MC44603P ON Semiconductor, MC44603P Datasheet - Page 15

• 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

Error Amplifier
inverting input and output is provided. It features a typical
DC voltage gain of 70 dB. The noninverting input is
internally biased at 2.5 V and is not pinned out. The
converter output voltage is typically divided down and
monitored by the inverting input. The maximum input bias
current with the inverting input at 2.5 V is −2.0 mA. This can
cause an output voltage error that is equal to the product of
the input bias current and the equivalent input divider source
resistance.
loop compensation. The output voltage is offset by two
diode drops (≈ 1.4 V) and divided by three before it connects
to the inverting input of the Current Sense Comparator. This
guarantees that no drive pulses appear at the Output (Pin 3)
when Pin 13 is at its lowest state (V
minimum feedback resistance is limited by the amplifier’s
minimum source current (0.2 mA) and the required output
voltage (V
clamp level:
A fully compensated Error Amplifier with access to the
The Error Amp output (Pin 13) is provided for external
R f(min) [
V
CT
OH
V
Output
(Pin 3)
low
) to reach the current sense comparator’s 1.0 V
CT
V
OSC
V
ref
3.6 V
1.6 V
3.0 (1.0 V) ) 1.4 V
0.2 mA
V
CSS
+ 1.6 V
OL
). The Error Amp
+ 22 kW
OPERATING DESCRIPTION
Figure 32. Soft−Start & D
http://onsemi.com
Soft-Start
15
Current Sense Comparator and PWM Latch
or as a voltage mode controller. In current mode operation,
the MC44603A uses the current sense comparator. The
output switch conduction is initiated by the oscillator and
terminated when the peak inductor current reaches the
threshold level established by the Error Amplifier output
R
C
R1
FB
The MC44603A can operate as a current mode controller
f
Compensation
Feedback
Foldback
R
Figure 33. Error Amplifier Compensation
max
Voltage
f
R2
Input
Input
Internal Clamp
13
14
5
2.5 V
From Power Supply Output
Amplifier
Error
+
1.0 mA
External Clamp
2R
1.0 V
R
GND 4
Current Sense
Comparator