MC44603P ON Semiconductor, MC44603P Datasheet - Page 21

• Manufacturer Part Number: MC44603P
• Description: Other Power Management Voltage/Current PWM
• Manufacturer: ON Semiconductor
• Type: PWM Mode Controllerr

Specifications of MC44603P

• Input Voltage Range: 18 V
• Mounting Style: Through Hole
• Package / Case: PDIP-16
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Undervoltage Lockout Section
been incorporated to guarantee that the IC is fully functional
before allowing system operation.
As depicted in Figure 48, an undervoltage lockout has
V
CC
1
Figure 48. V
V
7.5 V
1
V
9.0 V
disable2
disable1
C
UVLO1
0
C
startup
V
ref enable
Startup
14.5 V
CC
1 0
Management
(to Soft-Start)
UVLO1
R
F Stby
Voltage and Current
Sources Generator
Reference Block:
(V
Pin 15
ref
, I
ref
, ...)
R
ref
Pin 16
http://onsemi.com
21
I
Pin 16 and the ground:
R
level that is nearly equal to 9.0 V (V
generated to reset the maximum duty cycle and soft−start
block disabling the output stage as soon as V
lower than V
ready for the next startup, before the reference block is
disabled (refer to Figure 30). Finally, the upper limit for the
minimum normal operating voltage is 9.4 V (maximum
value of V
((V
MC44603A make it ideally suited for off−line converter
applications where efficient bootstrap startup techniques are
required.
ref
F Stby
This block particularly, produces V
Another resistor is connected to the Reference Block:
In addition to this, V
The large hysteresis and the low startup current of the
stup−th
that is determined by the resistor R
that is used to fix the standby frequency.
I ref +
)
disable1
min
disable1
= 13.6 V).
R ref
V ref
) and so the minimum hysteresis is 4.2 V.
. In this way, the circuit is reset and made
where V ref + 2.5 V (typically)
CC
is compared to a second threshold
ref
ref
disable1
(Pin 16 voltage) and
connected between
). UVLO1 is
CC
becomes