PL34063AP8 Datasheet, PDF (3/7 Pages) Cystech Electonics Corp. – DC-to-DC Converter Control Circuit

Block Diagram
Spec. No. : C501P8
Issued Date : 2003.03.21
CYStech Electronics Corp.
Revised Date :
Page No. : 3/7
..
SC
Pin1:1.6A Switch Collector
SE
Pin2:Darlington Switch Emitter
TC
Pin3:Oscilletor Timing Capacitor
Q2
QS
Q1
R
80Ω
CT
IPK
Oscillator
1.25V
Reference Voltage
Comparator
+
-
GND
Pin4:Power GND
DRI
Pin8:Driver Collector
IPK
Pin7:Highside Current Sense
Input, VCC-VIPK=300mV
VCC
Pin6:Power Supply Input
FB
Pin5:Feedback Comparator
Inverting Input
Application Information
Design Formula Table
Calculation
Step-Down
Step-Up
Voltage-Inverting
ton / toff
Vout+VF /
Vin(min) -Vsat-VOut
Vout+VF-Vin(min) /
Vin(min)-Vsat
|Vout| + VF /
Vin-Vsat
(ton + toff) max
CT
1/Fmin
4*10^-5ton
1/Fmin
4*10^-5ton
1/Fmin
4*10^-5ton
IC(switch)
2*Iout(max)
2*Iout(max)(ton+toff/toff)
2*Iout(max)(ton+toff/toff)
RS
0.3 / IC(switch)
0.3 / IC(switch)
0.3 / IC(switch)
L(min)
(Vin(min)-Vsat-Vout / IC(switch))
*ton(max)
(Vin(min)-Vsat / IC(switch))
*ton(max)
(Vin(min)-Vsat/ IC(switch))
*ton(max)
CO
IC(switch)*(ton+toff) /
8VRipple(P-P)
Iout*ton / VRipple(P-P)
Iout*ton / VRipple(P-P)
Vsat : Saturation voltage of the output switch.
VF : Forward voltage drop of the ringback rectifier.
The following power supply characteristics must be chosen :
Vin : Nominal input voltage.
Vout : Desired output voltage. |Vout|=1.25*(1+RB/RA)
Iout - Desired output current
Fmin : Minimum desired output switching frequency at the selected values for Vin and Iout.
VRipple(P-P) : Desired peak to peak output ripple voltage in practice, the calculated value will need to be increased due to the
capacitor equivalent series resistance and board layout. The ripple voltage should be kept to a low value since it will directly
effect the line and load regulation.
PL34063AP8
CYStek Product Specification