Datasheet

PM6644 Simplified application schematic
Doc ID 023203 Rev 1 13/35
Figure 18. Simplified block diagram
VIN
GND
3.3V reference
BYP_ON
VCC
REF3
BYP
2.1V (falling thr.)
900mV
+ -
VCC
VCC_OK
3.2V (rising thr.)
800mV
+ -
BYP_ON
REF
TON
- +
Ton_end
FB
Ton_pulse
GND
FB
FB
VCC-1V
+ -
S
1
S
2
D
CENB
Multiplexer
GND
BYP
FB=VCC
FB=0.9V
+ -
EN_ok
EN
2.4V (rising thr.)
1100mV
Not(Boot_fuses_OK)
GND
SW
Sink mos
3.8 V
generator
Not (BYP_ON)
EN_ok
SW
GND
LS mos
HS mos
HS gate
driver
LS gate
driver
Anticross conduction
HS command
LS command
Ton_start
HS command
-
+
PWM
COMPARATOR
S
R
Q
Q
+
-
+
FB
FB_REF
ToffMIN=500ns
Ton_pulse
Ton_end
GND
Α*SW
@LS mos on
320mV
0mV
EN
SMPS_enable
SW-GND
@
LS mos on
LS command
Ton_start
S
R
Q
Q
SW-GND
@LS mos on
0mV
-
+
REF
1.216V reference
generator
FB_REF=0.9V
GND
Vth_ref
+ -
Bias
reference
generator
EN
REF_OK
BIAS_OK
Ith_bias
+ -
REF_OK
BIAS
EN
EN
SMPS_enable
EN
EN
SMPS_enable
SMPS_enable
EN
EN
SMPS_enable
Fault Management
OVP
UVP
OVERTEMP
VCC_OK
EN
No Fault
Boot_fuses_OK
SS0, SS1
Start up
managment
VCC_OK
BOOT_FUSES _ OK
No Fault
SMPS_enable
SS0, SS1
FB
+ -
UVP
62% of
FB_REF
EN
SS_end
Die temperature
+ -
OVERTEMP
150°C
EN
Boot_fuses_OK
BOOT_FUSES_OK
EN_ok
120% of
FB _REF
FB
+ -
Boot_fuses_OK
OVP
EN
+ -
AM11778v1