NTE7154
Integrated Circuit
Control Circuit for Switch Mode Power Supplies
using MOS Transistors
Description:
The NTE7154 is an integrated circuit in an 8Lead DIP type package which controls the MOS power
transistor and performs all necessary regulation and monitoring functions in free running flyback con-
verters. Since good load regulation over a wide load range is attained, this device is particularly suit-
able for consumer as well as industrial power supplies.
Features:
D
FoldBack Characteristic Provides Overload Protection for External Diodes
D
Burst Operation Under ShortCircuit and No Load Conditions
D
Loop Error Protection
D
SwitchOff In Case of Too Low Line Voltage (Under Voltage SwitchOff)
D
Line Voltage Compensation of Overload Point
D
SoftStart for Smooth StartUp
D
Chip OverTemperature Protection (Thermal Shutdown)
D
OnChip Parasitic Transformer Oscillation Suppression Circuitry
D
Decrease of Regulated Voltage for Low Power Consumption
Absolute Maximum Ratings:
Supply Voltage (Pin1), V
1
0.3 to +3.0V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Voltage (Pin2, Pin3, Pin4, Pin7), V
2
, V
3
, V
4
, V
7
0.3V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Voltage (Pin6), V
6
0.3 to +20V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current (Pin1, Pin2, Pin3, Pin7), I
1
, I
2
, I
3
, I
7
3mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current (Pin4, Note 1), I
4
1.5A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current (Pin5, Note 1), I
5
0.5 to +1.5A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current (Pin6, Note 1), I
6
0.5A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current (Pin8), I
8
3 to +3mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Junction Temperature, T
J
+125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ambient Temperature Range, T
A
20
to +85
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
40
to +125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Resistance, JunctiontoAmbient, R
thJA
85
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Thermal Resistance, JunctiontoCase, R
thJC
45
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Note 1. t
p
50
s, V
0.1.
Electrical Characteristics: (V
CC
= 10V, T
A
= +25
C unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
StartUp Hysteresis
StartUp Current Drain
I
6E0
V
6
= V
6E
0.6
0.8
mA
SwitchOn Voltage
V
6E
11
12
13
V
SwitchOff Voltage
V
6A
4.5
5.0
5.5
V
SwitchOn Current
I
6E1
V
6
= V
6E
11
mA
SwitchOff Current
I
6A1
V
6
= V
6A
10
mA
Voltage Clamp (V
6
= 10V, IC Switched Off)
At Pin2 (V
6
< V
6E
)
V
2(Max)
I
2
= 1mA
5.6
6.6
9.0
V
At Pin3 (V
6
< V
6E
)
V
3(Max)
I
3
= 1mA
5.6
6.6
9.0
V
Control Range
Control Input Voltage
V
1R
400
410
420
mV
Voltage Gain of the Control Circuit in the
Control Range
V
R
V
R
= d(V
2S
V
2B
)/dV
1
, f = 1kHz
43
dB
Primary Current Simulation Voltage
Basic Value
V
sB
0.955 1.000 1.030
V
Overload Range and Short Circuit Operation
Peak Value in the Range of Secondary
Overload
V
2O
V
1
= V
1R
= 10mV
2.80
2.95
3.10
V
Maximum Ramp Amplitude
DV
2
V
2O
V
2B
1.82
1.95
2.08
V
Peak value in the Range of Secondary
ShortCircuit Operation
V
2S
V
1
= 0
2.3
2.5
2.7
V
Foldback Point Correction
Foldback Point Correction Current
I
2
V
3
= 3.7V
300
500
650
A
Generally Valid Data (V
6
= 10V) Voltage of the Zero Transition Detector
Positive Clamping Voltage
V
8P
I
8
= 1mA
0.75
V
Negative Clamping Voltage
V
8N
I
8
= 1mA
0.2
V
Threshold Voltage
V
8S
40
50
mV
Suppression of Transformer Ringing
TUL
3.0
3.8
4.5
s
Input Current
I
8
V
8
= 0
0
4
V
PushPull Output Stage Saturation Voltages
Pin5 Sourcing
V
SatU
I
5
= 0.1A
1.5
2.0
V
Pin5 Sinking
V
SatU
I
5
= +0.1A
1.0
1.2
V
I
5
= +0.5A
1.4
1.8
V
Output Slow Rate
Rising Edge
+dV
5
/dt
70
V/
s
Falling Edge
dV
5
/dt
100
V/
s
Reduction of Control Voltage
Current to Reduce the Control Voltage
I
1
V
7
= 1V
50
A
Electrical Characteristics (Cont'd): (V
CC
= 10V, T
A
= +25
C unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Protection Circuit
Undervoltage Protection for V
6
:
Voltage at Pin5 = V
5(min)
if V
6
< V
6(Min)
V
6(Min)
7.00
7.25
7.50
V
Overvoltage Protection for V
6
:
Voltage at Pin5 = V
5(min)
if V
6
> V
6(Min)
V
6(Max)
15.0
16.0
16.5
V
Undervoltage Protection for V
AC
:
Voltage at Pin5 = V
5(min)
if V
3
< V
3A
V
3A
V
2
= 0V
970
1005
1040
mV
Over Temperature: At the given chip temperature
the IC will switch V
5
to V
5(Min)
O
j
150
C
Voltage at Pin3 if one of the protection functions
was triggered; (V
3
will be clamped until
V
6
< V
6A
)
V
3Sat
I
3
= 750
A
0.4
0.8
V
Current Drain During Burst Operation
I
6
V
3
= V
2
= 0V
8
mA
Pin Connection Diagram
Output
Zero Crossing Detector Input
Primary Voltage Monitoring
1
2
3
4
Regulation Input
Primary Current Simulation
GND
8
7
6
5
SoftStart
Supply Voltage
8
5
.260 (6.6) Max
.430 (10.92)
Max
1
4
.300 (7.62)
.300 (7.62)
.200
(5.08)
.125 (3.18) Min
.100 (2.54)
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