iC-NG is a monolithic A/D converter which determines the angle value of two sinusoidal input signals phaseshifted at 90° with a given resolution and hysteresis. In this process a cycle is divided into 8 segments; each of these segments can be given a resolution of up to 32 angular steps. Resolutions of 1 to 256 divisions per cycle are possible.
The converter can be adjusted for each individual segment to suit various types of input signal, meaning that even distorted sine signals or triangular signals, for example, can be converted. In addition, the direction of rotation can be inverted and the zero position can be set in steps of 45°.
Output values and parameters are stored in registers connected to the internal 8-bit data bus. A parallel microcontroller interface gives read and write access to these registers. If an EEPROM is connected to the serial interface, the chip setup can be automatically read in following a reset.
The output value consists of an 8-bit word for interpolation within a cycle and a 24-bit position counter which logs the number of turns. In addition to normal accessibility, the output value can also be transferred serially.
The position counter can be reset via the zero pulse or stopped and started using the bi-directional MFP pin. When programmed as an output, pin MFP shows the change in output value or indicates when a certain position has been reached (interrupt output). After a reset, the interpolation result is correct after just a few clock cycles, even with static input signals.
If incremental mode is selected, the changes in angle are output as square-wave signals phase-shifted at 90° at pins D0(AX) and D1(BX) with a selected resolution and at pins D3(A4) and D4(B4) with a resolution of four. The suitably prepared zero signal is at D2(ZX) and D5(Z4). Pin D6(ROT) shows the direction of rotation. Tracks AX and BX are EX-OR-gated at pin D7(AXB).
The front-end amplifier connections are all lead out, enabling current or voltage inputs to be made. Complementary input signals can also be connected. The front-end amplifiers are compensated internally; the value of compensation can be programmed.
The internal clock frequency can be adjusted using an external resistor or can be fed in via pin RCLK. The clock pulses which occur between two changes in output are counted in order to calculate the number of revolutions. Low voltage and excessive input frequency errors are signaled at output NER (open drain). These error codes are stored in the relevant register.
• Absolute and incremental angle interpolation from orthogonal sinusoidal input signals
• Interpolating interface for MR sensors and optical analog encoders
Symmetry Electronics (and its e-commerce division: SemiconductorStore.com) is an authorized iC-Haus distributor.