IL4145A INTEGRAL | Alldatasheet
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Low Power Ground Fault Interrupter IL4145A
ORDERING INFORMATION
TA = -35° to 85° C for all packages. The IL4145AN is a low power cont roller for AC out let ground faul t interrupters. These devices detect hazardous grounding conditions, such as equipment (connected to opposite phases of t he AC line) in contact with a pool of water and open circuits t he l ine before a harm ful or l ethal shock occurs. Contained internally are a 26V zener shunt regul ator, an op am p, and an SCR driver. With the addition of two sense transformers, a bridge rectifier, an SCR, a relay, and a few additional com ponents, the IL4145AN will detect and prot ect agai nst bot h hot wi re t o ground and neut ral wire to ground faults. The simple l ayout and convent ional desi gn ensure ease of application and long-term reliability. No potentiomenter required Direct interface to SCR Supply voltage derived from AC line – 26V shunt Adjustable sensitivity Grounded neutral fault detection Meets U.L. 943 standards 450 µA quiescent current Ideal for 120 V or 220 V systems BLOCK DIAGRAM +Input VFB VREF +VS (+13V) (+26V) Op Amp Output SCR TriggerGround 6.5 V 6.5 V6.5 V 6.5 V 10K 10K 4.7K PIN ASSIGNMENT NC8 5GND +VSVREF +Input VFB Op Amp Output SCR Trigger ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit ICC Supply Current 18 mA PD Internal Power Dissipation 500 mW Tstg Storage Temperature Range -65 to +150 °C Topr Operating Temperature Range -35 to +85 °C TJ Junction Temperature 125 °C TL Lead Temperature 125 °C TA< 50°C 450 mW PD For TA> 50°C Derate at 6 mW/°C
ELECTRICAL CHARACTERISTICS (IS= 1.5 mA and TA= +25°C) Symbol Parameter Test Condition Min Max Unit VOH Detector Reference Voltage Pin 7 to Pin 3 6.8 8.1 ±V Shunt Regulator +VS Zener Voltage Pin 6 to Pin 4 25 29.2 V VREF Reference Voltage Pin 3 to Pin 4 12.5 14.6 V IS Quiescent Current +VS = 24 V 750 µA Operational Amplifier VIO Offset Voltage Pin 2 to Pin 3 -3.0 +3.0 mV VD +Output Voltage Swing Pin 7 to Pin 3 6.8 8.1 V VOL –Output Voltage Swing Pin 7 to Pin 3 -13.5 -9.5 V IOH +Output Source Current Pin 7 to Pin 3 ⎪-450⎪ ⎪-850⎪ µA IOL –Output Source Current Pin 7 to Pin 3 800 1200 µA BW Gain Bandwidth Product F = 50 KHz 1.0 MHz Resistors IS = 0 mA R1 R1 Pin 1 to Pin 3 8 12 kΩ R2 R2 Pin 2 to Pin 3 8 12 kΩ R3 R3 Pin 5 to Pin 4 3.5 5.9 kΩ SCR Trigger Voltage Pin 5 to Pin 4 VON Detector On 1.5 V VOFF Detector Off 0 10 mV ELECTRICAL CHARACTERISTICS (IS= 1.5 mA and -35°C ≤ TA ≤ +85°C) Symbol Parameter Test Condition Min Max Unit VOH Detector Reference Voltage Pin 7 to Pin 3 6.5 8.3 ±V Shunt Regulator +VS Zener Voltage Pin 6 to Pin 4 24 30 V VREF Reference Voltage Pin 3 to Pin 4 12 15 V IS Quiescent Current +VS = 23 V 800 µA Operational Amplifier VIO Offset Voltage Pin 2 to Pin 3 -5.0 +5.0 mV VD +Output Voltage Swing Pin 7 to Pin 3 6.5 8.3 V VOL –Output Voltage Swing Pin 7 to Pin 3 -14 -9 V Resistors IS = 0 mA R1 R1 Pin 1 to Pin 3 7.5 12.5 kΩ R2 R2 Pin 2 to Pin 3 7.5 12.5 kΩ R3 R3 Pin 5 to Pin 4 3.5 5.9 kΩ SCR Trigger Voltage Pin 5 to Pin 4 VON Detector On 1.3 V VOFF Detector Off 0 50 mV
The 26V shunt regulator voltage generated by the string of zener di odes is divided into three reference voltages: 3/4 VS , 1/2 VS , and 1/ 4 VS . VREF is at 1/2VS and is used as a reference t o create an artifical ground of +13V at the op amp noninverting input. Fig ure 1 shows a t hree-wi re 120V AC out let GFI application usi ng an IL4145AN. Faul t si gnals from the sense transformer are AC coupled into the input and are amplified according to the following equation: V7 = RSENSE x ISENSE/N Where V7 i s the RMS voltage at pin 7 relative to pin 3, RSENSE is the value of the feedback resistor connected from pin 7 to pin 1, ISENSE i s the fault current in amps RMS and N is th e turns ratio of the transformer. When V7 exceeds plus or minus 7.2V relative to pin 3 the SCR Trigger output will go high and fire the external SCR. The formula for V7 is approximate because