
AS3515 V15
austriamicrosystems
Data Sheet, Confidential
www.austriamicrosystems.com
Revision 3.1
40
- 66
6.14 15V Step-Up Converter
6.14.1 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.
It has an adjustable sink current (1.25 to 38.75mA) to provide e.g. dimming function when driving white LEDs as back-light.
Figure 16 15V Step-Up converter Block Diagram
BVDD
0.83V
1.33V
Σ
PWM-LOGIC
DRIVER
Ramp
Generatio
n
ISINK
VSS15
SW15
NMOS
15V
Power
Device
0.85
Ω typ.
Current
Sense
Pulse-Skip
Comparator
Error
Amplifier
Clock
Generation
VSS
VSS15
1.25 -
37.5 mA
6.14.2 Parameter
Table 41 15V Step-Up Converter Parameter
Symbol
Parameter
Notes
Min
Typ
Max
Unit
VSW
High Voltage Pin
Pin SW15
0
15
V
IVDD
Quiescent Current
Pulse Skipping mode
140
A
VFB
Feedback Voltage, Transient Pin ISINK
0
5.5
V
VFB
Feedback Voltage, during
Regulation
Pin ISINK
0.83
V
ISW_MAX
Current Limit
V15_ON = 1
510
mA
RSW
Switch Resistance
V15_ON = 0
0.85
Ω
ILOAD
Load Current
@ 15V output voltage
0
38.75
mA
VPULSESKIP
Pulse-skip Threshold
Voltage at pin ISINK, pulse skips are
introduces when load current becomes
too low.
1.33
V
FIN
Fixed Switching Frequency
0.6
MHz
COUT
Output Capacitor
Ceramic
1
F
L (Inductor)
ILOAD > 20mA
Use inductors with small CPARASITIC
(<100pF) for high efficency
17
22
27
H
ILOAD < 20mA
8
10
27
ams
AG
Technical
content
still
valid