UNISONIC TECHNOLOGIES CO., LTD GF2140 LINEAR INTEGRATED CIRCUIT LOW POWER TWO-WIRE GROUND FAULT INTERRUPTER DESCRIPTION As a low power controller for AC output appliance leakage current interrupters, the UTC GF2140 can detect hazardous current paths to ground, and trigger SCR to protect. SOP-8 FEATURES * Directly powered from the AC line * Build-in bridge rectifer * Interface to SCR * Adjustable trip current and time delay * Minimum external components * For two-wire system * Be used in 110V or 220V system ORDERING INFORMATION Ordering Number GF2140G-S08-R Package SOP-8 Packing Tape Reel MARKING www.unisonic.com.tw Copyright © 2015 Unisonic Technologies Co., Ltd 1 of 5 QW-R121-016.D GF2140 LINEAR INTEGRATED CIRCUIT PIN CONNECTIONS PIN DESCRIPTION PIN 1 2 3 4 5 6 7 8 PIN NAME RSET VFB VREF GND Line Neutral SCR Trigger C Delay I/O O I I I I O PIN FUNCTION Output of Leakage current first Input of leakage current Reference voltage Ground Line input Neutral input SCR Trigger The Delay time BLOCK DIAGRAM UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 5 QW-R121-016.D GF2140 LINEAR INTEGRATED CIRCUIT ELECTRICAL CHARACTERISTICS (ILINE=1.2mA, TA=25°C, RSET=290kΩ) PARAMETER Shunt Regulator (PIN 5-4) SYMBOL CONDITIONS MIN TYP MAX UNITS Regulator Voltage VREG I2-3=11μA ILINE=700μA, I2-3=9μA 6.1 6.1 6.5 6.5 7.5 7.5 Sense Amplifier (PIN 2-3) Offset Voltage Input Bias Current Gain Bandwidth SCR Trigger (PIN 7-6) VI(OFF) II(BIAS) fT Design Value Design Value Design Value -3.0 0 15 3.44 +3.0 30 mV nA MHZ Output Voltage VOUT Output Current Output Resistance Reference Voltage (PIN 3-4) Reference Voltage Delay Time (PIN 8-4) Delay Current Delay Time IOUT ZO I2-3=9μA I2-3=11μA V7-6=0V, I2-3=11μA V5-6=open, I2-3=0 0 1.4 300 4.0 0.1 2.0 420 4.7 10 2.6 600 5.4 mV V μA KΩ VREF ILINE=700μA 2.6 2.9 3.4 V I2-3=11μA C8-4=20nF 23 30 2.0 43 μA ms ID tD UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw V 3 of 5 QW-R121-016.D GF2140 LINEAR INTEGRATED CIRCUIT FUNCTIONAL DESCRIPTION (Refer to Block Diagram and Figure 1) The shunt regulator generated by a 6.5V zener diode is built into the internal bridge rectifier. It is divided to create an internal reference voltage of 2.9V connected to pin 3. The secondary of the sense transformer is AC coupled to the inverting input of the sense amplifier at pin 2; the non-inverting input is referenced to pin 3. A current feedback loop around the sense amplifier ensures a virtual ground will be presented to the secondary of the sense transformer. In this manner it acts as a current transformer instead of a voltage transformer. In this mode, the transformer’s characteristics are very predictable and circuit adjustments are not necessary in production. The AC coupled transformer secondary current then flows through the sense amplifier’s feedback loop, creating a full wave rectified version of the secondary fault current. This current passes through RSET at pin 1, generating a voltage equal to RSET times the peak fault current divided by the sense transformer turns ratio. This voltage is compared with the reference voltage at pin 3. If the voltage at pin 1 is greater than pin 3, a comparator will charge C2 through a 29uA current source at pin 8. If the voltage at pin 1 exceeds pin 3 for longer than the delay time, a 400uA current will pulse between pins 7 and 6 which will trigger the gate of the SCR. If the voltage at pin 1 exceeds pin 3 for less than the delay time, the SCR will not trigger. The fault current at which the controller triggers the SCR is dependent on the value of RSET and the time delay determined by C2. UL 943 requires the circuit interrupter trip when the ground fault exceeds 6mA and not trip when the fault current is less than 4mA. Supply Current Requirements The UTC GF2140 has a built-in diode bridge rectifier that provides power to the chip independent of the polarity of the AC line. This eliminates the external rectifier required for previous GFCI controllers. RLlNE limits the shunt regulator current to 2mA. The recommended value is 47K to 91K for 110V systems and 91K to 150K for 220V systems. The recommended maximum peak line current through RLlNE is 7mA. DO NOT connect a filter capacitor between pins 5 and 6 in an attempt to filter the supply voltage at the UTC GF2140. Proper operaton of the UTC GF2140 requires the internal supply voltage to be unfiltered. SCR Driver The SCR must have a high dV/dt rating to ensure that line noise (generated by electrically noisy appliances) does not falsely trigger the SCR. Also, the SCR must have a gate drive requirement less than 200uA. C3 is a noise filter that prevents high frequency line pulses from triggering the SCR. The relay solenoid used should have a 3 ms or less response time to meet the UL 943 timing requirement. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 5 QW-R121-016.D GF2140 LINEAR INTEGRATED CIRCUIT TYPICAL APPLICATION CIRCUIT Mov RTEST=15K TEST 1 500ZCT Line Load Hot Neutral Relay C2 =0.02μF RSET 290K C1=10μF 1 8 SCR 7 2 3 RLINE=91K GF2140 4 C3=10nF 6 5 C4=0.1μF Figure 1. Appliance Leakage Detector Circuit Application UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 5 of 5 QW-R121-016.D