參數(shù)資料
型號(hào)： TC1142-30EUA
廠商： Microchip Technology Inc.
英文描述： Inductorless -2x Boost/Buck Regulator
中文描述： 電感- 2x升壓/降壓穩(wěn)壓器
文件頁(yè)數(shù)： 6/12頁(yè)
文件大?。?/td> 419K
代理商： TC1142-30EUA
TC1142
DS21360B-page 6
2002 Microchip Technology Inc.
3.1
Output Voltage and Ripple
For a -2x boost:
In this case, the output voltage is given by:
EQUATION 3-1:
Here, f is the clock frequency and R
S
is the total ON
resistance of the switches connecting C2 to GND and
V
OUT
in phase 2 of the charge pump operating cycle
with the equivalent series resistance (ESR) of C2.
The output ripple voltage is given by:
EQUATION 3-2:
Here, ESR is the equivalent series resistance of C
OUT
.
In this case, the TC1142 is held in phase 2 until the
output voltage drops below V
R
. When this occurs, the
TC1142 reverts to phase 1 for a half period of the clock,
during which C2 is charged from C1. At the end of this
half-period, C2 is reconnected to C
OUT
to boost the
output voltage. During the phase 1 time period, the
output voltage will drop below V
R
before it is boosted
back, so the minimum output voltage is approximated
by:
EQUATION 3-3:
The output ripple voltage is given approximately by:
EQUATION 3-4:
For values of V
IN
higher than |V
R
/2| by several hundred
mV, the effect on ripple of the ESR of C
OUT
can be
neglected compared to the
“
overdrive
”
effect of V
IN
.
Here, it can be seen that V
RIPPLE
increases with
increasing V
IN
, but can be minimized by choosing small
C1 and C2 values and a large C
OUT
value.
3.2
Capacitor Selection
To maintain low output impedance and ripple, it is
recommended that capacitors with low equivalent
series resistance (ESR) be used. Additionally, larger
values of the output capacitor and smaller values of the
flying capacitors will reduce output ripple. For a
capacitor value of 4.7
μ
F for C
OUT
, and values of
0.47
μ
F for C1 and C2, the typical output impedance of
the TC1142 in regulation is 0.5
. For the capacitor ESR
not to have a noticeable effect on output impedance, it
should not be larger than 1/2fC
OUT
. This also makes its
effect on ripple voltage negligible. For V
IN
= 3.2V and
V
R
= -5V, the output ripple voltage is less than 70
mV
PP
. Table 3-1 summarizes output ripple versus
capacitor size for an input voltage of 3.2V and a
regulated output voltage of -5V.
Surface mount ceramic capacitors are preferred for
their small size, low cost and low ESR. Low ESR
tantalum capacitors also are acceptable. See Table 3-2
for a list of suggested capacitor suppliers.
TABLE 3-1:
VOLTAGE RIPPLE VS. C1/C2
FLYING CAPACITORS AND
OUTPUT CAPACITOR C
OUT
ESR = 0.1
, I
OUT
= 20mA
a.) For unregulated operation when V
IN
≤
|
|
.
2
V
R
V
OUT
= -|2V
IN
| + I
O
R
OUT
1 1 1 R
S
C2
f C1 C2 (C2 + C
OUT
)
where R
OUT
=
V
RIPPLE
= I
O
R
RIPPLE
1 1 ESR C2
2f(C2 + C
OUT)
2fC
OUT
(C2 + C
OUT
)
where
R
RIPPLE
=
b.) For regulated operation when V
IN
>
|
|
.
2
V
R
V
OUT
MIN
= -|V
R
| + I
O
R
OUT
where R
OUT
=
1 +
2fC
OUT
(C2 + C
OUT
)
V
RIPPLE
=
(2
VIN
–
|V
R
| + ESR I
O
C2 1 1
N
C2
1 +
(
C1 C2
)
where N =
(C2 + C
OUT
)
C1, C2
(
μ
F)
C
OUT
(
μ
F)
V
IN
(V)
V
OUT
(V)
V
RIPPLE
(mV)
0.1
0.22
0.33
0.47
0.68
1.0
0.1
0.22
0.33
0.47
0.68
1.0
4.7
4.7
4.7
4.7
4.7
4.7
10
10
10
10
10
10
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
-5
-5
-5
-5
-5
-5
-5
-5
-5
-5
-5
-5
14.6
31.4
46.1
63.9
88.7
123.2
7.0
15.1
22.4
31.5
44.7
63.8
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TC1142-4.0EUA 功能描述:電荷泵 -2xBoost/Buck 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
TC1142-4.0EUATR 功能描述:電荷泵 -2xBoost/Buck 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
TC1142-40EUA 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Inductorless -2x Boost/Buck Regulator
TC1142-5.0EUA 功能描述:電荷泵 -2xBoost/Buck 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
TC1142-5.0EUATR 功能描述:電荷泵 -2xBoost/Buck 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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