NCP1652DWR2G [ONSEMI]

Power Factor Controller (PFC), High Efficiency, Single Stage;
NCP1652DWR2G
型号: NCP1652DWR2G
厂家: ONSEMI    ONSEMI
描述:

Power Factor Controller (PFC), High Efficiency, Single Stage

开关 控制器 开关式稳压器 开关式控制器 功率因数校正 光电二极管 电源电路 开关式稳压器或控制器
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NCP1652, NCP1652A  
High-Efficiency Single  
Stage Power Factor  
Correction and Step-Down  
Controller  
http://onsemi.com  
MARKING  
The NCP1652 is a highly integrated controller for implementing  
power factor correction (PFC) and isolated step down acdc power  
conversion in a single stage, resulting in a lower cost and reduced part  
count solution. This controller is ideal for notebook adapters, battery  
chargers and other offline applications with power requirements  
between 75 W and 150 W. The single stage is based on the flyback  
converter and it is designed to operate in continuous conduction  
(CCM) or discontinuous conduction (DCM) modes.  
The NCP1652 increases the system efficiency by incorporating a  
secondary driver with adjustable nonoverlap delay for controlling a  
synchronous rectifier switch in the secondary side, an active clamp  
switch in the primary or both. In addition, the controller features a  
proprietary SoftSkipto reduce acoustic noise at light loads. Other  
features found in the NCP1652 include a high voltage startup circuit,  
voltage feedforward, brown out detector, internal overload timer, latch  
input and a high accuracy multiplier.  
DIAGRAMS  
20  
NCP1652  
AWLYYWWG  
SO20 WB  
DW SUFFIX  
CASE 751D  
1
NCP1652G  
AWLYWW  
SOIC16  
D SUFFIX  
CASE 751B  
NCP1652AG  
AWLYWW  
Features  
Dual Control Outputs with Adjustable Non Overlap Delay for  
Driving a Synchronous Rectifier Switch, an Active Clamp Switch or  
Both  
Voltage Feedforward Improves Loop Response  
A
= Assembly Location  
= Wafer Lot  
= Year  
= Work Week  
= PbFree Package  
WL  
YY  
WW  
G
Frequency Jittering Reduces EMI Signature  
Proprietary SoftSkipat Light Loads Reduces Acoustic Noise  
Brown Out Detector  
Internal 150 ms Fault Timer  
ORDERING INFORMATION  
See detailed ordering and shipping information in the package  
dimensions section on page 32 of this data sheet.  
Independent LatchOff Input Facilitates Implementation of  
Overvoltage and Overtemperature Fault Detectors  
Single Stage PFC and Isolated Step Down Converter  
Continuous or Discontinuous Conduction Mode Operation  
Average Current Mode Control (ACMC), Fixed Frequency Operation  
High Accuracy Multiplier Reduces Input Line Harmonics  
Adjustable Operating Frequency from 20 kHz to 250 kHz  
These are PbFree Devices  
Typical Applications  
Notebook Adapter  
High Current Battery Chargers  
Front Ends for Distributed Power Systems  
High Power Solid State Lighting  
© Semiconductor Components Industries, LLC, 2010  
1
Publication Order Number:  
April, 2010 Rev. 3  
NCP1652/D  
NCP1652, NCP1652A  
SO20 WB  
SOIC16  
CT  
1
Startup  
GND  
CT  
Startup  
16  
15  
14  
13  
12  
11  
10  
9
20  
19  
18  
17  
16  
15  
14  
13  
12  
11  
1
2
Ramp Comp  
AC IN  
2
3
4
5
6
Ramp Comp  
AC IN  
NC  
OUT B  
OUT A  
NC  
3
4
FB  
FB  
GND  
Out B  
Out A  
V
FF  
V
CC  
CM  
AC COMP  
LatchOff  
I
spos  
V
FF  
5
6
I
7
8
avg  
CM  
R
delay  
7
8
NC  
NC  
V
CC  
spos  
avg  
(Top View)  
I
I
AC COMP  
LatchOff  
9
R
10  
delay  
Figure 1. Pin Connections  
http://onsemi.com  
2
NCP1652, NCP1652A  
Overload  
Timer  
OVLD  
Enable  
FB overload  
comparator  
Jitter  
Jitter  
t
FB  
+
+
S
Q
R
OVLD  
CT  
Adj.  
V
OVLD  
Clock  
DC Max  
Oscillator  
DC Max  
Startup  
V
BrownOut  
Comparator  
+
Enable  
x 2  
FF  
Out  
Sawtooth  
counter  
V
FF  
Reset  
+
Dual HV  
startup  
current source  
V
BO  
BO  
Ramp. Comp.  
Adj.  
Ramp Comp  
V
HV current  
CC(off)  
Reset  
Reset  
Start  
V
CC  
Management  
GND  
Ramp  
Comp  
V
AC In skip  
comparator  
CCOK  
V
DD  
+
+
V
DD  
V
V
SSKIP(sync)  
DD  
Output  
Driver  
Clock  
Softskip Ramp  
R
FB skip  
Delay  
Adj.  
FB  
DC Max  
Comparator  
Delay  
OUTB  
t
SSKIP  
+
Start  
Terminate  
+
Inst. current B  
V
SSKIP  
Delay  
Transient Load Detect  
Comparator  
+
AC IN  
S
+
+
Q
OUTA  
Ramp Comp  
Output  
Driver  
R
V
SSKIP(TLD)  
VtoI  
VtoI  
PWM Skip  
Comparator  
FB  
21.33kW  
FB  
Reference  
Generator  
+
VtoI  
+ inverter  
gm  
+
V
CC  
AC error  
Amplifier  
PWM  
comparator  
V
V
FF  
FF  
21.33kW  
+
BO  
OVLD  
Latch  
4V  
CM  
V
OK  
CC  
Inst. current A  
Blanking  
+
I
spos  
t
gm  
LEB  
AC COMP  
Blanking  
Current sense  
amplifier  
Inst.  
current B  
t
LEB  
V
DD  
OVP Comparator  
+
I
avg  
+
I
latch(clamp)  
V
latch(high)  
blanking  
(delay)  
t
Latch  
LatchOff  
OTP Comparator  
S
Q
R
+
Latch  
I
Delay  
latch(shdn)  
R
delay  
+
V
latch(low)  
V
latch(clamp)  
Reset  
Figure 2. Detailed Block Diagram  
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3
NCP1652, NCP1652A  
PIN FUNCTION DESCRIPTION  
Pin  
16 Pin  
20 Pin  
Symbol  
Description  
1
1
C
An external timing capacitor (C ) sets the oscillator frequency. A sawtooth between 0.2 V and 4  
T
T
V sets the oscillator frequency and the gain of the multiplier.  
2
2
RAMP COMP  
A resistor (R ) between this pin and ground adjust the amount of ramp compensation that is  
added to the current signal. Ramp compensation is required to prevent subharmonic oscilla-  
tions. This pin should not be left open.  
RC  
3
4
3
4
AC IN  
FB  
The scaled version of the full wave rectified input ac wave is connected to this pin by means of  
a resistive voltage divider. The line voltage information is used by the multiplier.  
An error signal from an external error amplifier circuit is fed to this pin via an optocoupler or  
other isolation circuit. The FB voltage is a proportional of the load of the converter. If the voltage  
on the FB pin drops below V  
the controller enters SoftSkipto reduce acoustic noise.  
SSKIP  
5
6
5
6
VFF  
CM  
Feedforward input. A scaled version of the filtered rectified line voltage is applied by means of a  
resistive divider and an averaging capacitor. The information is used by the Reference Generat-  
or to regulate the controller.  
Multiplier output. A capacitor is connected between this pin and ground to filter the modulated  
output of the multiplier.  
7
8
9
NC  
NC  
7
AC COMP  
Sets the pole for the ac reference amplifier. The reference amplifier compares the low fre-  
quency component of the input current to the ac reference signal. The response must be slow  
enough to filter out most of the high frequency content of the current signal that is injected from  
the current sense amplifier, but fast enough to cause minimal distortion to the line frequency  
information. The pin should not be left open.  
8
9
10  
11  
12  
Latch  
LatchOff input. Pulling this pin below 1.0 V (typical) or pulling it above 7.0 V (typical) latches  
the controller. This input can be used to implement an overvoltage detector, an overtemperature  
detector or both. Refer to Figure 69 for a typical implementation.  
Rdelay  
A resistor between this pin and ground sets the nonoverlap time delay between OUTA and  
OUTB. The delay is adjusted to prevent cross conduction between the primary MOSFET and  
synchronous rectification MOSFET or optimize the resonant transition in an active clamp stage.  
10  
I
An external resistor and capacitor connected from this terminal to ground, to set and stabilizes  
the gain of the current sense amplifier output that drives the ac error amplifier.  
AVG  
11  
12  
13  
14  
I
Positive current sense input. Connects to the positive side of the current sense resistor.  
Positive input supply. This pin connects to an external capacitor for energy storage. An internal  
Spos  
V
CC  
current source supplies current from the STARTUP pin V . Once the voltage on V reaches  
CC  
CC  
approximately 15.3 V, the current source turns off and the outputs are enabled. The drivers are  
disabled once V reaches approximately 10.3 V. If V drops below 0.85 V (typical), the star-  
CC  
CC  
tup current is reduced to less than 500 mA.  
13  
14  
15  
16  
OUTA  
OUTB  
Drive output for the main flyback power MOSFET or IGBT. OUTA has a source resistance of  
13 W (typical) and a sink resistance of 8 W (typical).  
Secondary output of the PWM Controller. It can be used to drive synchronous rectifier, and  
active clamp switch, or both. OUTB has source and sink resistances of 22 W (typical) and 11  
(typical), respectively.  
15  
16  
17  
18  
19  
20  
GND  
NC  
Ground reference for the circuit.  
