NCP1254.pdf 데이터시트 (총 25 페이지) - 파일 다운로드 NCP1254 데이타시트 다운로드

No Preview Available !

NCP1254
Product Preview
Current-Mode PWM
Controller for Off-line
Power Supplies featuring
Peak Power Excursion
The NCP1254 is a highly integrated PWM controller capable of
delivering a rugged and high performance offline power supply in a
TSOP6 package. With a supply range up to 35 V, the controller hosts
a jittered 65kHz switching circuitry operated in peak current mode
control. When the power on the secondary side starts to decrease, the
controller automatically folds back its switching frequency down to a
minimum level of 26 kHz. As the power further goes down, the part
enters skip cycle while freezing the peak current setpoint.
To help building rugged converters, the controller features several
key protective features: a nondissipative Over Power Protection for a
constant maximum output current regardless of the input voltage, two
latched over voltage protection inputs either through a dedicated pin
or via the Vcc input and a duallevel autorecovery/latched overload/
shortcircuit timer.
The controller architecture is designed to authorize a transient peak
power excursion when the current setpoint hits the limit. At this point,
the switching frequency is increased from 65 kHz to 130 kHz until the
peak event disappears. The timer duration is then modulated as the
converter crosses a peak power excursion mode (long) or undergoes a
short circuit (short).
Features
65kHz Fixedfrequency Currentmode Control Operation with
130kHz Excursion
Internal and Adjustable Over Power Protection (OPP) Circuit
Frequency Foldback down to 26 kHz and Skipcycle in Light Load
Conditions
Adjustable Slope Compensation
Internally Fixed 4ms Softstart
Fixed Timerbased Autorecovery Overload/Shortcircuit Protection
100% to 25% Timer Reduction from Overload to Shortcircuit Fault
Double Vcc Hiccup for a Reduced Average Power in Fault Mode
Frequency Jittering in Normal and Frequency Foldback Modes
Latched OVP Input for Improved Robustness and Latched OVP on Vcc
Up to 35V Vcc Maximum Rating
Extremely Low Noload Standby Power
This is a PbFree Device
Typical Applications
Converters requiring peakpower capability such as printers power
supplies, acdc adapters for game stations.
This document contains information on a product under development. ON Semiconductor
reserves the right to change or discontinue this product without notice.
http://onsemi.com
1
TSOP6
CASE 318G
STYLE 13
MARKING DIAGRAM
54xAYWG
G
1
54 = Specific Device Code
x = A or B
A = Assembly Location
Y = Year
W = Work Week
G = PbFree Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
GND 1
6 DRV
FB 2
OPP/Latch 3
5 VCC
4 CS
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 2 of this data sheet.
© Semiconductor Components Industries, LLC, 2013
March, 2013 Rev. P1
1
Publication Order Number:
NCP1254/D

No Preview Available !

Vbulk
OVP
OPP
NCP1254
16
25
34
NCP1254
.
.
.
ramp
comp.
Vout
Figure 1. Typical Application Schematic
Table 1. PIN FUNCTION DESCRIPTION
Pin No. Pin Name
Function
1 GND
2 FB
Feedback pin
3 OPP/OVP Adjust the Over Power Protection
Latches off the part
4 CS Current sense + ramp compensation
5 Vcc Supplies the controller – protects the IC
6 DRV
Driver output
Description
The controller ground.
Hooking an optocoupler collector to this pin will allow regula-
tion via peak current mode control or frequency modulation in
highpower conditions.
A resistive divider from the auxiliary winding to this pin sets the
OPP compensation level. When brought above 3 V, the part is
fully latched off.
This pin monitors the primary peak current but also offers a
means to introduce slope compensation.
This pin is connected to an external auxiliary voltage. An OVP
comparator monitors this pin and offers a means to latch the
converter in fault conditions.
The driver’s output to an external MOSFET gate.
Table 2. OPTIONS AND ORDERING INFORMATION
Controller
Frequency
NCP1254ASN65T1G
65 kHz
NCP1254BSN65T1G
65 kHz
OCP Latched
Yes
No
OCP Autorecovery
No
Yes
http://onsemi.com
2

No Preview Available !

