參數(shù)資料
型號(hào)： LTC3553EUD#PBF
廠商： LINEAR TECHNOLOGY CORP
元件分類： 電源管理
英文描述： 1-CHANNEL POWER SUPPLY SUPPORT CKT, PQCC20
封裝： 3 X 3 MM, 0.75 MM HEIGHT, LEAD FREE, PLASTIC, QFN-20
文件頁(yè)數(shù)： 10/36頁(yè)
文件大?。?/td> 518K
代理商： LTC3553EUD#PBF
LTC3553
18
3553fa
NTC Thermistor
The battery temperature is measured by placing a nega-
tive temperature coefcient (NTC) thermistor close to the
battery pack. To use this feature connect the NTC therm-
istor, RNTC, between the NTC pin and ground and a bias
resistor, RNOM, from VBUS to NTC, as shown in Figure 1.
RNOM should be a 1% resistor with a value equal to the
value of the chosen NTC thermistor at 25°C (R25). The
LTC3553 will pause charging when the resistance of the
NTC thermistor drops to 0.54 times the value of R25
or approximately 54k (for a Vishay curve 1 thermistor,
this corresponds to approximately 40°C). If the battery
charger is in constant-voltage mode, the safety timer also
pauses until the thermistor indicates a return to a valid
temperature. As the temperature drops, the resistance of
the NTC thermistor rises. The LTC3553 is also designed
to pause charging when the value of the NTC thermistor
increases to 3.17 times the value of R25. For a Vishay
curve 1 thermistor this resistance, 317k, corresponds to
approximately 0°C. The hot and cold comparators each
have approximately 3°C of hysteresis to prevent oscillation
about the trip point.
Alternate NTC Thermistors and Biasing
The LTC3553 provides temperature qualied charging if
a grounded thermistor and a bias resistor are connected
to NTC. By using a bias resistor whose value is equal to
the room temperature resistance of the thermistor (R25)
the upper and lower temperatures are preprogrammed
to approximately 40°C and 0°C, respectively (assuming
a Vishay curve 1 thermistor).
The upper and lower temperature thresholds can be
adjusted by either a modication of the bias resistor value
or by adding a second adjustment resistor to the circuit.
If only the bias resistor is adjusted, then either the upper
or the lower threshold can be modied but not both. The
other trip point will be determined by the characteristics
of the thermistor. Using the bias resistor in addition to an
adjustment resistor, both the upper and the lower tem-
perature trip points can be independently programmed
with the constraint that the difference between the upper
and lower temperature thresholds cannot decrease.
Examples of each technique are given below.
NTC thermistors have temperature characteristics which
are indicated on resistance-temperature conversion ta-
bles. The Vishay-Dale thermistor NTHS0603N011-N1003F,
used in the following examples, has a nominal value of
100k and follows the Vishay curve 1 resistance-tempera-
ture characteristic.
In the explanation below, the following notation is used.
R25 = Value of the thermistor at 25°C
RNTC|COLD = Value of thermistor at the cold trip point
RNTC|HOT = Value of the thermistor at the hot trip point
rCOLD = Ratio of RNTC|COLD to R25
rHOT = Ratio of RNTC|HOT to R25
RNOM = Primary thermistor bias resistor (see Figure 2)
R1 = Optional temperature range adjustment resistor (see
Figure 2)
OPERATION
Figure 1. Typical NTC Thermistor Circuit
–
+
–
+
RNOM
100k
RNTC
100k
NTC
VBUS
NTC_ENABLE
3553 F01
NTC BLOCK
TOO_COLD
TOO_HOT
0.76 VBUS
(NTC RISING)
0.35 VBUS
(NTC FALLING)
0.017 VBUS
(NTC FALLING)
–
+
20
15
相關(guān)PDF資料
PDF描述
LTC3554EPD#TRPB 0.5 A BATTERY CHARGE CONTROLLER, 1295 kHz SWITCHING FREQ-MAX, PQCC20
LTC3560IS6#TRPBF 2.1 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6
LTC3563EDC 1.75 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6
LTC3568EDD#TR 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10
LTC3568IDD 4 A SWITCHING REGULATOR, 4000 kHz SWITCHING FREQ-MAX, PDSO10
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3554 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators
LTC3554EPD 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators
LTC3554EPD#PBF 功能描述:IC USB POWER MANAGER 20-UTQFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 應(yīng)用:手持/移動(dòng)設(shè)備 電流 - 電源:- 電源電壓:3 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 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-LLP-EP（4x4） 包裝:Digi-Reel® 配用:LP3905SD-30EV-ND - BOARD EVALUATION LP3905SD-30 其它名稱:LP3905SD-30DKR
LTC3554EPD#TRPBF 功能描述:IC USB POWER MANAGER 20-UTQFN RoHS:是 類別:集成電路 (IC) >> PMIC - 電源管理 - 專用 系列:- 應(yīng)用說明:Ultrasound Imaging Systems Application Note 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:37 系列:- 應(yīng)用:醫(yī)療用超聲波成像，聲納 電流 - 電源:- 電源電壓:2.37 V ~ 6 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:56-WFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:56-TQFN-EP（8x8） 包裝:管件
LTC3554EPDPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators
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

*
*
*