Datasheet

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TPS54283 , , TPS54286
SLUS749C – JULY 2007 – REVISED OCTOBER 2007
Table 4. Definition of Symbols
C
DJ
Average junction capacitance of the rectifier diode from 0V to VIN(max)
C
OSS
Average output capacitance of the switching MOSFET from 0V to VIN(max)
C
OUT
Output Capacitor
D
(max)
Maximum steady state operating duty cycle
D
(min)
Minimum steady state operating duty cycle
ESR
(max)
Maximum allowable output capacitor ESR
f
SW
Switching frequency
I
BP
Output Current of BP regulator due to external loads
I
DD
Switching quiescent current with no load on BP
I
D(avg)
Average diode conduction current
I
D(peak)
Peak diode conduction current
I
IN(avg)
Average input current
I
IN(rms)
Root mean squared (RMS) input current
I
L(avg)
Average inductor current
I
L(rms)
Root mean squared (RMS) inductor current
I
L(peak)
Peak current in inductor
I
LRIP(max)
Maximum allowable inductor ripple current
L
(min)
Minimum inductor value to maintain desired ripple current
I
OUT(max)
Maximum designed output current
I
RMS(cin)
Root mean squared (RMS) current through the input capacitor
I
RIPPLE
Inductor peak to peak ripple current
I
QSW(rms)
Root mean squared current through the switching MOSFET
P
CON
Power loss due to conduction through switching MOSFET
P
D(max)
Maximum power dissipation in diode
R
DS(on)
Drain to source resistance of the switching MOSFET when “ ON ”
P
SW
Power loss due to switching
P
REG
Power loss due to the internal regulator
V
BP
Output Voltage of BP regulator
V
(BR)R(min)
Minimum reverse breakdown voltage rating for rectifier diode
V
FB
Regulated feedback voltage
V
FD
Forward voltage drop across rectifier diode
V
IN
Power stage input voltage
V
OUT
Regulated output voltage
V
RIPPLE(cap)
Peak to Peak ripple voltage due to ideal capacitor (ESR = 0  )
V
RIPPLE(tot)
Maximum allowable peak to peak output ripple voltage
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