If optimum efficiency is desired it wise to place Schottky diode across the bottom MOSFET so can conduct inductor flyback voltage and not body . Click OK and put the simulation statement anywhere schematic. lengthf new wpc Inst hed ge b context TP var ipd ipt secall true false sj evt nd function args QueryID fbpkgiid SERP. The setting box should look like FIG waveform above starts at stays until after which it rises to [...]
From We can see that dt is equal to half the period so say Since our capacitor current positive for ON time and OFF above equation holds true regardless duty cycle. Move the mouse to Vout logo at top of plot pane and right click [...]
I have never had much luck with the parametric searches on MOSFET websites. Therefore current rating of diode can be lot less than peak inductor [...]
Two such capacitors in parallel will yield an ESR ripple of mV. Hitting the F key undoes this action. Tying the FREQ pin to INTVCC see datasheet sets frequency kHz thus switching period of . If cursors are selected differential voltages and phases can be displayed [...]
Failing that download all the results to spreadsheet and sort from there. Since the top of is connected LTC internal linear regulator INTVCC via diode this capacitor charges [...]
We can now work out the charging ripple. display block n t if return LowerCase dexOf chromn chrdef mozsbr mozlbr moztsb sj evt nd onP var function ue . If the circuit is sensitive to fast current changes on input radio transmitter say connected rail using SEPIC converter buck only mode will give much quieter operation. It is also useful to calculate the duty cycle of converter [...]
A but over change of close to what we calculated. uF should suffice. Run this simulation LT with Vin starting . If the circuit is sensitive to fast current changes on input radio transmitter say connected rail using SEPIC converter buck only mode will give much quieter operation. The inductor current ramps up according equation where V is voltage across inductance value and dt change with time through [...]
Go to Bing homepageSign My saves resultsAny time LTspice Tutorial Part Analog Circuit Design mMoving the crosshairs over cursor and left clicking mouse enables move measure magnitude phase response of box. If we want to magnify certain area of the plot move crosshairs desired part left click mouse and holding it down drag over be magnified. The final LTspice circuit can be downloaded here right click over link and save as file LTC Buck Converter Running simulation seen that ripple current is mA switching frequency kHz time ns duty cycle [...]
Our ESR ripple calculations assumed two capacitors in parallel reduce the so . The LTC datasheet can be downloaded here outline schematic is shown FIG With V input and output duty cycle of converter has selectable fixed frequency operation. This part will be the best compromise between RDSON and QG ideal for top MOSFET. Luckily the suggested LTspice circuit for LTC comes with an extremely good top MOSFET Renesas RJK. Probing the OUT node will plot frequency response of filter clearly showing roll above kHz [...]
Display block return if function yle. Plot the output voltage. For convenience the output capacitor ESR has been reduced Ohms illustrate ripple due discharge. Referring to FIG output side of the inductor tries fly positive push current right hand its switched left flies negative try sink into effort maintain flow. I m able to move the cursor over whatever value using [...]
