TL384XB Datasheet, PDF (12/21 Pages) Texas Instruments – HIGH-PERFORMANCE CURRENT-MODE PWM CONTROLLERS

TL284xB, TL384xB
HIGH-PERFORMANCE CURRENT-MODE PWM CONTROLLERS
SLVS610A – AUGUST 2006 – REVISED SEPTEMBER 2006
APPLICATION INFORMATION (continued)
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DEAD TIME
vs
TIMING CAPACITANCE
100
V_CC = 15 V
R_T ≥ 5 kΩ
40 _{TA = 25°C}
TIMING RESISTANCE
vs
FREQUENCY
100
C_T = 10 nF
C_T = 4.7 nF
40
C_T = 22 nF
10
C_T = 1 nF
4
1
0.4
0.1
0
10 ^{CT = 22 nF}
C_T = 47 nF
4
C_T = 100 nF
4
10
V_CC = 15 V
T_A = 25°C
1
40
100
100
1k
10k
100k
1M
C_T − Timing Capacitance − nF
f − Frequency − Hz
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 I_SENSE terminal.
REF
R_T
4.7 kΩ
2N2222
A
V_CC
100 kΩ
1-kΩ
Error Amplifier Adjust
4.7 kΩ
5 kΩ
I_SENSE
Adjust
COMP
VFB
TL284xB
TL384xB
V_REF
V_CC
I_SENSE
OUTPUT
R_T/C_T
GND
0.1 µF
0.1 µF
1 kΩ, 1 W _OUTPUT
GND
C_T
Figure 4. Open-Loop Laboratory Test Fixture
12
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