NCP1561 Datasheet, PDF (1/22 Pages) ON Semiconductor – Push-Pull PWM Controller for 48 V Telecom Systems

NCP1561
Push−Pull PWM Controller
for 48 V Telecom Systems
The NCP1561 Push−Pull PWM controller contains all the features
and flexibility needed to implement high efficiency dc−dc converters
using voltage or current−mode control. This device can be configured
in any dual ended topology such as push−pull or half−bridge. It can
also be used for forward topologies requiring a 50% maximum duty
cycle. This device is ideally suited for 48 V telecom, 42 V automotive
systems and 12 V input applications.
The NCP1561 cost effectively reduce system part count by
incorporating a high voltage startup regulator, line undervoltage
detector, single resistor oscillator setting, dual mode overcurrent
protection, soft−start and single resistor feedforward ramp generator.
The oscillator frequency can be adjusted up to 250 kHz.
Features
• Internal High Voltage Startup Regulator
• Minimum Operating Voltage of 21.5 V
• Voltage or Current−Mode Control Capability
• Single Resistor Oscillator Frequency Setting
• Adjustable Frequency up to 250 kHz
• Fast Line Feedforward
• Line Undervoltage Lockout
• Dual Mode Overcurrent Protection
• Programmable Maximum Duty Cycle Control
• Maximum Duty Cycle Proportional to Line Voltage
• Programmable Soft−Start
• Precision 5.0 V Reference
Typical Applications
• 48 V Telecommunication Power Converters
• Industrial Power Converters
• 42 V Automotive Systems
+
C1
Vin
−
C2
M4
TX1
OUT1
http://onsemi.com
MARKING
DIAGRAM
16
16
1
SO−16
D SUFFIX
CASE 751B
NCP1561
AWLYWW
1
NCP1561 = Device Code
A
= Assembly Location
WL
= Wafer Lot
Y
= Year
WW
= Work Week
PIN ASSIGNMENTS
V_in
UV
RAMP_OUT
FF
CS
CSKIP
R_T
DC_MAX
V_AUX
OUT1
GND
OUT2
RAMP_IN
V_REF
V_EA
SS
ORDERING INFORMATION
Device
Package
Shipping^†
NCP1561DR2
SO−16 2500 Units/Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
Lout
Startup
Feedforward
M3
Cout
OUT2
NCP1561
OUT1
High Side
Driver
Driver
M1
OUT2
Opto
Error
Amplifier
Figure 1. Half−Bridge Block Diagram
© Semiconductor Components Industries, LLC, 2004
1
August, 2004 − Rev. 3
Publication Order Number
NCP1561/D