NTE NTE7154

NTE7154
Integrated Circuit
Control Circuit for Switch Mode Power Supplies
using MOS Transistors
Description:
The NTE7154 is an integrated circuit in an 8–Lead DIP type package which controls the MOS power
transistor and performs all necessary regulation and monitoring functions in free running flyback converters. Since good load regulation over a wide load range is attained, this device is particularly suitable for consumer as well as industrial power supplies.
Features:
D Fold–Back Characteristic Provides Overload Protection for External Diodes
D Burst Operation Under Short–Circuit and No Load Conditions
D Loop Error Protection
D Switch–Off In Case of Too Low Line Voltage (Under Voltage Switch–Off)
D Line Voltage Compensation of Overload Point
D Soft–Start for Smooth Start–Up
D Chip Over–Temperature Protection (Thermal Shutdown)
D On–Chip Parasitic Transformer Oscillation Suppression Circuitry
D Decrease of Regulated Voltage for Low Power Consumption
Absolute Maximum Ratings:
Supply Voltage (Pin1), V1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to +3.0V
Supply Voltage (Pin2, Pin3, Pin4, Pin7), V2, V3, V4, V7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V
Supply Voltage (Pin6), V6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to +20V
Supply Current (Pin1, Pin2, Pin3, Pin7), I1, I2, I3, I7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3mA
Supply Current (Pin4, Note 1), I4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –1.5A
Supply Current (Pin5, Note 1), I5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 to +1.5A
Supply Current (Pin6, Note 1), I6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A
Supply Current (Pin8), I8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –3 to +3mA
Operating Junction Temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +125°C
Ambient Temperature Range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –20° to +85°C
Storage Temperature Range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40° to +125°C
Thermal Resistance, Junction–to–Ambient, RthJA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85°C/W
Thermal Resistance, Junction–to–Case, RthJC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45°C/W
Note 1. tp ≤ 50µs, V ≤ 0.1.
Electrical Characteristics: (VCC = 10V, TA = +25°C unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
–
0.6
0.8
mA
Start–Up Hysteresis
Start–Up Current Drain
I6E0
V6 = V6E
Switch–On Voltage
V6E
11
12
13
V
Switch–Off Voltage
V6A
4.5
5.0
5.5
V
Switch–On Current
I6E1
V6 = V6E
–
11
–
mA
Switch–Off Current
I6A1
V6 = V6A
–
10
–
mA
At Pin2 (V6 < V6E)
V2(Max)
I2 = 1mA
5.6
6.6
9.0
V
At Pin3 (V6 < V6E)
V3(Max)
I3 = 1mA
5.6
6.6
9.0
V
400
410
420
mV
–
43
–
dB
Voltage Clamp (V6 = 10V, IC Switched Off)
Control Range
Control Input Voltage
V1R
Voltage Gain of the Control Circuit in the
Control Range
–VR
VR = d(V2S – V2B)/dV1, f = 1kHz
Primary Current Simulation Voltage
Basic Value
VsB
0.955 1.000 1.030
V
Overload Range and Short Circuit Operation
Peak Value in the Range of Secondary
Overload
V2O
V1 = V1R = 10mV
2.80
2.95
3.10
V
Maximum Ramp Amplitude
DV2
V2O – V2B
1.82
1.95
2.08
V
Peak value in the Range of Secondary
Short–Circuit Operation
V2S
V1 = 0
2.3
2.5
2.7
V
–I2
V3 = 3.7V
300
500
650
µA
Foldback Point Correction
Foldback Point Correction Current
Generally Valid Data (V6 = 10V) Voltage of the Zero Transition Detector
Positive Clamping Voltage
V8P
I8 = 1mA
–
0.75
–
V
Negative Clamping Voltage
V8N
I8 = –1mA
–
–0.2
–
V
Threshold Voltage
V8S
40
50
–
mV
Suppression of Transformer Ringing
TUL
3.0
3.8
4.5
µs
V8 = 0
0
–
4
µV
Input Current
–I8
Push–Pull Output Stage Saturation Voltages
Pin5 Sourcing
VSatU
I5 = –0.1A
–
1.5
2.0
V
Pin5 Sinking
VSatU
I5 = +0.1A
–
1.0
1.2
V
I5 = +0.5A
–
1.4
1.8
V
Output Slow Rate
Rising Edge
+dV5/dt
–
70
–
V/µs
Falling Edge
–dV5/dt
–
100
–
V/µs
–
50
–
µA
Reduction of Control Voltage
Current to Reduce the Control Voltage
–I1
V7 = 1V
Electrical Characteristics (Cont’d): (VCC = 10V, TA = +25°C unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
Protection Circuit
Undervoltage Protection for V6:
Voltage at Pin5 = V5(min) if V6 < V6(Min)
V6(Min)
7.00
7.25
7.50
V
Overvoltage Protection for V6:
Voltage at Pin5 = V5(min) if V6 > V6(Min)
V6(Max)
15.0
16.0
16.5
V
970
1005
1040
mV
–
150
–
°C
I3 = 750µA
–
0.4
0.8
V
V3 = V2 = 0V
–
8
–
mA
Undervoltage Protection for VAC:
Voltage at Pin5 = V5(min) if V3 < V3A
V3A
Over Temperature: At the given chip temperature
the IC will switch V5 to V5(Min)
Voltage at Pin3 if one of the protection functions
was triggered; (V3 will be clamped until
V6 < V6A)
Current Drain During Burst Operation
V2 = 0V
Oj
V3Sat
I6
Pin Connection Diagram
Regulation Input 1
8 Zero Crossing Detector Input
7 Soft–Start
6 Supply Voltage
Primary Current Simulation 2
Primary Voltage Monitoring 3
GND 4
8
5 Output
5
.260 (6.6) Max
1
4
.430 (10.92)
Max
.300 (7.62)
.200
(5.08)
.125 (3.18) Min
.100 (2.54)
.300 (7.62)