參數(shù)資料
型號(hào)： ISL88550A
廠商： Intersil Corporation
英文描述： Synchronous Step Down Controller with Sourcing and Sinking LDO Regulator
中文描述： 同步降壓控制器，具有采購(gòu)和下沉LDO穩(wěn)壓器
文件頁(yè)數(shù)： 15/25頁(yè)
文件大小： 928K
代理商： ISL88550A
15
FN6168.0
October 12, 2005
FIGURE 23. ADJUSTABLE CURRENT LIMIT THRESHOLD
FIGURE 24.
VALLEY CURRENT-LIMIT THRESHOLD
POR, UVLO, and Soft-Start
Internal Power-on reset (POR) occurs when AV
DD
rises
above approximately 2V, resetting the fault latch and the
soft-start counter, powering up the reference, and preparing
the Buck Regulator for operation. Until AV
DD
reaches 4.25V
(typical), AV
DD
undervoltage lockout (UVLO) circuitry inhibits
switching. The controller inhibits switching by pulling UGATE
low and holding LGATE low when OVP and shutdown
discharge are disabled (OVP/UVP = REF or GND) or forcing
LGATE high when OVP and shutdown discharge are
enabled (OVP/UVP = AV
DD
or OPEN). See Table 3 for
detailed truth table for OVP/UVP and Shutdown settings.
When AV
DD
rises above 4.25V, the controller activates the
Buck Regulator and initializes the internal soft start. The
Buck Regulator’s internal soft-start allows a gradual increase
of the current limit level during startup to reduce the input
surge currents. The ISL88550A divides the soft-start period
into five phases. During the first phase, the controller limits
the current limit to only 20% of the full current limit. If the
output does not reach regulation within 425μs, soft start
enters the second phase, and the current limit is increased
by another 20%. This process repeats until the maximum
current limit is reached, after 1.7ms, or when the output
reaches the nominal regulation voltage, whichever occurs
first. Adding a capacitor in parallel with the external ILIM
resistors creates a continuously adjustable analog soft-start
function for the Buck Regulator’s output.
For most applications, LDO soft start is not necessary
because of output charging current is limited to
approximately 3.0A. For 20μF LDO output capacitors, the
minimum rise time is about 30μs. However, soft start in the
LDO section can be realized by tying a capacitor between
the SS pin and ground. When STBY# is driven low, or during
thermal shutdown of the LDO’s, the SS capacitor is
discharged. When STBY# is driven high or when the thermal
limit is removed, an internal 4μA (typ) current charges the
SS capacitor. The resulting linear ramp voltage on SS
linearly increases the current-limit comparator thresholds to
both the VTT and VTTR outputs, until full current limit is
attained when SS reaches approximately 1.6V. This lowering
of the current limit during start-up limits the initial in-rush
current peaks, particularly when driving higher output
capacitances. For good tracking, choose the value of the SS
cap less than 390pF. Leave SS floating to disable the soft-
start feature.
Power OK (POK1)
POK1 is an open-drain output for a window comparator that
continuously monitors V
OUT
. POK1 is actively held low when
SHDNA# is low and during the Buck Regulator outputs soft-
start. After the digital soft-start terminates, POK1 becomes
high impedance as long as the output voltage is within ±10%
of the nominal regulation voltage set by FB. When V
OUT
+
-
+
-
VDD-1V
1.0V
LX
ILIM
ISL88550A
REF
9R
R
RA
RB
CILIM
CREF
ILIMIT
ILOAD
IPEAK
I
ILOAD(MAX)
I
I
LIM VAL
)
I
LOAD
I
2
-----
–
=
ISL88550A
相關(guān)PDF資料
PDF描述
ISL88550AIRZ Synchronous Step Down Controller with Sourcing and Sinking LDO Regulator
ISL88550AIRZ-T Synchronous Step Down Controller with Sourcing and Sinking LDO Regulator
ISL88694 Octal Transparent D-Type Latches With 3-State Outputs 20-SOIC -40 to 85
ISL88694IH5 SMBus Accelerator (SMA)
ISL88694IH5-TK SMBus Accelerator (SMA)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISL88550AEVAL1 功能描述:EVALUATION BOARD 1 ISL88550A RoHS:否 類別:編程器，開發(fā)系統(tǒng) >> 過(guò)時(shí)/停產(chǎn)零件編號(hào) 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 傳感器類型:CMOS 成像，彩色（RGB） 傳感范圍:WVGA 接口:I²C 靈敏度:60 fps 電源電壓:5.7 V ~ 6.3 V 嵌入式:否 已供物品:成像器板 已用 IC / 零件:KAC-00401 相關(guān)產(chǎn)品:4H2099-ND - SENSOR IMAGE WVGA COLOR 48-PQFP4H2094-ND - SENSOR IMAGE WVGA MONO 48-PQFP
ISL88550AEVAL1Z 功能描述:EVALUATION BOARD 1 ISL88550A RoHS:是 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
ISL88550AIRZ 功能描述:電壓模式 PWM 控制器 INTEGRTD DDR PWR CNT RLR 2 8LD 5X5 TQFN 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
ISL88550AIRZ-T 功能描述:DC/DC 開關(guān)控制器 INTEGRTD DDR PWR CNT RLR 2 8LD 5X5 TQFN RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
ISL88550AIRZ-T7 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 Integrated DDR Power Controller, 28LD 5x5 TQFN Pb-free, 1K O RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*