Main Features; Block Diagram And Functional Descriptions - Nokia NPL-4 Series Manual

NPL-4/5/RM-104
System Module and User Interface

Main features

The ASIC supports three magnetometer axis. The ASIC features are:
• Pre-amplifier followed by a single-shot sigma delta type of ADC for each measurement
channel
• H-bridge for driving the SET/RESET coil inside the magnetometer element
• Internal voltage reference for the ADC and the magnetometer bridge
• Digital control interfaces (I2C, CBUS, UART)
• Control registers
• One-bit digital control output signal to turn on/off the external linear regulator

Block diagram and functional descriptions

I2CClk
I2C slave interface
I2CDa
CBusClk
CBusEnX
CBUS interface
CBusDa
UARTRx
UART interface
UARTTx
VBridge
TankCharge
2
SRVdd
2
SROp
Magnetometer
SET/RESET
3
SROm
generator
3
SRVss
2
InX
Pre - amplifier
2
InY
Pre - amplifier
InZ 2
Pre - amplifier
The magnetometer interface has three differential inputs for X-, Y- and Z-bridge respec-
tively. The measurement path for each axis can be enabled/disabled separately and the
power consumption of any unused path is minimized. The magneto-resistive bridges of
all axes are biased by a single reference voltage (2.2 V) provided by the internal band-
gap reference.
Copyright © 2005 Nokia Corporation. All rights reserved.
Page 52
Figure 20: Block Diagram
write cmd,addr
write data (8)
read addr
read data (8)
write cmd,addr
write data (16)
read addr
read data (16)
write cmd,addr
write data (8)
read addr
read data (8)
Bandgap
reference
Sigma-delta ADC
Sigma-delta ADC
Sigma-delta ADC
REGISTERS CONTROL
measurement
Nokia Customer Care
Clk
DVdd
DVss
CLOCK
DIVIDER
internal
clocks
ClrX
reset
RegCtrl
SMC
TMC
DTest1
data
DTest2
DTest3
AVdd
AVss
Single shot
counters
Issue 2 05/05