Datasheet

TL284x, TL384x
CURRENT-MODE PWM CONTROLLERS
SLVS038G − JANUARY 1989 − REVISED FEBRUARY 2008
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
Z
i
Z
f
VFB
COMP
2.5 V
0.5 mA
Error
Amplifier
NOTE A: Error amplifier can source or sink up to 0.5 mA.
+
−
Figure 1. Error-Amplifier Configuration
NOTE A: Peak current (I
S
) is determined by the formula:
A small RC filter formed by resistor R
f
and capacitor C
f
may be required to suppress switch transients.
COMP
ISENSE
GND
R
S
C
f
R
f
Error
Amplifier
2R
R1 V
Current-Sense
Comparator
I
S
(
max
)
+
1V
R
S
I
S
(see Note A)
+
−
Figure 2. Current-Sense Circuit
C
T
R
T
(see Note A)
NOTE A: For R
T
> 5 kΩ:
REF
RT/CT
GND
f [
1.72
R
T
C
T
Figure 3. Oscillator Section