isl6237 Intersil Corporation, isl6237 Datasheet - Page 20

• Manufacturer Part Number: isl6237
• Description: High-efficiency, Quad-output, Main Power Supply Controllers For Notebook Computers
• Manufacturer: Intersil Corporation

.
(t
or OPEN), VOUT1
(t
VOUT2
(t
VOUT1
(t
or OPEN), VOUT2
ON
ON
ON
ON
= GND, REF,
= GND),
= VCC),
= VCC, REF,
SMPS
TABLE 2. APPROXIMATE K-FACTOR ERRORS
FREQUENCY
SWITCHING
(kHz)
400
500
200
300
20
K-FACTOR
(µs)
2.5
2.0
5.0
3.3
APPROXIMATE
ERROR (%)
K-FACTOR
±10
±10
±10
±10
ISL6237
For loads above the critical conduction point, the actual
switching frequency is:
where:
• V
• V
• t
f
=
inductor discharge path, including synchronous rectifier,
inductor, and PC board resistances
charging path, including high-side switch, inductor, and PC
board resistances
ON
DROP1
DROP2
------------------------------------------------------ -
t
ON
V
is the on-time calculated by the ISL6237
OUT
V
IN
is the sum of the parasitic voltage drops in the
+
is the sum of the parasitic voltage drops in the
+
V
V
DROP1
DROP2
March 16, 2007
FN6418.1
(EQ. 2)