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 D D D D D Low Supply Voltage Protection Loop Fault Protection Demagnetization/Overvoltage Protection Maximum Duty Cycle Clamp Feed Forward Control 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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VCC +1.4V Maximum Emitter Voltage (Pin14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +5V Operating Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0° to +70°C Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65° to +150°C DC Electrical Characteristics: (TA = +25°C, VCC = 12V unless otherwise specified) Parameter Reference Sections Internal Reference Voltage (Vref) Test Conditions Min Typ Max Unit TA = +25°C 3.57 3.72 3.95 V TA = 0° to +70°C 3.53 – 4.00 V – –100 – ppm/°C 7.8 8.4 8.8 V – 200 – ppm/°C Temperature Coefficient of Vref Internal Zener Reference (VZ) Temperature Coefficient of VZ IL = –7mA DC Electrical Characteristics (Cont’d): (TA = +25°C, VCC = 12V unless otherwise specified) Parameter Min Typ Max Unit TA = 0° to +70°C 50 – 100k Hz Initial Accuracy Oscillator R = 5kΩ – 5 – % Duty Cycle Range fo = 20kHz 0 – 98 % Voltage at Pin5 = 2V TA = 0° to +70°C – 0.2 20 µA – 0.2 20 µA 40 50 60 % of Duty Cycle Pin1, Low Supply Voltage Protection Thresholds 8.0 9.0 10.5 V Pin3, Feedback Loop Protection Trip Threshold 400 600 720 mV –7 –15 –35 µA 470 600 720 mV at 250mV, TA = +25°C – –0.6 –10 µA at 250mV, TA = 0° to +70°C – – –20 µA Pin16, Feed Forward Duty Cycle Control Voltage at Pin16 = 2VZ 30 40 50 % Original Duty Cycle Pin16, Feed Forward Input Current (Note 1) at 16V, VCC = 18V, TA = +25°C – 0.2 5.0 µA at 16V, VCC = 18V, TA = 0° to +70°C – – 10 µA 0 – 0.8 V 2 – VZ V Voltage at Pin9 = 0V, TA = +25°C – –65 –125 µA Voltage at Pin9 = 0V, TA = 0° to +70°C – – –125 µA 0 – 0.8 V 2 – VZ V at = 0V, TA = +25°C – –85 –125 µA 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 Inhibit Delay Time for 20% Overdrive at 40mA IOUT – 0.7 0.8 µs 0.56 0.60 0.70 V Current Limit, High Level 0.40 0.48 0.50 V Low Level in terms of High Level 0.75 0.80 0.85 V Oscillator Section Frequency Range Modulator Modulation Input Current Housekeeping Function Pin6, Input Current Pin6, Duty Cycle Limit Control Pin3, Pull–Up Current Test Conditions at 2V, TA = 0° to +70°C For 50% Maximum Duty Cycle, 15kHz to 50kHz/41% of VZ at 2V Pin13, Demagnetization/Over Voltage TA = 0° to +70°C Protection Trip on Threshold Pin13, Input Current External Synchronization Pin9 OFF Pin9 ON Pin9 Sink Current Remote Pin10 OFF Pin10 ON Pin10 Sink Current Current Limiting Pin11, IIN Single Pulse Inhibit Delay Trip Level: Shut Down, Slow Start, Low Level Note 1. Does not include current for timing resistors or capacitors. DC Electrical Characteristics (Cont’d): (TA = +25°C, VCC = 12V unless otherwise specified) Parameter Test Conditions Min Typ Max Unit 6.2 – 9.5 V Output Voltage Swing (VOL) – – 0.7 V Open Loop Gain 54 60 – dB Feedback Resistor 10k – – Ω – 3 – MHz – – 0.5 V Output Current (Pin15) 40 – – mA Maximum Emitter Voltage (Pin14) 5 6 – V – – 10 mA IZ = 0, Voltage Forced, VCC = 12V, TA = 0° to +70°C – – 15 mA ICC = 10mA Current Fed 19 – 24 V ICC = 30mA Current Fed 20 – 30 V Error Amplifier Output Voltage Swing (VOH) Small Signal Bandwidth Output Stage VCE(sat) IC = 40mA Supply Voltage/Current ICC VCC IZ = 0, Voltage Forced, VCC = 12V, TA = +25°C Pin Connection Diagram VCC 1 VZ 2 Feedback 3 Gain 4 Modulation 5 Duty Cycle Control 6 16 Feed Forward 15 Output (Collector) 14 Output (Emitter) 13 Demagnetization/Overvoltage 12 GND 11 Current Limiting RT 7 10 Remote ON/OFF CT 8 9 External Sync 16 9 .260 (6.6) Max 1 8 .300 (7.62) .785 (19.9) Max .200 (5.08) Max .245 (6.22) Min .100 (2.54) .700 (17.7)