AS3525-A/-B C22O22
Data Sheet, Confidential
7.4.16
15V Step-Up Converter
7.4.16.1 General
The integrated Step-Up DC/DC Converter is a high efficiency current-mode PWM regulator, providing an output voltage up to 15V. A constant
switching-frequency results in a low noise on supply and output voltages. When using an additional transistor the output voltage can be up to 25V
to drive 6 white LED in series.
It has an adjustable sink current (1.25 to 38.75mA) to provide e.g. dimming function when driving white LEDs as back-light.
7.4.16.2 Parameter
Table 141 15V Step-Up Converter Parameter
Symbol
VSW
Parameter
Notes
Min
Typ
140
Max
Unit
V
High Voltage Pin
Quiescent Current
Pin SW15
Pulse Skipping mode
0
15
IVDD
µA
V
VFB
Feedback Voltage, Transient Pin ISINK
0
5.5
1.0
VFB
Feedback Voltage, during
Regulation
Pin ISINK
0.65
0.83
V
ISW_MAX
RSW
Current Limit
V15_ON = 1
350
510
750
1.54
45
mA
Switch Resistance
Load Current
V15_ON = 0
0.85
Ω
mA
V
ILOAD
@ 15V output voltage
0
VPULSESKIP
Pulse-skip Threshold
Voltage at pin ISINK, pulse skips are
introduces when load current becomes
too low.
1.2
1.33
1.5
FIN
COUT
Fixed Switching Frequency
Output Capacitor
0.5
17
0.55
1
0.6
27
MHz
µF
Ceramic
L (Inductor)
ILOAD > 20mA
Use inductors with small CPARASITIC
(<100pF) for high efficency
22
µH
ILOAD < 20mA
Minimum On-Time
Maximum Duty Cycle
8
10
91
27
180
94
tMIN_ON
MDC
90
88
ns
%
Guaranteed per design
BVDD=3.6V; Tamb=25ºC; unless otherwise specified
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