it does not include the sense transformer characteristics. Grounded neutral fault detection is accomplished when a short or fault closes a m agnetic path between the sense transformer and t he grounded neut ral transformer. The resultant AC coupling closes a p ositive feed back p ath around the op am p, and therefore the op amp oscillates. When the peaks of the oscillation voltage exceed the SCR trigger comparator thresholds, the SCR o utput will go high. Shunt Regulator RLINE limits the current into the shunt regulator; 220V applicatio ns will req uire su bstitu tin g a 4 7kΩ 2W resistor. In addi tion t o suppl ying power t o t he IC , t he s h u n t regulator creates internal reference voltages (see above). Operational Amplifier RSENSE is a feedback resistor that sets gain and therefore sensitivity to n ormal fau lts. To ad just RSENSE, follow this procedure: apply the desired fault current (a di fference i n current of 5m A i s t he UL 943 standard). Adjust RSENSE upward until the SCR activates. A fixed resistor can be used for RSENSE, since the resultant ±15% variation in sensitivity will meet UL’s 943 4-6mA specification window. The rol l-off frequency i s great er than the grounded neutral fau lt o scillation freq uency, in o rder to preserve loop gain for oscillation (whi ch is determ ined by the inductance of the 200:1 transformer and C4). The senst ivity to grounded neut ral faul ts is adjust ed by changing th e freq uency o f o scillation. Increasing the frequency reduces the sensitiv ity by reducing the loop gain of the p ositive feed back circu it. As freq uency increases, the signal becom es at tenuated and t he l oop gain d ecreases. W ith th e v alues sh own th e circu it will detect a grounded neut ral fault having resi stance of 2Ω or less. The input to the op am p are protected from overvoltage by back-toback diodes. SCR Driver The SCR used must have a hi gh dV/dt rating to ensure that line noise (generated by noisy appliances such as a drill motor) does not falsely trig ger th e SCR. Also , th e SCR must have a gat e dri ve requi rement of l ess t han 200µA. CF is a noise filter capacitor that prevents narrow pulses from firing the SCR. The rel ay sol enoid used shoul d have a 3ms or less response time i n order t o m eet t he UL 943 t iming requirement. Sense Transformers and Cores The sense and grounded neut ral t ransformer cores are usually fabricated u sing h igh p ermeability lam inated steel rings. Their single turn prim ary is created by passing the line and neut ral wires through the center of its core. The secondary i s usual ly from 200 to 1500 turns. Two-Wire Application Circuit Figure 2 shows t he diagram of a 2-wi re 120V AC outlet GFI ci rcuit usi ng an IL4145AN. This circuit is not designed to det ect grounded neut ral faul ts. Thus, t he grounded neutral transformer and capaci tors C3 and C 4 of Figure 1 are not used.
- Value depends on transformer characteristics.
Figure 1. GFI Application Circuit (Three-Wire Outlet)
- Value depends on transformer characteristics.
Figure 2. GFI Application Circuit (Two-Wire Outlet)
6.5V Q20 6.5V Q18 6.5V Q17 6.5VQ8 Q15 Q4C2 10 pF 50K R14 1.3K 10K 50K 450 Q14 Q23 Q10 Q16 4 pF Q12 Q1 Q2 (-) (+)(1) Q22 10K R10 Q11 Q13 (2) VFB +Input 39K R3 4.7K R13 30K 250K (7) (5) (4) (3) (6) (+13V) VREF +VS(+26V) Ground Op Amp Output Sbstrate SCR Trigger R12 7.2K 5.6V
(MS – 001BA) Symbol MIN MAX A 8.51 10.16 B 6.1 7.11 C 5.33 D 0.36 0.56 F 1.14 1.78 G H J 0° 10° K 2.92 3.81 NOTES: L 7.62 8.26 1. Dimensions “A”, “B” do not include mold flash or protrusions. M 0.2 0.36 Maximum mold flash or protrusions 0.25 mm (0.010) per side. N 0.38 D SUFFIX SOIC (MS - 012AA) Symbol MIN MAX A 4.8 5 B 3.8 4 C 1.35 1.75 D 0.33 0.51 F 0.4 1.27 G H J 0° 8° NOTES: K 0.1 0.25 1. Dimensions A and B do not include mold flash or protrusion. M 0.19 0.25 1.27 5.72 Dimension, mm Dimension, mm 2.54 7.62 A BH C K C M J F M P G D R x 45 SEATING PLANE 0.25 (0.010) M T -T- L H M J A B F G D SEATING PLANE N K 0.25 (0.010) M T -T- C