20% PEAK CURRENT LIMIT
I L
0
1.015*V OUT_NOMINAL
V OUT
V OUT_NOMINAL
FIGURE 25. SKIP MODE OPERATION WAVEFORMS
10
FN6829.5
September 21, 2011
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| ISL9104AIRUFZ-T | 功能描述:IC REG BUCK SYNC 2.5V 0.5A 6TDFN 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 |
| ISL9104AIRUFZ-T7A | 功能描述:IC REG BUCK SYNC 2.5V 0.5A 6TDFN 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 |
| ISL9104AIRUJZ-T | 功能描述:IC REG BUCK SYNC 2.8V .5A 6UTDFN 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 |
| ISL9104AIRUJZ-T7A | 功能描述:IC REG BUCK SYNC 2.8V 0.5A 6TDFN 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 |
| ISL9104AIRUNEVAL1Z | 功能描述:EVAL BOARD 1 FOR ISL9104AIRUN RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
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