NC  
HV  
Connect the rectified input line voltage directly to this pin to enable the internal startup regulator.  
A constant current source supplies current from this pin to the capacitor connected to the V  
CC  
pin, eliminating the need for a startup resistor. The charge current is typically 5.5 mA. Maximum  
input voltage is 500 V.  
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4
NCP1652, NCP1652A  
MAXIMUM RATINGS (Notes 1 and 2)  
Rating  
Symbol  
Value  
Unit  
Start_up Input Voltage  
Start_up Input Current  
V
0.3 to 500  
$100  
V
mA  
HV  
HV  
I
Power Supply Input Voltage  
Power Supply Input Current  
V
0.3 to 20  
$100  
V
mA  
CC  
CC  
I
Latch Input Voltage  
Latch Input Current  
V
0.3 to 10  
$100  
V
mA  
Latch  
Latch  
I
OUTA Pin Voltage  
OUTA Pin Current  
V
outA  
0.3 to 20  
$1.0  
V
A
outA  
I
OUTB Pin Voltage  
OUTB Pin Current  
V
outB  
0.3 to 20  
$600  
V
mA  
outB  
I
All Other Pins Voltage  
All Other Pins Current  
0.3 to 6.5  
$100  
V
mA  
Thermal Resistance, JunctiontoAir  
0.1 in” Copper  
0.5 in” Copper  
q
°C/W  
JA  
130  
110  
Thermal Resistance, JunctiontoLead  
R
50  
°C/W  
W
ΘJL  
Maximum Power Dissipation @ T = 25°C  
P
MAX  
0.77  
A
Operating Temperature Range  
Storage Temperature Range  
T
40 to 125  
55 to 150  
°C  
J
T
°C  
STG  
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 series contains ESD protection and exceeds the following tests:  
16 pin package:  
Pin 115: Human Body Model 2000 V per JEDEC standard JESD22, Method A114.  
Machine Model 200 V per JEDEC standard JESD22, Method A115.  
Pin 16 is the high voltage startup of the device and is rated to the maximum rating of the part, 500 V.  
20 pin package:  
Pin 119: Human Body Model 2000 V per JEDEC standard JESD22, Method A114.  
Machine Model 200 V per JEDEC standard JESD22, Method A115.  
Pin 20 is the high voltage startup of the device and it is rated to the maximum  
rating of the part, or 500 V.  
2. This device contains Latchup protection and exceeds 100 mA per JEDEC Standard JESD78.  
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5
NCP1652, NCP1652A  
VCC  
EMI Filter  
Latch  
+
_
+
+
NTC  
FB  
1
CT  
HV  
GND  
Ramp Comp  
OUTB  
OUTA  
AC IN  
FB  
FB  
VCC  
VFF  
VCC  
NCP1652  
CM  
Ispos  
Iavg  
AC COMP  
10  
11  
Latch  
LATCH  
Rdelay  
Figure 3. Typical Application Schematic  
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6
NCP1652, NCP1652A  
ELECTRICAL CHARACTERISTICS (V = 15 V, V  
= 3.8 V, V = 2.0 V, V = 2.4 V, V  
= open, V  
= 49.9 kW,  
= 100 mV,  
CC  
AC IN  
FB  
FF  
Latch  
ISPOS  
C
C
= 1 nF, C = 470 pF, C  
= 0.27 nF, C  
= 0.1 nF, C = 10 nF, R  
= 76.8 kW, R  
OUTA  
T
IAVG  
Latch  
M
IAVG  
delay  
= 330 pF, R = 43 kW, For typical Value T = 25°C, for min/max values T = 40°C to 125°C, unless otherwise noted)  
OUTB  
RC  
J
J
Parameter  
Test Condition  
Symbol  
Min  
Typ  
Max  
Unit  
OSCILLATOR  
Frequency  
f
90  
100  
6.8  
110  
kHz  
%
osc  
Frequency Modulation in Percentage  
of f  
OSC  
Frequency Modulation Period  
Ramp Peak Voltage  
6.8  
4.0  
0.10  
ms  
V
V
CT(peak)  
Ramp Valley Voltage  
V
V
CT(valley)  
Maximum Duty Ratio  
R
= open  
D
94  
%
V
delay  
Ramp Compensation Peak Voltage  
AC ERROR AMPLIFIER  
Input Offset Voltage (Note 3)  
Error Amplifier Transconductance  
Source Current  
V
4
RCOMP(peak)  
Ramp I  
, V = 0 V  
AVG FB  
ACV  
40  
100  
70  
mV  
mS  
mA  
IO  
g
m
V
= 2.0 V, V  
V
= 2.0 V,  
= 2.0 V,  
I
EA(source)  
25  
AC COMP  
AC IN  
= 1.0 V  
FF  
Sink Current  
V
= 2.0 V, V  
V
I
EA(sink)  
25  
70  
mA  
AC COMP  
A C_IN  
= 5.0 V  
FF  
CURRENT AMPLIFIER  
Input Bias Current  
V
= 0 V  
CAI  
40  
53  
0
80  
20  
mA  
mV  
V
ISPOS  
bias  
Input Offset Voltage  
Current Limit Threshold  
V
= 5.0 V, V  
= 0 V  
CAV  
20  
AC COMP  
ISpos  
IO  
ILIM  
force OUTA high, V  
= 3.0 V,  
= open  
V
0.695  
0.74  
0.77  
AC COMP  
Ramp_Comp  
ramp V  
, V  
ISPOS  
Leading Edge Blanking Duration  
Bandwidth  
t
200  
1.5  
5.3  
ns  
LEB  
MHz  
V/V  
PWM Output Voltage Gain  
PWMk  
ISVk  
4.0  
6.0  
4
PWMk +  
(V  
* C  
)
ILIM  
AVIO  
Current Limit Voltage Gain (See  
Current Sense Section)  
15.4  
18.5  
0.55  
23  
V/V  
V
V
(AVG)  
ISVK +  
VI  
SPOS  
REFERENCE GENERATOR  
Reference Generator Gain  
k
2
V
@ V  
AC_REF  
FF  
k +  
V
@ V  
AC_IN  
FB  
Reference Generator output voltage  
(low input ac line and full load)  
V
= 1.2 V, V = 0.765 V,  
RG  
RG  
RG  
RG  
3.61  
1.16  
1.85  
0.55  
100  
4.36  
1.35  
2.18  
0.65  
4.94  
1.61  
2.58  
0.78  
100  
Vpk  
Vpk  
Vpk  
Vpk  
mV  
AC IN  
FF  
out1  
out2  
out3  
out4  
offset  
V
= 4 V  
FB  
Reference Generator output voltage  
(high input ac line and full load)  
V
= 3.75 V, V = 2.39 V,  
AC IN FF  
V
FB  
= 4.0 V  
Reference Generator output Voltage  
(low input as line and minimum load)  
V
= 1.2 V, V = 0.765 V,  
AC IN FF  
V
FB  
= 2.0 V  
Reference Generator output voltage  
(high input ac line and minimum load)  
V
= 3.75 V, V = 2.39 V,  
AC IN FF  
V
FB  
= 2.0 V  
Reference Generator output offset  
voltage  
RG  
3. Guaranteed by Design  
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7
NCP1652, NCP1652A  
ELECTRICAL CHARACTERISTICS (V = 15 V, V  
= 3.8 V, V = 2.0 V, V = 2.4 V, V  
= open, V  
= 49.9 kW,  
= 100 mV,  
CC  
AC IN  
FB  
FF  
Latch  
ISPOS  
C
C
= 1 nF, C = 470 pF, C  
= 0.27 nF, C  
= 0.1 nF, C = 10 nF, R  
= 76.8 kW, R  
OUTA  
T
IAVG  
Latch  
M
IAVG  
delay  
= 330 pF, R = 43 kW, For typical Value T = 25°C, for min/max values T = 40°C to 125°C, unless otherwise noted)  
OUTB  
RC  
J
J
Parameter  
Test Condition  
Symbol  
Min  
Typ  
Max  
Unit  
AC INPUT  
Input Bias Current Into Reference  
Multiplier & Current Compensation  
Amplifier  
I
0.01  
mA  
AC IN(IB)  
DRIVE OUTPUTS A and B  
Drive Resistance (Thermally Limited)  
OUTA Sink  
W
V
OUTA  
= 1 V  
R
SNK1  
R
SRC1  
8
10.8  
18  
24  
OUTA  
OUTA Source  
I
= 100 mA  
OUTB Sink  
OUTB Source  
V
OUTB  
= 1 V  
R
SNK2  
R
SRC2  
10  
21  
22  
44  
OUTB  
I
= 100 mA  
Rise Time (10% to 90%)  
ns  
ns  
OUTA  
OUTB  
t
r1  
t
r2  
40  
25  
Fall Time (90% to 10%)  
OUTA  
OUTB  
t
f1  
t
f2  
20  
10  
DRV Low Voltage  
OUTA  
mV  
I
= 100 mA  
= 100 mA  
V
V
1.0  
1.0  
100  
100  
OUTA  
OUTB  
OUTA(low)  
OUTB(low)  
OUTB  
I
NonOverlap Adjustable Delay Range  
(Note 3)  
t
0.08  
2.8  
ms  
delay(range)  
NonOverlap Adjustable Delay  
Measured at 50% of V  
,
ns  
OUT  
C
= C  
= 100 pF  
OUTA  
OUTB  
Leading  
Trailing  
OUTA Rising to OUTB falling  
OUTB Rising to OUTA falling  
t
250  
250  
450  
420  
550  
550  
delay(lead)  
delay(trail)  
t
NonOverlap Adjustable Delay  
Matching  
OUTA Rising to OUTB Falling or OUTB  
Rising to OUTA Falling  
t
55  
%
delay(match)  
SoftSkip]  
Skip Synchronization to ac Line  
Voltage Threshold  
V
ACIN  
Increasing, V = 1.5 V  
V
210  
267  
40  
325  
mV  
mV  
FB  
SSKIP(SYNC)  
Skip Synchronization to ac Line  
Voltage Threshold Hysteresis  
V
ACIN  
Decreasing  
V
SSKIP  
(SYNCHYS)  
Skip Ramp Period (Note 3)  
t
2.5  
ms  
V
SSKIP  
Skip Voltage Threshold  
NCP1652  
V
SSKIP  
1.04  
0.36  
1.24  
0.41  
1.56  
0.46  
NCP1652A  
Skip Voltage Hysteresis  
