AIC1569A
ꢀ BLOCK DIAGRAM
POWER-ON
RESET
VCC
OVP
115%
110%
+
−
OVP
+
−
VSEN
PGOOD
OCSET
POWER GOOD
90%
50%
+
−
+
−
OVER
+
−
IOCS
CURRENT
µ
10 A
200µA
SS
PHASE
BOOT
4V
UGATE
GND
SOFT
START
CONTROL
LOGIC
REFERENCE
5-BITS DAC
VDAC
VCC
VID0
VID1
VID2
VID3
VID4
+
−
LGATE
PGND
+
−
ERROR AMP
PWM
COMPARATOR
FB
COMP
RT
OSCILLATOR
ꢀ PIN DESCRIPTIONS
equation:
PIN 1: VSEN - Converter output voltage sense
pin. Connect this pin to the
converter output. The PGOOD
and OVP comparator circuits use
this signal to report output voltage
status and perform overvoltage
protection function.
IOCS × ROCSET
IPEAK =
RDS(ON)
If FB pin voltage is sensed to be
below 50% of the internal voltage
reference VDAC, the over current
comparator cycles the soft-start
function.
PIN 2:OCSET- Current limit sense pin. Connect a
resistor ROCSET from this pin to the
drain of the external MOSFET.
ROCSET, an internal 200µA current
source (IOCS), and the external
PIN 3:SS
- Soft start pin. Connect a capacitor
from this pin to ground. An internal
10µA current source provides soft
start function for the converter.
MOSFET on-resistance (RDS(ON)
jointly set the over current trip
point according to the following
)
5
AIC [ ANALOG INTERGRATIONS CORPORATION ]
