UC3844B STMicroelectronics, UC3844B Datasheet - Page 7

• Manufacturer Part Number: UC3844B
• Description: Current Mode PWM
• Manufacturer: STMicroelectronics

Figure 10: Output Saturation Voltagevs. Load
Figure 12: Output Waveform.
Figure 14: Oscillator and Output Waveforms.
10%
90%
V
(V)
-1
-2
3
2
1
0
sat
0
R
C
T
T
V
80 s Pulsed Load 120Hz Rate
V
i
Current.
=15V
T
i
A
=-40˚C
T
200
A
=25˚C
Sink Saturation
(Load to V
Source Saturation
(Load to Ground)
8
4
50ns/DIV
400
PWM
I
D
i
)
CLOCK
T
OSCILLATOR
T
A
600
A
=25˚C
5V REG
=-40˚C
7
5
V
C
T
D95IN341
GND
A
i
V
GND
L
=15V
i
I
= 1.0nF
= 25°C
O
(mA)
6
Figure 11: Supply Current vs. Supply Voltage.
Figure 13: Output Cross Conduction
OUTPUT
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
I
(mA)
V
CC
20
15
10
O
I
5
0
i
0
OUTPUT
OUTPUT
CT
CT
10
LARGE R
SMALL R
100ns/DIV
20
T
T
/LARGE C
/SMALL C
D95IN344
30
R
C
V
I
T
Sense
A
FB
T
T
=25˚C
=10K
=3.3nF
=0V
V
C
T
T
T
D95IN342
A
i
=0V
L
100mA/DIV
=30V
= 15pF
= 25°C
20V/DIV
V
i
(V)
7/15