TL284xB, TL384xB
HIGH-PERFORMANCE CURRENT-MODE PWM CONTROLLERS
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SLVS610A–AUGUST 2006–REVISED SEPTEMBER 2006
APPLICATION INFORMATION (continued)
TIMING RESISTANCE
DEAD TIME
vs
vs
FREQUENCY
TIMING CAPACITANCE
100
40
100
40
C
T
= 10 nF
V
R
T
A
= 15 V
≥ 5 kΩ
= 25°C
CC
T
C
T
= 4.7 nF
C
T
= 22 nF
C
T
= 1 nF
10
4
C
T
= 22 nF
10
4
C
T
= 47 nF
1
C
T
= 100 nF
0.4
V
CC
= 15 V
T
A
= 25°C
1
0.1
100
1k
10k
100k
1M
0
4
10
40
100
f − Frequency − Hz
C
T
− Timing Capacitance − nF
Open-Loop Laboratory Test Fixture
In the open-loop laboratory test fixture (see Figure 4), high peak currents associated with loads necessitate
careful grounding techniques. Timing and bypass capacitors should be connected close to the GND terminal in a
single-point ground. The transistor and 5-kΩ potentiometer sample the oscillator waveform and apply an
adjustable ramp to the ISENSE terminal.
REF
R
T
A
V
4.7 kΩ
CC
2N2222
100 kΩ
V
REF
COMP
VFB
0.1 µF
TL284xB
TL384xB
1-kΩ
V
CC
Error Amplifier Adjust
0.1 µF
1 kΩ, 1 W
I
5 kΩ
SENSE
OUTPUT
GND
OUTPUT
GND
4.7 kΩ
I
SENSE
Adjust
R /C
T
T
C
T
Figure 4. Open-Loop Laboratory Test Fixture
12
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