OPP
Vlatch
NCP1254
600ns time
constant
OVP
gone?
Up counter
RST
4
SQ
Q
R
Power on
reset
Jitter mod.
Vcc and logic
management
UVLO
double hiccup
Vdd power
on reset
100% to
25% change
VOVP
SC
Vcc
20 ms
option
latch/AR
1ms
blanking
65 kHz
clock
Rlimit
Vcc
Vref
Clamp
Frequency
increase to
130 kHz
Frequency
foldback
SQ
Q
R
IpFlag,
PON reset
Vcc
Drv
VFswp
Vskip
Vfold
vdd
RFB
FB
/4
CS
VSC
LEB
Rramp
SC
4 ms
SS
The softstart is
activated during:
Ip flag
the startup sequence
the autorecovery burst mode
VFB < 1 V ? setpoint = 250 mV
VOPP
250 mV
peak current
freeze
+ Vlimit + VOPP
Vlimit
Figure 2. Internal Circuit Architecture
GND
http://onsemi.com
3

No Preview Available !

NCP1254
Table 3. MAXIMUM RATINGS TABLE
Symbol
Rating
Value
Unit
Vcc
Power Supply voltage, Vcc pin, continuous voltage
0.3 to 35
V
Maximum voltage on lowpower pins CS, FB and OPP
0.3 to 10
V
VDRV
IOPP
Maximum voltage on drive pin
Maximum injected current into the OPP pin
0.3 to Vcc+0.3
2
V
mA
ISCR
RθJA
TJ,max
Iscr
Maximum continuous current into the Vcc pin while in latched mode
Thermal Resistance JunctiontoAir
Maximum Junction Temperature
Maximum continuous current into Vcc pin when latched
Storage Temperature Range
3
360
150
3
60 to +150
mA
°C/W
°C
mA
°C
HBM
Human Body Model ESD Capability (All pins except HV) per JEDEC JESD22A114F
2
kV
MM Machine Model ESD Capability (All pins except DRV) per JEDEC JESD22A115C
200
V
CDM
ChargedDevice Model ESD Capability per JEDEC JESD22C101E
500 V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. This device contains latchup protection and exceeds 100 mA per JEDEC Standard JESD78.
Table 4. ELECTRICAL CHARACTERISTICS
(For typical values TJ = 25°C, for min/max values TJ = 40°C to +125°C, Max TJ = 150°C, Vcc = 12 V unless otherwise noted)
Symbol
Rating
Pin Min Typ Max
Unit
SUPPLY SECTION
VCCON
VCC(min)
VCCHYST
VZENER
ICC1
VCC increasing level at which driving pulses are authorized
VCC decreasing level at which driving pulses are stopped
Hysteresis VccONVcc(min)
Clamped Vcc when latched off @ ICC = 500 mA
Startup current
5 15.8
18
20
V
58
8.8 9.4
V
56 − − V
57 V
5
15 mA
ICC2
Internal IC consumption with VFB = 3.2 V, FSW = 65 kHz and CL = 0
5
1.4 2.2 mA
ICC3
Internal IC consumption with VFB = 3.2 V, FSW = 65 kHz and CL = 1 nF 5
2.1 3.0 mA
ICC4
Internal IC consumption with VFB = 4.5 V, FSW = 130 kHz and CL = 0
5
1.7 2.5 mA
ICC5
Internal IC consumption with VFB = 4.5 V, FSW = 130 kHz and CL = 1 nF 5
3.1 4.0 mA
ICCstby
Internal IC consumption while in skip mode
(Vcc = 12 V, driving a typical 6A/600V MOSFET)
750 mA
ICCLATCH
Current flowing into VCC pin that keeps the controller latched:
Tj = 40°C to 125°C
5
40
mA
Rlim
DRIVE OUTPUT
SCR currentlimit series resistor
5 4 kW
Tr Output voltage risetime @ CL = 1 nF, 1090% of output signal 6 40
Tf Output voltage falltime @ CL = 1 nF, 1090% of output signal 6 30
ROH
Source resistance
6 13
ROL
Sink resistance
66
Isource
Peak source current, VGS = 0 V (Note 2)
6 300
Isink
Peak sink current, VGS = 12 V (Note 2)
6 500
2. Guaranteed by design
3. See characterization table for linearity over negative bias voltage – we recommend keeping the level on pin 3 below 300 mV.
4. A 1MW resistor is connected from pin 4 to the ground for the measurement.
ns
ns
W
W
mA
mA
http://onsemi.com
4

No Preview Available !

