NTE NTE7154 Datasheet

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), V
Supply Voltage (Pin2, Pin3, Pin4, Pin7), V
Supply Voltage (Pin6), V
Supply Current (Pin1, Pin2, Pin3, Pin7), I
Supply Current (Pin4, Note 1), I
Supply Current (Pin5, Note 1), I
Supply Current (Pin6, Note 1), I
Supply Current (Pin8), I
Operating Junction Temperature, T
Ambient Temperature Range, T
Storage Temperature Range, T

1

, V3, V4, V

2

6

, I2, I3, I

1
4
5
6

8

J

A

stg

Thermal Resistance, Junction–to–Ambient, R
Thermal Resistance, Junction–to–Case, R

Note 1. t

≤ 50µs, V ≤ 0.1.

p

thJC

thJA

–0.3 to +3.0V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

–0.3V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–0.3 to +20V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

3mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–1.5A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–0.5 to +1.5A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.5A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–3 to +3mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

+125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–20° to +85°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

–40° to +125°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

85°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45°C/W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Characteristics: (VCC = 10V, TA = +25°C unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

Start–Up Hysteresis

Start–Up Current Drain I

6E0

Switch–On Voltage V
Switch–Off Voltage V
Switch–On Current I
Switch–Off Current I

6E1
6A1

Voltage Clamp (V6 = 10V, IC Switched Off)
At Pin2 (V6 < V6E) V
At Pin3 (V6 < V6E) V

2(Max)I2
3(Max)I3

Control Range

Control Input Voltage V
Voltage Gain of the Control Circuit in the

–V

Control Range

Primary Current Simulation Voltage

Basic Value V

Overload Range and Short Circuit Operation

Peak Value in the Range of Secondary

V

Overload
Maximum Ramp Amplitude DV
Peak value in the Range of Secondary

V

Short–Circuit Operation

6E
6A

V6 = V

V6 = V
V6 = V

6E

6E
6A

– 0.6 0.8 mA

11 12 13 V

4.5 5.0 5.5 V

– 11 – mA
– 10 – mA

= 1mA 5.6 6.6 9.0 V
= 1mA 5.6 6.6 9.0 V

1R

VR = d(V2S – V2B)/dV1, f = 1kHz – 43 – dB

R

sB

V1 = V1R = 10mV 2.80 2.95 3.10 V

2O

V2O – V

2

V1 = 0 2.3 2.5 2.7 V

2S

2B

400 410 420 mV

0.955 1.000 1.030 V

1.82 1.95 2.08 V

Foldback Point Correction

Foldback Point Correction Current –I

V3 = 3.7V 300 500 650 µA

2

Generally Valid Data (V6 = 10V) Voltage of the Zero Transition Detector
Positive Clamping Voltage V
Negative Clamping Voltage V
Threshold Voltage V

I8 = 1mA – 0.75 – V

8P

I8 = –1mA – –0.2 – V

8N
8S

40 50 – mV
Suppression of Transformer Ringing TUL 3.0 3.8 4.5 µs
Input Current –I

V8 = 0 0 – 4 µV

8

Push–Pull Output Stage Saturation Voltages

Pin5 Sourcing V
Pin5 Sinking V

SatUI5
SatUI5

= –0.1A – 1.5 2.0 V
= +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

Reduction of Control Voltage

Current to Reduce the Control Voltage –I

V7 = 1V – 50 – µA

1