Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
ADP3179JRU Datasheet(PDF) 8 Page - Analog Devices |
|
ADP3179JRU Datasheet(HTML) 8 Page - Analog Devices |
8 / 16 page REV. A –8– ADP3159/ADP3179 There are many useful references for quickly designing a power inductor. Table II gives some examples. Table II. Magnetics Design References Magnetic Designer Software Intusoft (http://www.intusoft.com) Designing Magnetic Components for High-Frequency DC-DC Converters McLyman, Kg Magnetics ISBN 1-883107-00-08 Selecting a Standard Inductor The companies listed in Table III can provide design consul- tation and deliver power inductors optimized for high power applications upon request. Table III. Power Inductor Manufacturers Coilcraft (847) 639-6400 http://www.coilcraft.com Coiltronics (561) 752-5000 http://www.coiltronics.com Sumida Electric Company (408) 982-9660 http://www.sumida.com COUT Selection—Determining the ESR The required equivalent series resistance (ESR) and capacitance drive the selection of the type and quantity of the output capaci- tors. The ESR must be small enough to contain the voltage deviation caused by a maximum allowable CPU transient cur- rent within the specified voltage limits, giving consideration also to the output ripple and the regulation tolerance. The capaci- tance must be large enough that the voltage across the capacitor, which is the sum of the resistive and capacitive voltage deviations, does not deviate beyond the initial resistive deviation while the inductor current ramps up or down to the value corresponding to the new load current. The maximum allowed ESR also repre- sents the maximum allowed output resistance, ROUT. The cumulative errors in the output voltage regulation cuts into the available regulation window, VWIN. When considering dynamic load regulation this relates directly to the ESR. When consider- ing dc load regulation, this relates directly to the programmed output resistance of the power converter. Some error sources, such as initial voltage accuracy and ripple voltage, can be directly deducted from the available regulation window, while other error sources scale proportionally to the amount of voltage positioning used, which, for an optimal design, should utilize the maximum that the regulation window will allow. The error determination is a closed-loop calculation, but it can be closely approximated. To maintain a conservative design while avoiding an impractical design, various error sources should be considered and summed statistically. The output ripple voltage can be factored into the calculation by summing the output ripple current with the maximum output current to determine an effective maximum dynamic current change. The remaining errors are summed separately according to the formula: VV V k I II k k kk mV WIN VID VID O OO RCS CSF RT EA =× × + + ++ = ( – ) – ∆ ∆ 2 1 2 95 2 2 22 (5) where kVID = 0.5% is the initial programmed voltage tolerance from the graph of TPC 6, kRCS = 2% is the tolerance of the current sense resistor, kCSF = 10% is the summed tolerance of the current sense filter components, kRT = 2% is the tolerance of the two termination resistors added at the COMP pin, and kEA = 8% accounts for the IC current loop gain tolerance including the gm tolerance. The remaining window is then divided by the maximum output current plus the ripple to determine the maximum allowed ESR and output resistance: RR V II mV AA m E MAX OUT MAX WIN OO () () . == + = + = ∆ Ω 95 15 3 8 5 (6) The output filter capacitor bank must have an ESR of less than 5 m Ω. One can, for example, use five ZA series capacitors from Rubycon which would give an ESR of 4.8 m Ω. Without ADOPT voltage positioning, the ESR would need to be less than 3 m Ω, yielding a 50% increase to eight Rubycon output capacitors. COUT—Checking the Capacitance As long as the capacitance of the output capacitor is above a critical value and the regulating loop is compensated with ADOPT, the actual value has no influence on the peak-to-peak deviation of the output voltage to a full step change in the load current. The critical capacitance can be calculated as follows: C I RV L A m HmF OUT CRIT O E OUT () . .. = × × = Ω× ×µ = 15 51 7 15 26 (7) The critical capacitance for the five ZA series Rubycon capaci- tors is 2.6 mF while the equivalent capacitance is 5 mF. The capacitance is safely above the critical value. RSENSE The value of RSENSE is based on the maximum required output current. The current comparator of the ADP3159 has a mini- mum current limit threshold of 69 mV. Note that the 69 mV value cannot be used for the maximum specified nominal cur- rent, as headroom is needed for ripple current and tolerances. |
Número de pieza similar - ADP3179JRU |
|
Descripción similar - ADP3179JRU |
|
|
Enlace URL |
Política de Privacidad |
ALLDATASHEET.ES |
¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes 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 |