NTLJF3117P_1 Datasheet, PDF (1/2 Pages) ON Semiconductor – Typical Uses for FETKY Devices

Typical Uses for FETKY® Devices
(MOSFET + Schottky Co-packaged)
Introduction
In consumer electronic circuits, Schottky diodes are often seen
working with power MOSFETs to implement system level power
solutions. There are different reasons for integrating a Schottky
diode with a MOSFET. Typical examples of these circuits include
reverse protection, asynchronous DC/DC conversion, free-wheeling
rectification, switching efficiency improvement, and more.
Examples
DC-DC Buck Circuit
A MOSFET plus a Schottky diode is the most typical buck converter
circuit seen throughout the portable electronics market. The Schottky
diode is used as a rectifying element closing the current loop after the
main switch turns off.
FETKY
L1
Vin
Vout
C1
GND
Vin
ON/OFF
Q1
D1
FETKY
L1
DC-DC Buck Circuit
C2
GND
Vout
Li-Ion Charging Circuit
The FET^CK¹Y device can be used^FEQas^T1^Kch^Yargin^Dg¹elements^C2for multiple
powe_Vr_insources ^Os^Nu^/c^Oh^FFas car battery cha^Drg¹er, wall charger_V, _oo_ur_t USB
conGnNecDtion. A Schottky is preferred over a standard diodeGbNeDcause
onof _{rtmhealloCow1peerraVt}f_iorOant_Nsin./Og _Fre_Fsulting
in
m_Qini₁mum
power
consumption
C2 R1
during
GND
Vin
FETKY
D1
GND
Vout
C1
ON/OFF
FET^QK¹Y
D1
C2 R1
GND
GND
Vin
Li-Ion Charging Circuit
Vout
C1
GND
Vin
FE^QT¹KY
ON/OFF
D1
C2 R1
GND
Vout
L1
Vin
Vout
C1
GND
ON/OFF
Vin
C1
Vin
GND
C1
ON/OFF
ON/OFF
Q1
D1
C2
FETKY
L1
GND
Vout
FETKY
Q1
D1
D1
C2
Vout
GND
Q1
C2 R1
Protection Circuit
GND
FETKY
GND
The Schottky diode actually provides a by-pass channel and keeps
rever_Vse_involtage across the MOSFET to les^Ds¹than a P-N diode_Vod_uro_t p.
C1
ON/OFF
FE_DT_1QK₁Y
C2 R1
GND
Vin
GND
Vout
C1
GND
Q1
FETKY
ON/OFF
D1
C2 R1
GND
Protection Circuit
Vin
Vout
Switching Efficiency Improvement
ArecStcif_Vhy_Cioi_nn1tgtkMy _OdSioFdEeT
time between the
o^{OtconNa/in/moO}fpbf^{FrecFoyvcpelleaecofefQ}fidcti¹heiennctpwy.ao^{FIrtapEcloloTewnlK}ed^{LwrYu1iMcthtOsC}StdhF^{2ueEriTnssygRnptVcr1heohevureotdnnetoainudgs-}
th^Ge^Nb^Dody diode of the bottom M_QOS₁FET from turning on and^Gs^Nt^Doring
charge during the dead-time.
as much^C1as 2%.
This
approach
c_Da₁n
improve efficiency
C2
Vin
GND
C1
L1
FETKY
Q1
D1
Vout
GND
C2
GND
GND
Switching Circuit
Portfolio
Please see our lastest portfolio of FETKY devices on the reverse side of
this card. For additional information on our FETKY, and other MOSFET
portfolio devices, please visit our website at www.onsemi.com.
FETKY is a registered trademark of International Rectifier.