Electronic Components Datasheet Search |
|
AN1262 Datasheet(PDF) 8 Page - STMicroelectronics |
|
AN1262 Datasheet(HTML) 8 Page - STMicroelectronics |
8 / 42 page AN1262 APPLICATION NOTE 8/42 All of the above mentioned calculation steps are summarized in table 6. Table 6. Preliminary Calculations (step 2) 8 OPERATING CONDITIONS @ VIN = VDCMIN From the thermal point of view the heaviest operating conditions for the IC, and for most of the other parts of the converter as well, are usually encountered at minimum input voltage. That is why the operating conditions @ Vin = VDCmin need being evaluated. This will be done with the aid of the relationships in table 7. Table 7. Relationship useful for calculating converter's operating conditions @ Vin = VDCmin Symbol Parameter Definition PinT Transformer Input Power VDS(on)x Max. average drop on RDS(on) in ON-state Dx Maximum Duty Cycle VDSmax Maximum drain Voltage in OFF-state VDSmax = VPKmax + VR + Vspike Ippkx Max. Peak Primary Current Symbol Description Definition D Duty Cycle (switch ON-time to switching period ratio) Ippk Peak Primary Current Ippk = Ippkx IpDC DC Primary Current IpRMS Total RMS Primary Current IpAC RMS Primary Current (AC component only) D‘ Secondary diode conduction time to switching period ratio Ispk Peak Secondary Current IsDC DC Secondary Current IsDC = Iout P inT V out V F + () I ou t ⋅ η T ------------------------------------------- = V DS on () V inmin V R + 1 V inmin V R ⋅ P in R DS on () ⋅ ---------------------------------- + -------------------------------------------- ≈ D X V R V inm i n V DS on ()x – () V R + ----------------------------------------------------------------- = Ip pkx P inT V inm i n V DS on ()x – ---------------------------------------------- 2 D X ------- ⋅ = D V inm i n V DS on ()x – V DCmin V DS on ()x – ------------------------------------------------- = D X ⋅ Ip DC DIp pk ⋅ 2 ------------------- = Ip RM S Ip pk D 3 ---- ⋅ = Ip AC Ip RMS 2 Ip DC 2 – = D' V DCmin V DS on ()x – V R ------------------------------------------------- D ⋅ = Is pk 2I out ⋅ D' ----------------- = |
Similar Part No. - AN1262 |
|
Similar Description - AN1262 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |