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參數(shù)資料
| 型號： | LT1054C |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | SWITCHED-CAPACITOR VOLTAGE CONVERTERS WITH REGULATORS |
| 中文描述： | 開關與監(jiān)管電容電壓轉換器 |
| 文件頁數(shù)： | 8/26頁 |
| 文件大?。?/td> | 444K |
| 代理商： | LT1054C |
SLVS033F FEBRUARY 1990 REVISED NOVEMBER 2004
8
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
A review of a basic switched-capacitor building block is helpful in understanding the operation of the LT1054. When
the switch shown in Figure 12 is in the left position, capacitor C1 charges to the voltage at V1. The total charge on
C1 is q1 = C1V1. When the switch is moved to the right, C1 is discharged to the voltage at V2. After this discharge
time, the charge on C1 is q2 = C1V2. The charge has been transferred from the source V1 to the output V2. The
amount of charge transferred is shown in equation 1.
q
q1
q2
C1(V1
V2)
If the switch is cycled f times per second, the charge transfer per unit time (i.e., current) is as shown in equation 2.
I
f
q
f
C1(1
V2)
To obtain an equivalent resistance for a switched-capacitor network, this equation can be rewritten in terms of voltage
and impedance equivalence as shown in equation 3.
I
V1
V2
1 fC1
V1
V2
R
EQUIV
C2
C1
V2
f
V1
RL
Figure 12. Switched-Capacitor Building Block
A new variable, R
EQUIV
, is defined as R
EQUIV
= 1
÷
fC1. The equivalent circuit for the switched-capacitor network is
shown in Figure 13. The LT1054 has the same switching action as the basic switched-capacitor building block. Even
though this simplification does not include finite switch-on resistance and output-voltage ripple, it provides an insight
into how the device operates.
C2
V2
V1
RL
REQUIV
R
EQUIV
1
fC1
Figure 13. Switched-Capacitor Equivalent Circuit
These simplified circuits explain voltage loss as a function of oscillator frequency (see Figure 7). As oscillator
frequency is decreased, the output impedance eventually is dominated by the 1/fC1 term, and voltage losses rise.
Voltage losses also rise as oscillator frequency increases. This is caused by internal switching losses that occur due
to some finite charge being lost on each switching cycle. This charge loss per-unit-cycle, when multiplied by the
switching frequency, becomes a current loss. At high frequency, this loss becomes significant and voltage losses
again rise.
The oscillator of the LT1054 is designed to operate in the frequency band where voltage losses are at a minimum.
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相關PDF資料 |
PDF描述 |
|---|---|
| LT1054I | SWITCHED-CAPACITOR VOLTAGE CONVERTERS WITH REGULATORS |
| LT1054CJ8 | Switched-Capacitor Voltage Converter with Regulator |
| LT1054MJ8 | Switched-Capacitor Voltage Converter with Regulator |
| LT1054IN8 | Switched-Capacitor Voltage Converter with Regulator |
| LT1054CH | Switched-Capacitor Voltage Converter with Regulator |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT1054CDW | 功能描述:電荷泵 Bipolar Regulated V RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| LT1054CDW | 制造商:Texas Instruments 功能描述: |
| LT1054CDWE4 | 功能描述:電荷泵 Switched-Capacitor Voltage Converter RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| LT1054CDWG4 | 功能描述:電荷泵 Swed-Capacitor Vltg Converters RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| LT1054CDWR | 功能描述:電荷泵 Bipolar Regulated V RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
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