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参数资料
| 型号： | TC1240ECH |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHED CAPACITOR CONVERTER, 125 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封装： | SOT-23A, 6 PIN |
| 文件页数： | 12/16页 |
| 文件大小： | 472K |
| 代理商： | TC1240ECH |
2002 Microchip Technology Inc.
DS21516B-page 5
TC1240/TC1240A
3.0
DETAILED DESCRIPTION
The TC1240 and TC1240A charge pump converters
double the voltage applied to the VIN pin. Conversion
consists of a two-phase operation (Figure 3-1). During
the first phase, switches S2 and S4 are open and S1
and S3 are closed. During this time, C1 charges to the
voltage on VIN and load current is supplied from C2.
During the second phase, S2 and S4 are closed, and
S1 and S3 are open.
During this second phase, C1 is level shifted upward by
VIN volts. This connects C1 to the reservoir capacitor
C2, allowing energy to be delivered to the output as
needed. The actual voltage is slightly lower than 2 x VIN
since the four switches (S1-S4) have a non-resistance
and the load drains charge from reservoir capacitor C2.
FIGURE 3-1:
IDEAL SWITCHED
CAPACITOR CHARGE
PUMP DOUBLER
4.0
TYPICAL APPLICATIONS
4.1
Output Voltage Considerations
The TC1240 and TC1240A perform voltage doubling
but do not provide regulation. The output voltage will
droop in a linear manner with respect to load current.
The value of this equivalent output resistance is
approximately 12
nominal at +25°C and VIN =+5.0V
for the TC1240A and 17
nominal at +25°C and VIN =
+2.8V for the TC1240. VOUT is approximately +10.0V at
light loads for the TC1240A and +5.6V for the TC1240,
and droops according to the equation below:
VDROOP =IOUT xROUT
VOUT =2x VIN –VDROOP
4.2
Charge Pump Efficiency
The overall power efficiency of the charge pump is
affected by four factors:
1.
Losses from power consumed by the internal
oscillator,switch drive,etc.(which vary with
input
voltage,
temperature
and
oscillator
frequency).
2.
I2R losses due to the on-resistance of the
MOSFET switches on-board the charge pump.
3.
Charge pump capacitor losses due to effective
series resistance (ESR).
4.
Losses that occur during charge transfer (from
commutation capacitor to the output capacitor)
when a voltage difference between the two
capacitors exists.
Most of the conversion losses are due to factors (2) and
(3) above. These losses are given by Equation 4-1(b).
EQUATION 4-1:
OUT = 2 x VI
C1
C2
TC1240/TC1240A
VIN
S1
S3
S4
S2
OSC
VIN
a) PLOSS(2, 3) =IOUT
2 xR
OUT
b) IOUT
2 x [1/ [f
FSW(C1) ] + 8RSWITCH +
4ESRC1 + ESRC2]
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TC1240ECHTR | 功能描述:电荷泵 Positive Doubling RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| TC1240ECHTR-CUT TAPE | 制造商:Microchip 功能描述:TC1240 Series 2.5 to 5.5 V Positive Doubling Charge Pump w/ Shutdown - SOT-23-6 |
| TC1240I/CHTR | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Positive Doubling Charge Pumps with Shutdown in a SOT-23 Package |
| TC1240ICHTR | 制造商:Microchip Technology Inc 功能描述: |
| TC124A | 制造商:Thomas & Betts 功能描述:Fittings Connector 1.25inch Steel |
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