MLX90129 Просмотр технического описания (PDF) - Melexis Microelectronic Systems
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MLX90129 Datasheet PDF : 60 Pages
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MLX90129
13.56MHZ SENSOR TAG / DATALOGGER IC
7. General Description
7.1. Block diagram
MLX90129
SENSSUP1
SENS1
SENS2
SENSSUP2
SENS3
SENS4
VBAT
VREG
VFIELD
Sensor Signal
Conditioner
Power
management
COIL1
COIL2
RFID front-end
Register
File
(configuration)
Ee-latches
(configuration)
Digital
controller
Eeprom
Oscillator
Wake up timer
VSS
XIN
XOUT
SS
SCLK
MISO
MOSI
IRQ
The sensor signal conditioner is used to amplify, filter and convert the output voltage of resistive sensors. There may be an
external single-ended or differential resistive sensor, or the internal temperature sensor. The two external sensors are
supplied by a stable reference voltage, provided by an integrated voltage regulator. The sensor output voltage is amplified
by a programmable-gain amplifier, and its offset voltage can be compensated. This way the sensor signal level can be
conditioned such that it optimally fits to the input range of the A/D converter. The ADC converts the analog signal into a 16-
bit digital code that can be stored or transmitted.
The power management unit deals with the different power modes of the chip: it monitors the battery level, scavenges the
energy coming from a RFID 13,56MHz field and makes the power-on reset signal. A regulator is used to supply the digital
parts, but can also be used to supply some other external devices.
The Oscillators’ block contains different kinds of oscillators: a very low power, low frequency 1kHz RC oscillator used as a
wake-up timer, a low-power 32.768kHz quartz oscillator that can be used for an accurate time basis, and a high frequency
5MHz RC oscillator used for the digital controller.
The Register File contains all the configuration parameters of the chip. It may be loaded from the EEPROM after power-on,
or as the result of a specific request from RFID or SPI.
The EE-Latches are used when device configuration parameters have to be immediately available.
The RFID front-end receives an external 13,56-MHz magnetic field, sensed on an external antenna coil. The antenna design is
made easy thanks to an internal programmable high-Q capacitance (tuned during the test phase). From the antenna output
voltage, it makes a stable clamped DC supply voltage, recovers the clock, and controls the modulation of the carrier and the
demodulation of the incoming signal.
The EEPROM is a 4-kbit non-volatile memory, organized as 256 words of 16 bits divided in 39 reserved for configuration, 2
for default trimming value (EE-Latches #03,#04 and #09) backup and 215 available for the application (around 3.4 kbits user
memory). Its access is protected by several security levels.
The Digital Controller manages the accesses of the different interfaces (SPI, RFID) with the different memories (EEPROM,
register file) and the sensor. It comprises the RFID ISO-15693 and SPI protocols, controls the sensor signal conditioner and
stores or sends the ADC output code. It can also run some standalone applications, thanks to its unit called Direct Memory
Access (DMA).
REVISION 011 - JUNE 13, 2017
3901090129
Page 12 of 60
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