NCV1077P065G [ONSEMI]

Automotive High-Voltage Switcher for Low Power SMPS;
NCV1077P065G
型号: NCV1077P065G
厂家: ONSEMI    ONSEMI
描述:

Automotive High-Voltage Switcher for Low Power SMPS

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NCV1072, NCV1075,  
NCV1076, NCV1077  
Automotive High-Voltage  
Switcher for Low Power  
SMPS  
www.onsemi.com  
The NCV107x products integrate a fixed frequency current mode  
controller with a 670 V MOSFET. Available in a PDIP7 package, the  
NCV107x offer a high level of integration, including softstart,  
frequencyjittering, shortcircuit protection, skipcycle, a maximum  
peak current set point, ramp compensation, and a Dynamic  
SelfSupply (eliminating the need for an auxiliary winding).  
Unlike other monolithic solutions, the NCV107x is quiet by nature:  
during nominal load operation, the part switches at one of the available  
frequencies (65, 100 or 130 kHz). When the output power demand  
diminishes, the IC automatically enters frequency foldback mode and  
provides excellent efficiency at light loads. When the power demand  
reduces further, it enters into a skip mode to reduce the standby  
consumption down to a no load condition.  
MARKING  
DIAGRAM  
PDIP7  
P SUFFIX  
CASE 626A  
V107xyyy  
AWL  
YYWWG  
AYW  
Vz7xyG  
G
SOT223  
ST SUFFIX  
CASE 318E  
Protection features include: a timer to detect an overload or a  
shortcircuit event, Overvoltage Protection with autorecovery and  
AC input line voltage detection.  
1
For improved standby performance, the connection of an auxiliary  
winding stops the DSS operation and helps to reduce input power  
consumption below 50 mW at high line.  
x
y
= Current Limit (2, 5, 6 or 7)  
= Oscillator Frequency  
= A(65 kHz), B(100 kHz), 130(130 kHz)  
= 0 (with brownin), C (without brownin)  
= 065, 100, 130  
= Assembly Location  
= Wafer Lot  
= Year  
z
yyy  
A
WL  
Y, YY  
Features  
Builtin 670 V MOSFET with R  
11 W (NCV1072/75)  
of 4.7 W (NCV1076/77) /  
DS(on)  
W, WW = Work Week  
G or G = PbFree Package  
Large Creepage Distance Between Highvoltage Pins  
CurrentMode Fixed Frequency Operation – 65 / 100 / 130 kHz  
Peak Current: NCV1072 with 250 mA, NCV1075 with 450 mA,  
NCV1076 with 650 mA and NCV1077 with 800 mA  
Fixed Ramp Compensation  
ORDERING INFORMATION  
Only limited options are released to market. Other  
options available upon customer request. See status and  
detailed ordering and shipping information on pages 2 &  
27 of the document.  
SkipCycle Operation at Low Peak Currents Only: No Acoustic  
Noise!  
Dynamic SelfSupply: No Need for an Auxiliary Winding  
Internal 1 ms SoftStart  
Internal Temperature Shutdown  
AutoRecovery Output Short Circuit Protection with  
NCV Prefix for Automotive and Other Applications  
Requiring Unique Site and Control Change  
Requirements; AECQ100 Qualified and PPAP  
Capable  
TimerBased Detection  
AutoRecovery Overvoltage Protection with Auxiliary  
Winding Operation  
These Devices are PbFree, Halogen Free/BFR Free  
and are RoHS Compliant  
Frequency Jittering for Better EMI Signature, Including  
Frequency Foldback Mode  
No Load Input Consumption < 50 mW  
Typical Applications  
Options With or Without Brownin Function Available  
Frequency Foldback to Improve Efficiency at Light  
Load  
Auxiliary & Standby Isolated Power Supplies for  
HEV/EV  
© Semiconductor Components Industries, LLC, 2018  
1
Publication Order Number:  
July, 2019 Rev. 6  
NCV1070/D  
NCV1072, NCV1075, NCV1076, NCV1077  
PIN CONNECTIONS  
V
1
2
3
4
8
7
V
CC  
1
2
3
CC  
GND  
GND  
FB  
4
GND  
GND  
FB  
DRAIN  
5
DRAIN  
(Top View)  
(Top View)  
PDIP7  
SOT223  
Figure 1. Pin Connections  
INDICATIVE MAXIMUM OUTPUT POWER  
R
I  
230 Vac  
19 W  
85265 Vac  
DS(on)  
IPK  
NCV1072 / 1075  
NCV1076 / 1077  
11 W 450 mA  
4.7 W 800 mA  
10 W  
15 W  
25 W  
NOTE: Informative values only, with T  
= 50°C, F  
= 65 kHz, Self supply via Auxiliary winding and circuit mounted on minimum  
amb  
SW  
copper area as recommended.  
QUICK SELECTION TABLE  
NCV1072  
NCV1075  
NCV1076  
NCV1077  
R
(W)  
11  
4.7  
DS(on)  
Ipeak (mA)  
250  
100  
No  
450  
100  
P
650  
100  
P
800  
100  
S
Freq (kHz)  
65  
130*  
No  
65  
P
130  
No  
65  
P
130  
No  
65  
P
130  
No  
Release to Market Status  
No  
NOTE: PDIP7 Release (P)/SOT223 released (S)  
*130 kHz on demand only  
Figure 2. Typical Application Example  
www.onsemi.com  
2
NCV1072, NCV1075, NCV1076, NCV1077  
PIN FUNCTION DESCRIPTION  
Pin N5  
1
Pin Name  
Function  
Pin Description  
V
CC  
Powers the internal circuitry  
This pin is connected to an external capacitor. The V includes an  
active shunt which serves as an autorecovery over voltage protection.  
CC  
2
3
4
NC  
GND  
FB  
The IC Ground  
Feedback signal input  
By connecting an optocoupler to this pin, the peak current set point is  
adjusted accordingly to the output power demand.  
5
6
7
8
Drain  
Drain connection  
The internal drain MOSFET connection  
This unconnected pin ensures adequate creepage distance  
GND  
GND  
The IC Ground  
The IC Ground  
Vcc  
Drain  
V
clamp  
I
OVP  
Vcc OVP  
UVLO  
Reset  
Vdd  
+
Vcc  
Management  
S
R
Q
80us  
filter  
SCP  
t
Q
OFF UVLO  
Ipflag  
SCP  
t
recovery  
line  
detection  
LineOK  
TSD  
UVLO  
Vcc  
OFF  
LineOK  
Jittering  
DRV  
OSC  
Sawtooth  
S
Q
Sawtooth  
Foldback  
Q
R
I
FBskip  
Ramp  
compensation  
SKIP  
GND  
+
DRV  
200 ns  
LEB  
SKIP = ”1” −−> shut  
down some blocks to  
reduce consumption  
+
V
FB(REF)  
R
FB(up)  
to CS setpoint  
I
FB  
Reset  
+
FB  
Soft  
Start  
I
freeze  
Ipk(0)  
Reset SS as recovering from  
SCP, TSD, Vcc OVP, or UVLO  
+
I
Ipflag  
FBfault  
Figure 3. Simplified Internal Circuit Architecture  
www.onsemi.com  
3
NCV1072, NCV1075, NCV1076, NCV1077  
MAXIMUM RATINGS TABLE  
Symbol  
Rating  
Value  
Unit  
V
V
CC  
Power Supply Voltage on all pins, except Pin 5(Drain)  
Drain voltage  
0.3 to 10  
0.3 to 670  
BVdss  
V
I
Drain current peak during transformer saturation (T = 150°C, Note 3):  
DS(PK)  
J
NCV1072/75:  
NCV1076/77:  
870  
2200  
mA  
mA  
Drain current peak during transformer saturation (T = 25°C, Note 3):  
J
NCV1072/75:  
NCV1076/77:  
1500  
3900  
mA  
mA  
I_V  
Maximum Current into Pin 1 when Activating the 8.2 V Active Clamp  
PDIP7, P Suffix, Case 626A  
15  
mA  
CC  
R
0.36 Sq. Inch  
1.0 Sq. Inch  
77  
°C/W  
q
JA  
JunctiontoAir, 2.0 oz Printed Circuit Copper Clad  
Maximum Junction Temperature  
60  
TJ  
150  
°C  
°C  
kV  
V
MAX  
Storage Temperature Range  
60 to +150  
ESD Capability, Human Body Model (All pins except HV)  
ESD Capability, Machine Model  
2
200  
1
ESD Capability, Charged Device Model  
kV  
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality  
should not be assumed, damage may occur and reliability may be affected.  
