IL34063A
Calculation
Parameter
Step-Up
(Discontinuous mode)
Vout +VF-V in(min)
Vin(min) - Vsat
Step-Down
(Continuous mode)
Vout +VF
Voltage Inverting
(Discontinuous mode)
êVout ê+ VF
ton/toff
Vin(min) - Vsat - Vout
1/fmin
Vin - Vsat
(ton + toff)max
CT
1/fmin
1/fmin
4.5x10-5ton
4.5x10-5ton
4.5x10-5ton
IPK(switch)
RSC
CO
2Iout(max)
2Iout(max)[(ton/toff)+1]
0.3/IPK(switch)
2Iout(max)[(ton/toff)+1]
0.3/IPK(switch)
0.3/IPK(switch)
IPK(switch) (ton + toff)
8Vripple(p-p)
Ioutton
Ioutton
º
º
Vripple(p-p)
Vripple(p-p)
L(min)
Vin(min) - Vsat
IPK(switch)
Vin(min)-Vsat-Vout
Vin(min) - Vsat
IPK(switch)
ton(max)
ton(max)
ton(max)
IPK(switch)
NOTES:
Vsat = Saturation voltage of the output switch
VF = Forward voltage drop of the output rectifier
THE FOLLOWING POWER SUPPLY CHARACTERISTICS MUST BE CHOSEN:
Vin = Nominal input voltage
Vout = Desired output voltage, êVout ê = 1.25(1+R2/R1)
Iout = Desired output current
fmin = Minimum desired output switching frequency at the selected values of Vin and lo
Vripple = Desired peak to peak output ripple voltage. In practice, the calculated capacitor value will and to be
increased due to its equivalent series resistance and board layout. The ripple voltage should be kept to a low
value since it will directly affect the line and load regulation.
Step-up With External NPN Switch
8
VOUT
1
S Q
+
Q1
R
2
7
RSC
Ipk
Oscillator
3
VIN
Comparator
6
5
1.25V
Reference
Regulator
+
-
4
Rev. 01
IKSEMICON [ IK SEMICON CO., LTD ]
