AS8118 Single Phase Instantaneous Energy Metering IC with On-Chip Calibration, Stepper Motor Drive and LED Output - - The AS8118 offers three different pulse outputs. A stepper motor drive output for directly driving a stepper motor display, a LED output for energy consumption indication and a dedicated high frequency output for fast single point system calibration. The AS8118 is available in either surface mount SOIC-18 or dual-in-line DIP-18 packages. Block Diagram PROG - The on-chip anti-creep circuit ensures that the AS8118 does not output pulses when the meter is in a no-load condition and that the IEC1036 anti-creep test requirements are fully complied with, for both direct or transformer connection meters. VSSD - VDDD - Extremely accurate, surpassing the accuracy requirements of the IEC 1036 Specification less than 0.1% error over a 600 : 1 dynamic range On-chip programmable current input gain suitable for use with low-resistance shunt resistor or current transformer On-chip programming for output pulse rate selection On-chip calibration eliminates the need for an external resistor network or trim-potentiometer Programmable on-chip creep prevention under noload condition All on-chip programmable functions may be reprogrammed a second time Outputs directly drive an electromechanical counter or counters with a two phase stepper motor and consumption LED indicator Fast calibration pulse output for high speed manual or automated calibration On-chip voltage reference and power supply monitoring Bi-directional or unidirectional energy measurement, with direction indication output available VSSA - control block and non-volatile calibration memory for the on-chip programming. The on-chip programming enables the setting of the current input gain, the anti-creep threshold, the output pulse rates and the system calibration. The high level of integration ensures a minimum number of non-critical external components are required. VDDA Features FEATURES Description Revision 1.7, 22-Nov-04 Σ∆-mod Digital Filter Power Calculation IP IN Σ∆-mod Digital Filter VREF XIN XOUT CAL Crystal Osc LED Control MON POR MOP Figure 1 DIRO The highly integrated AS8118 design includes all the required functional blocks. The blocks comprise of analog to digital converters (ADC) for the voltage and current channels, digital filters, a digital signal processing block, a VP VN TM The AS8118 is ideal for use in ‘stand alone’ kWh meter applications, where the IC directly drives an electromechanical counter with a two-phase stepper motor, or for more complex meter applications, the AS8118 interfaces directly to a micro-controller. Non-volatile Calibration AGND Buffer DIRI The AS8118 is a very accurate single-phase bi-directional instantaneous energy measurement integrated circuit, which surpasses all the accuracy requirements for IEC1036 alternating current static watt-hour meters. The measured energy is converted into pulses with the number of output pulses being proportional to the measured energy. Block diagram of the AS8118 Page 1 of 1