SLA7020M Ver la hoja de datos (PDF) - Sanken Electric co.,ltd.
Número de pieza
componentes Descripción
Fabricante
SLA7020M Datasheet PDF : 10 Pages
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SLA7024M, SLA7026M, SLA7027MU, SLA7022MU, SLA7029M,
SMA7022MU, SMA7029M, SLA7020M, SLA7021M and SDK03M
Application Note
Fig. 6 Circuit for fixing the coil current
Vb(5V)
r1
SLA7024M
SLA7026M
r6
r5
3,(14) SLA7027MU
Fig. 9 Output current lOPD vs. Variable current resistor rx
SLA7024M, SLA7026M, SLA7029M, SLA7027MU, SLA7022MU,
SLA7020M, SLA7021M, SMA7029M, SMA7022MU, SDK03M
2
Power down
signal
rX
r2
Tr
9,(10)
C3
Fig. 7 Circuit for fixing the coil current
Vb(5V)
r1
Power down
signal
rX r2
Tr
r6
SDK03M
r5
3
C3
10 13 15
RS
Fig. 8 and 9 show the graphs of equations q and w,
respectively.
1.5
RS =0.5Ω
1
0.5
00
RS =0.8Ω
RS =1Ω
IOPD=
1
1+r1r(2r2· +rrXX)
· Vb
RS
r1=510Ω
r2=100Ω
Vb=5V
2.0
4.0
6.0 8.00 1000 1200
Variable current resistor rX (Ω)
NOTE:
Ringing noise is produced in the current detection resistor
Rs when the MOSFET is switched ON and OFF through
chopping. This noise is also generated in feedback signals
from Rs which may therefore causes the comparator to
malfunction.
To prevent chopping malfunctions, r5(r6) and C3(C4) are
added in order to act as noise filter.
However, when the values of these constants are increased,
the response from Rs to the comparator becomes slow.
Hence, the value of the output current lo is higher to some
extent than the computed value.
Fig. 8 Output current Io vs. Current detection resistor Rs
SLA7024M, SLA7026M, SLA7029M, SLA7027MU,
SLA7022MU, SLA7020M, SLA7021M, SMA7029M,
4 SMA7022MU, SDK03M
3
IO= r1r+2 r2·
Vb
RS
r1=510Ω
2
r2=100Ω
rx=∞
Vb=5V
1
0
0
1
2
3
4
Current detection resistor RS (Ω)
18
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