NCP1280_05 Datasheet, PDF (2/18 Pages) ON Semiconductor – Active Clamp Voltage Mode PWM Controller for Off-Line Applications

NCP1280
1
V_in
I_START
Disable
V_AUX
16
V_AUX
C_AUX
+
14
−
GND
V_in
+
1.49 V
−
3
V_AUX(ON)/V_AUX(OFF)
Disable_V_REF
+
−
One Shot
Pulse
(250 ns)
S
Q
Monotonic
Start
Latch
(Reset
Dominant)
R
5.0 V Reference
DIS
V_REF
11
Disable_V_REF
R_D
UV/OV
+
−
+
3.6 V−
V_REF
CSKIP ^{11 mA}
Disable _−
+
6
C_CSKIP
5
CS
−
+
+
One Shot
2V
−
Pulse
(600 ns)
+
−
+
0.6 V
−
Clock
STOP
Disable_ss
S
Q
Output
Latch
(Reset
Dominant)
R
Delay
Logic
12
t_D
DIS ₁₅
OUT1
V_AUX
DIS
13
OUT2
V_AUX
V_REF
+
+−
0.5 V
−
6 mA
9
Disable_ss
Soft Start
− + ^Comparator
CURRENT MIRROR
I₁
I₁
2
Oscillator Ramp
2V
SS
C_SS
7
R_T
R_T
V_in
STOP
+
* Trimmed during
1.3 V* manufacturing to obtain
−
1.3 V with R_T = 101 kW
10 pF
+
2V
−
Clock
One Shot
Pulse
+
−
+
2V
−
R_{FF 4}
5.3 kW
FF
I_{FF 6.7 kW}
+
V
−
I
+
V
125 kW
+
−
FF Ramp
(Adjustable)
PWM
Comparator
+−
10
V_EA
2 kW
20 kW
Max DC
+ − Comparator
2V
40 kW
+
32 kW
V_DC(inv)
−
27 kW
V_REF
R_MDP
8
DC_MAX
R_P
10 pF C_FF
Figure 2. NCP1280 Functional Block Diagram
http://onsemi.com
2