SLUA159 Datasheet, PDF (25/28 Pages) Texas Instruments – Zero Voltage Switching Resonant Power Conversion

APPLICATION NOTE
10 ' Zero Voltage Switching Calculations and Equations
20 ' Using the Continuous Current Buck Topology
30 ' in a Typical DC/DC Converter Power Supply Application
40 '
50 PRINTER$ = "lptl:": ' Printer at parallel port #l **********
60 '
70 ' Summary of Variables and Abbreviations
80 '
90 ' Cr = Resonant Capacitor
100 ' Lr = Resonant Inductor
110 ' Zr = Resonant Tank Impedance
120 ' Fres = Resonant Tank Frequency (Hz)
130 '
140 ' VImin = Minimum DC Input Voltage
150 ' VImax = Maximum DC Input Voltage
160 ' Vdson = Mosfet On Voltage = Io*Rds
170 ' Rds = Mosfet On Resistance
180 ' Vdsmax = Peak MOSFET Off State Voltage
190 ’ Vo = DC Output Voltage
200 ' Vdo = Output Diode Voltage Drop
210 ' Iomax = Maximum Output Current
220 ' Iomin = Minimum Output Current
230 '
240 ' Start with parameters for low voltage dc/dc buck regulator
250 '
260 ' ****Define 5 Vi and 5 Io data points ranging from min to max*****
270 ' (Suggestion: With broad ranges, use logarithmic spread)
280 DATA 18,20,22,24,27 : 'Vi data
290 DATA 2.5,4,6,8,10 : ‘Io data
300 FRES = 500000!
310 VO = 5!
320 VDO = .8
330 RDS = .8
340 SAFT = .95
350 '
360 FOR J = 1 TO 5: READ VI(J): NEXT
370 FOR K = 1 TO 5: READ IO(K): NEXT
380 CLS
390 PRINT "For output to screen, enter 'S' or 'S'."
400 INPUT "Otherwise output will be sent to printer : ", K$
410 IF K$ = "S" OR K$ = "s" THEN K$ = "scrn:" ELSE K$ = PRINTER$
420 OPEN K$ FOR OUTPUT AS #1: CLS
430 PRINT #1, "================================================"
440 PRINT #1, "Zero Voltage Switching Times (uSec) vs. Vi, IO”
450 PRINT #1,"=========================================================="
460 '
U-138
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