 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
AN-1071 Datasheet(PDF) 6 Page - International Rectifier |
|
||||||||||||||||||||||||||||||
AN-1071 Datasheet(HTML) 6 Page - International Rectifier |
|
|
6 / 14 page  AN-1071 6 www.irf.com Power Losses in the MOSFETs The losses in the power switches are very dif- ferent between linear amplifiers and Class D amplifiers. First lets look at the losses in a lin- ear Class AB amplifier. The losses can be de- fined as: () t d t K R Vcc t K Vcc P L C ⋅ • ⋅ ⋅ ⋅ − ⋅ ⋅ = ∫ ω ω ω π π sin 2 sin 1 2 2 1 0 Where K is the ratio of V bus to output voltage. This can then be simplified down to the follow- ing equation for the linear amplifier Power switch losses: − ⋅ ⋅ = 2 2 8 2 2 K K R Vcc P L tot π π Note that the power loss is not related to the output device parameters. Fig 5) below shows the power loss vs K. K=2/ƒÎ L CC R V Pc 8 2 . 0 2 Loss K=1 Fig 5) Power Loss vs. K for Linear Class AB Amplifier Now lets look at the losses for a Class D ampli- fier. The total power loss in the output devices for a Class D amplifier are given by: Pgd Pcond Psw P TOTAL + + = Psw are the switching losses and are given by the equation: PWM f DS D PWM BUS OSS f t V I f V C Psw ⋅ ⋅ ⋅ + ⋅ ⋅ = 2 Pcond are the conduction losses and are given by the equation: Po R R Pcond L ON DS ⋅ = ) ( Pgd are the gate drive losses and are given by the equation: PWM f Vgs Qg Pgd ⋅ ⋅ ⋅ = 2 As can be seen in a Class D amplifier the out- put losses are dependant on the parameters of the device used, so optimization is needed to have the most effective device, based on Qg, R DS(on), COSS, and tf . Fig 6 below shows the power losses vs K for the Class D amplifier. Loss Efficiency can be improved further! K=1 www.irf. Fig 6 Power Loss vs. K for Class D Amplifie |
Similar Part No. - AN-1071 |
|
Similar Description - AN-1071 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.NET |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
