ASTEC Semiconductor
Description
The AS2214 is a full featured, pulse width modulation
controller. Based on an improved AS3842, the AS2214
provides additional features that reduce component count
and improve specifications in a wide range of power supply
designs. The added functionality includes AC power and
bulk voltage sensing, over-voltage input, as well as the ability
to latch off or bounce through different fault conditions.
The PWM function is controlled by the current sense com-
parator for normal current mode control and a second
comparator for voltage mode soft start. A buffered RAMP
signal is available for slope compensation without loading
the oscillator. The output stage is a high current totem pole
output that sees only 85 ns delay from the PWM comparator.
The AS2214 requires less than 10µA of startup current. The
undervoltage lockout (UVLO) thresholds are nominally 13.8V
for turn on and 8 V for turn off. A precision 2.5 V bandgap
reference serves as an input for the error amplifier. The
oscillator discharge current is trimmed to provide guaran-
teed duty cycle clamping.
AS2214
Primary Side PWM Controller
Features
•
Low Startup Current
•
Bulk and AC sensing
•
Soft Start
•
Single-start or auto-restart
modes
•
Oscillator trimmed for precision
duty cycle clamp
•
Standard temperature range
extended to 105°C
•
Remote on / off control
•
Buffered Ramp for slope
compensation
•
Standard current mode control
Pin Configuration — Top view
Ordering Information
Package Temperature Range Order Code
14-Pin Plastic DIP 0 to 105° C AS2214N
12
1V
CC
OUT
11
2V
REG
GND
10
3COMP BOK
9
4V
FB
LEN
8
5ISNS ACP
6SS OV
7RAMP RT/CT
14
13
83