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Typical Application Circuit
Note: V
OUT
= V
FB
x (1+R
A
/R
B
)
R
B
=0.7K~5K ohm
V
IN
=12V, I
MAX
= 4A
V
OUT
L1 Value
2.5V
22uH
3.3V
27uH
5V
33uH
Function Description
PWM Control
The RS6514 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of
the RS6514, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage
produced by the switching can easily be removed through a filter because the switching frequency remains
constant. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load
current.
Under Voltage Lockout
The under voltage lockout circuit of the RS6514 assures that the high-side MOSFET driver outputs remain in the
off state whenever the supply voltage drops below 3.3V. Normal operation resumes once V
CC
rises above 3.5V.
R
DS(ON)
Current Limiting
The current limit threshold is setting by the external resistor connecting from V
CC
supply to OCSET. The internal
100uA sink current crossing the resistor sets the voltage at the pin of OCSET. When the PWM voltage is less than
the voltage at OCSET, an over-current condition is triggered.
I
LOAD
× R
DS(ON)
=I
OCSET
× R
OCSET
See above formula for setting the current limit value.
DS-RS6514-02
March, 2009
www.Orister.com
ORISTER [ ORISTER CORPORATION ]
