HAL810
2. Functional Description
2.1. General Function
The HAL810 is a monolithic integrated circuit which
provides a pulse-width modulated output signal
(PWM). The duty cycle of the PWM signal is propor-
tional to the magnetic flux through the Hall plate.
The external magnetic field component perpendicular
to the branded side of the package generates a Hall
voltage. The Hall IC is sensitive to magnetic north and
south polarity. This voltage is converted to a digital
value, processed in the Digital Signal Processing Unit
(DSP) according to the settings of the EEPROM regis-
ters, converted to a pulse-width modulated output sig-
nal, and stabilized by a push-pull output transistor
stage. The function and the parameters for the DSP
are explained in Section 2.2. on page 8.
The setting of the LOCK register disables the program-
ming of the EEPROM memory for all time. This regis-
ter cannot be reset.
As long as the LOCK register is not set, the output
characteristics can be adjusted by programming the
EEPROM registers. The IC is addressed by modulat-
ing the supply voltage (see Fig. 2–1). In the supply
voltage range from 4.5 V to 5.5 V, the sensor gener-
DATA SHEET
ates a PWM output signal. After detecting a command,
the sensor reads or writes the memory and answers
with a digital signal on the output pin. The PWM output
is switched off during the communication.
The open-circuit detection provides a defined output
voltage if the V
DD
or GND line is broken. Internal tem-
perature compensation circuitry and the choppered off-
set compensation enables operation over the full tem-
perature range with minimal changes in accuracy and
high offset stability. The circuitry also rejects offset
shifts due to mechanical stress from the package. The
non-volatile memory consists of redundant EEPROM
cells. In addition, the sensor IC is equipped with
devices for overvoltage and reverse-voltage protection
at all pins.
8
V
DD
(V)
7
6
5
HAL
810
V
DD
V
OUT
(V)
V
DD
GND
OUT digital protocol
PWM
Fig. 2–1:
Programming with V
DD
modulation
V
DD
Internally
Stabilized
Supply and
Protection
Devices
Temperature
Dependent
Bias
Oscillator
Open-Circuit
Detection
Protection
Devices
Switched
Hall Plate
A/D
Converter
Digital
Signal
Processing
Output
Conditioning
100
Ω
OPA
OUT
EEPROM Memory
Supply
Level
Detection
Lock Control
GND
Digital
Output
10 kΩ
Fig. 2–2:
HAL810 block diagram
6
Feb. 6, 2009; DSH000034_003EN
Micronas
MICRONAS [ MICRONAS ]
