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參數(shù)資料
| 型號(hào)： | ISL6244 |
| 廠商： | Intersil Corporation |
| 英文描述： | Multi-Phase PWM Controller(多相PWM控制器) |
| 中文描述： | 多相PWM控制器（多相脈寬調(diào)制控制器） |
| 文件頁數(shù)： | 16/25頁 |
| 文件大?。?/td> | 845K |
| 代理商： | ISL6244 |
16
FN9106.3
December 28, 2004
NOTE: Switching frequency 500kHz and R
FB
= 2.67k
.
Fault Monitoring and Protection
The ISL6244 actively monitors voltage and current feedback
to detect fault conditions. Fault monitors trigger protective
measures to prevent damage to a microprocessor load. One
common power good indication signal is provided for linking
to external system monitors. The schematic in Figure 23
outlines the interaction between the fault monitors and the
power good signal.
Power Good Signal
The power good pin (PGOOD) is an open-drain logic output
which indicates that the converter is operating properly and
the output voltage is within a set window. The under-voltage
(UV) and over-voltage (OV) comparators create the output
voltage window. The controller also takes advantage of
current feedback to detect output over-current (OC)
conditions. PGOOD pulls low during shutdown and releases
high during soft-start once the output voltage reaches the
DAC level. Once high, PGOOD will only transition low when
the controller is disabled or a fault condition is detected. It
will return high under certain circumstances once a fault
clears.
Under-Voltage Protection
The voltage on V
DIFF
is internally offset by 350mV before it
is compared with the DAC reference voltage. By positively
offsetting the output voltage, an UV threshold is created
which moves relative to the VID code. During soft-start, the
slow rising output voltage eventually exceeds the UV
threshold. If a fault condition arises during operation and the
output voltage drops below the UV threshold, PGOOD will
immediately pull low, but converter operation will continue.
PGOOD will return high once the output voltage again
reaches regulation.
If the ISL6244 is disabled during operation, the PGOOD
signal will not pull low until the output voltage decays below
the UV threshold.
Over-Voltage Protection
When the output of the differential amplifier (VDIFF) reaches
2.2V, PGOOD immediately goes low indicating a fault. Two
protective actions are taken by the ISL6244 to protect the
microprocessor load.
All PWM outputs are commanded low, directing the Intersil
drivers to turn on the lower MOSFETs. This shunts the
output to ground preventing any further increase in output
voltage. The PWM outputs remain low until VDIFF falls to the
programmed DAC level at which time they go into a high-
impedance state. The Intersil drivers respond by turning off
both upper and lower MOSFETs. If the over-voltage
condition recurs, the ISL6244 will again command the lower
MOSFETs to turn on. The ISL6244 will continue to protect
the load in this fashion as long as the over-voltage repeats.
Once an over-voltage condition is detected, normal PWM
operation ceases and PGOOD remains low until the
ISL6244 is reset. Cycling the voltage on EN below 1.23V or
the bias to VCC below the POR-falling threshold will reset
the controller.
Over-Current Protection
The ISL6244 monitors individual channel current to detect an
over-current condition. Each channel current is continually
compared with a constant 85
μ
A reference current. Once any
of the currents exceeds the reference current, the comparator
triggers the converter to shutdown. The POR circuit places all
PWM signals in a high-impedance state which commands the
drivers to turn off both upper and lower MOSFETs. PGOOD
pulls low and the system remains in this state while the
controller counts 2048 phase clock cycles. This is followed by
a soft-start attempt (see
Soft-Start
).
FIGURE 22. SOFT-START WAVEFORMS FOR ISL6244 BASED
MULTI-PHASE BUCK CONVERTER
1ms/DIV
EN, 5V/DIV
VOUT, 500mV/DIV
t
DELAY
t
RAMP1
t
RAMP2
FIGURE 23. POWER GOOD AND PROTECTION CIRCUITRY
POR
CIRCUIT
-
+
2.2V
VDIFF
-
+
85
μ
A
I
CHx
-
+
DAC
REFERENCE
OV
OC
UV
350mV
-
PGOOD
+
ISL6244
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL6244CR | 功能描述:IC REG CTRLR BUCK PWM 32-QFN RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
| ISL6244CR-T | 功能描述:IC REG CTRLR BUCK PWM 32-QFN RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
| ISL6244CRZ | 功能描述:電流型 PWM 控制器 VER OF ISL6244CR RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL6244CRZ-T | 功能描述:電流型 PWM 控制器 VER OF ISL6244CR-T RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| ISL6244EVAL1 | 功能描述:EVALUATION BOARD ISL6244 RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評(píng)估板 - DC/DC 與 AC/DC（離線）SMPS 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:True Shutdown™ 主要目的:DC/DC，步升 輸出及類型:1，非隔離 功率 - 輸出:- 輸出電壓:- 電流 - 輸出:1A 輸入電壓:2.5 V ~ 5.5 V 穩(wěn)壓器拓?fù)浣Y(jié)構(gòu):升壓 頻率 - 開關(guān):3MHz 板類型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
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