NCP1205 ON Semiconductor, NCP1205 Datasheet - Page 2

• Manufacturer Part Number: NCP1205
• Description: Single Ended Pwm Controller Featuring Qr Operation And Soft Frequency Foldback
• Manufacturer: ON Semiconductor

1. PDIP−14 has different pinouts. Please see Pin Connections.
2. Pin 2, 7, 8, 9 and 14 are nonconnected on PDIP−14.
3. Pin 2, 3, 8, 9, 10, 15 and 16 are nonconnected on SOIC−16.
PIN FUNCTION DESCRIPTION
PDIP−8
NA
Demag
1
2
3
4
5
6
7
8
HV
FB
Ct
PDIP−14
Pin No.
1
2
3
4
10
12
13
11
1
3
4
5
6
PDIP−8
SOIC−16
11
12
13
14
1
4
5
6
7
8 V
7 Drive
6 Isense
5 GND
CC
Pin Name
Demag
Isense
GND
OVP
V
Drv
HV
FB
Ct
CC
Startup rail
Zero primary−current
detection
Feedback signal to
control the PWM
Timing capacitor
The IC’s ground
Overvoltage input
The primary−current
sensing pin
This pin drives the
external switcher
Powers the IC
Demag
OVP
Function
NC
NC
HV
FB 4
PIN CONNECTIONS
Ct
http://onsemi.com
1
2
3
5
6
7
PDIP−14
2
14
13
12
10
11
9
8
Connected to the rectified HV rail, this pin provides a
charging path to V
This pin ensures the restart of the main switcher when
operating in free−run.
This level modulates the peak current level in free−running
operation and modulates the frequency in VFM operation.
By adding a capacitor from Ct to the ground, the user selects
the minimum/maximum operating frequency.
By applying a 2.8 V typical level on this pin, the IC is
permanently latched−off until V
This pin senses the primary current via an external shunt
resistor.
The IC is able to deliver or absorb 250 mA peak currents
while delivering a clamped driving signal.
A positive voltage up to 30 V maximum can be applied upon
this pin before the IC stops.
NC
V
Drive
Isense
GND
NC
NC
CC
CC
Demag
bulk capacitor.
OVP
Description
NC
NC
NC
HV
FB
Ct
−
1
2
3
4
5
6
7
8
CC
falls below UVLO
SOIC−16
16
15
14 V
10
13 Drive
12 Isense
11 GND
9
NC
NC
NC
NC
L
CC
.