Fixed Frequency Controllers
Low Cost and Low Power Consumption. . .
Fixed frequency controllers from ON Semiconductor are the perfect solution for many applications. DVD
players, set-top boxes, notebook power adapters, printers, scanners, LCD monitors, and a wealth of other end
products use our controllers. Extremely low standby power helps you easily meet applicable regulations. The
Dynamic Self-Supply (DSS) feature of our devices saves cost by avoiding the use of an auxiliary transformer
winding, and current-mode topologies give tighter control of output voltage. Our fixed frequency controllers
can help you meet your toughest design challenges while still keeping cost to a minimum.
Key Features & Benefits
~
Dynamic Self Supply (DSS) capability
i
No auxiliary transformer winding
~
Current-mode control with adjustable skip-cycle and Soft-
Skip™capability
i
Provides excellent efficiency at light loads
i
No acoustic noise generation
~
Fixed frequencies up to 200 kHz
i
Offers suitable solution for all applications
~
High-voltage start-up-current source
i
Clean loss less start-up sequence
HV Pin Handles Up to
500 V Directly
~
Frequency jittering
i
Reduces EMI signature
~
Go-to-standby for PFC front stage
i
Minimizes standby losses
~
Internal short–circuit protection independent of auxiliary voltage
i
Reliable short-circuit protection, immediately reducing the
output power
~
Under-voltage lockout at 7.6 V typical
i
Suitable for applications already using UC3843
+
AC
Input
EMI
Filter
Output
Voltage
−
Latch
Input
Latch Protection
skip/latch HV
FB
CS
V
CC
Gnd
Drv
HV Pin
Protection
Adjust
Skip
Level
Decoupling
Capacitors
NCP1271
NCP1271
Demo Board
Compensation
Ramp
Primary Current Limitation
Current-Mode Operation
NCP1271 Typical Schematic for Fixed Frequency Controller with Soft-Skip™
Ramp
Compensation
500V Off-Line
Starup FET
Freq Jittering
Dynamic Self
Supply
FIXED
FREQUENCY
CONTROLLERS
Device
Max
Output
Power
(W)
Mode
Standby
Power
Method
Adj Skip
Adj Skip
Adj Skip
Adj Skip
Adj Skip
Adj Skip
Adj Skip
Adj Skip w/ TLD
5
Skip Cycle
Output
Gate Drive
(mA) @
V
CC
= 11V
250
250
250
500
500
500
500
500
200
Frequency
Options
(kHz)
40,60,100
60,100
40,60,100
65,100,133
65,100,133
Adj Up to 150
65,100,133
65,100
Adj Up to 1000
Brown-Out
Soft-Start
Enable
4
4
4
4
4
4
4
4
Latch
OVP
4
Package(s)
SO-8, PDIP-8
SO-8, PDIP-8
SO-8, PDIP-8
SO-8, PDIP-7
SO-7, PDIP-7
SO-8, PDIP-8
SO-8, PDIP-8
SO-7
SO-16
Low End
Yes
Do you
need low
Standby
power?
No
What
features
do you
need?
High End
NCP1200
150/40
1
Current
NCP1201
150
Current
NCP1203
150
Current
NCP1216/A
2
150/100
1
Current
NCP1217/A
2
150
Current
NCP1212
150
Current
NCP1230
150
Current
NCP1271
150
Current
NCP1282/1562*
400
Voltage
4
4
4
4
4
4
4*
4
4
4
4
4
4
4
4
4
4
4
4
4
4
3
4
3
4
4
4
4
4
4
4
4
4
EXT
EXT
EXT
INT
INT
EXT
INT
INT
EXT
4
4
1. Maximum power output with DSS 2. “A” Versions Have a 50% Max Duty Cycle for Forward Topologies 3. Only Available on “A” Versions 4. Overvoltage Protection 5. Transient Load Detection * NCP1562 has 100 V startup FET
Please visit our website at www.onsemi.com for additional options.
ON Semiconductor
Page 5
ONSEMI [ ON SEMICONDUCTOR ]
