TLI4970-D025T4_15 Datasheet, PDF (10/29 Pages) Infineon Technologies AG – High precision miniature coreless magnetic current sensor for AC

2.2
Block Diagram
TLI4970-D025T4
Functional Description
Figure 2-2 Functional block diagram of the TLI4970-D025T4
2.3
Functional Description
The current, flowing through the current rail on the primary side, induces a magnetic field. This is measured by two
differential Hall probes. The signal from the two Hall probes is directly digitalized by a Sigma-Delta-A/D converter
(ADC). After the programmable digital low-pass filter, the raw current signal is fed into the DSP. The differential
measurement principle of the magnetic field provides a very good suppression of any ambient magnetic stray
fields.
The temperature (T) and the mechanical stress (S) of the chip are measured and converted independently of the
primary current by a second ADC. The Digital Signal Processing Unit (DSP) uses both temperature and stress
information to compensate the raw current signal according to internally stored calibration tables. The interface
unit (IF) transmits the fully compensated value via the SPI interface.
Furthermore several parameters like low pass filter settings or over current detection (OCD) levels can be
programmed via a Serial Inspection and Configuration Interface (SICI) which are described in the TLI4970
programming guide.
For fast over current detection, the raw analog signal from the Hall probes is fed into a programmable comparator.
This comparator has a programmable glitch filter to suppress fast switching transients in the signal and to avoid
false triggers. The open-drain output of the OCD-Pin allows readout of over current signals for several TLI4970-
D025T4 sensors by only one microcontroller input pin.
Data Sheet
10
Rev. 1.0, 2015-07-02