Analog integrated circuit GC-NIP

2 channelinterpolationwith ABZ interface

The input signals are subjected to an AMAC-specific internal gain and offset control and the signal period is divided up to 8192 times. For the absolute position of a two-channel nonius system, a resolution of up to 22 bit can be achieved. Input and output of the GC-NIP are designed for 3.3V interfaces. The IC comprises six instrumentation amplifiers with adjustable gain factors. Encoders with voltage interface or measuring brigdes can be connected directly. Sensors with current interface and photodiode-arrays are adapted by a simple external circuit. The IC operates on both single-ended or differential input signals. The noise of the sensor signals is prevented by a switching analog filter. Additionally, a digital hysteresis can suppress the edge noise of the output signals at low input frequencies and at standstill. The quality of the signals issued by the sensors is monitored in the IC. For that purpose it is possible to activate 9 sources separately producing an error signal. For the calculation of the absolute position a set of sensor- or scale-specific correction coefficients can be placed in the EEPROM of the IC. In that way, harmonics of the sinusoidal signals or inaccuracies of the measuring scale do not lead to errors in the absolute position value. The determination of the correction coefficients is realized by a simple software-based calibration procedure. Providing absolute position and incremental square-wave-signals (ABZ) in parallel, the GC-NIP is well-suited for the use in motor-feedback-systems.