Applications Note AN36
Issue1 - JULY 2002
APPLICATION REQUIREMENTS
Introduction
The unbuffered type have a differential low
level signal output with the shape of this
signal being a direct representation of the
magnetic field from the permanent magnet
Rotor. These sensors are connected to the
ZXBM using the differential inputs H+ and H-
on Pins 2 and 3 respectively. See Figure 1 for
connection details. R1 in Figure 1 should be
chosen to suit the Hall sensor type and is
provided to bias to the Hall device.
A typical electronics application circuit for a
2-phase, DC brushless motor will consist of,
but not be restricted to, three main building
blocks. First will be the controller itself
containing the functions as described in the
datasheet. Attached to this will be a Hall
device as a means of monitoring and
controlling the commutation of the motor
and finally there will be the power driver
devices used to switch the two Phase
windings.
On top of these three building blocks will be
other items such as the Speed Control
stimulus circuit, e.g. a thermistor. Further
functions may be required dependant upon
application, perhaps as a means of ‘value
adding’ to the overall final product. Some
ideas of this nature will also be discussed in a
later section.
The first part of the Applications Note,
however, discusses the various interface
aspects of the external component
requirements to the ZXBM200x series. To aid
clarity in this first section any circuits given
will show only the areas of interest to that
section of discussion. This is followed by a
section of practical examples that will include
circuits in their entirety.
Figure 1
Connection of unbuffered (naked) Hall
The Hall Sensor
Two types of Hall sensor can be used in
conjunction with the ZXBM200x controllers,
those having an unbuffered output stage,
sometimes known as a ‘naked’ Hall, and
those with a buffered output. Figures 1 and 2
show the two respective types and their
connection to the ZXBM2001.
Figure 2
Connection of buffered Hall
AN 36 - 2
ZETEX [ ZETEX SEMICONDUCTORS ]
