FAQ
Le funzioni della reattanza PFC sono: modellare la corrente in ingresso in modo che segua la tensione di rete AC (miglioramento del fattore di potenza), immagazzinare e trasferire energia per regolare la tensione DC in uscita, sopprimere la corrente di inrush in ingresso, filtrare la corrente di ripple e agire da filtro EMI.
Nel serbatoio risonante LLC sono presenti 2 componenti, Lr e Cr.
Frequenza di risonanza serie fr = 1/2π√(Lr*Cr) → Lr = 1/((2πfr)²*Cr)
The standard industry solution for this power level is to use interleaving PFC stages, or stepping up to a 3-phase PFC topology. It means the circuit needs 2 PFC chokes for interleaving topology or 3 PFC chokes for 3-phase PFC topology, not single phase PFC topology.
ITG dispone di soluzioni termiche che utilizzano un adesivo termico ad alta conducibilità per colmare il gap tra la reattanza PFC e la camicia termica (thermal jacket) ITG. Questo metodo consente di mantenere lo stesso ingombro con dimensioni molto simili.
When PFC choke, we have to decide the topology at first. The topology will affect the parameters of PFC choke. Inductance when load, Isat, and DCR are key electrical parameters.
Sì, ITG dispone di soluzioni termiche che utilizzano un adesivo termico ad alta conducibilità per colmare il gap tra la reattanza PFC e la camicia termica (thermal jacket) ITG. Questo consente di asportare efficacemente il calore dalla reattanza PFC.
Absolutely! ITG is continuously dedicated to developing innovative solutions and expanding our molded inductor portfolio. For a performance upgrade, we highly recommend our SMF series (featuring flat wire technology), which significantly optimizes DCR, enhances Isat, and improves overall efficiency. Please feel free to contact the ITG sales team or visit our website to request samples or obtain technical support.
Sì, potete tranquillamente utilizzare un induttore testato a 200 kHz per la vostra applicazione a 125 kHz.
A 125 kHz, la resistenza in corrente alternata diminuisce, le perdite nel nucleo si riducono e l'induttanza rimane stabile.
We generally do not recommend using molded inductors in applications with very high step-up/down voltage ratios, as they have relatively lower rated voltages compared to assembly inductors. Molded inductors are composed of high-density metal powders, where insulation relies entirely on a thin coating layer over each particle. During the high-tonnage compaction process, this coating layer can be slightly compromised, reducing the insulation resistance between the powder particles. When a high voltage is applied, this lower insulation resistance may lead to increased leakage current. Therefore, for designs requiring high voltage conversion ratios, we highly recommend considering assembly inductors instead.
Gli induttori risonanti con tolleranza del 10% rappresentano una soluzione a basso costo.
Gli induttori risonanti con tolleranza del 5% sono la soluzione ideale per convertitori risonanti a frequenza fissa, convertitori LLC con un intervallo di controllo della frequenza ristretto, convertitori risonanti interleaved e applicazioni con requisiti severi in termini di efficienza e budget termico.
Assembly Inductors: Typically offer lower DCR, lower core loss, and higher rated voltage.
This makes them exceptionally well-suited for high-current and high step-up/down ratio applications, such as core power supplies for CPUs, GPUs, and ASICs.
Molded Inductors: Feature highly flexible dimensions and better cost-efficiency. They are ideal for applications with severe space constraints, lower step-up/down ratios, or peripheral power rails (side rails) with moderate Isat requirements.
Nella serie RL130815, il codice A indica un'elevata precisione dell'induttanza (tolleranza del 5%), mentre il codice B indica una tolleranza dell'induttanza del 10%.
The main advantages of molded inductors include compact size, low EMI, and soft saturation performance. Consequently, they are highly suitable for applications with strict space limitations, stringent EMI requirements, or potential risks of sudden inductance collapse.
Gli induttori risonanti (come quelli utilizzati nei convertitori LLC o phase-shift) operano in condizioni particolari che rendono l'ACR il principale fattore limitante per l'efficienza.
Pubblicando esplicitamente l'ACR nel datasheet, ITG comunica con precisione quanto efficacemente la disposizione degli avvolgimenti (che si tratti di filo piatto, posizionamento specializzato o Litz parziale) sia riuscita a mitigare la grave penalità dovuta al campo di frangia (fringing field) alle alte frequenze.
Isat (Saturation Current): Defines the amount of DC current that causes the inductance to drop by a specified percentage (typically 20% or 30%) due to magnetic saturation.
Irms (RMS Current): Focuses on the temperature rise of the inductor body, representing the continuous DC current that causes the component's temperature to increase by a specified increment (typically △T=40℃).
Dipende dalla topologia PFC, dalla frequenza di funzionamento, dall'efficienza target, dalle dimensioni, dal costo e da altri fattori.
The primary advantage of the magnetic powder is its soft saturation characteristic.
Soft saturation means that as the DC current increases, the inductance drops gradually rather than dropping abruptly.
This prevents a sudden collapse of inductance, thereby protecting the circuit from current spikes.
The core differences between assembly and molded inductors lie in their manufacturing processes and physical structures.
- Assembly Inductors: Manufactured by assembling
coils with pre-formed magnetic cores, resulting in a structure with
distinct air gaps. - Molded Inductors: Constructed by placing
pre-wound coils into a mold, filling it with magnetic powder (typically
iron or alloy powder), and applying tonnage-level pressure to form a gapless
structure.
Due to this gapless design, molded inductors effectively minimize EMI and acoustic noise. Furthermore, the molding process allows for smaller, lower-profile form factors, making them ideal for space-constrained and cost-sensitive applications.