BU52004GUL_10 Datasheet, PDF (6/12 Pages) Rohm – Omnipolar Detection Hall ICs (Polarity detection for both S and N features dual outputs)

BU52004GUL, BU52014HFV
Technical Note
● Description of Operations
Micropower Operation (Small current using intermittent action)
IDD
Period 50ms
Startup time
Standby
The dual output bipolar detection Hall IC adopts an
intermittent operation method to save energy. At startup, the
Hall elements, amp, comparator and other detection circuits
power ON and magnetic detection begins. During standby,
the detection circuits power OFF, thereby reducing current
consumption. The detection results are held while standby
is active, and then output.
Fig.20
t
Reference period: 50ms (MAX100ms)
Reference startup time: 48μs
(Offset Cancelation)
V_DD
I
B_×
GND
Fig.21
＋
Hall Voltage
－
(Magnetic Field Detection Mechanism)
The Hall elements form an equivalent Wheatstone (resistor)
bridge circuit. Offset voltage may be generated by a
differential in this bridge resistance, or can arise from
changes in resistance due to package or bonding stress. A
dynamic offset cancellation circuit is employed to cancel this
offset voltage.
When Hall elements are connected as shown in Fig. 21 and a
magnetic field is applied perpendicular to the Hall elements,
voltage is generated at the mid-point terminal of the bridge.
This is known as Hall voltage.
Dynamic cancellation switches the wiring (shown in the
figure) to redirect the current flow to a 90˚ angle from its
original path, and thereby cancels the Hall voltage.
The magnetic signal (only) is maintained in the sample/hold
circuit during the offset cancellation process and then
released.
S
N
S
S
N
S
N
Flux direction
Flux direction
Fig.22
The Hall IC cannot detect magnetic fields that run horizontal to the package top layer.
Be certain to configure the Hall IC so that the magnetic field is perpendicular to the top layer.
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2010.01 - Rev.D