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 10
μ
A 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
1
V
CC
OUT
11
2
V
REG
GND
10
3
COMP
BOK
9
4
V
FB
LEN
8
5
ISNS
ACP
6
SS
OV
7
RAMP
RT/CT
14
13
83