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參數(shù)資料
| 型號： | ISL6526ACRZ |
| 廠商： | INTERSIL CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Single Synchronous Buck Pulse-Width Modulation (PWM) Controller |
| 中文描述： | 2 A SWITCHING CONTROLLER, 625 kHz SWITCHING FREQ-MAX, PQCC16 |
| 封裝： | 5 X 5 MM, PLASTIC, MO-220-VHHB, QFN-16 |
| 文件頁數(shù)： | 8/15頁 |
| 文件大?。?/td> | 340K |
| 代理商： | ISL6526ACRZ |
8
FN9055.8
March 20, 2007
If the output voltage desired is 0.8V, simply route the output
back to the FB pin through R1, but do not populate R4.
Overcurrent Protection
The overcurrent function protects the converter from a shorted
output by using the upper MOSFET on-resistance, r
DS(ON)
, to
monitor the current. This method enhances the converter’s
efficiency and reduces cost by eliminating a current sensing
resistor.
The overcurrent function cycles the soft-start function in a
hiccup mode to provide fault protection. A resistor (R
OCSET
)
programs the overcurrent trip level (see Typical Application
diagrams on pages 3 and 4). An internal 20
μ
A (typical) current
sink develops a voltage across R
OCSET
that is referenced 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.
Figure 3 illustrates the protection feature responding to an
overcurrent event. At time t0, an overcurrent condition is
sensed across the upper MOSFET. As a result, the regulator
is quickly shutdown and the internal soft-start function begins
producing soft-start ramps. The delay interval seen by the
output is equivalent to three soft-start cycles. The fourth
internal soft-start cycle initiates a normal soft-start ramp of
the output, at time T1. The output is brought back into
regulation by time T2, as long as the overcurrent event has
cleared.
Had the cause of the overcurrent still been present after the
delay interval, the overcurrent condition would be sensed
and the regulator would be shut down again for another
delay interval of three soft-start cycles. The resulting hiccup
mode style of protection would continue to repeat
indefinitely.
The overcurrent function will trip at a peak inductor current
(I
PEAK)
determined by:
I
x R
DS ON
(
)
where I
OCSET
is the internal OCSET current source (20
μ
A
typical). The OC trip point varies mainly due to the MOSFET
r
DS(ON)
variations. To avoid overcurrent tripping in the
normal operating load range, find the R
OCSET
resistor from
the equation above with:
1. The maximum r
DS(ON)
at the highest junction
temperature.
2. The minimum I
OCSET
from the specification table.
3. Determine I
PEAK
for
where
Δ
I is the output inductor ripple current.
,
For an equation for the ripple current see the section under
component guidelines titled ‘Output Inductor Selection’.
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 ISL6526, ISL6526A incorporate a MOSFET shoot-
through protection method which allows a converter to sink
current as well as source current. Care should be exercised
when designing a converter with the ISL6526, ISL6526A
when it is known that the converter may sink current.
FIGURE 2. OUTPUT VOLTAGE SELECTION
+
R1
C3
C
OUT
+3.3V
V
OUT
R4
L
OUT
ISL6526,
ISL6526A
C4
Q1
FB
UGATE
VCC
BOOT
D1
R2
C2
C1
R3
PHASE
LGATE
Q2
CPVOUT
VIN
FIGURE 3. OVERCURRENT PROTECTION RESPONSE
0V
TIME
V
OUT
(2.5V)
T1
T0
T2
INTERNAL SOFT-START FUNCTION
DELAY INTERVAL
I
PEAK
----------------------------------------------------
=
(EQ. 3)
I
PEAK
I
OUT MAX
)
I
2
(
----------
)
+
>
ISL6526, ISL6526A
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| ISL6526AEVAL1 | 功能描述:EVALUATION BOARD 1 ISL6526A RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 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 |
| ISL6526AEVAL2 | 功能描述:EVALUATION BOARD 2 ISL6526A RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 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 |
| ISL6526AIB | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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) |
| ISL6526AIB-T | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC 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) |
| ISL6526AIR | 功能描述:電壓模式 PWM 控制器 Single Synch Buck RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
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