V
45  
90  
140  
mV  
V
SSKIP(HYS)  
Skip Transient Load Detect Threshold  
(Note 3)  
V
= V  
+0.55 V  
V
SSKIP(TLD)  
1.75  
SSKIP(TLD)  
SSKIP  
FEEDBACK INPUT  
PullUp Current Source  
PullUp Resistor  
V
FB  
= 0.5 V  
I
600  
750  
6.7  
5.7  
920  
mA  
kW  
V
FB  
R
FB  
FB(open)  
Open Circuit Voltage  
V
5.3  
6.3  
STARTUP AND SUPPLY CIRCUITS  
Supply Voltage  
V
V
Startup Threshold  
V
Increasing  
Decreasing  
Decreasing  
V
14.3  
9.3  
15.4  
10.2  
7.0  
16.3  
11.3  
CC  
CC(on)  
V
CC(off)  
Minimum Operating Voltage  
Logic Reset Voltage  
V
CC  
V
CC  
V
CC(reset)  
Inhibit Threshold Voltage  
3. Guaranteed by Design  
V
HV  
= 40 V, I  
= 500 mA  
V
inhibit  
0.83  
1.15  
inhibit  
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8
NCP1652, NCP1652A  
ELECTRICAL CHARACTERISTICS (V = 15 V, V  
= 3.8 V, V = 2.0 V, V = 2.4 V, V  
= open, V  
= 49.9 kW,  
= 100 mV,  
CC  
AC IN  
FB  
FF  
Latch  
ISPOS  
C
C
= 1 nF, C = 470 pF, C  
= 0.27 nF, C  
= 0.1 nF, C = 10 nF, R  
= 76.8 kW, R  
OUTA  
T
IAVG  
Latch  
M
IAVG  
delay  
= 330 pF, R = 43 kW, For typical Value T = 25°C, for min/max values T = 40°C to 125°C, unless otherwise noted)  
OUTB  
RC  
J
J
Parameter  
Test Condition  
Symbol  
Min  
Typ  
Max  
Unit  
STARTUP AND SUPPLY CIRCUITS  
Inhibit Bias Current  
V
= 40 V, V = 0.8 * V  
I
40  
500  
mA  
HV  
CC  
inhibit  
inhibit  
-
Minimum Startup Voltage  
Startup Current  
I
= 0.5 mA, V = V  
– 0.5 V  
V
start(min)  
40  
V
start  
CC  
CC(on)  
V
= V  
– 0.5 V, V = Open  
I
start  
3.0  
5.62  
8.0  
mA  
mA  
CC  
CC(on)  
FB  
OffState Leakage Current  
V
= 400 V, T = 25°C  
I
HV(off)  
HV  
J
J
T = 40°C to 125°C  
17  
15  
40  
80  
Supply Current  
Device Disabled (Overload)  
Device Switching  
mA  
V
OSC  
= Open  
I
I
0.72  
6.25  
1.2  
7.2  
FB  
CC1  
CC2  
f
[ 100 kHz  
FAULT PROTECTION  
Overload Timer  
t
120  
4.7  
162  
4.9  
360  
5.2  
ms  
V
OVLD  
Overload Detect Threshold  
V
OVLD  
BrownOut Detect Threshold (entering  
V
Decreasing, V = 2.5 V,  
V
0.41  
0.45  
0.49  
V
FF  
FB  
BO(low)  
BO(high)  
BO(HYS)  
fault mode)  
V
= 2.0 V  
AC IN  
BrownOut Exit Threshold (exiting  
fault mode)  
V
Increasing, V = 2.5 V,  
V
0.57  
0.63  
174  
0.69  
V
FF  
FB  
= 2.0 V  
V
AC IN  
BrownOut Hysteresis  
V
mV  
LATCH INPUT  
PullDown Latch Voltage Threshold  
PullUp Latch Voltage Threshold  
Latch Propagation Delay  
V
Decreasing  
Increasing  
V
0.9  
5.6  
30  
42  
2.5  
0.98  
7.0  
56  
1.1  
8.4  
90  
58  
4.5  
V
V
Latch  
latch(low)  
latch(high)  
latch(delay)  
V
V
Latch  
V
Latch  
= V  
t
ms  
mA  
V
latch(high)  
Latch Clamp Current (Going Out)  
V
= 1.5 V  
I
51  
Latch  
Latch  
latch(clamp)  
Latch Clamp Voltage (I  
Going In)  
I
= 50 mA  
V
I
3.27  
95  
Latch  
latch(clamp)  
LatchOff Current Shutdown  
(Going In)  
V
Increasing  
mA  
Latch  
latch(shdn)  
3. Guaranteed by Design  
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9
NCP1652, NCP1652A  
110  
105  
100  
95  
8.0  
7.5  
7.0  
6.5  
6.0  
90  
50  
25  
0
25  
50  
75  
100  
125  
150  
50  
25  
0
25  
50  
75  
100  
125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 4. Oscillator Frequency (fOSC) vs.  
Junction Temperature  
Figure 5. Oscillator Frequency Modulation in  
Percentage of fOSC vs. Junction Temperature  
4.1  
4.05  
4.0  
8.0  
7.5  
7.0  
6.5  
6.0  
3.95  
3.9  
3.85  
3.8  
50  
25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 6. Oscillator Frequency Modulation  
Period vs. Junction Temperature  
Figure 7. Ramp Peak Voltage vs. Junction  
Temperature  
4.1  
4.05  
4.0  
100  
98  
96  
94  
92  
90  
3.95  
3.9  
3.85  
3.8  
50  
50  
25  
0
25  
50  
75  
100  
125  
150  
25  
0
25  
50  
75  
100 125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 8. Maximum Duty Ratio vs. Junction  
Temperature  
Figure 9. Ramp Compensation Peak Voltage  
vs. Junction Temperature  
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10  
NCP1652, NCP1652A  
90  
85  
80  
75  
70  
65  
60  
55  
50  
90  
85  
80  
75  
70  
65  
60  
55  
50  
50  
25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 10. Error Amplifier Source Current vs.  
Junction Temperature  
Figure 11. Error Amplifier Sink Current vs.  
Junction Temperature  
60.0  
57.5  
55.0  
52.5  
50.0  
47.5  
45.0  
42.5  
40.0  
50  
25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
Figure 12. Current Amplifier Input Bias  
Current vs. Junction Temperature  
770  
760  
750  
740  
730  
720  
710  
700  
6.0  
5.8  
5.6  
5.4  
5.2  
5.0  
50  
25  
0
25  
50  
75  
100  
125 150  
50 25  
0
25  
50  
75  
100  
125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 13. Current Limit Threshold vs.  
Junction Temperature  
Figure 14. PWM Output Voltage Gain vs.  
Junction Temperature  
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11  
NCP1652, NCP1652A  
5.25  
4.75  
4.25  
3.75  
3.25  
2.75  
2.25  
1.75  
1.25  
0.75  
0.25  
22  
21  
20  
19  
18  
17  
16  
R
R
Gout1  
Gout3  
R
R
Gout2  
Gout4  
50 25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100  
125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 15. Oscillator CS Limit Voltage Gain vs.  
Junction Temperature  
Figure 16. Oscillator Reference Generator  
Output Voltage vs. Junction Temperature  
14  
12  
16  
14  
10  
12  
8.0  
6.0  
4.0  
10  
8.0  
6.0  
50 25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 17. OUTA Sink Resistance vs. Junction  
Temperature  
Figure 18. OUTA Source Drive Resistance vs.  
Junction Temperature  
32  
30  
28  
26  
24  
22  
20  
18  
16  
14  
16  
14  
V
CC  
= 15 V  
V
= 15 V  
CC  
CI = 100 pF  
12  
10  
8.0  
6.0  
50  
25  
0
25  
50  
75  
100 125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 19. OUTB Sink Resistance vs.  
Junction Temperature  
Figure 20. OUTB Source Drive Resistance vs.  
Junction Temperature  
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12  
NCP1652, NCP1652A  
130  
110  
90  
160  
140  
120  
100  
80  
70  
50  
30  
50  
60  
50  
25  
0
25  
50  
75  
100  
125  
150  
25  
0
25  
50  
75  
100  
125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 21. OUTA Low Voltage vs. Junction  
Temperature  
Figure 22. OUTB Low Voltage vs. Junction  
Temperature  
600  
550  
500  
450  
400  
350  
300  
9
7
5
3
1
OUTA Rising to OUTB Falling  
OUTB Rising to OUTA Falling  
50  
25  
0
25  
50  
75  
100 125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 23. NonOverlap Adjustable Delay vs.  
Figure 24. NonOverlap Adjustable Delay  
Junction Temperature  
Matching vs. Junction Temperature  
300  
280  
260  
240  
220  
200  
1.25  
1.24  
1.23  
1.22  
1.21  
1.20  
50  
25  
0
25  
50  
75  
100 125  
150  
50  
25  
0
25  
50  
75  
100 125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 25. Skip Synchronization to ac Line  
Voltage Threshold vs. Junction Temperature  
Figure 26. Skip Voltage Threshold vs. Junction  
Temperature  
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13  
NCP1652, NCP1652A  
100  
95  
90  
85  
80  
780  
755  
730  
705  
680  
50  
25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 27. Skip Voltage Hysteresis vs.  
Junction Temperature  
Figure 28. Feedback PullUp Current Source  
vs. Junction Temperature  
15.75  
15.55  
15.35  
15.15  
14.95  
14.75  
6.2  
6.0  
5.8  
5.6  
5.4  
5.2  
50  
25  
0
25  
50  
75  
100  
125  
150  
50  
25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 29. Feedback Open Circuit Voltage vs.  
Junction Temperature  
Figure 30. Startup Threshold vs. Junction  
Temperature  
10.5  
10.3  
10.1  
9.9  
9.7  
9.5  
50  
25  
0
25  
50  
75  
100 125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
Figure 31. Minimum Operating Voltage vs.  
Junction Temperature  
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14  
NCP1652, NCP1652A  
1000  
950  
900  
850  
800  
750  
700  
650  
350  
330  
310  
290  
270  
250  
50  
25  
0
25  
50  
75  
100 125  
150  
50 25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 32. Inhibit Threshold Voltage vs.  
Junction Temperature  
Figure 33. Inhibit Bias Current vs. Junction  
Temperature  
25.0  
24.5  
24.0  
23.5  
23.0  
22.5  
22.0  
6.0  
5.8  
5.6  
5.4  
5.2  
5.0  
V
= V 0.5 V  
CC  
CC  
I
= 0.5 mA  
start  
50  
25  
0
25  
50  
75  
100 125  
150  
50  
25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 34. Minimum Startup Voltage vs.  
Junction Temperature  
Figure 35. Startup Current vs. Junction  
Temperature  
850  
825  
800  
775  
750  
725  
700  
675  
650  
30  
25  
20  
15  
10  
50  
25  
0
25  
50  
75  
100  
125  
150  
50  
25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 36. OffState Leakage Current vs.  
Figure 37. Supply Current Device Disabled  
(Overload) vs. Junction Temperature  
Junction Temperature  
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NCP1652, NCP1652A  
200  
6.75  
6.55  
6.35  
6.15  
5.95  
5.75  
180  
160  
140  
120  
100  
50 25  
0
25  
50  
75  
100  
125 150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 38. Supply Current Device Switching  
vs. Junction Temperature  
Figure 39. Overload Timer vs. Junction  
Temperature  
5.5  
5.3  
5.1  
4.9  
4.7  
4.5  
500  
480  
460  
440  
420  
400  
50  
25  
0
25  
50  
75  
100  
125  
150  
50  
25  
0
25  
50  
75  
100  
125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 40. Overload Detect Threshold vs.  
Junction Temperature  
Figure 41. BrownOut Detect Threshold vs.  
Junction Temperature  
180  
175  
170  
165  
160  
650  
640  
630  
620  
610  
600  
50  
25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 42. BrownOut Exit Threshold vs.  
Figure 43. BrownOut Hysteresis vs. Junction  
Junction Temperature  
Temperature  
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NCP1652, NCP1652A  
1000  
980  
960  
940  
920  
900  
7.5  
V
CC  
7.3  
7.1  
6.9  
6.7  
6.5  
50  
25  
0
25  
50  
75  
100  
125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 44. Latch PullDown Voltage Threshold  
Figure 45. Latch PullUp Threshold vs.  
vs. Junction Temperature  
Junction Temperature  
7.5  
7.3  
7.1  
6.9  
6.7  
6.5  
60  
58  
56  
54  
52  
50  
50  
25  
0
25  
50  
75  
100  
125 150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 46. Latch PullUp Voltage Threshold  
Figure 47. Latch Propagation Delay vs.  
Junction Temperature  
vs. Junction Temperature  
55  
54  
53  
52  
51  
50  
50 25  
0
25  
50  
75  
100  
125  
150  
T , JUNCTION TEMPERATURE (°C)  
J
Figure 48. Latch Clamp Current vs. Junction  
Temperature  
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NCP1652, NCP1652A  
3.5  
3.4  
3.3  
3.2  
3.1  
3.0  
100  
98  
96  
94  
92  
90  
50  
25  
0
25  
50  
75  
100 125  
150  
50 25  
0
25  
50  
75  
100 125 150  
T , JUNCTION TEMPERATURE (°C)  
J
T , JUNCTION TEMPERATURE (°C)  
J
Figure 49. Latch Clamp Voltage vs. Junction  
Temperature  
Figure 50. LatchOff Current Shutdown vs.  
Junction Temperature  
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18  
NCP1652, NCP1652A  
DETAILED DEVICE DESCRIPTION  
Introduction  
designer familiarity and a vast range of available  
components. But, because it processes the power twice, the  
search is always on for a more compact and power efficient  
solution.  
The NCP1652 controller offers the convenience of  
shrinking the frontend converter (PFC preregulator) and  
the dcdc converter into a single power processing stage as  
shown in Figure 52.  
The NCP1652 is a highly integrated controller combining  
PFC and an isolated step down acdc power conversion in  
a single stage, resulting in a lower cost and reduced part  
count solution. This controller is ideal for notebook  
adapters, battery chargers and other offline applications  
with power requirements between 75 W and 150 W with an  
output voltage greater than 12 V. The single stage is based  
on the flyback converter and it is designed to operate in CCM  
or DCM modes.  
NCP1652 Based  
SingleStage  
Flyback Converter  
Rectifier  
&
Filter  
AC  
Input  
V
out  
Power Factor Correction (PFC) Introduction  
Power factor correction shapes the input current of  
offline power supplies to maximize the real power  
available from the mains. Ideally, the electrical appliance  
should present a load that emulates a pure resistor, in which  
case the reactive power drawn by the device is zero. Inherent  
in this scenario is the freedom from input current harmonics.  
The current is a perfect replica of the input voltage (usually  
a sine wave) and is exactly in phase with it. In this case the  
current drawn from the mains is at a minimum for the real  
power required to perform the needed work, and this  
minimizes losses and costs associated not only with the  
distribution of the power, but also with the generation of the  
power and the capital equipment involved in the process.  
The freedom from harmonics also minimizes interference  
with other devices being powered from the same source.  
Another reason to employ PFC in many of today’s power  
supplies is to comply with regulatory requirements. Today,  
electrical equipment in Europe must comply with the  
European Norm EN6100032. This requirement applies to  
most electrical appliances with input power of 75 W or  
greater, and it specifies the maximum amplitude of  
Figure 52. Single Stage Power Converter  
This approach significantly reduces the component count.  
The NCP1652 based solution requires only one each of  
MOSFET, magnetic element, output rectifier (low voltage)  
and output capacitor (low voltage). In contrast, the 2stage  
solution requires two or more of the abovelisted  
components. Elimination of certain highvoltage  
components (e.g. high voltage capacitor and high voltage  
PFC diode) has significant impact on the system design. The  
resultant cost savings and reliability improvement are often  
worth the effort of designing a new converter.  
Single PFC Stage  
While the single stage offers certain benefits, it is  
important to recognize that it is not a recommended solution  
for all requirements. The following three limitations apply  
to the single stage approach:  
The output voltage ripple will have a 2x line frequency  
component (120 Hz for North American applications)  
that can not be eliminated easily. The cause of this  
ripple is the elimination of the energy storage element  
that is typically the boost output capacitor in the  
2stage solution. The only way to reduce the ripple is to  
increase the output filter capacitance. The required  
value of capacitance is inversely proportional to the  
output voltage – hence this approach is not  
th  
linefrequency harmonics up to and including the 39  
harmonic. While this requirement is not yet in place in the  
US, power supply manufacturers attempting to sell products  
worldwide are designing for compliance with this  
requirement.  
Typical Power Supply with PFC  
A typical power supply consists of a boost PFC  
preregulator creating an intermediate X400 V bus and an  
isolated dcdc converter producing the desired output  
voltage as shown in Figure 51. This architecture has two  
power stages.  
recommended for low voltage outputs such as 3.3 V or  
5 V. However, if there is a followon dcdc converter  
stage or a battery after the single stage converter, the  
low frequency ripple should not cause any concerns.  
The holdup time will not be as good as the 2stage  
approach – again due to the lack of an intermediate  
energy storage element.  
DCDC  
Converter  
with isolator  
Rectifier  
&
Filter  
AC  
Input  
PFC  
Preregulator  
V
out  
In a single stage converter, one FET processes all the  
power – that is both a benefit and a limitation as the  
stress on that main MOSFET is relatively higher.  
Similarly, the magnetic component (flyback  
Figure 51. Typical Two Stage Power Converter  
A two stage architecture allows optimization of each  
individual power stage. It is commonly used because of  
transformer/inductor) can not be optimized as well as in  
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19  
 
NCP1652, NCP1652A  
Active  
Clamp  
the 2stage solution. As a result, potentially higher  
leakage inductance induces higher voltage spikes (like  
the one shown in Figure 53) on the MOSFET drain.  
This may require a MOSFET with a higher voltage  
rating compared to similar dcinput flyback  
applications.  
V
in  
V
out  
Figure 56. Active Clamp  
The first two methods result in dissipation of the leakage  
energy in the clamping circuits – the dissipation is  
2
proportional to LI where L is the leakage inductance of the  
transformer and I is the peak of the switch current at  
turnoff. An RDC snubber is simple and has the lowest cost,  
but constantly dissipates power. A TVS provides good  
voltage clamping at a slightly higher cost and dissipates  
power only when the drain voltage exceeds the voltage  
rating of the TVS.  
The active clamp circuit provides an intriguing alternative  
to the other methods. It requires addition of a MOSFET and  
a high voltage capacitor as part of the active clamp circuit,  
thus adding complexity, but it results in a complete reuse of  
the leakage inductance energy. As a result, the transformer  
construction is no longer critical and one can use cheaper  
cost solution. Also, the active clamp circuit reduces the  
voltage stress on the primary switch and that can lead to  
Figure 53. Typical Drain Voltage Waveform of a  
Flyback Main Switch  
There are a few methods to clamp the voltage spike on the  
main switch, a resistorcapacitordiode (RCD) clamp, a  
transient voltage suppressor (TVS) or an active clamp using  
a MOSFET and capacitor can be used as shown in  
Figures 54 to 56.  
usage of lower cost or lower on resistance (R  
MOSFET. Finally, the turnon switching losses are  
eliminated because the active clamp circuit allows the  
)
DS(on)  
RCD  
Clamp  
V
in  
V
out  
discharge of the MOSFET C  
turnon. The energy stored in the leakage inductance is  
utilized for this transition.  
capacitance prior to the  
OSS  
R
C
D
In many applications, the added complexity of the active  
clamp circuit may not be justified. However, the OUTB of  
the NCP1652 is also usable for another purpose,  
synchronous  
rectification  
control.  
Synchronous  
rectification for flyback converters is an emerging  
requirement for flyback converters. The OUTB signal from  
NCP1652 is ideal for interfacing with a secondary side  
synchronous rectifier controller such as NCP4303 as shown  
in Figure 57. As shown in Figure 57, using the OUTB  
(coupled through pulse transformer or Ycapacitor) as a  
trigger for the NCP4303 allows guaranteed turnoff of the  
secondary side synchronous MOSFET prior to turnon of  
the primary switch. In any CCM flyback converter, this is a  
critical requirement to prevent crossconduction and  
NCP1652 and NCP4303 combination is the first such  
chipset that guarantees the operation without  
crossconduction.  
Figure 54. RCD Clamp  
TVS  
Clamp  
V
in  
V
out  
TVS  
Figure 55. TVS Clamp  
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20  
 
NCP1652, NCP1652A  
V
IN  
V
OUT  
DRV  
TRIG  
NCP4303  
OUTB  
NCP1652  
OUTA  
Figure 57. NCP1652 and NCP4302 based single stage PFC with synchronous rectification.  
The NCP1652 incorporates a secondary driver, OUTB,  
with adjustable non overlap delay for controlling a  
synchronous rectifier switch in the secondary side, an active  
clamp switch in the primary or both. In addition, the  
controller features a proprietary SoftSkipto reduce  
acoustic noise at light loads. Other features found in the  
NCP1652 include a high voltage startup circuit, voltage  
feedforward, brown out detector, internal overload timer,  
latch input and a high accuracy multiplier.  
compensation is also added to the input signal to allow CCM  
operation above 50% duty cycle.  
High Voltage Startup Circuit  
The NCP1652 internal high voltage startup circuit  
eliminates the need for external startup components and  
provides a faster startup time compared to an external  
startup resistor. The startup circuit consists of a constant  
current source that supplies current from the HV pin to the  
supply capacitor on the V pin (C ). The startup current  
CC  
CC  
(I ) is typically 5.5 mA.  
start  
NCP1652 PFC Loop  
The NCP1652 incorporates a modified version of average  
current mode control used for achieving the unity power  
factor. The PFC section includes a variable reference  
generator, a low frequency voltage regulation error  
amplifier (AC error AMP), ramp compensation (Ramp  
Comp) and current shaping network. These blocks are  
shown in the lower portion of the bock diagram (Figure 51).  
The inputs to the reference generator include feedback  
signal (FB), scaled AC input signal (AC_IN) and  
The OUTA and OUTB drivers are enabled and the startup  
current source is disabled once the V voltage reaches  
CC  
V , typically 15.3 V. The controller is then biased by  
CC(on)  
the V capacitor. The drivers are disabled if V decays to  
CC  
CC  
its minimum operating threshold (V ) typically 10.3 V.  
CC(off)  
Upon reaching V  
the gate drivers are disabled. The  
CC(off)  
V
V
capacitor should be sized such V  
is kept above  
CC  
CC  
while the auxiliary voltage is building up.  
CC(off)  
Otherwise, the system will not start.  
feedforward input (V ). The output of the reference  
The controller operates in double hiccup mode while in  
FF  
generator is a rectified version of the input sinewave scaled  
overload or V . A double hiccup fault disables the  
CC(off)  
by the FB and V values. The reference amplitude is  
proportional to the FB and inversely proportional to the  
drivers, sets the controller in a low current mode and allows  
V to discharge to V . This cycle is repeated twice to  
CC  
FF  
CC(off)  
square of the V . This, for higher load levels and/or lower  
input voltage, the signal would be higher.  
The function of the AC error amp is to force the average  
current output of the current sense amplifier to match the  
reference generator output. The output of the AC error  
amplifier is compensated to prevent response to fast events.  
minimize power dissipation in external components during  
a fault event. Figure 58 shows double hiccup mode  
operation. A softstart sequence is initiated the second time  
FF  
V
CC  
reaches V . If the controller is latched upon  
CC(on)  
reaching V , the controller stays in hiccup mode.  
CC(on)  
During this mode, V never drops below V  
, the  
CC  
CC(reset)  
This output (V ) is fed into the PWM comparator through  
controller logic reset level. This prevents latched faults to be  
cleared unless power to the controller is completely  
removed (i.e. unplugging the supply from the AC line).  
error  
a reference buffer. The PWM comparator sums the V  
and  
error  
the instantaneous current and compares it to a 4.0 V  
threshold to provide the desired duty cycle control. Ramp  
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21  
NCP1652, NCP1652A  
V
CC  
V
V
CC(on)  
CC(off)  
t
OUTA  
t
Fault Timer  
(internal)  
Overload  
applied  
t
t
OVLD  
Figure 58. VCC Double Hiccup Operation with a Fault Occurring while the Startup Circuit is Disabled  
An internal supervisory circuit monitors the V voltage  
typically 0.85 V. Once V  
exceeds V , the startup  
inhibit  
CC  
CC  
to prevent the controller from dissipating excessive power  
current source is enabled. This behavior is illustrated in  
Figure 59. This slightly increases the total time to charge  
if the V  
pin is accidentally grounded. A lower level  
CC  
current source (I  
) charges C from 0 V to V  
,
V , but it is generally not noticeable.  
CC  
inhibit  
CC  
inhibit  
Figure 59. Startup Current at Various VCC Levels  
The rectified ac line voltage is provided to the power stage  
to achieve accurate PFC. Filtering the rectified ac line  
voltage with a large bulk capacitor distorts the PFC in a  
single stage PFC converter. A peak charger is needed to bias  
the HV pin as shown in Figure 60. Otherwise, the HV pin  
follows the ac line and the startup circuit is disabled every  
time the ac line voltage approaches 0 V. The V capacitor  
CC  
is sized to bias the controller during power up.  
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22  
 
NCP1652, NCP1652A  
Peak Charger  
V
OUT  
V
IN  
HV  
OUTA  
NCP1652  
Figure 60. Peak charger  
Adjustable Dead Time  
The startup circuit is rated at a maximum voltage of 500 V.  
Power dissipation should be controlled to avoid exceeding  
the maximum power dissipation of the controller. If  
dissipation on the controller is excessive, a resistor can be  
placed in series with the HV pin. This will reduce power  
dissipation on the controller and transfer it to the series  
resistor.  
OUTA and OUTB have an adjustable dead time between  
transitions to prevent simultaneous conduction of the main  
and synchronous rectifier or active clamp MOSFETs. The  
delay is also used to optimize the turnoff transition of the  
active clamp switch to achieve zerovolt switching of the  
main switch in an active clamp topology. Figure 61 shows  
the timing relationship between OUTA and OUTB.  
Drive Outputs  
The NCP1652 has out off phase output drivers with an  
adjustable nonoverlap delay (t ). The main output, OUTA,  
t (lead)  
delay  
t (trail)  
delay  
D
drives the primary MOSFET. The secondary output, OUTB,  
is designed to provide a logic signal used to control a  
synchronous rectification switch in the secondary side, an  
active clamp switch in the primary or both. The outputs are  
OUTA  
OUTB  
biased directly from V and their high state voltage is  
CC  
approximately V  
.
CC  
OUTA has a source resistance of 13 W (typical) and a sink  
resistance of 8.0 W (typical) OUTB has a source resistance  
22 W (typical) and a sink resistance of 10 W (typical). OUTB  
is a purposely sized smaller than OUTA because the gate  
charge of an active switch or logic used with synchronous  
rectification is usually less than that of the primary  
MOSFET. If a higher drive capability is required, an external  
discrete driver can be used.  
Figure 61. Timing relationship between OUTA and  
OUTB.  
The dead time between OUTA and OUTB is adjusted by  
connecting a resistor, R , from the R pin to ground. The  
D
D
overlap delay is proportional to R . The delay time can be  
D
set between 80 ns and 1.8 ms using the formula:  
tdelay(in ns) + 8.0   Rdelay(in kW) with  
The drivers are enabled once V reaches V  
and  
CC  
CC(on)  
there are no faults present. They are disabled once V  
Rdelay varying between 10 kW and 230 kW  
CC  
discharges to V . OUTB is always the last pulse  
CC(off)  
generated when the outputs are disabled due to a fault  
(latchoff, V , overload, or brownout). The last pulse  
terminates at the end of the clock cycle. This ensures the  
active clamp capacitor is reset.  
The high current drive capability of OUTA and OUTB  
may generate voltage spikes during switch transitions due to  
parasitic board inductance. Shortening the connection  
length between the drivers and their loads and using wider  
connections will reduce inductanceinduce spikes.  
AC Error Amplifier and Buffer  
CC(off)  
The AC error amplifier (EA) shapes the input current into  
a high quality sine wave by forcing the filtered input current  
to follow the output of the reference generator. The output  
of the reference generator is a full wave rectified ac signal  
and it is applied to the non inverting input of the EA. The  
filtered input current, I , is the current sense signal at the  
in  
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23  
 
NCP1652, NCP1652A  
ISpos pin multiplied by the current sense amplifier gain. It  
is applied to the inverting input of the AC EA.  
reference generator output. A pole-zero pair is created by  
placing (R and capacitor (C series  
a
)
)
COMP  
COMP  
The AC EA is a transconductance amplifier. A  
transconductance amplifier generates an output current  
proportional to its differential input voltage. This amplifier  
has a nominal gain of 100 mS (or 0.0001 A/V). That is, an  
input voltage difference of 10 mV causes the output current  
to change by 1.0 mA. The AC EA has typical source and sink  
currents of 70 mA.  
combination at the output of the AC EA. The AC COMP pin  
provides access to the AC EA output.  
The output of the AC EA is inverted and converted into a  
current using a second transconductance amplifier. The  
output of the inverting transconductance amplifier is  
V
Figure 62 shows the circuit schematic of the  
ACEA(buffer).  
AC EA buffer. The AC EA buffer output current, I  
is given by Equation 1.  
,
ACEA(out)  
The filtered input current is a high frequency signal. A low  
frequency pole forces the average input current to follow the  
VDD  
x 4  
I
ACEA(out)  
To PWM  
+
+
comparator  
2.8V  
V
AC_REF  
21.33kW  
37.33kW  
g
= 100mS  
m
+
I
AVG  
gm  
+
AC error  
amplifier  
R
IAVG  
AC COMP  
R
AC_COMP  
Figure 62. AC EA Buffer Amplifier  
2.8 * VACEA  
amplifier is a wide bandwidth amplifier with a differential  
input. The current sense amplifier has two outputs, PWM  
(eq. 1)  
+ ǒ  
Ǔ@ 4  
IACEA(out)  
37.33k  
Output and I  
Output. The PWM Output is the  
AVG  
The voltage at the PWN non-inverting input is determined  
by I , the instantaneous switch current along and the  
ramp compensation current. OUTA is terminated once the  
voltage at the PWM non-inverting input reaches 4 V.  
instantaneous switch current which is filtered by the internal  
leading edge blanking (LEB) circuitry prior to applying it to  
the PWM Comparator non inverting input. The second  
output is a filtered current signal resembling the average  
value of the input current. Figure 63 shows the internal  
architecture of the current sense amplifier.  
ACEA(out)  
Current Sense Amplifier  
A voltage proportional to the main switch current is  
applied to the current sense input, IS . The current sense  
POS  
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NCP1652, NCP1652A  
I
p
I
spos  
g
= 250mS  
m
Inst. current A  
blanking  
To PWM  
+
g
m
t
comparator  
LEB  
R
CS  
Current sense  
amplifier  
Inst. current B  
blanking  
To PWM skip  
comparator  
t
LEB  
I
AVG  
V
IAVG  
To AC error  
amplifier  
R
IAVG  
Figure 63. Current Sense Amplifier  
VISPOS  
Caution should be exercised when designing a filter  
between the current sense resistor and the IS input, due  
ICS + IIN  
+
(eq. 3)  
POS  
4k  
to the low impedance of this amplifier. Any series resistance  
due to a filter creates a voltage offset (V ) due to its input  
The PWM Output delivers current to the positive input of  
the PWM input where it is added to the AC EA and ramp  
compensation signal.  
Output generates a voltage signal to a buffer  
amplifier. This voltage signal is the product of I  
OS  
bias current, CA  
. The input bias current is typically  
Ibias  
60 mA. The voltage offset is given by Equation 2.  
The I  
AVG  
V
OS + CAIbias @ Rexternal  
(eq. 2)  
and an  
AVG  
external R  
resistor filtered by the capacitor on the I  
IAVG  
AVG  
The offset adds a positive offset to the current sense signal.  
The ac error amplifier will then try to compensate for the  
average output current which appears never to go to zero and  
cause additional zero crossing distortion.  
pin, C  
. The pole frequency, f , set by C  
should be  
IAVG  
P
IAVG  
significantly below the switching frequency to remove the  
high frequency content. But, high enough to not to cause  
significant distortion to the input full wave rectified  
sinewave waveform. A properly filtered average current  
signal has twice the line frequency. Equation 4 shows the  
A voltage proportional to the main switch current is  
applied to the IS  
pin. The IS  
pin voltage is converted  
POS  
POS  
into a current, i , and internally mirrored. Two internal  
1
relationship between C  
(in nF) and f (in kHz).  
IAVG  
P
currents are generated, I and I  
. I is a high frequency  
AVG CS  
CS  
signal which is a replica of the instantaneous switch current.  
is a low frequency signal. The relationship between  
1
CIAVG  
+
(eq. 4)  
I
AVG  
2 @ p @ RIAVG @ fP  
V
ISPOS  
and I and I  
is given by Equation 3.  
CS  
AVG  
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NCP1652, NCP1652A  
Oscillator  
The gain of the low frequency current buffer is set by the  
resistor at the I pin, R . R sets the scaling factor  
between the primary peak and primary average currents.  
The oscillator controls the switching frequency, f, the jitter  
frequency and the gain of the multiplier. The oscillator ramp  
is generated by charging the timing capacitor on the CT Pin,  
AVG  
IAVG IAVG  
The gain of the current sense amplifier, A , is given by  
CA  
C , with a 200 mA current source. This current source is  
T
Equation 5.  
tightly controlled during manufacturing to achieve a  
controlled and repeatable oscillator frequency. The current  
RIAVG  
(eq. 5)  
ACA  
+
4k  
source turns off and C is immediately discharged with a  
T
The current sense signal is prone to leading edge spikes  
during the main switch turn on due to parasitic capacitance  
and inductance. This spike may cause incorrect operation of  
the PWM Comparator. Filtering the current sense signal will  
inevitably change the shape of the current pulse. The  
NCP1652 incorporates LEB circuitry to block the first  
200 ns (typical) of each current pulse. This removes the  
leading edge spikes without altering the current signal  
waveform.  
pull down transistor once the oscillator ramp reaches its peak  
voltage, V , typically 4.0 V. The pull down transistor  
CT(peak)  
turns off and the charging current source turns on once the  
oscillator ramp reaches its valley voltage, V  
.
CT(valley)  
Figure 64 shows the resulting oscillator ramp and control  
circuitry.  
VDD  
x 1.2  
To PWM  
comparator  
I
AVG  
To PWM skip  
comparator  
R
IAVG  
VDD  
C
T
+
C
T
+
4.0 V / 0.1 V  
Oscillator  
Figure 64. Oscillator Ramp and Control Circuitry  
The relationship between the oscillator frequency in kHz  
and timing capacitor in pF is given by Equation 6.  
A low frequency oscillator modulates the switching  
frequency, reducing the controller EMI signature and  
allowing the use of a smaller EMI filter. The frequency  
modulation or jitter is typically 5% of the oscillator  
frequency.  
47000  
CT  
+
(eq. 6)  
f
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26  
 
NCP1652, NCP1652A  
Output Overload  
The Feedback Voltage, V , is directly proportional to the  
260 mV. A new SoftSkipperiod starts once the voltage  
on the ACIN pin increases to 260 mV.  
FB  
output power of the converter. An internal 6.7 kW resistor  
pullsup the FB voltage to the internal 6.5 V reference. An  
external optocoupler pulls down the FB voltage to regulate  
the output voltage of the system. The optocoupler is off  
during power up and output overload conditions allowing  
the FB voltage to reach its maximum level.  
The NCP1652 monitors the FB voltage to detect an  
overload condition. A typical startup time of a single PFC  
stage converter is around 100 ms. If the converter is out of  
regulation (FB voltage exceeds 5.0 V) for more that 150 ms  
(typical) the drivers are disabled and the controller enters the  
double hiccup mode to reduce the average power  
dissipation. A new startup sequence is initiated after the  
double hiccup is complete. This protection feature is critical  
to reduce power during an output short condition.  
An increase in output load current terminates a  
SoftSkipevent. A transient load detector terminates a  
SoftSkipperiod once V voltage exceeds V  
by  
FB  
SSKIP  
more than 550 mV. This ensures the required output power  
is delivered during a load transient and the output voltage  
does not fall out of regulation. Figure 66 shows the  
relationship between SoftSkipand the transient load  
detector.  
SoftSkipCycle Mode  
The FB voltage reduces as the output power demand of the  
V
SSKIP  
converter reduces. Once V  
drops below the skip  
FB  
V
FB  
threshold, V , 1.30 V (typical) the drivers are disabled.  
SSKIP  
The skip comparator hysteresis is typically 180 mV.  
The converter output voltage starts to decay because no  
additional output power is delivered. As the output voltage  
decreases the feedback voltage increases to maintain the  
output voltage in regulation. This mode of operation is  
known as skip mode. The skip mode frequency is dependent  
of load loop gain and output capacitance and can create  
audible noise due to mechanical resonance in the  
Figure 66. Load transient during SoftSkip]  
transformer and snubber capacitor.  
SoftSkipmode reduces audible noise by slowly  
increasing the primary peak current until it reaches its  
maximum value. The minimum skip ramp period, t  
2.5 ms. Figure 65 shows the relationship between V  
A
proprietary  
The output of the SoftSkipComparator is ored with  
the PWM Comparator output to control the duty ratio. The  
SoftSkipComparator controls the duty ratio in skip  
mode and the PWM Comparator controls the duty cycle  
during normal operation. In skip mode, the noninverting  
input of the SoftSkipComparator exceeds 4 V, disabling  
the drivers. As the FB voltage increases, the voltage at the  
noninverting input is ramp down from 4 V to 0.2 V to  
enable the drivers.  
, is  
SSKIP  
,
FB  
V
SSKIP  
and the primary current.  
Multiplier and Reference Generator  
The NCP1652 uses a multiplier to regulate the average  
output power of the converter. This controller uses a  
proprietary concept for the multiplier used within the  
reference generator. This innovative design allows greatly  
improved accuracy compared to a conventional linear  
analog multiplier. The multiplier uses a PWM switching  
circuit to create a scalable output signal, with a very well  
defined gain.  
Figure 65. SoftSkip] operation.  
Skip mode operation is synchronous of the ac line voltage.  
The output of the multiplier is the ac-reference signal. The  
ac-reference signal is used to shape the input current. The  
multiplier has three inputs, the error signal from an external  
The NCP1652 disables SoftSkipwhen the rectified ac  
line voltage drops to its valley level. This ensures the  
primary current always ramp up reducing audible noise. A  
skip event occurring as the ac line voltage is decreasing,  
causes the primary peak current to ramp down instead of  
ramp up. Once the skip period is over the primary current is  
only determined by the ac line voltage. A SoftSkipevent  
terminates once the ACIN pin voltage decreases below  
error amplifier (V ), the full wave rectified ac input  
FB  
(AC_IN) and the feedforward input (V ).  
FF  
The FB signal from an external error amplifier circuit is  
applied to the V pin via an optocoupler or other isolation  
FB  
circuit. The FB voltage is converted to a current with a V-I  
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27  
 
NCP1652, NCP1652A  
converter. There is no error in the output signal due to the  
series rectifier as shown in Figure 67.  
factored by the AC_IN comparator output. The resulting  
signal is filtered by the low pass R-C filter on the CM pin.  
The low pass filter removes the high frequency content. The  
gain of the multiplier is determined by the V-I converter, the  
resistor on the CM pin, and the peak and valley voltages of  
the oscillator sawtooth ramp.  
The scaled version of the full wave rectified input ac wave  
is applied to the AC_IN pin by means of a resistive voltage  
divider. The multiplier ramp is generated by comparing the  
scaled line voltage to the oscillator ramp with the AC_IN  
Comparator. The current signal from the V-I converter is  
FB  
Multiplier  
VtoI  
+
AC IN  
CM  
V
@ V  
FB AC_IN  
V
+ k @  
AC_REF  
2
V
FF  
Oscillator  
AC_REF  
Divide  
2
V
FF  
V
FF  
Square  
Figure 67. Reference Generator  
V
FB @ VAC_IN  
The third input to the reference generator is the V signal.  
FF  
VAC_REF  
+
@ k  
The V signal is a dc voltage proportional to the ac line  
FF  
(eq. 8)  
2
VFF  
voltage. A resistive voltage divider attenuates the full wave  
rectified line voltage between 0.7 and 5.0 V. The full wave  
rectified line is then averaged with a capacitor. The ac  
average voltage must be constant over each half cycle of the  
line. Line voltage ripple (120 Hz or 100 Hz) ripple on the  
The multiplier transfer function is given by Equation 8.  
The output of the multiplier is the AC_REF. It connects to  
the AC Error Amplifier.  
where, k is the reference generator gain, typically 0.55. The  
output of the reference generator is clamped at 4.5 V to limit  
the maximum output power.  
V
signal adds ripple to the output of the multiplier. This  
FF  
will distort the ac reference signal and reduce the power  
factor and increase the line current distortion. Excessive  
filtering delays the feedforward signal reducing the line  
transient response. A good starting point is to set the filter  
time constant to one cycle of the line voltage. The user can  
then optimize the filter for line transient response versus  
Feedforward maintains  
a
constant input power  
independent of the line voltage. That is, for a given FB  
voltage, if the line voltage doubles (AC_IN), the  
feedforward term quadruples and reduces the output of the  
error amplifier in half to maintain the same input power.  
power factor. The average voltage on the V pin is:  
FF  
AC Error Amplifier Compensation  
A pole-zero pair is created by placing a series combination  
2
p
Ǹ
VFF  
+
Vac 2a  
(eq. 7)  
of R  
and C  
at the output of the AC error amplifier  
COMP  
COMP  
Where, a is the voltage divider ratio, normally 0.01.  
(EA). The value of the compensation components is  
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28  
 
NCP1652, NCP1652A  
dependent of the average input current and the instantaneous  
switch current. The gain of the average input current or slow  
loop is given by Equation 9.  
where, V  
is the low line ac input voltage, D is the duty  
in(LL)  
ratio, P is the output power, P is the input power, h is the  
out  
in  
efficiency, L is the primary inductance and t is the on  
P
on  
time. Typical efficiency for this topology is around 88%.  
The current sense resistor is selected to achieve maximum  
signal resolution at the input of the ac reference amplifier.  
The maximum voltage input of the ac reference amplifier to  
prevent saturation is 4.5 V. This together with the  
instantaneous peak current is used to calculate the current  
RIAVG  
ǒ Ǔ@ 2.286  
@ gm @ RAC_COMP  
(
)
(eq. 9)  
+ ǒ Ǔ  
ALF  
4k  
The low frequency gain is the product of the current sense  
averaging circuit, the transconductance amplifier and the  
gain of the AC error amplifier.  
A current proportional to the instantaneous current is  
generated using a 4 kW resistor in the current sense amplifier  
input. This proportional current is applied to a 21.33 kW at  
the PWM comparator input to generate a current sense  
sense resistor, R , using Equation 16.  
CS  
4k @ ǒV  
Ǔ
in(LL) @ D  
(eq. 16)  
R
CS + 4.5  
Ǹ
R
IAVG @ Pin @ 2  
voltage signal. The high frequency or fast loop gain, A , is  
HF  
calculated using Equation 10.  
Ramp Compensation  
21.33k  
Subharmonic oscillations are observed in peak  
current-mode controllers operating in continuous  
conduction mode with a duty ratio greater than 50%.  
Injecting a compensation ramp on the current sense signal  
eliminates the subharmonic oscillations. The amount of  
compensation is system dependent and it is determined by  
the inductor falling di/dt.  
AHF  
+
+ 5.333  
(eq. 10)  
4k  
Equation 11 shows system stability requirements. That is,  
the low frequency gain has to be less than one half of the high  
frequency gain.  
RIAVG  
5.333  
ǒ
Ǔ@ (2.286) t  
(eq. 11)  
ǒ Ǔ  
@ gm @ RAC_COMP  
2
4k  
The NCP1652 has built in ramp compensation to facilitate  
system design. The amount of ramp compensation is set by  
Equation 12 is obtained by re-arranging Equation 11 for  
R
R
. This equation provides the maximum value for  
the user with a resistor, R  
, between the Ramp Comp  
AC_COMP  
RCOMP  
.
pin and ground. The Ramp Comp pin buffers the oscillator  
ramp generated on the C pin. The current across R  
AC_COMP  
T
RCOMP  
4666  
(eq. 12)  
R
AC_COMP t  
is internally mirrored with a 1:1.2 ratio. The inverted ac error  
amplifier and the instantaneous switch current signals are  
added to the ramp compensation mirrored current. The  
resulting current signal is applied to an internal 21.33 kW  
between the PWM Comparator non inverting input and  
ground as shown in Figure 64.  
The maximum voltage contribution of the ramp  
compensation signal to the error signal, V  
Equation 17.  
R
IAVG @ gm  
The control loop zero, f , is calculated using Equation 13.  
Z
The control loop zero should be set at approximately at  
1/10 of the oscillator frequency, f  
capacitor is calculated using Equation 14.  
th  
. The compensation  
OSC  
1
(eq. 13)  
(eq. 14)  
fz +  
, is given by  
RCOMP  
2p @ CAC_COMP @ RAC_COMP  
1
(eq. 17)  
102.38k  
CAC_COMP  
+
ǒ
Ǔ@ 21.33k  
(
)
(
)
1.2 @ VCT(peak)  
2p @ fOSC @ RAC_COMP  
VRCOMP  
+
+
10  
RRCOMP  
RRCOMP  
Current Sense Resistor  
where, V  
is the oscillator ramp peak voltage,  
CT(peak)  
The PFC stage has two control loops. The first loop  
controls the average input current and the second loop  
controls the instantaneous current across the main switch.  
The current sense signal affects both loops. The current  
sense signal is fed into the positive input of the error  
amplifier to control the average input current. In addition,  
the current sense information together with the ramp  
compensation and error amplifier signal control the  
instantaneous primary peak current.  
typically 4.0 V.  
For proper ramp compensation, the ramp signal should  
match the falling di/dt (which has been converted to a dv/dt)  
of the inductor at 50% duty cycle. Both the falling di/dt and  
output voltage need to be reflected by the transformer turns  
ratio to the primary side. Equations 18 through 23 assist in  
the derivation of equations for R and R  
.
CS  
COMP  
2
NP  
@ ǒ Ǔ  
NS  
Vout  
LS  
Vout  
LP  
di  
(eq. 18)  
(eq. 19)  
+
+
The primary peak current, I , is calculated using  
PK  
dtsecondary  
Equation 15,  
NS  
N
Vout  
Ǹ
di  
dtprimary  
di  
P
Vin(LL) @ ton  
2 @ Pout  
+
@
+
(eq. 15)  
IPK  
+
)
dtsecondary NP  
LP NS  
h @ Vin(LL) @ D 0.88 @ 2 @ LP  
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29  
 
NCP1652, NCP1652A  
di  
latch is Set dominant which means that if both R and S are  
high the S signal will dominate and Q will be high, which  
will hold the power switch off.  
(eq. 20)  
VRCOMP  
+
@ T @ RCS @ AHF  
dtprimary  
NS  
LP @ 102.38k  
NP T @ AHF @ Vout @ RRCOMP  
The NCP1652 uses a pulse width modulation scheme  
based on a fixed frequency oscillator. The oscillator  
generates a voltage ramp as well as a pulse in sync with the  
falling edge of the ramp. The pulse is an input to the PWM  
Logic and Driver block. While the oscillator pulse is present,  
the latch is reset, and the output drive is in its low state. On  
the falling edge of the pulse, the OUTA goes high and the  
power switch begins conduction.  
The instantaneous inductor current is summed with a  
current proportional to the ac error amplifier output voltage.  
This complex waveform is compared to the 4 V reference  
signal on the PWM comparator inverting input. When the  
signal at the non-inverting input to the PWM comparator  
exceeds 4 V, the output of the PWM comparator toggles to  
a high state which drives the Set input of the latch and turns  
the power switch off until the next clock cycle.  
(eq. 21)  
RCS  
+
@
At low line and full load, the output of the ac error  
amplifier output is nearly saturated in a low state. While the  
ac error amplifier output is saturated, I  
not contribute to the voltage across the internal 21.33 kW  
resistor on the PWM comparator non-inverting input. In this  
operation mode, the voltage across the 21.33 kW resistor is  
determined solely by the ramp compensation and the  
instantaneous switch current as given by Equation 22.  
is zero and does  
ACEA  
ton  
(eq. 22)  
+ ǒ  
Ǔ
Vref(PWM)  
VRCOMP  
@
) VINST  
T
The voltage reference of the PWM Comparator,  
, is 4 V. For these calculations, 3.8 V is used to  
provide some margin. The maximum instantaneous switch  
V
REF(PWM)  
current voltage contribution,  
Equation 23.  
V
,
is given by  
INST  
BrownOut  
The NCP1652 incorporates a brownout detection circuit  
to prevent the controller operate at low ac line voltages and  
reduce stress in power components. A scaled version of the  
rectified line voltage is applied to the VFF Pin by means of  
a resistor divider. This voltage is used by the brown out  
detector.  
A brownout condition exists if the feedforward voltage  
is below the brownout exit threshold, V  
0.45 V. The brownout detector has 180 mV hysteresis. The  
controller is enabled once V is above 0.63 V and V  
V
INST + IPK @ RCS @ AHF  
(eq. 23)  
Substituting Equation 23 in Equation 22, setting  
at 3.8 V (provides margin) and solving for  
V
REF(PWM)  
R
Equation 24 is obtained.  
RCOMP,  
+ ǒ3.8 * 5.333 @ I  
Ǔ @ ton  
102.38k  
RRCOMP  
(eq. 24)  
(eq. 25)  
T
PK @ RCS  
, typically  
BO(high)  
Replacing Equation 24 in Equation 21 we obtain:  
FF  
CC  
3.8  
reaches V  
. OUTB is the last drive pulse. Figure 68  
RCS  
+
CC(on)  
N
N
A
@V  
@t  
on  
out  
P
shows the relationship between the brownout, V , OUTA  
and OUTB signals.  
P
S
HF  
CC  
ǒ
Ǔ
@
) 5.333 IPK  
L
PWM Logic  
The PWM and logic circuits are comprised of a PWM  
comparator, an RS flip-flop (latch) and an OR gate. The  
http://onsemi.com  
30  
 
NCP1652, NCP1652A  
V
CC  
V
V
CC(on)  
CC(off)  
t
t
OUTA  
OUTB  
Last OUTB Pulase  
t
V
FF  
V
BO(low)  
V
BO(high)  
BrownOut  
t
Figure 68. Relationship Between the BrownOut, VCC, OUTA and OUTB  
Vaux or VCC  
VDD  
OVP comparator  
+
+
V
latch(high)  
I
latch(clamp)  
blanking  
LatchOff  
t
latch(delay)  
OTP comparator  
S
R
Ilatch(shdn)  
Q
Latch  
+
+
V
NTC  
latch(low)  
V
latch(clamp)  
Reset  
Figure 69.  
Latch Input  
Once the controller is latched, OUTA is disabled and OUTB  
generates a final pulse that ends with the oscillator period.  
No more pulses are generated after OUTB is terminated.  
Figure 70 shows the relationship between the LatchOff,  
The NCP1652 has a dedicated latch input to easily latch  
the controller during overtemperature and overvoltage  
faults (See Figure 69). The controller is latched if the  
LatchOff pin voltage is pulled below 1 V or above 6.5 V.  
V , OUTA and OUTB signals.  
CC  
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31  
 
NCP1652, NCP1652A  
V
CC  
V
V
CC(on)  
CC(off)  
t
OUTA  
OUTB  
t
Last OUTB Pulase  
t
LatchOff  
LatchOff  
LatchOff  
V
latch(high)  
V
latch(low)  
t
Figure 70. Relationship Between the LatchOff, VCC, OUTA and OUTB  
The LatchOff pin is clamped at 3.5 V. A 50 mA (typical)  
LatchOff input features a 50 ms (typical) filter to prevent  
pullup current source is always on and a 100 mA (typical)  
pulldown current source is enabled once the LatchOff pin  
voltage reaches 3.5 V (typical). This effectively clamps the  
LatchOff pin voltage at 3.5 V. A minimum pullup or  
pulldown current of 50 mA is required to overcome the  
internal current sources and latch the controller. The  
latching the controller due to noise or a line surge event.  
The startup circuit continues to cycle V  
between  
CC  
V
CC(on)  
and V  
while the controller is in latch mode.  
CC(off)  
The controller exits the latch mode once power to the system  
is removed and V drops below V  
.
CC(reset)  
CC  
APPLICATION INFORMATION  
ON Semiconductor provides an electronic design tool,  
facilitate design of the NCP1652 and reduce development  
cycle time. The design tool can be downloaded at  
www.onsemi.com.  
The electronic design tool allows the user to easily  
determine most of the system parameters of a single PFC  
stage The tool evaluates the power stage as well as the  
frequency response of the system.  
ORDERING INFORMATION  
Device  
NCP1652DWR2G  
Package  
Shipping  
SO20 WB  
(PbFree)  
1000 / Tape & Reel  
2500 / Tape & Reel  
2500 / Tape & Reel  
NCP1652DR2G  
NCP1652ADR2G  
SO16  
(PbFree)  
SO16  
(PbFree)  
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging  
Specifications Brochure, BRD8011/D.  
http://onsemi.com  
32  
NCP1652, NCP1652A  
PACKAGE DIMENSIONS  
SO20 WB  
CASE 751D05  
ISSUE G  
D
A
q
NOTES:  
1. DIMENSIONS ARE IN MILLIMETERS.  
2. INTERPRET DIMENSIONS AND TOLERANCES  
PER ASME Y14.5M, 1994.  
20  
11  
3. DIMENSIONS D AND E DO NOT INCLUDE MOLD  
PROTRUSION.  
E
B
4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.  
5. DIMENSION B DOES NOT INCLUDE DAMBAR  
PROTRUSION. ALLOWABLE PROTRUSION  
SHALL BE 0.13 TOTAL IN EXCESS OF B  
DIMENSION AT MAXIMUM MATERIAL  
CONDITION.  
1
10  
MILLIMETERS  
DIM MIN  
MAX  
2.65  
0.25  
0.49  
0.32  
12.95  
7.60  
20X B  
A
A1  
B
C
D
E
2.35  
0.10  
0.35  
0.23  
12.65  
7.40  
M
S
S
B
T
0.25  
A
A
e
1.27 BSC  
H
h
10.05  
0.25  
0.50  
0
10.55  
0.75  
0.90  
7
SEATING  
PLANE  
L
18X e  
q
_
_
A1  
C
T
http://onsemi.com  
33  
NCP1652, NCP1652A  
PACKAGE DIMENSIONS  
SOIC16  
CASE 751B05  
ISSUE K  
NOTES:  
1. DIMENSIONING AND TOLERANCING PER ANSI  
Y14.5M, 1982.  
A−  
2. CONTROLLING DIMENSION: MILLIMETER.  
3. DIMENSIONS A AND B DO NOT INCLUDE MOLD  
PROTRUSION.  
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE.  
5. DIMENSION D DOES NOT INCLUDE DAMBAR  
PROTRUSION. ALLOWABLE DAMBAR PROTRUSION  
SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D  
DIMENSION AT MAXIMUM MATERIAL CONDITION.  
16  
9
8
B−  
P 8 PL  
M
S
B
0.25 (0.010)  
1
MILLIMETERS  
INCHES  
MIN  
0.386  
DIM MIN  
MAX  
MAX  
0.393  
0.157  
0.068  
0.019  
0.049  
A
B
C
D
F
9.80  
3.80  
1.35  
0.35  
0.40  
10.00  
G
4.00 0.150  
1.75 0.054  
0.49 0.014  
1.25 0.016  
F
R X 45  
K
_
G
J
1.27 BSC  
0.050 BSC  
0.19  
0.10  
0
0.25 0.008  
0.25 0.004  
0.009  
0.009  
7
K
M
P
R
C
7
0
_
_
_
_
T−  
SEATING  
PLANE  
5.80  
0.25  
6.20 0.229  
0.50 0.010  
0.244  
0.019  
J
M
D
16 PL  
M
S
S
A
0.25 (0.010)  
T
B
SOLDERING FOOTPRINT  
8X  
6.40  
16X  
1.12  
1
16  
16X  
0.58  
1.27  
PITCH  
8
9
DIMENSIONS: MILLIMETERS  
The products described herein (NCP1652), may be covered by one or more of the following U.S. patents; 6,373,734. There may be other patents pending.  
ON Semiconductor and  
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice  
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability  
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.  
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All  
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights  
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications  
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should  
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,  
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death  
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal  
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.  
PUBLICATION ORDERING INFORMATION  
LITERATURE FULFILLMENT:  
N. American Technical Support: 8002829855 Toll Free  
USA/Canada  
Europe, Middle East and Africa Technical Support:  
Phone: 421 33 790 2910  
Japan Customer Focus Center  
Phone: 81357733850  
ON Semiconductor Website: www.onsemi.com  
Order Literature: http://www.onsemi.com/orderlit  
Literature Distribution Center for ON Semiconductor  
P.O. Box 5163, Denver, Colorado 80217 USA  
Phone: 3036752175 or 8003443860 Toll Free USA/Canada  
Fax: 3036752176 or 8003443867 Toll Free USA/Canada  
Email: orderlit@onsemi.com  
For additional information, please contact your local  
Sales Representative  
NCP1652/D  

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