NCP1254
Table 4. ELECTRICAL CHARACTERISTICS
(For typical values TJ = 25°C, for min/max values TJ = 40°C to +125°C, Max TJ = 150°C, Vcc = 12 V unless otherwise noted)
Symbol
Rating
Pin Min
Typ Max
Unit
DRIVE OUTPUT
VDRVlow
DRV pin level at VCC close to VCC(min)
with a 33kW resistor to GND
68 − − V
VDRVhigh
DRV pin level at VCC = VOVP 0.2 V – DRV unloaded
CURRENT COMPARATOR
6 10 12 14 V
IIB
VLimit1
VLimit2
Input Bias Current @ 0.8 V input level on pin 4
Maximum internal current setpoint – Tj = 25°C – pin 3 grounded
Maximum internal current setpoint –
Tj from 40° to 125°C – pin 3 grounded
4 0.02 mA
4 0.744 0.8 0.856
V
4 0.72 0.8 0.88 V
VfoldI
VfreezeI
TDEL
TLEB
TSS
Default internal voltage set point for frequency foldback
trip point 59% of Vlimit
Internal peak current setpoint freeze (31% of Vlimit)
Propagation delay from current detection to gate offstate
Leading Edge Blanking Duration
Internal softstart duration activated upon startup, autorecovery
4
4
4
4
475 mV
250 mV
100 150 ns
300 ns
4 ms
IOPPo
Setpoint decrease for pin 3 biased to –250 mV (Note 3)
4
31.3
%
IOOPv
IOOPv
Voltage setpoint for pin 3 biased to 250 mV (Note 3), Tj = 25°C
Voltage setpoint for pin 3 biased to 250 mV (Note 3),
Tj from 40° to 125°C
4 0.51 0.55
0.6
4 0.5 0.55 0.62
V
V
IOPPs
Setpoint decrease for pin 3 grounded
40
%
INTERNAL OSCILLATOR
fOSC,nom
Oscillation frequency, VFB < VFbtrans, pin 3 grounded
VFBtrans
Feedback voltage above which Fsw increases
fOSC,max
Maximum oscillation frequency for VFB above VFBmax
VFBmax
Feedback voltage above which Fsw is constant
Dmax
Maximum duty ratio
fjitter Frequency jittering in percentage of fOSC
fswing
Swing frequency over the whole frequency range
FEEDBACK SECTION
61 65 71 kHz
3.2
V
120 130 140 kHz
3.8 4.1 4.2
V
76 80 84 %
±5
%
240 Hz
Rup
Internal pullup resistor
2 15 kW
Req
Equivalent ac resistor from FB to gnd
2 13 kW
Iratio
Pin 2 to current setpoint division ratio
4
VfreezeF
Feedback voltage below which the peak current is frozen
2
1
V
FREQUENCY FOLDBACK
VfoldF
Frequency foldback level on the feedback pin –
59% of maximum peak current
1.9
V
Ftrans
Vfold,end
Vskip
Skip
hysteresis
Transition frequency below which skipcycle occurs
End of frequency foldback feedback level, Fsw = Fmin
Skipcycle level voltage on the feedback pin
Hysteresis on the skip comparator (Note 2)
22 26 30 kHz
1.5 V
400 mV
30 mV
2. Guaranteed by design
3. See characterization table for linearity over negative bias voltage – we recommend keeping the level on pin 3 below 300 mV.
4. A 1MW resistor is connected from pin 4 to the ground for the measurement.
http://onsemi.com
5