Current Mode PWM Controller
KA3843A(AM)
PIN FUNCTION
N
1
2
3
4
5
6
7
8
FUNCTION
COMP
V
FB
I
SENSE
R
T
/C
T
GROUND
OUTPUT
V
CC
V
ref
DESCRIPTION
This pin is the Error Amplifier output and is made for loop compensation.
This is the inverting input of the Error Amplifier. It is normally connected to the
switching power supply output through a resistor divider.
A voltage proportional to inductor current is connected to this input. The PWM
uses this information to terminate the output switch conduction.
The oscillator frequency and maximum Output duty cycle are programmed by
connecting resistor R
T
to V
ref
and capacitor C
T
to ground.
This pin is the combined control circuitry and power ground.
This output directly drives the gate of a power MOSFET. Peak currents up to 1A
are sourced and sink by this pin.
This pin is the positive supply of the integrated circuit.
This is the reference output. It provides charging current for capacitor C
T
through
resistor R
T
.
APPLICATION INFORMATION
Figure 1. Error Amp Configuration
WS
WS
Figure 2. Undervoltage Lockout
3
WINGS [ WING SHING COMPUTER COMPONENTS ]
