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參數資料
| 型號： | LMC7660IM |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩壓器 |
| 英文描述： | Switched Capacitor Voltage Converter |
| 中文描述： | SWITCHED CAPACITOR CONVERTER, 10 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | PLASTIC, SOP-8 |
| 文件頁數： | 7/12頁 |
| 文件大小： | 134K |
| 代理商： | LMC7660IM |
Typical Applications
(Continued)
Getting Up … and Down
The LMC7660 can also be used as a positive voltage multi-
plier. This application, shown in Figure 9 requires 2 addi-
tional diodes. During the first
through D1; D2 is reverse biased. In the next
1
2
cycle S2 is
open and S1 is closed. Since C
1 is charged to V
+
V
and
is referenced to V
+
through S1, the junction of D1 and D2 is
1
2
cycle S2 charges C
p
1
at V
+
+ (V
+
V
). D1 is reverse biased in this interval. This
application uses only two of the four switches in the 7660.
The other two switches can be put to use in performing a
negative conversion at the same time as shown in Figure 10
In the
1
2
cycle that D1 is charging C
1, C
2 is connected
from ground to V
via S2 and S4, and C
2 is storing C
2’s
charge. In the interval that S1 and S3 are closed, C
1 pumps
the junction of D1 and D2 above V
+
, while C
p
2 is refreshed
from V
+
.
Thermometer Spans 180C
Using the combined negative and positive multiplier of Fig-
ure 11 with an LM35 it is possible to make a μPower ther-
mometer that spans a 180C temperature range. The LM35
temperature sensor has an output sensitivity of 10 mV/C,
while drawing only 50 μA of quiescent current. In order for
the LM35 to measure negative temperatures, a pull down to
a negative voltage is required. Figure 11 shows a thermom-
eter circuit for measuring temperatures from 55C to
+125C and requiring only two 1.5V cells. End of battery life
can be extended by replacing the up converter diodes with
Schottky’s.
Regulating V
out
It is possible to regulate the output of the LMC7660 and still
maintain μPower performance. This is done by enclosing the
LMC7660 in a loop with a LP2951. The circuit of Figure 12
will regulate V
to 5V for I
= 10 mA, and V
= 6V. For V
in
>
7V, the output stays in regulation up to I
=25 mA. The er-
ror flag on pin 5 of the LP2951 sets low when the regulated
output at pin 4 drops by about 5%. The LP2951 can be shut-
down by taking pin 3 high; the LMC7660 can be shutdown by
shorting pin 7 and pin 8.
DS009136-12
FIGURE 8. Split V
+
in Half
DS009136-13
FIGURE 9. Positive Voltage Multiplier
DS009136-14
FIGURE 10. Combined Negative Converter and Positive Multiplier
7
www.national.com
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LMC7660IM/NOPB | 功能描述:電荷泵 Switched Cap Vltg 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 |
| LMC7660IM/NOPB | 制造商:Texas Instruments 功能描述:DC/DC Charge Pump Converter (DC-DC) IC |
| LMC7660IMX | 功能描述:電荷泵 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 |
| LMC7660IMX/NOPB | 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 |
| LMC7660IMX/SL110705 | 制造商:Texas Instruments 功能描述: |
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