1. This device series contains ESD protection and exceeds the following tests:  
Human Body Model 2000 V per JEDEC JESD22A114F  
Machine Model Method 200 V per JEDEC JESD22A115A  
Charged Device Model 1000 V per JEDEC JESD22C101E  
2. This device contains latchup protection and exceeds 100 mA per JEDEC Standard JESD78  
3. Maximum drain current I  
is obtained when the transformer saturates. It should not be mixed with short pulses that can be seen at turn  
DS(PK)  
on. Figure 4 below provides spike limits the device can tolerate.  
Figure 4. Spike Limits  
www.onsemi.com  
4
 
NCV1072, NCV1075, NCV1076, NCV1077  
ELECTRICAL CHARACTERISTICS  
(For all NCV107X products: For typical values T = 25°C, for min/max values T = 40°C to +125°C, V = 8 V unless otherwise noted)  
J
J
CC  
Symbol  
Rating  
Pin  
Min  
Typ  
Max  
Unit  
SUPPLY SECTION AND V MANAGEMENT  
CC  
V
CC(on)  
V
CC  
increasing level at which the switcher starts operation  
NCV1072/75  
NCV1076/77  
V
1
1
7.8  
7.7  
8.2  
8.1  
8.6  
8.5  
V
V
decreasing level at which the HV current source restarts  
1
1
1
6.5  
6.1  
6.8  
6.3  
4
7.2  
6.6  
V
V
CC(min)  
CC  
CC  
CC  
V
V
V
decreasing level at which the switcher stops operation (UVLO)  
voltage at which the internal latch is reset (guaranteed by design)  
CC(off)  
V
V
CC(reset)  
V
Offset voltage above V  
at which the internal clamp activates  
mV  
CC(clamp)  
CC(on)  
(measured in skip mode)  
NCV1072/75  
1
1
130  
130  
190  
190  
300  
300  
NCV1076/77  
I
Internal IC consumption, Mosfet switching  
NCV1072/75  
NCV1076/77  
mA  
CC1  
1
1
0.7  
1.0  
1.0  
1.3  
I
Internal IC consumption, FB is 0 V (No switching on MOSFET)  
1
360  
mA  
CCskip  
POWER SWITCH CIRCUIT  
R
Power Switch Circuit onstate resistance (Id = 50 mA)  
5
W
DS(on)  
NCV1072/75  
T = 25°C  
11  
19  
16  
24  
J
T = 125°C  
J
NCV1076/77  
T = 25°C  
4.7  
8.7  
6.9  
10.75  
J
T = 125°C  
J
BV  
Power Switch Circuit & Startup breakdown voltage  
5
5
670  
V
DSS  
(ID  
= 120 mA, T = 25°C)  
(off)  
J
I
Power Switch & Startup breakdown voltage offstate leakage current  
T = 125°C (Vds = 670 V)  
mA  
ns  
DSS(off)  
85  
J
Switching characteristics (R =50 W, V set for I  
= 0.7 x Ilim)  
L
DS  
drain  
t
on  
t
off  
Turnon time (90% 10%)  
Turnoff time (10% 90%)  
5
5
20  
10  
INTERNAL STARTUP CURRENT SOURCE  
I
Highvoltage current source, V  
NCV1076/77  
NCV1072/75  
V
CC(on)  
200 mV  
mA  
start1  
=
5
5
5.2  
5
9.2  
9
12.2  
12  
I
Highvoltage current source, V = 0 V  
5
1
0.5  
2.2  
mA  
V
start2  
CC  
V
VCC Transient level for Istart1 to Istart2 toggling point  
CCTH  
CURRENT COMPARATOR  
I
Maximum internal current setpoint at 50% duty cycle  
mA  
IPK  
FB pin open, Tj = 25°C  
NCV1072  
250  
450  
650  
800  
NCV1075  
NCV1076  
NCV1077  
I
Maximum internal current setpoint at beginning of switching cycle  
mA  
IPK(0)  
FB pin open, Tj = 25°C  
NCV1072  
254  
467  
689  
846  
282  
508  
765  
940  
310  
549  
NCV1075  
NCV1076  
841  
NCV1077  
1034  
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product  
performance may not be indicated by the Electrical Characteristics if operated under different conditions.  
4. The final switch current is: I  
/ (V /L + S ) x V /L + V /L x t  
, with S the builtin slope compensation, Vin the input voltage, L  
prop a P  
IPK(0)  
in  
P
a
in  
P
in  
P
the primary inductor in a flyback, and t  
5. NCV1072 130 kHz on demand only.  
the propagation delay.  
prop  
6. Oscillator frequency is measured with disabled jittering.  
www.onsemi.com  
5
NCV1072, NCV1075, NCV1076, NCV1077  
ELECTRICAL CHARACTERISTICS  
(For all NCV107X products: For typical values T = 25°C, for min/max values T = 40°C to +125°C, V = 8 V unless otherwise noted)  
J
J
CC  
Symbol  
Rating  
Pin  
Min  
Typ  
Max  
Unit  
CURRENT COMPARATOR  
I
I
I
Final switch current with a primary slope of 200 mA/ms,  
=65 kHz (Note 4)  
mA  
IPKSW  
IPKSW  
IPKSW  
F
SW  
NCV1072  
296  
510  
732  
881  
NCV1075  
NCV1076  
NCV1077  
Final switch current with a primary slope of 200 mA/ms,  
=100 kHz (Note 4)  
mA  
mA  
F
SW  
NCV1072  
293  
500  
706  
845  
NCV1075  
NCV1076  
NCV1077  
Final switch current with a primary slope of 200 mA/ms,  
=130 kHz  
F
SW  
NCV1072 (Note 5)  
NCV1075  
291  
493  
684  
814  
NCV1076  
NCV1077  
T
Softstart duration (guaranteed by design)  
Leading Edge Blanking Duration  
1
ms  
ns  
ns  
SS  
T
LEB  
prop  
200  
100  
T
Propagation delay from current detection to drain OFF state  
INTERNAL OSCILLATOR  
f
f
f
Oscillation frequency, 65 kHz version, Tj = 25°C (Note 6)  
Oscillation frequency, 100 kHz version, Tj = 25°C (Note 6)  
Oscillation frequency, 130 kHz version, Tj = 25°C (Note 5 et 6)  
59  
90  
117  
65  
100  
130  
6
71  
110  
143  
kHz  
kHz  
kHz  
%
OSC  
OSC  
OSC  
f
Frequency jittering in percentage of f  
jitter  
OSC  
f
Jittering swing frequency  
300  
Hz  
swing  
D
Maximum dutycycle  
NCV1072/75  
NCV1076/77  
%
max  
62  
65  
68  
69  
72  
73  
FEEDBACK SECTION  
FB current for which Fault is detected  
FB current for which internal current setpoint is 100% (I  
I
4
4
4
4
35  
44  
90  
3.3  
mA  
mA  
mA  
V
FBfault  
I
)
IPK(0)  
FB100%  
I
FB current for which internal current setpoint is I  
FBFreeze  
Freeze  
V
Equivalent pullup voltage in linear regulation range  
(Guaranteed by design)  
FB(REF)  
R
Equivalent feedback resistor in linear regulation range  
(Guaranteed by design)  
4
19.5  
kW  
FB(up)  
FREQUENCY FOLDBACK & SKIP  
Start of frequency foldback feedback level  
I
4
4
4
68  
100  
25  
mA  
mA  
FBfold  
I
End of frequency foldback feedback level, F = F  
FBfold(end)  
sw  
min  
F
min  
The frequency below which skipcycle occurs  
21  
29  
kHz  
mA  
I
The feedback level to enter skip mode  
120  
FBskip  
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product  
performance may not be indicated by the Electrical Characteristics if operated under different conditions.  
4. The final switch current is: I  
/ (V /L + S ) x V /L + V /L x t  
, with S the builtin slope compensation, Vin the input voltage, L  
prop a P  
IPK(0)  
in  
P
a
in  
P
in  
P
the primary inductor in a flyback, and t  
5. NCV1072 130 kHz on demand only.  
the propagation delay.  
prop  
6. Oscillator frequency is measured with disabled jittering.  
www.onsemi.com  
6
NCV1072, NCV1075, NCV1076, NCV1077  
ELECTRICAL CHARACTERISTICS  
(For all NCV107X products: For typical values T = 25°C, for min/max values T = 40°C to +125°C, V = 8 V unless otherwise noted)  
J
J
CC  
Symbol  
Rating  
Pin  
Min  
Typ  
Max  
Unit  
FREQUENCY FOLDBACK & SKIP  
I
Internal minimum current setpoint (I = I )  
FBFreeze  
mA  
Freeze  
FB  
NCV1072  
NCV1075  
NCV1076  
NCV1077  
88  
168  
228  
280  
RAMP COMPENSATION  
S
The internal ramp compensation @ 65 kHz  
mA/ms  
mA/ms  
a(65)  
NCV1072  
NCV1075  
NCV1076  
NCV1077  
4.2  
7.5  
15  
18  
S
a(100)  
S
a(130)  
The internal ramp compensation @ 100 kHz  
NCV1072  
NCV1075  
NCV1076  
NCV1077  
6.5  
11.5  
23  
28  
The internal ramp compensation @ 130 kHz  
NCV1072 (Note 5)  
NCV1075  
NCV1076  
NCV1077  
8.4  
15  
30  
36  
PROTECTIONS  
t
Fault validation further to error flag assertion  
40  
53  
ms  
ms  
SCP  
t
OFF phase in fault mode  
NCV1072/5/6/7  
recovery  
420  
I
t
V
clamp current at which the switcher stops pulsing  
mA  
OVP  
CC  
NCV1072/75/76/77  
5
6
8.5  
80  
91  
11  
The filter of V OVP comparator  
ms  
OVP  
CC  
V
The drain pin voltage above which allows MOSFET operate, which is  
72  
110  
V
HV(EN)  
detected after TSD, UVLO, SCP, or V OVP mode. (only for versions  
CC  
with brownin)  
TEMPERATURE MANAGEMENT  
TSD Temperature shutdown (Guaranteed by design)  
Hysteresis in shutdown (Guaranteed by design)  
150  
°C  
°C  
50  
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product  
performance may not be indicated by the Electrical Characteristics if operated under different conditions.  
4. The final switch current is: I  
/ (V /L + S ) x V /L + V /L x t  
, with S the builtin slope compensation, Vin the input voltage, L  
prop a P  
IPK(0)  
in  
P
a
in  
P
in  
P
the primary inductor in a flyback, and t  
5. NCV1072 130 kHz on demand only.  
the propagation delay.  
prop  
6. Oscillator frequency is measured with disabled jittering.  
www.onsemi.com  
7
 
NCV1072, NCV1075, NCV1076, NCV1077  
TYPICAL CHARACTERISTICS  
8.4  
8.3  
8.2  
8.1  
8.0  
7.9  
7.0  
6.9  
6.8  
6.7  
6.6  
6.5  
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 5. VCC(on) vs. Temperature  
Figure 6. VCC(min) vs. Temperature  
6.6  
6.5  
6.4  
6.3  
6.2  
6.1  
240  
220  
200  
180  
160  
140  
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 7. VCC(off) vs. Temperature  
Figure 8. VCC(clamp) vs. Temperature  
0.80  
0.75  
0.70  
0.65  
0.60  
40  
35  
30  
25  
20  
15  
10  
NCV1072/75  
NCV1076/77  
100  
5
0
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 9. ICC1 vs. Temperature  
Figure 10. RDS(on) vs. Temperature  
www.onsemi.com  
8
NCV1072, NCV1075, NCV1076, NCV1077  
TYPICAL CHARACTERISTICS  
12  
11  
10  
9
110  
100  
90  
80  
70  
8
7
6
60  
50  
5
4
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
Figure 11. IDSS(off) vs. Temperature  
Figure 12. Istart1 vs. Temperature  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
1000  
NCV1077  
900  
800  
700  
600  
500  
400  
NCV1076  
NCV1075  
300  
200  
NCV1072  
100 125  
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 13. Istart2 vs. Temperature  
Figure 14. IIPK(0) vs. Temperature  
72  
70  
68  
66  
110  
100  
90  
100 kHz  
80  
70  
60  
50  
65 kHz  
100  
64  
62  
50  
25  
0
25  
50  
75  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 15. FOSC vs. Temperature  
Figure 16. D(max) vs. Temperature  
www.onsemi.com  
9
NCV1072, NCV1075, NCV1076, NCV1077  
TYPICAL CHARACTERISTICS  
65  
60  
55  
50  
29  
28  
27  
26  
25  
24  
23  
22  
21  
45  
40  
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 17. Fmin vs. Temperature  
Figure 18. tSCP vs. Temperature  
10  
510  
490  
9.5  
9.0  
8.5  
8.0  
7.5  
7.0  
470  
450  
430  
410  
390  
370  
350  
50  
25  
0
25  
50  
75  
100  
125  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
Figure 19. t  
vs. Temperature  
Figure 20. IOVP vs. Temperature  
recovery  
6
5
110  
105  
100  
95  
NCV1076/77  
4
3
2
NCV1072/75  
90  
85  
80  
1
0
50 25  
0
25  
50  
75  
100  
125 150  
50  
25  
0
25  
50  
75  
100  
125  
TEMPERATURE (°C)  
T , JUNCTION TEMPERATURE (°C)  
J
Figure 21. VHV(EN) vs. Temperature  
Figure 22. Drain Current Peak during Transformer  
Saturation vs. Junction Temperature  
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10  
NCV1072, NCV1075, NCV1076, NCV1077  
TYPICAL CHARACTERISTICS  
1.100  
1.075  
1.050  
1.025  
1.000  
0.975  
0.950  
0.925  
40 20  
0
20  
40  
60  
80  
100 125  
TEMPERATURE (°C)  
Figure 23. Breakdown Voltage vs. Temperature  
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11  
NCV1072, NCV1075, NCV1076, NCV1077  
APPLICATION INFORMATION  
Introduction  
resumes operation. If the fault is still there, e.g. a  
broken optocoupler, the controller protects the load  
through a safe burst mode.  
The NCV107x offers a complete currentmode control  
solution. The component integrates everything needed to  
build a rugged and lowcost SwitchMode Power Supply  
(SMPS) featuring low standby power. The Quick Selection  
Table on page 2 details the differences between references,  
mainly peak current setpoints and operating frequency.  
Line detection: An internal comparator monitors the  
drain voltage as recovering from one of the following  
situations:  
Short Circuit Protection,  
Currentmode operation: the controller uses  
currentmode control architecture.  
V OVP is confirmed,  
CC  
UVLO  
TSD  
670 V Power MOSFET: Due to ON Semiconductor  
Very High Voltage Integrated Circuit technology, the  
circuit hosts a high*voltage power MOSFET featuring  
a 11/4.7 W RDS(on) – TJ = 25°C. This value lets the  
designer build a power supply up to respectively 10 W  
and 15 W operated on universal mains. An internal  
current source delivers the startup current, necessary to  
crank the power supply.  
If the drain voltage is lower than the internal threshold  
(V  
), the internal power switch is inhibited. This  
HV(EN)  
avoids operating at too low ac input. This is also called  
brownin function in some fields. This detection can be  
inhibited on demand on NCV1076/77 versions.  
Frequency jittering: an internal lowfrequency  
modulation signal varies the pace at which the  
Dynamic SelfSupply: Due to the internal high voltage  
current source, this device could be used in the  
application without the auxiliary winding to provide  
supply voltage.  
oscillator frequency is modulated. This helps spreading  
out energy in conducted noise analysis. To improve the  
EMI signature at low power levels, the jittering remains  
active in frequency foldback mode.  
Short circuit protection: by permanently monitoring the  
feedback line activity, the IC is able to detect the  
presence of a shortcircuit, immediately reducing the  
SoftStart: a 1 ms softstart ensures a smooth startup  
sequence, reducing output overshoots.  
Frequency foldback capability: a continuous flow of  
pulses is not compatible with noload/lightload  
standby power requirements. To excel in this domain,  
the controller observes the feedback current  
output power for a total system protection. A t  
timer  
SCP  
is started as soon as the feedback current is below  
threshold, I , which indicates the maximum peak  
FB(fault)  
current. If at the end of this timer the fault is still  
present, then the device enters a safe, autorecovery  
burst mode, affected by a fixed timer recurrence,  
information and when it reaches a level of I  
, the  
FBfold  
oscillator then starts to reduce its switching frequency  
as the feedback current continues to increase (the power  
demand continues to reduce). It can go down to 25 kHz  
t . Once the short has disappeared, the controller  
recovery  
resumes and goes back to normal operation.  
(typical) reached for a feedback level of I  
FBfold(end)  
Builtin V Over Voltage Protection: when the  
CC  
(100 mA roughly). At this point, if the power continues  
to drop, the controller enters classical skipcycle mode.  
auxiliary winding is used to bias the V pin (no DSS),  
CC  
an internal active clamp connected between V and  
CC  
Skip: if SMPS naturally exhibits a good efficiency at  
nominal load, they begin to be less efficient when the  
output power demand diminishes. By skipping  
ground limits the supply dynamics to V  
. In  
CC(clamp)  
case the current injected in this clamp exceeds a level  
of 6.0 mA (minimum), the controller immediately stops  
unneeded switching cycles, the NCV107x drastically  
reduces the power wasted during light load conditions.  
switching and waits a full timer period (t  
) before  
recovery  
attempting to restart. If the fault is gone, the controller  
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12  
NCV1072, NCV1075, NCV1076, NCV1077  
APPLICATION INFORMATION  
Startup Sequence  
When the power supply is first powered from the mains  
outlet, the internal current source is biased and charges up  
source turns off and pulses are delivered by the output stage:  
the circuit is awake and activates the power MOSFET if the  
bulk voltage is above V  
level. Figure 24 details the  
HV(EN)  
the V capacitor from the drain pin. Once the voltage on  
simplified internal circuitry.  
CC  
this V capacitor reaches the V  
level, the current  
CC  
CC(on)  
V
bulk  
I1  
R
limit  
Drain  
5
I
start1  
I
CC1  
1
I2  
I
clamp  
+
-
C
VCC  
V
clamp  
V
V
CC(on)  
CC(min)  
I
> I  
OVP  
clamp  
--> OVP fault  
8
Figure 24. The Internal Arrangement of the Startup Circuitry  
Being loaded by the circuit consumption, the voltage on  
the V capacitor goes down. When V is below V  
whose low frequency depends on the V capacitor and the  
CC  
IC consumption. A 1.4 V ripple takes place on the V pin  
CC  
CC  
CC(min)  
CC  
level, it activates the internal current source to bring V  
whose average value equals (V  
+ V )/2.  
CC(min)  
CC  
CC(on)  
toward V  
level and stops again: a cycle takes place  
Figure 25 portrays a typical operation of the DSS.  
CC(on)  
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13  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Figure 25. The Charge/Discharge Cycle Over a 1 mF VCC Capacitor  
As one can see, even if there is auxiliary winding to  
protection (OVP) circuit and immediately stops the output  
pulses for t duration (420 ms typically). Then a new  
provide energy for V , it happens that the device is still  
CC  
recovery  
biased by DSS during startup time or some fault mode  
when the voltage on auxiliary winding is not ready yet. The  
startup attempt takes place to check whether the fault has  
disappeared or not. The OVP paragraph gives more design  
details on this particular section.  
V
V
V
capacitor shall be dimensioned to avoid V crosses  
CC  
CC  
level, which stops operation. The DV between  
CC(off)  
CC(min)  
Fault Condition – ShortCircuit on VCC  
In some fault situations, a shortcircuit can purposely  
and V  
is 0.4 V. There is no current source to  
CC(off)  
charge V capacitor when driver is on, i.e. drain voltage is  
CC  
occur between V and GND. In high line conditions (V  
CC  
HV  
close to zero. Hence the V capacitor can be calculated  
CC  
= 370 V ) the current delivered by the startup device will  
DC  
using  
seriously increase the junction temperature. For instance,  
ICC1Dmax  
since I  
equals 5 mA (the min corresponds to the highest  
start1  
(eq. 1)  
C
VCC w  
f
OSC @ DV  
T ), the device would dissipate 370 x 5 m = 1.85 W. To avoid  
j
this situation, the controller includes a novel circuitry made  
Take the NCV1072 65 kHz device as an example. C  
should be above  
VCC  
of two startup levels, I  
and I  
. At powerup, as long  
start1  
start2  
as V is below a 2.4 V level, the source delivers I  
CC  
start2  
0.8m @ 72%  
59 kHz @ 0.4  
(around 500 mA typical), then, when V reaches 2.4 V, the  
CC  
source smoothly transitions to I  
and delivers its nominal  
start1  
value. As a result, in case of shortcircuit between V and  
CC  
A margin that covers the temperature drift and the voltage  
drop due to switching inside FET should be considered, and  
thus a capacitor above 0.1 mF is appropriate.  
GND, the power dissipation will drop to 370 x 500u =  
185 mW. Figure 25 portrays this particular behavior.  
The first startup period is calculated by the formula C x V  
= I x t, which implies a 1m x 2.4 / 500u = 4.8 ms startup time  
for the first sequence. The second sequence is obtained by  
The V capacitor has only a supply role and its value  
CC  
does not impact other parameters such as fault duration or  
the frequency sweep period for instance. As one can see on  
Figure 24, an internal active zener diode, protects the  
toggling the source to 8 mA with a delta V of V  
CC(on)  
V
CCTH  
= 8.2 – 2.4 = 5.8 V, which finally leads to a second  
switcher against lethal V runaways. This situation can  
CC  
startup time of 1m x 5.8 / 8m = 0.725 ms. The total startup  
time becomes 4.8m + 0.725m = 5.525 ms. Please note that  
this calculation is approximated by the presence of the knee  
in the vicinity of the transition.  
occur if the feedback loop optocoupler fails, for instance,  
and you would like to protect the converter against an over  
voltage event. In that case, the internal current increase  
incurred by the V rapid growth triggers the over voltage  
CC  
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14  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Fault Condition – Output ShortCircuit  
asserted, Ipflag, indicating that the system has reached its  
maximum current limit set point. The assertion of this flag  
triggers a fault counter t (53 ms typically). If at counter  
As soon as V  
reaches V , drive pulses are  
CC(on)  
CC  
internally enabled. If everything is correct, the auxiliary  
SCP  
winding increases the voltage on the V pin as the output  
completion, Ipflag remains asserted, all driving pulses are  
stopped and the part stays off in t duration (about  
CC  
voltage rises. During the startsequence, the controller  
smoothly ramps up the peak drain current to maximum  
recovery  
420 ms). A new attempt to restart occurs and will last 53 ms  
providing the fault is still present. If the fault still affects the  
output, a safe burst mode is entered, affected by a low  
dutycycle operation (11%). When the fault disappears, the  
power supply quickly resumes operation. Figure 26 depicts  
this particular mode:  
setting, i.e. I , which is reached after a typical period of  
IPK  
1 ms. When the output voltage is not regulated, the current  
coming through FB pin is below I  
level (35 mA  
FBfault  
typically), which is not only during the startup period but  
also anytime an overload occurs, an internal error flag is  
Figure 26. In Case of ShortCircuit or Overload, the NCV107X Protects Itself and the Power Supply Via a Low  
Frequency Burst Mode. The VCC is Maintained by the Current Source and Selfsupplies the Controller.  
AutoRecovery Over Voltage Protection  
triggering the OVP as we discussed, but also to avoid  
disturbing the V in low / light load conditions. The below  
The particular NCV107X arrangement offers a simple  
way to prevent output voltage runaway when the  
optocoupler fails. As Figure 27 shows, an active zener diode  
CC  
lines detail how to evaluate the R  
value...  
limit  
Selfsupplying controllers in extremely low standby  
applications often puzzles the designer. Actually, if a SMPS  
operated at nominal load can deliver an auxiliary voltage of  
monitors and protects the V pin. Below its equivalent  
CC  
breakdown voltage, that is to say 8.4 V typical, no current  
flows in it. If the auxiliary V pushes too much current  
an arbitrary 16 V (V ), this voltage can drop below 10 V  
CC  
nom  
inside the zener, then the controller considers an OVP  
situation and stops the internal drivers. When an OVP  
occurs, all switching pulses are permanently disabled. After  
(V ) when entering standby. This is because the  
recurrence of the switching pulses expands so much that the  
stby  
low frequency refueling rate of the V capacitor is not  
CC  
t
delay, it resumes the internal drivers. If the failure  
enough to keep a proper auxiliary voltage. Figure 28  
portrays a typical scope shot of a SMPS entering deep  
standby (output unloaded). Thus, care must be taken when  
recovery  
symptom still exists, e.g. feedback optocoupler fails, the  
device keeps the autorecovery OVP mode.  
Figure 27 shows that the insertion of a resistor (R  
)
calculating R  
1) to not trigger the V over current latch  
limit  
limit  
CC  
between the auxiliary dc level and the V pin is mandatory  
(by injecting 6 mA into the active clamp – always use the  
minimum value for worse case design) in normal operation  
CC  
a) not to damage the internal 8.4 V zener diode during an  
overshoot for instance (absolute maximum current is  
15 mA) b) to implement the failsafe optocoupler protection  
(OVP) as offered by the active clamp. Please note that there  
cannot be bad interaction between the clamping voltage of  
but 2) not to drop too much voltage over R  
when entering  
limit  
standby. Otherwise, the converter will enter dynamic self  
supply mode (DSS mode), which increases the power  
dissipation. Based on these recommendations, we are able to  
the internal zener and V  
actually built on top of V  
since this clamping voltage is  
with a fixed amount of offset  
bound R  
between two equations:  
CC(on)  
limit  
CC(on)  
(200 mV typical). R  
should be carefully selected to avoid  
limit  
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15  
 
NCV1072, NCV1075, NCV1076, NCV1077  
This number decreases compared to normal operation since  
the part in standby does almost not switch. It is around  
0.36 mA for the NCV1072 65 kHz version.  
V
nom * V  
V
stby * VCC(min)  
CC(clamp) v Rlimit v  
(eq. 2)  
Itrip  
ICCskip  
V
is the level above which the auxiliary voltage must  
CC(min)  
Where:  
be maintained to keep the controller away from the dynamic  
self supply mode (DSS mode), which is not a problem in  
itself if low standby power does not matter.  
V
nom  
V
stby  
is the auxiliary voltage at nominal load  
is the auxiliary voltage when standby is entered  
I
is the current corresponding to the nominal operation. It  
trip  
If a further improvement on standby efficiency is  
thus must be selected to avoid false tripping in overshoot  
conditions. Always use the minimum of the specification for  
a robust design, i.e. I < I  
concerned, it is good to obtain V around 8 V at no load  
condition in order not to reactivate the internal clamp  
circuit.  
CC  
.
trip  
OVP  
I
is the controller consumption during skip mode.  
CCskip  
I
> I  
OVP  
clamp  
Figure 27. A More Detailed View of the NCV107x Offers Better Insight on How to Properly Wire an Auxiliary Winding  
Since R  
shall not bother the controller in standby, e.g.  
1.08. The OVP latch will activate when the clamp current  
exceeds 6 mA. This will occur when Vauxiliary growsup  
to:  
limit  
keep V  
to above V  
(7.2 V maximum), we  
CC  
CC(min)  
purposely select a V  
well above this value. As explained  
nom  
before, experience shows that a 40% decrease can be seen on  
auxiliary windings from nominal operation down to standby  
mode. Let’s select a nominal auxiliary winding of 13 V to  
offer sufficient margin regarding 7.2 V when in standby  
1. 8.4 + 0.77k x (6m + 0.8m) 13.6 V for the first  
boundary (R  
= 0.77 kW)  
limit  
2. 8.4 + 2.2k x (6m +0.8m) 23.4 V for the second  
boundary (R = 2.2 kW)  
limit  
(R  
limit  
also drops voltage in standby...). Plugging the values  
Due to a 1.08 ratio between the auxiliary V and the  
CC  
in Equation 2 gives the limits within which R  
shall be  
limit  
power winding, the OVP will be seen as a lower overshoot  
on the real output:  
selected:  
1. 13.6 / 1.08 12.6 V  
13 * 8.4  
8 * 7.2  
v Rlimit v  
2. 23.4 / 1.08 21.7 V  
6m  
0.36m  
As one can see, tweaking the R  
selection of a given overvoltage output level. Theoretically  
predicting the auxiliary drop from nominal to standby is an  
value will allow the  
limit  
that is to say: 0.77 kW < Rlimit < 2.2 kW.  
If we design a 65 kHz power supply delivering 12V, then  
the ratio between auxiliary and power must be: 13 / 12 =  
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16  
 
NCV1072, NCV1075, NCV1076, NCV1077  
almost impossible exercise since many parameters are  
involved, including the converter time constants. Fine  
tuning of R thus requires a few iterations and  
variations but also the output voltage excursion in fault.  
Once properly adjusted, the failsafe protection will  
preclude any lethal voltage runaways in case a problem  
would occur in the feedback loop.  
limit  
experiments on a breadboard to check the auxiliary voltage  
Figure 28. The Burst Frequency Becomes so Low That it is Difficult to Keep an Adequate Level on the Auxiliary  
CC...  
