Datasheet

APPLICATION INFORMATION
Oscillator Frequency vs Timing Resistance
Maximum Duty Cycle vs Timing Resistor
V
REF
V
CC
OUTPUT
GND
C
T
1 kW 1 W
0.1 µF
0.1 µF
R
T
2N2222
5 k
I
Adjust
W
SENSE
4.7 kW
4.7 kW
1 k
Error Amp
Adjust
W
COMP
UC2843A
V
FB
I
SENSE
R /C
T T
GND
OUTPUT
V
CC
V
REF
100 kW
1
2
3
4
5
6
7
8
UC2843A-Q1
www.ti.com ........................................................................................................................................................................................................ SGLS384 – MAY 2008
Figure 6. Oscillator
A. High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass
capacitors should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used
to sample the oscillator waveform and apply an adjustable ramp to pin 3.
Figure 7. Open-Loop Laboratory Text Fixture
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Product Folder Link(s): UC2843A-Q1