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參數(shù)資料
| 型號： | ZXCP330 |
| 廠商： | Zetex Semiconductor |
| 元件分類： | DC/DC變換器 |
| 英文描述： | SWITCHED CAPACITOR DC-DC CONVERTER |
| 中文描述： | 開關電容DC - DC轉(zhuǎn)換器 |
| 文件頁數(shù)： | 5/9頁 |
| 文件大?。?/td> | 341K |
| 代理商： | ZXCP330 |
Operational description
The ZXCP330 uses a standard switched capacitor
voltage doubler topology to generate a regulated
outputof3.3Vfromaninputvoltageofbetween2Vand
4.4V. A 500kHz internal clock generates two phases.
During
1 (Phi One) the flying capacitor is connected
betweenVinandgroundfor1 s. During 2thebottom
plateisconnectedtoV
IN
andthetopplateconnectedto
V
OUT
. A proportion of the output voltage is compared
with a silicon band gap to maintain regulation. This is
achieved by disabling the switching operation when
the output voltage is above 3.3V and re-enabling when
the output voltage falls below 3.3V. When the input
voltage is near the higher limit, a large amount of
charge is acquired by the flying capacitor during
which would result in excessive output ripple. For this
reason, the 2 phase is cut short if the voltage exceeds
3.3V, so that the full charge on the flying capacitor is
not delivered to the output capacitor, hence ripple is
reduced
.
1,
When the charge pump is disabled, the current drawn
bytheswitchesthemselvesis<1 A. Thismeansthatat
zero loads, the load on the output will only consist of
thedividerdrivingtheoutputcomparatorandtheband
gapcircuit,resultingthedevicecyclingveryslowlyand
drawing only 20 A.
When the circuit is either waiting for the next cycle or
when it is shutdown by taking the ENABLE pin low, it
remainsinthe 1statesothattheflyingcapacitorstays
charged to the input voltage ready for 2 to be enabled
immediately. During shutdown all analogue circuits
areswitchedoff,resultinginacurrentdrainof<100nA.
Power efficiency
The ZXCP330 is essentially a regulated voltage
doubling charge pump. As for all voltage doubling
charge pumps the input current is always twice the
output current. The efficiency equation for an ideal
voltage doubler is given below:
=
=
×
×
=
P
P
V
2I
I
V
V
2V
OUT
IN
OUT
OUT
OUT
IN
OUT
IN
The ZXCP330 maintains good efficiency at light loads
because of its inherently low power design. At higher
loads switching losses are minimal so efficiency is
close to the ideal. See Efficiency vs Output current
graph in the typical characteristics section.
Short circuit/thermal protection
When the output of the ZXCP330 is short circuited, the
resultant current depends on 2 factors. At low input
voltages, the internal resistance of the switches limits
the current and so it will increase with input voltage.
However since, under this condition, all the input
power is dissipated in the chip, it will self-heat. When
the input voltage reaches around 3.2V, the value
depending on the thermal mounting of the device, the
chiptemperaturereachesanominalvalueof150 Cand
a thermal shutdown circuit inhibits the switching. The
device will then cool and the thermal shutdown will
re-enable the switching.
It will cycle in and out of
operationindefinitelyuntiltheshortcircuitisremoved.
Since the thermal shutdown circuit is then maintaining
constant die temperature, it becomes a “constant
power sink”, so an increase in the input voltage results
in the on time becoming proportionately less so the
current decreases to maintain constant power.
Capacitor selection
Output capacitors are a critical choice in the overall
performance of the solution. Output voltage ripple,
converter output power and turn-on time are
influenced by the choice of capacitor. To reduce noise
and output voltage ripple multi layer ceramic
capacitors are recommended for use at the ZXCP330
input and output because of their inherently low ESR,
typically <0.1 .
The ZXCP330 will function satisfactorily over a wide
range of capacitor values and load currents. However,
to achieve maximum output current and minimum
output ripple it is important to choose the values
carefully. Available output current increases with the
value of the flying capacitor, with input voltage and
with clock frequency (which is fixed internally). Ripple
increases with input voltage and the ratio of the flying
capacitor to the output capacitor.
ZXCP330
PROVISIONAL ISSUE A - DECEMBER 2001
5
Block Diagram
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相關代理商/技術(shù)參數(shù) |
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|---|---|
| ZXCP330E6 | 制造商:ZETEX 制造商全稱:ZETEX 功能描述:SWITCHED CAPACITOR DC-DC CONVERTER |
| ZXCP330E6TA | 功能描述:IC REG SWITCHED CAP DBL SOT23 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:兩者兼有 輸出數(shù):1 輸出電壓:5V，1 V ~ 10 V 輸入電壓:3.5 V ~ 28 V PWM 型:電流模式 頻率 - 開關:220kHz ~ 1MHz 電流 - 輸出:600mA 同步整流器:無 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:16-SSOP（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應商設備封裝:16-QSOP |
| ZXCT1008 | 制造商:DIODES 制造商全稱:Diodes Incorporated 功能描述:AUTOMOTIVE HIGH-SIDE CURRENT MONITOR |
| ZXCT1008_07 | 制造商:ZETEX 制造商全稱:ZETEX 功能描述:AUTOMOTIVE HIGH-SIDE CURRENT MONITOR |
| ZXCT1008FTA | 功能描述:電流和電力監(jiān)控器、調(diào)節(jié)器 Automotive Tem Range RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Current Regulators 電源電壓-最大:48 V 電源電壓-最小:5.5 V 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:HPSO-8 封裝:Reel |
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