Datasheet

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SBVS070B − JUNE 2006 − REVISED MAY 2009
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14
a) Simplified probe interface circuit.
The probe is connected between S1 and S2.
b) Without an external magnetic field, the hysteresis curve is
symmetrical and the probe loop generates 50% duty cycle.
c) An external magnetic flux (H) generated from the primary current
(I
PRIM
) shifts the hysteresis curve of the magnetic field probe in the
H-axis and the probe loop generates a nonsymmetrical duty cycle.
B
H
500ns/div
2V/div500mV/div
V(IS1)
V(PWM)/10
B
H
500ns/div
2V/div500mV/div
V(IS1)
V(PWM)/10
55
Ω
IS2 IS1
Probe
V
DD1
PWM
CMP
18
Ω
V
REF
=0.5V
NOTE: MOS components function as switches only.
55
Ω
Figure 2. Magnetic Probe, Hysteresis, and Duty Cycle