SG6846A — Highly Integrated Green-Mode PWM Controller
( 1 ) Normal
operation
(4 )
V
DD
< 12 V ?
NO
YES
NO
(2 )
I
P
> 2 / 3 I
PK
?
(5 )
Timing = 1700 ms
YES
SCP
NO
(6 )
V
DD
< = 12 V ?
(3 )
Timing = 100 ms
OCP
(7 ) Gate off
SCP
Figure 6. SG6846A OCP/SCP Logic Flow Diagram
Electrical Characteristics
(Continued)
V
DD
= 15V and T
A
= 25°C unless otherwise noted.
Symbol
Oscillator Section
f
OSC
Parameter
Test Condition
Min.
Typ.
Max.
Unit
Normal PWM Frequency
Center
Frequency
Jitter Range
R
I
= 26kΩ, V
FB
>V
N
62
±3.7
65
±4.2
130
±8.4
47.0
±2.90
4.4
11.5
22.5
2.1
4.2
1.6
1.45
85
68
±4.7
136
±9.4
49.2
±3.26
4.9
12.8
25.0
2.3
4.7
1.8
1.62
kHz
f
OSC,MAX
Maximum PWM
Frequency
Center
Frequency
Jitter Range
R
I
= 13kΩ, V
FB
>V
N
124
±7.4
kHz
f
OSC,MIN
t
hop-1
t
hop-3
f
OSC-G
V
FB-N
Center
Minimum PWM Frequency Frequency
Jitter Range
Jitter Period
Green-Mode Minimum Frequency
Pin, FB voltage
FB Pin Frequency
Reduction Threshold Jitter Range
FB Voltage at f
OSC-G
Pin, FB voltage
Jitter Range
R
I
= 36kΩ, V
FB
>V
N
R
I
= 26kΩ, V
FB
≥
V
N
R
I
= 26kΩ, V
FB
= V
G
R
I
= 26kΩ
R
I
= 26kΩ, V
FB
= V
N
44.8
±2.54
3.9
10.2
18.0
1.9
3.7
1.4
1.27
kHz
ms
kHz
V
KHz
V
KHz
Hz/mV
V
FB-G
S
G
f
DV
f
DT
R
I
= 26kΩ, V
FB
= V
G
R
I
= 26kΩ
V
DD
= 11.5V to 20V
T
A
= -30 to 85°C
Slope for Green-Mode Modulation
Frequency Variation vs. V
DD
Deviation
Frequency Variation vs. Temperature
Deviation
5
1.5
5.0
%
%
Continued on following page…
© 2008 Fairchild Semiconductor Corporation
SG6846A • Rev. 1.1.4
www.fairchildsemi.com
7