Datasheet

CP-
VIN
VOUT
GND
CP+
ENA
VIN
VOUT
(5V)
ENABLE
/DISABLE
C
OUT
C
IN
C
F
charging FLY CFLY
discharging discharge LO AD(MAX)
Q = c v = C V ,
T
Q = i t = 2 I , half duty.
2
´ ´ D
æ ö
´ ´ ´
ç ÷
è ø
LOAD(MAX) FLY CFLY
T
2 I = C V
2
æ ö
\ ´ ´ ´ D
ç ÷
è ø
æ ö
´ ´
ç ÷
è ø
\ ³
D D ´ ¦
LOAD(MAX)
LOAD(MAX)
FLY
CFLY CFLY
T
2 I
I
2
C =
V V
( )
= + ´
´ ´
LOAD(MAX)
OUT(RIPPLE) LOAD(MAX) COUT
OUT
I
V 2I ESR
2 f C
´
´ ´ = ´
´
OUT OUT
IN OUT Q
IN IN
V I
PD(out)
Efficiency(%) = 100 = 100 , I 2 I + I
PD(in) V I
TPS60150
SLVS888B –DECEMBER 2008– REVISED FEBRUARY 2011 www.ti.com
SHUTDOWN MODE
An enable pin on the regulator may be used to place the device into an energy-saving shutdown mode. In this
mode, the output is disconnected from the input and the input quiescent current is reduced to 1μA maximum.
CAPACITOR SELECTION
For minimum output voltage ripple, the output capacitor (C
OUT
) should be a surface-mount ceramic capacitor.
Tantalum capacitors generally have a higher Effective Series Resistance (ESR) and may contribute to higher
output voltage ripple. Leaded capacitors also increase ripple due to the higher inductance of the package itself.
To achieve the best operation with low input voltage and high load current, the input and flying capacitors (C
IN
and C
F
, respectively) should also be surface-mount ceramic types.
Figure 25. Capacitors
Generally, C
FLY
can be calculated by simple equation as follows,
(1)
Both equation should be same,
(2)
If I
LOAD
= 140 mA, f = 1.5MHZ, and ΔV
CFLY
= 100mV, the minimum value of the flying capacitor should be 1μF.
Output capacitance, C
OUT
, is also strongly related to output ripple voltage and loop stability,
(3)
The minimum output capacitance for all output levels is 2.2μF due to control stability. Larger ceramic capacitors
or low ESR capacitors can be used to lower the output ripple voltage.
Table 2. Suggested Capacitors (Input / Output / Flying Capacitor)
Dielectric Rated working
Manufacturer Part number Value Tolerance Package Size
material voltage
4.7uF
X7R 6.3V
2.2uF
The efficiency of the charge pump regulator varies with the output voltage, the applied input voltage and the load
current.
The approximate efficiency in normal operating mode is given by:
(4)
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