V
Figure 29 describes the main signal variations when the  
part operates in autorecovery OVP:  
Figure 29. If the VCC Current Exceeds a Certain Threshold, an AutoRecovery Protection is Activated  
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NCV1072, NCV1075, NCV1076, NCV1077  
Improving the precision in autorecovery OVP  
SoftStart  
Given the OVP variations the internal trip current  
dispersion incur, it is sometimes more interesting to explore  
a different solution, improving the situation to the cost of a  
minimal amount of surrounding elements. Figure 30 shows  
that adding a simple zener diode on top of the limiting  
resistor, offers a better precision since what matters now is  
The NCV107X features a 1 ms softstart which reduces  
the poweron stress but also contributes to lower the output  
overshoot. Figure 31 shows a typical operating waveform.  
The NCV107X features a novel patented structure which  
offers a better softstart ramp, almost ignoring the startup  
pedestal inherent to traditional currentmode supplies:  
the internal V  
breakdown plus the zener voltage. A  
CC(on)  
resistor in series with the zener diodes keeps the maximum  
current in the V pin below the maximum rating of 15 mA  
CC  
just before trip the OVP.  
Vcc  
D1  
Rlimit  
Laux  
Ground  
Figure 30. A Simple Zener Diode Added in Parallel  
VCCON  
Drain current  
Figure 31. The 1 ms softstart sequence  
Jittering  
sawtooth is internally generated and modulates the clock up  
and down with a fixed frequency of 300 Hz. Figure 32  
shows the relationship between the jitter ramp and the  
frequency deviation. It is not possible to externally disable  
the jitter.  
Frequency jittering is a method used to soften the EMI  
signature by spreading the energy in the vicinity of the main  
switching component. The NCV107X offers a 6%  
deviation of the nominal switching frequency. The sweep  
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18  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Jitter ramp  
68.9kHz  
65kHz  
Internal  
61.1kHz  
sawtooth  
adjustable  
Figure 32. Modulation Effects on the Clock Signal by the Jittering Sawtooth  
Frequency Foldback  
Line Detection  
An internal comparator monitors the drain voltage as  
recovering from one of the following situations:  
Short Circuit Protection,  
The reduction of noload standby power associated with  
the need for improving the efficiency, requires to change the  
traditional fixedfrequency type of operation. This device  
implements a switching frequency folback when the  
V OVP is confirmed,  
CC  
feedback current passes above a certain level, I  
, set  
FBfold  
UVLO  
TSD  
around 68 mA. At this point, the oscillator enters frequency  
foldback and reduces its switching frequency.  
The internal peak current setpoint is following the  
feedback current information until its level reaches the  
If the drain voltage is lower than the internal threshold  
V
HV(EN)  
(91 Vdc typically), the internal power switch is  
inhibited. This avoids operating at too low ac input. This is  
also called brownin function in some fields.  
minimal freezing level point of I  
. The only way to  
Freeze  
further reduce the transmitted power is to diminish the  
operating frequency down to F (25 kHz typically). This  
min  
value is reached at a feedback current level of I  
.
FBfold(end)  
Below this point, if the output power continues to decrease,  
the part enters skip cycle for the best noisefree performance  
in noload conditions. Figures 33 and 34 depict the adopted  
scheme for the part.  
Figure 33. By Observing the Current on the Feedback Pin, the Controller Reduces its Switching Frequency for an  
Improved Performance at Light Load  
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NCV1072, NCV1075, NCV1076, NCV1077  
Figure 34. Ipk Setpoint is Frozen at Lower Power Demand.  
Feedback and Skip  
In this linear operating range, the dynamic resistance is  
Figure 35 depicts the relationship between feedback  
voltage and current. The feedback pin operates linearly as  
19.5 kW typically (R  
) and the effective pull up voltage  
FB(up)  
is 3.3 V typically (V  
). When I is below 40 mA, the  
FB(REF)  
FB  
the absolute value of feedback current (I ) is above 40 mA.  
FB voltage will jump to close to 4.5 V.  
FB  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
Figure 35. Feedback Voltage vs. Current  
Figure 36 depicts the skip mode block diagram. When the  
FB current information reaches I , the internal clock to  
comparator is minimized to lower the ripple of the auxiliary  
voltage for V pin and V of power supply during skip  
FBskip  
CC  
OUT  
set the flipflop is blanked and the internal consumption of  
mode. It easies the design of V over load range.  
CC  
the controller is decreased. The hysteresis of internal skip  
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20  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Figure 36. Skip Cycle Schematic  
Ramp Compensation and Ipk Setpoint  
Here we got a table of the ramp compensation, the initial  
current set point, and the final current setpoint of different  
versions of switcher.  
In order to allow the NCV107X to operate in CCM with  
a duty cycle above 50%, a fixed slope compensation is  
internally applied to the currentmode control.  
Fsw  
Sa  
Ipk(Duty = 50%)  
Ipk(0)  
65 kHz  
100 kHz  
130 kHz  
65 kHz  
4.2 mA/ms  
6.5 mA/ms  
8.4 mA/ms  
7.5 mA/ms  
11.5 mA/ms  
15 mA/ms  
15 mA/ms  
23 mA/ms  
30 mA/ms  
18 mA/ms  
28 mA/ms  
36 mA/ms  
NCV1072  
NCV1075  
NCV1076  
NCV1077  
250 mA  
282 mA  
100 kHz  
130 kHz  
65 kHz  
450 mA  
650 mA  
800 mA  
508 mA  
765 mA  
940 mA  
100 kHz  
130 kHz  
65 kHz  
100 kHz  
130 kHz  
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21  
NCV1072, NCV1075, NCV1076, NCV1077  
The Figure 37 depicts the variation of I setpoint vs. the power switcher duty ratio, which is caused by the internal ramp  
PK  
compensation.  
Figure 37. IPK Setpoint Varies with Power Switch On Time, Which is Caused by the Ramp Compensation  
Design Procedure  
maximum voltage that can be reflected during toff  
.
The design of an SMPS around a monolithic device does  
not differ from that of a standard circuit using a controller  
and a MOSFET. However, one needs to be aware of certain  
characteristics specific of monolithic devices. Let us follow  
the steps:  
As a result, the Flyback voltage which is reflected  
on the drain at the switch opening cannot be larger  
than the input voltage. When selecting  
components, you thus must adopt a turn ratio  
which adheres to the following equation:  
V min = 90 Vac or 127 Vdc once rectified, assuming a low  
bulk ripple  
in  
ǒ
Ǔ
N Vout ) Vf t Vin,min  
(eq. 3)  
2. In our case, since we operate from a 127 V DC rail  
while delivering 12 V, we can select a reflected  
voltage of 120 Vdc maximum. Therefore, the turn  
ratio Np:Ns must be smaller than  
V max = 265 Vac or 375 Vdc  
in  
V
= 12 V  
= 10 W  
out  
P
out  
Operating mode is CCM  
Vreflect  
120  
h = 0.8  
+
+ 9.6  
1. The lateral MOSFET bodydiode shall never be  
forward biased, either during startup (because of  
a large leakage inductance) or in normal operation  
as shown by Figure 38. This condition sets the  
12 ) 0.5  
V
out ) Vf  
or Np:Ns < 9.6. Here we choose N = 8 in this case.  
We will see later on how it affects the calculation.  
350  
250  
150  
50.0  
50.0  
> 0 !!  
1.004M  
1.011M  
1.018M  
1.025M  
1.032M  
Figure 38. The DrainSource Wave Shall Always be Positive  
www.onsemi.com  
22  
 
NCV1072, NCV1075, NCV1076, NCV1077  
DIL  
K +  
ILavg  
and defines the amount of ripple we want in CCM  
(see Figure 39).  
Small K: deep CCM, implying a large primary  
inductance, a low bandwidth and a large  
leakage inductance.  
