NTE NTE1672 Datasheet
NTE1672
Integrated Circuit
Power Supply Control Circuit
Description:
The NTE1672 is a control circuit in a 16–Lead DIP type package designed for use in switched mode
power supplies. This single monolithic chip incorporates all the control and housekeeping (protection)
functions required in switched mode power supplies, including an internal temperature compensated
reference source, internal Zener references, sawtooth generator, pulse width modulator, output
stage, and various protection circuits.
Features:
D Stabilized Power Supply
D Temperature Compensated Reference Source
D Sawtooth Generator
D Pulse Width Modulator
D Remote ON/OFF Switching
D Current Limiting
D Low Supply Voltage Protection
D Loop Fault Protection
D Demagnetization/Overvoltage Protection
D Maximum Duty Cycle Clamp
D Feed Forward Control
D External Synchronization
Absolute Maximum Ratings:
Supply
Voltage Forced Mode +18V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current Fed Mode 30mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Transistor (at 20 – 30V Max)
Output Current 40mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Collector Voltage (Pin15) V
Maximum Emitter Voltage (Pin14) +5V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Ambient Temperature Range 0° to +70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range –65° to +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Electrical Characteristics:
Parameter Test Conditions Min Typ Max Unit
Reference Sections
Internal Reference Voltage (V
Temperature Coefficient of V
Internal Zener Reference (VZ) IL = –7mA 7.8 8.4 8.8 V
Temperature Coefficient of V
(TA = +25°C, VCC = 12V unless otherwise specified)
) TA = +25°C 3.57 3.72 3.95 V
ref
TA = 0° to +70°C 3.53 – 4.00 V
ref
Z
– –100 – ppm/°C
– 200 – ppm/°C
CC
+1.4V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Electrical Characteristics (Cont’d): (TA = +25°C, VCC = 12V unless otherwise specified)
Parameter Test Conditions Min Typ Max Unit
Oscillator Section
Frequency Range
Initial Accuracy Oscillator R = 5kΩ – 5 – %
Duty Cycle Range fo = 20kHz 0 – 98 %
Modulator
Modulation Input Current
Housekeeping Function
Pin6, Input Current
Pin6, Duty Cycle Limit Control For 50% Maximum Duty Cycle,
Pin1, Low Supply Voltage Protection
Thresholds
Pin3, Feedback Loop Protection Trip
Threshold
Pin3, Pull–Up Current at 2V –7 –15 –35 µA
Pin13, Demagnetization/Over Voltage
Protection Trip on Threshold
Pin13, Input Current at 250mV, TA = +25°C – –0.6 –10 µA
Pin16, Feed Forward Duty Cycle
Control
Pin16, Feed Forward Input Current
(Note 1)
External Synchronization
Pin9 OFF
Pin9 ON 2 – V
Pin9 Sink Current Voltage at Pin9 = 0V, TA = +25°C – –65 –125 µA
Remote
Pin10 OFF
Pin10 ON 2 – V
Pin10 Sink Current at = 0V, TA = +25°C – –85 –125 µA
Current Limiting
Pin11, I
IN
Single Pulse Inhibit Delay Inhibit Delay Time for 20% Overdrive
Trip Level: Shut Down, Slow Start,
Low Level
Current Limit, High Level 0.40 0.48 0.50 V
Low Level in terms of High
Level
TA = 0° to +70°C 50 – 100k Hz
Voltage at Pin5 = 2V TA = 0° to +70°C – 0.2 20 µA
at 2V, TA = 0° to +70°C
– 0.2 20 µA
40 50 60 % of Duty
15kHz to 50kHz/41% of V
Z
Cycle
8.0 9.0 10.5 V
400 600 720 mV
TA = 0° to +70°C 470 600 720 mV
at 250mV, TA = 0° to +70°C – – –20 µA
Voltage at Pin16 = 2V
Z
30 40 50 % Original
Duty Cycle
at 16V, VCC = 18V, TA = +25°C – 0.2 5.0 µA
at 16V, V
= 18V, TA = 0° to +70°C – – 10 µA
CC
0 – 0.8 V
Z
V
Voltage at Pin9 = 0V, TA = 0° to +70°C – – –125 µA
0 – 0.8 V
Z
V
at = 0V, TA = 0° to +70°C – – –125 µA
at = 250mV, TA = +25°C – –2 –20 µA
at = 250mV, TA = 0° to +70°C – – –40 µA
– 0.7 0.8 µs
at 40mA I
OUT
0.56 0.60 0.70 V
0.75 0.80 0.85 V
Note 1. Does not include current for timing resistors or capacitors.
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