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參數(shù)資料
| 型號： | MAX4920BETD+T |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 2/19頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC CTLR OVP/OCP BATT PWR 14-TDFN |
| 產(chǎn)品培訓(xùn)模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標(biāo)準(zhǔn)包裝： | 2,500 |
| 類型： | 過壓和過流控制器 |
| 應(yīng)用： | 手機(jī)，數(shù)碼相機(jī)，媒體播放器 |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 14-WFDFN 裸露焊盤 |
| 供應(yīng)商設(shè)備封裝： | 14-TDFN-EP（3x3） |
| 包裝： | 帶卷 (TR) |
MAX4919B/MAX4920B/MAX4921B
PWR_HOLD
PWR_HOLD controls the turn-on of the 1.8A (min) cur-
rent-limit switch (P2). When a voltage is present at IN,
and VUVLO < VIN < VOVLO for 25ms, ACOK pulls low
and issues an internal one-shot pulse that turns on P2
temporarily for 1.2s (typ). During the 1.2s one-shot peri-
od, the MAX4919B/MAX4920B/MAX4921B must see a
low-to-high transition at PWR_HOLD (and PWR_HOLD
must remain high), for P2 to remain on (see Figure 7).
P2 turns off when PWR_HOLD and PWR_ON are low,
and when the HP_PWR and ACOK internal one-shot
timers have expired.
When a voltage at IN is not present, HP_PWR controls
the turn-on of P2. Upon a low-to-high transition at
HP_PWR (and HP_PWR remaining high), the
MAX4919B/MAX4920B/MAX4921B issue an internal
HP_PWR one-shot signal that turns on P2 temporarily
for 1.2s (typ). During the 1.2s one-shot period, the
MAX4919B/MAX4920B/MAX4921B must see a low-to-
high transition at PWR_HOLD (and PWR_HOLD must
remain high) for P2 to remain on. P2 turns off when
PWR_HOLD and PWR_ON are low, and when the
HP_PWR and ACOK internal one-shot timers have
expired (see Figure 8).
Current Limiting
The MAX4919B/MAX4920B/MAX4921B feature an inter-
nal 1.8A (min) current-limiting switch (P2) at BTO. The
current limit remains in effect throughout BTI’s input
supply-voltage range.
The current limit takes care of two situations: when P2 is
initially turned on, and when P2 is already on and a
short circuit occurs (see Figure 9). When P2 is turned
on, the current can be high because BTO = 0 and a
large load capacitor needs to be charged. The protec-
tion circuit prevents the load current from exceeding
the 1.8A (min) current-limit value, and BTO will have a
smooth turn-on (the larger the capacitor, the slower the
turn-on). The 10ms blanking time avoids a false fault
assertion. At the end of the blanking time, if the device
is still limiting, a fault is asserted and P2 immediately
turns off. When the switch is already on and a short-cir-
cuit condition occurs at BTO, the device limits the cur-
rent. If the fault condition duration is greater than the
blanking time, P2 turns off.
Before P2 turns on again, any condition that is attempt-
ing to turn it on must be first removed, i.e. the one-shot
(from IN or HP_PWR) must be completed, and PWR_ON
and PWR_HOLD must be low. If the three conditions are
satisfied, P2 turns on again only if either IN or
PWR_HOLD is cycled OFF and ON.
Low-Battery Operation
The MAX4919B/MAX4920B/MAX4921B operate in low-
battery mode when the battery voltage at BTI is greater
than 2.15V but less than 2.8V (typ). In low-battery opera-
tion, PWR_ON does not influence the behavior of the
internal switch.
When an adapter and car kit are not present, the internal
switch is typically controlled by PWR_HOLD. If PWR_ON
is high (ONOK is low) and BTI falls below 2.8V, ONOK
pulls high, but the internal switch remains on since
PWR_HOLD is high. If PWR_ON is high and PWR_HOLD
is low when VBTI falls below the 2.8V threshold, the inter-
nal switch turns off immediately. Upon BTI rising above
2.8V again, PWR_ON is again enabled and ONOK goes
back to its previous logic level before a low condition at
BTI occurred.
Battery Power-Up Logic with Overvoltage
and Overcurrent Protection
10
______________________________________________________________________________________
PWR_ON
ONOK
Figure 5. ONOK Timing Diagram
BT1
P2
PWR_ON
VLVBTI
VUVBTI
ON
OFF
ON
ONOK
OFF
Figure 6. BTI Falling and Rising Above Its Thresholds
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX4921BETD+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX4921BETD+T | 功能描述:電池管理 Battery Power-Up Logic RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX4924ELT+T | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Overvoltage Protector RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MAX4925ELT+ | 制造商:Maxim Integrated Products 功能描述:OVP PROTECTOR WITH EXTERNAL PFET - Bulk |
| MAX4925ELT+T | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 Overvoltage Protector RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
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