Datasheet


SLUS489 − OCTOBER 2001
8
www.ti.com
functional block diagram
UDG−0104
3
VOUT
VOUT
3
1
4
5
6
8
S
YNC/SD
CCS
RT
CCM
BUCK
PFM
FB
TPS43000
9
10
11
12
13
14
15
VIN
VOUT
NDR
V
GND
PDR
V
VP
SWP
R
VREF
1.246 V
800 mV
784 mV
+
200 mV
DELAY
TO ZERO
REFGOOD
REFBAD
+
300 mV
VINEST 2.75 V
+
VBEST
VDD
LEB
++
10 mV
+
IZERO
RECTOFF
(STOP SWITCH
RECTIFICATION)
3−BIT UP
COUNTER
+
SQ
QR
++
150 mV
250 mV
+
SWN LEB
6−BIT
UP/DOWN
COUNTER
RESET
SHUTDOWN
FOR 900
CYCLES THEN
SOFT−START
RESET
HICCUP
(STOP SWITCHING FOR 900
CYCLES THEN SOFT−START)
IMAX
(STOP ENERGIZING INDICATOR)
16
2
7COMP
ERROR
AMPLIFIER
+
SOFT
START
PWM
COMPARATOR
HICCUP
800 mV
SHUTDOWN
TIMER AND
OSCILLATOR
SHUTDOWN
(SD)
95% MAXIMUM DUTY
CYCLE NON−BUCK
SQ
QR
ANTI
CROSS
CONDUCTION
&
TOPOLOGY
STEERING
LOGIC
NDRV_RAIL
LPM
VINEST
VINEST
+
+
SQ
QR
3.6 V
3.3 V
LPM
RECTOFF IMAX
1.6 R
RESET
784 mV
+
+
REFGOOD
RECTIFY
VIN
VIN
UVLO
SLEEP
SLEEP
SD
REFBAD
SLEEP
HICCUP
PWM ENABLE