I
Lavg  
Large K: approaching BCM where the rms  
losses are worse, but smaller inductance,  
leading to a better leakage inductance.  
From Equation 6, a K factor of 1 (50% ripple), gives  
an inductance of:  
2
(
)
127   0.44  
L +  
+ 3.8 mH  
65k   1   12.75  
Vin,min @ dmax  
Figure 39. Primary Inductance Current Evolution in  
CCM  
127   0.44  
3.8   65k  
DIL +  
+
LFSW  
3. Lateral MOSFETs have a poorly doped  
bodydiode which naturally limits their ability to  
sustain the avalanche. A traditional RCD clamping  
network shall thus be installed to protect the  
MOSFET. In some low power applications, a  
simple capacitor can also be used since  
+ 223 mA peaktopeak  
The peak current can be evaluated to be:  
Iavg  
d
DIL  
DIL  
98m  
0.44  
Ipeak  
+
)
+ Ipeak  
+
)
2
2
+ 335 mA  
Lf  
On I , I  
can also be calculated:  
L
Lavg  
ǒ
Ǔ
V
drain,max + Vin ) N Vout ) Vf ) Ipeak  
Ǹ
Ctot  
DIL  
I
Lavg + Ipeak  
*
+ 0.34 * 0.112 + 223 mA  
(eq. 4)  
2
6. Based on the above numbers, we can now evaluate  
the conduction losses:  
where L is the leakage inductance, C the total  
f
tot  
capacitance at the drain node (which is increased by  
the capacitor you will wire between drain and  
source), N the N :N turn ratio, V the output  
2
DIL  
Id,rms  
+
2 * IpeakDIL )  
dǒI  
Ǹ
P
S
out  
peak  
3
voltage, V the secondary diode forward drop and  
f
finally, Ipeak the maximum peak current. Worse case  
occurs when the SMPS is very close to regulation,  
0.2232  
3
2
0.44ǒ0.335 * 0.335 @ 0.223 )  
+
Ǹ
e.g. the V target is almost reached and Ipeak is still  
out  
pushed to the maximum. For this design, we have  
+ 154 mA  
selected our maximum voltage around 650 V (at V  
in  
= 375 Vdc). This voltage is given by the RCD clamp  
installed from the drain to the bulk voltage. We will  
see how to calculate it later on.  
If we take the maximum R  
temperature, i.e. 24 W, then conduction losses worse  
case are:  
for a 125°C junction  
ds(on)  
4. Calculate the maximum operating dutycycle for  
this flyback converter operated in CCM:  
P
cond + Id,rms 2RDS(on) + 570 mW  
7. Offtime and ontime switching losses can be  
ǒ
Ǔ
N Vout ) Vf  
1
estimated based on the following calculations:  
dmax  
+
+
+ 0.44  
V
ǒ
Ǔ
N Vout ) Vf ) Vin,min  
in,min  
1 )  
ǒV  
Ǔ
Ipeak bulk ) Vclamp toff  
NǒV )V Ǔ  
(eq. 5)  
out  
f
Poff  
+
+
2Tsw  
5. To obtain the primary inductance, we have the  
choice between two equations:  
(eq. 7)  
(
)
0.335   127 ) 120 @ 2   10n  
2   15.4m  
ǒ
Ǔ2  
Vind  
(eq. 6)  
L +  
+ 36 mW  
fswKPin  
where  
www.onsemi.com  
23  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Where, assume the V  
reflected voltage.  
is equal to two times of  
8. The theoretical total power is then 0.570 + 0.036 +  
clamp  
0.0055 = 611 mW  
9. If the NCV107X operates at DSS mode, then the  
losses caused by DSS mode should be counted as  
losses of this device on the following calculation:  
ǒ
ǒ
ǓǓ  
Ivalley Vbulk ) N Vout ) Vf ton  
Pon  
+
+
6Tsw  
P
DSS + ICC1 @ Vin,max + 1m @ 375 + 375 mW  
(eq. 8)  
(
)
0.111   127 ) 100   20n  
(eq. 9)  
6   15.4m  
+ 5.5 mW  
MOSFET protection  
As in any Flyback design, it is important to limit the drain  
excursion to a safe value, e.g. below the MOSFET BVdss  
which is 670 V. Figure 40a, b, c present possible  
implementations:  
It is noted that the overlap of voltage and current seen  
on MOSFET during turning on and off duration is  
dependent on the snubber and parasitic capacitance  
seen from drain pin. Therefore the t and t in  
off  
on  
Equations 7 and 8 have to be modified after  
measuring on the bench.  
a
b
c
Figure 40. Different Options to Clamp the Leakage Spike  
Figure 40a: the simple capacitor limits the voltage  
according to The lateral MOSFET bodydiode shall never  
be forward biased, either during startup (because of a large  
leakage inductance) or in normal operation as shown by  
Figure 38. This condition sets the maximum voltage that can  
V
is usually selected 5080 V above the reflected  
clamp  
value N x (V + V ). The diode needs to be a fast one and  
a MUR160 represents a good choice. One major drawback  
of the RCD network lies in its dependency upon the peak  
out  
f
current. Worse case occurs when I  
and V are maximum  
peak  
in  
be reflected during t . As a result, the Flyback voltage  
and V is close to reach the steadystate value.  
off  
out  
which is reflected on the drain at the switch opening cannot  
be larger than the input voltage. When selecting  
components, you thus must adopt a turn ratio which adheres  
to the following equation: Equation 3. This option is only  
valid for low power applications, e.g. below 5 W, otherwise  
chances exist to destroy the MOSFET. After evaluating the  
leakage inductance, you can compute C with Equation 4.  
Typical values are between 100 pF and up to 470 pF. Large  
capacitors increase capacitive losses...  
Figure 40c: this option is probably the most expensive of  
all three but it offers the best protection degree. If you need  
a very precise clamping level, you must implement a zener  
diode or a TVS. There are little technology differences  
behind a standard zener diode and a TVS. However, the die  
area is far bigger for a transient suppressor than that of zener.  
A 5 W zener diode like the 1N5388B will accept 180 W peak  
power if it lasts less than 8.3 ms. If the peak current in the  
worse case (e.g. when the PWM circuit maximum current  
limit works) multiplied by the nominal zener voltage  
exceeds these 180 W, then the diode will be destroyed when  
the supply experiences overloads. A transient suppressor  
like the P6KE200 still dissipates 5 W of continuous power  
but is able to accept surges up to 600 W @ 1 ms. Select the  
zener or TVS clamping level between 40 to 80 V above the  
reflected output voltage when the supply is heavily loaded.  
Figure 40b: the most standard circuitry is called the RCD  
network. You calculate R  
and C  
using the  
clamp  
clamp  
following formulae:  
ǒ
Ǔ
ǒ
Ǔ
2 Vclamp Vclamp * Vout ) Vf N  
(eq. 10)  
(eq. 11)  
Rclamp  
+
Lleak peak  
Vclamp  
VrippleFswRclamp  
I
2Fsw  
Cclamp  
+
www.onsemi.com  
24  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Power Dissipation and Heatsinking  
The NCV107X welcomes two dissipating terms, the DSS  
currentsource (when active) and the MOSFET. Thus, P  
75°C/W and thus dissipate more power. The maximum  
power the device can thus evacuate is:  
tot  
T
Jmax * Tambmax  
(eq. 12)  
= P  
+ P . It is mandatory to properly manage the  
MOSFET  
DSS  
Pmax +  
RqJA  
heat generated by losses. If no precaution is taken, risks exist  
to trigger the internal thermal shutdown (TSD). To help  
dissipating the heat, the PCB designer must foresee large  
copper areas around the package. Take the PDIP7 package  
as an example, when surrounded by a surface greater than  
which gives around 930 mW for an ambient of 50°C and a  
maximum junction of 120°C. If the surface is not large  
enough, assuming the R  
is 100°C/W, then the maximum  
qJA  
power the device can evacuate becomes 700 mW. Figure 41  
gives a possible layout to help drop the thermal resistance.  
