Press Release

13-bit real-time interpolation now with BiSS C for uninterrupted absolute encoder measurement

The new 13-Bit Interpolator for fast absolute optical or magnetic encoders features the new open BiSS C interface standard protocal in a single integrated chip.

Source: iC-Haus
10/15/2009

For the first time ever high-resolution sine-to-digital converter iC-NQC provides the microelectronics industry with a BiSS C slave protocol that enables bidirectional data exchange at the same time as the cyclic output of measurement data. Normalized addresses device information is available that indexes the relevant standard device profile or a description file. An optional electronic ID plate can also be used to describe the measurement application.

In essence, iC-NQC is an interpolation circuit with signal error compensation for sinusoidal sensor signals,
like those generated by optical or magnetic GMR, AMR or Hall position sensors, for example. Both decimal and binary resolutions of up to 8,192 angle steps per signal period can be set; these can be output as an absolute value via a BiSS/SSI Interface at clock rates of up to 10 MHz and at the same time incrementally as encoder quadrature signals with A/B and an index Z.

A signal conditioning unit is integrated to correct typical sensor errors; this unit intercepts the analog signal path via several D/A converters. As iC-NQC can compensate for offset, amplitude and phase errors, interpolation results are considerably improved, with an accuracy of 10 bits or an angle error of +/- 0.35° maximum per signal period.

Binary resolutions of between 8 and 8,192 angle steps or decimal resolutions from 25 to 2,000 angle steps can be selected. For incremental output, the maximum tracking rate and minimum transition distance can be stipulated; for the output of an absolute angle via the serial interface an automatic resolution adaptation feature can be activated in order to trail high input frequencies of up to 250 kHz. A scalable 24-bit period counter also enables signal periods to be tracked.

An integrated I2C interface provides access to an external EEPROM with 2 to 16kbit that can store the CRC-checked configuration and ca. 1 kilobyte for other application data. On startup iC-NQC automatically reads the setup and checks the CRC or waits for the configuration via the BiSS-interface.

Typical applications include:
- Incremental and absolute encoders for BiSS and SSI
- Magnetic linear position measurement systems
- Optical linear scales
- Synchronous evaluation of sine encoders for inverters
- PC measuring cards for 1 V, 11 ƒÝA and TTL encoder signals

With a single supply of +5 V the device operates within the industrial operating temperature range of -20 to +85°C, and optional from -40 to +125°C and has a space-saving 20-pin TSSOP, 6.4 x 6.4 mm package. The iC-NQC (-20 to +85°C) is in production and available at $7.65 each, in 1000pcs quantities.
The new NQ6D demo board with user software supports easy evaluation on the PC using the available BiSS to USB-adapter.

About BiSS (Bidirectional Serial Sensor)-Interface
BiSS is an open standard for fast data exchange between motion sensors and control systems. For more information, or free a license, see: http://www.biss-interface.com .

Introducing iC-Haus
iC-Haus GmbH is one of the leading independent German manufacturers of standard iCs (ASSP) and customized ASiC semiconductor solutions. The company has been active in the design, production and sales of application-specific iCs for industrial, automotive and medical technology since 1984 and is represented worldwide. The iC-Haus cell libraries in CMOS, BCD and bipolar technologies are fully equipped to realize the design of sensor, laser, opto and actuator ASiCs. The iCs are assembled either in standard plastic packages or using chip-on-board technology to manufacture complete microsystems and multichip modules, also in combination with sensors as an optoBGATM.