ꢀ ꢁꢂ ꢃꢄ ꢂꢅ
ꢀ ꢁꢂ ꢃꢄ ꢂꢆ
SLUS557B − MARCH 2003 − REVISED APRIL 2004
APPLICATION INFORMATION
GAIN AND PHASE
vs
VOLTAGE
vs
FREQUENCY
TIME
100
80
5
4
3
V
IN
V
OUT
GAIN
60
40
20
0
0
2
PHASE
−20
−90
−40
100
−180
100 M
1
1 k
10 k
100 k
1 M
10 M
0
0.2
t
0.4
0.6
0.8
1.0
− Delay Time− µs
f
− Frequency − Hz
delay
OSC
Figure 3. Open Loop Frequency Response
Figure 4. Unity Gain Slew Rate
CONTROL METHODS
UC2802x
UC2802x
CT
6
CT
C
T
OSCILLATOR
6
7
OSCILLATOR
I
SENSE
RAMP
*
RAMP
7
1.25 V
1.25 V
*
C
T
R
SENSE
From
Error Amplifier
From
Error Amplifier
UDG−03050
* A small filter may be required to supress switch noise.
UDG−03050
Figure 5. Voltage Mode Control
Figure 6. Peak Current Mode Control
9
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