2
1.0 cm of 35 mm copper, it becomes possible to drop its  
thermal resistance junctiontoambient, R  
down to  
qJA  
Figure 41. A Possible PCB Arrangement to Reduce the Thermal Resistance JunctiontoAmbient  
A 10 W NCV1075 based Flyback Converter Featuring  
Low Standby Power  
is made via a NCP431 whose low bias current (50 mA) helps  
to lower the no load standby power.  
Figure 43 depicts a typical application showing a  
NCV107565 kHz operating in a 10 W converter. To leave  
more room for the MOSFET, it is recommended to disable  
the DSS by shorting the J3. In this application, the feedback  
Measurements have been taken from a demonstration  
board implementing the diagram in Figure 43 and the  
following results were achieved with auxiliary winding to  
bias the device:  
100 Vac  
115 Vac  
230 Vac  
265 Vac  
No load consumption with  
auxiliary winding  
26 mW  
28 mW  
38 mW  
45 mW  
www.onsemi.com  
25  
 
NCV1072, NCV1075, NCV1076, NCV1077  
Figure 42. Vout = 12 V  
R_L3  
15  
T1  
MA5597AL  
C9  
10 nF  
Figure 43. A 12 V – 0.85 A Universal Mains Power Supply  
www.onsemi.com  
26  
NCV1072, NCV1075, NCV1076, NCV1077  
ORDERING INFORMATION  
(Only options marked with * are qualified and released to market. Other options available upon customer request.)  
Brownin  
Function  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
No  
Device  
Frequency  
65 kHz  
R
(W)  
Ipk (mA)  
250  
250  
450  
450  
450  
650  
650  
650  
800  
800  
800  
250  
250  
450  
450  
450  
650  
650  
650  
800  
800  
800  
800  
DS(on)  
NCV1072P065G  
NCV1072P100G  
NCV1075P065G*  
NCV1075P100G*  
NCV1075P130G  
NCV1076P065G*  
NCV1076P100G*  
NCV1076P130G  
NCV1077P065G*  
NCV1077P100G  
NCV1077P130G  
NCV1072STAT3G  
NCV1072STBT3G  
NCV1075STAT3G  
NCV1075STBT3G  
NCV1075STCT3G  
NCV1076STAT3G  
NCV1076STBT3G  
NCV1076STCT3G  
NCV1077STAT3G  
NCV1077STBT3G*  
NCV1077CSTBT3G*  
NCV1077STCT3G  
11  
100 kHz  
65 kHz  
11  
11  
100 kHz  
130 kHz  
65 kHz  
11  
11  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
11  
100 kHz  
130 kHz  
65 kHz  
100 kHz  
130 kHz  
65 kHz  
100 kHz  
65 kHz  
11  
11  
100 kHz  
130 kHz  
65 kHz  
11  
11  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
4.7  
100 kHz  
130 kHz  
65 kHz  
100 kHz  
100 kHz  
130 kHz  
Yes  
Package Type  
Shipping  
†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.  
www.onsemi.com  
27  
NCV1072, NCV1075, NCV1076, NCV1077  
PACKAGE DIMENSIONS  
PDIP7 (PDIP8 LESS PIN 6)  
CASE 626A  
ISSUE C  
NOTES:  
D
A
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994.  
E
2. CONTROLLING DIMENSION: INCHES.  
3. DIMENSIONS A, A1 AND L ARE MEASURED WITH THE PACK-  
AGE SEATED IN JEDEC SEATING PLANE GAUGE GS3.  
4. DIMENSIONS D, D1 AND E1 DO NOT INCLUDE MOLD FLASH  
OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS ARE  
NOT TO EXCEED 0.10 INCH.  
H
8
5
4
E1  
5. DIMENSION E IS MEASURED AT A POINT 0.015 BELOW DATUM  
PLANE H WITH THE LEADS CONSTRAINED PERPENDICULAR  
TO DATUM C.  
1
6. DIMENSION eB IS MEASURED AT THE LEAD TIPS WITH THE  
LEADS UNCONSTRAINED.  
7. DATUM PLANE H IS COINCIDENT WITH THE BOTTOM OF THE  
LEADS, WHERE THE LEADS EXIT THE BODY.  
8. PACKAGE CONTOUR IS OPTIONAL (ROUNDED OR SQUARE  
CORNERS).  
NOTE 8  
c
b2  
B
END VIEW  
WITH LEADS CONSTRAINED  
NOTE 5  
TOP VIEW  
INCHES  
DIM MIN MAX  
−−−−  
A1 0.015  
MILLIMETERS  
A2  
A
MIN  
−−−  
0.38  
2.92  
0.35  
MAX  
5.33  
−−−  
4.95  
0.56  
e/2  
A
0.210  
−−−−  
NOTE 3  
A2 0.115 0.195  
L
b
b2  
C
0.014 0.022  
0.060 TYP  
0.008 0.014  
0.355 0.400  
1.52 TYP  
0.20  
9.02  
0.13  
7.62  
6.10  
0.36  
10.16  
−−−  
8.26  
7.11  
D
SEATING  
PLANE  
D1 0.005  
0.300 0.325  
E1 0.240 0.280  
−−−−  
A1  
D1  
E
C
M
e
eB  
L
0.100 BSC  
−−−− 0.430  
0.115 0.150  
−−−− 10°  
2.54 BSC  
−−−  
2.92  
−−−  
10.92  
3.81  
10°  
e
eB  
8X  
b
END VIEW  
M
NOTE 6  
M
M
M
B
0.010  
C A  
SIDE VIEW  
www.onsemi.com  
28  
NCV1072, NCV1075, NCV1076, NCV1077  
PACKAGE DIMENSIONS  
SOT223 (TO261)  
CASE 318E04  
ISSUE N  
D
b1  
NOTES:  
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994.  
2. CONTROLLING DIMENSION: INCH.  
MILLIMETERS  
INCHES  
NOM  
0.064  
0.002  
0.030  
0.121  
0.012  
0.256  
0.138  
0.091  
0.037  
−−−  
4
2
DIM  
A
A1  
b
b1  
c
D
E
e
e1  
L
L1  
MIN  
1.50  
0.02  
0.60  
2.90  
0.24  
6.30  
3.30  
2.20  
0.85  
0.20  
1.50  
6.70  
NOM  
1.63  
0.06  
0.75  
3.06  
0.29  
6.50  
3.50  
2.30  
0.94  
−−−  
1.75  
7.00  
MAX  
1.75  
0.10  
0.89  
3.20  
0.35  
6.70  
3.70  
2.40  
1.05  
−−−  
MIN  
MAX  
0.068  
0.004  
0.035  
0.126  
0.014  
0.263  
0.145  
0.094  
0.041  
−−−  
H
E
E
0.060  
0.001  
0.024  
0.115  
0.009  
0.249  
0.130  
0.087  
0.033  
0.008  
0.060  
0.264  
1
3
b
e1  
e
2.00  
7.30  
0.069  
0.276  
0.078  
0.287  
C
q
H
E
A
q
0.08 (0003)  
A1  
L
L1  
0°  
10°  
0°  
10°  
SOLDERING FOOTPRINT  
3.8  
0.15  
2.0  
0.079  
6.3  
0.248  
2.3  
0.091  
2.3  
0.091  
2.0  
0.079  
mm  
inches  
1.5  
0.059  
ǒ
Ǔ
SCALE 6:1  
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are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.  
ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent  
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NCV1070/D  

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