Construisez une matrice de charge à deux rails, testez la régulation croisée sous des charges inégales et décidez quand une alimentation à deux sorties n'est pas la bonne architecture.
Réponse directe. Ne pas approuver une alimentation à double sortie à partir de watts totaux seuls. Définissez le courant minimum, typique et maximum sur chaque rail, puis testez chaque paire crédible, en particulier lorsqu 'un rail est fortement chargé et que l'autre est léger ou inactif. La régulation croisée est le changement sur une sortie causé par un changement de charge sur un autre. Si l'un des rails quitte la fenêtre de tension de l'équipement, choisissez des alimentations séparées ou une post-régulation: un régulateur en aval pour le rail concerné.
Visualisation conceptuelle générée par l'IA d'une matrice de charge de rail à deux axes. Il ne s'agit pas d'un diagramme de circuit, d'un produit WEHO, d'une usine, d'une installation client ou d'un résultat mesuré.
L'erreur d'achat: un nombre de watts cache deux axes de charge
Les équipes OEM commencent souvent par une vérification arithmétique soignée: additionnez les charges de 5 V et 24 V, comparez le résultat avec la puissance globale de l'alimentation, et passez à autre chose.
La véritable exigence est une enveloppe de fonctionnement bidimensionnelle:
- le courant demandé par le rail A;
- le courant demandé par le rail B;
- les combinaisons qui se produisent pendant le démarrage, le fonctionnement normal, la veille, le service et la récupération d'erreur;
- la fenêtre de tension tolérée par chaque charge en aval à ses propres bornes.
Un external design note on multiple-output flyback converters Expliquer le risque sous-jacent: une sortie est généralement régulée plus directement, tandis que d'autres sorties peuvent être affectées par le couplage du transformateur, les chutes de redresseur et la résistance à l'enroulement.Cette référence décrit la conception du convertisseur, et non la topologie interne d'une unité WEHO particulière.La leçon d'achat est plus étroite et utile: Ne présumez pas que deux sorties se comportent comme deux fournitures indépendantes, à moins que la documentation et la validation du produit ne l'indiquent.
Construire une enveloppe de chargement rail à partir des états d'équipement
Commencez par les états, pas par les moyennes. Un registre de charge utile a une ligne par état et une colonne par rail.
| Équipement État | Le rail actuel | Rail B actuellement | Durée d'état | Autorisation du voltage rail-A | Voltage rail-B autorisé | Preuve source |
|---|---|---|---|---|---|---|
| Puissance appliquée, contrôleurs maintenus en réinitialisation | ___à | ___à | par ms/s | ___à__V | ___à__V | Composante de données |
| Boot et énumération périphérique | ___à | ___à | par ms/s | ___à__V | ___à__V | Mesure/données |
| Activité minimale normale | ___à | ___à | continuellement | ___à__V | ___à__V | Load liste |
| Activité maximale normale | ___à | ___à | ___ | ___à__V | ___à__V | Sequence révision |
| Attendre ou dormir | ___à | ___à | continuellement | ___à__V | ___à__V | Mesure/données |
| Redémarrer après un événement de protection | ___à | ___à | par ms/s | ___à__V | ___à__V | Spécification de contrôle |
Ne pas inventer une charge minimale simplement pour compléter le tableau. Utiliser la spécification actuelle de chaque dispositif en aval ou une mesure contrôlée. Inclure des tolérances et des événements simultanés. Un rail logique peut être au maximum alors que les actionneurs sont désactivés; plus tard, le rail de l'actionneur peut s'intensifier alors que le rail logique tombe. Ce sont précisément les conditions hors diagonale qu “un seul test de ”pleine charge" manque.
Convertir la table d'état en matrice de test
At minimum, evaluate these static corners:
- both rails at their credible minimum loads;
- rail A maximum, rail B minimum;
- rail A minimum, rail B maximum;
- both rails at their credible maximum loads;
- each normal operating state that is not represented by those corners.
Then add transitions between credible states. For example, move the actuator rail from idle to its largest permitted step while the control rail remains at its normal load. Repeat the reverse transition. The purpose is not to create arbitrary abuse conditions; it is to reproduce the equipment’s documented operating sequence.
Run the matrix at the input-voltage and ambient conditions required by the project, following the power-supply documentation. Record voltage at both the supply terminals and the downstream load. Cable, connector and protection-device drop is a system result, not cross-regulation inside the supply, but both affect whether the load receives an acceptable voltage.
Préciser les limites d'acceptation avant de demander un échantillon
“Stable” is not an acceptance criterion. For each rail, record:
- steady-state minimum and maximum voltage at the load;
- permitted transient deviation and its duration;
- maximum ripple/noise under the measurement method defined for the project;
- startup order, monotonicity or delay requirements, if the loads require them;
- behavior required when either rail is unloaded, overloaded or disconnected;
- recovery behavior after the fault is removed.
Use the downstream component limits to establish these values. Do not copy a generic percentage from another design. If a processor, sensor, relay or interface module has an undervoltage threshold, the margin should be assessed at that device—not only at the power-supply terminals.
The separate WEHO guide on multi-output power-supply sequencing addresses startup and shutdown order. This article addresses a different question: whether each rail remains within its required voltage window as the other rail’s load changes. Teams deciding whether they need one or several supplies can also consult Single Output vs Multi Output Enclosed Power Supply.
Un exemple d'exigence travaillée-pas une revendication de performance de produit
Assume an OEM’s preliminary load study produces this envelope:
- a 5 V logic rail varies from 0.45 A in standby to 2.20 A during processing;
- a 24 V peripheral rail varies from 0.10 A at idle to 1.40 A during an operating step;
- the logic devices must remain inside their documented input window during the peripheral step;
- the peripheral voltage must also remain inside its own load limits at the far connector.
These are hypothetical requirement values, not measurements of a WEHO supply. The useful test points are not just 2.20 A plus 1.40 A. They include (0.45 A, 0.10 A), (2.20 A, 0.10 A), (0.45 A, 1.40 A) and (2.20 A, 1.40 A), plus the actual transitions between states. If the 5 V rail moves outside its allowed window when the 24 V load changes, the proposed supply fails this project even when its total output power appears adequate.
That result may be solved by changing the supply, adding a properly engineered post-regulator, changing the load architecture or separating the rails. The correct response depends on measured behavior, thermal conditions, efficiency and the downstream tolerance—not on headline watts.
Ce qu 'établissent les pages publiées de la série D de la WEHO
The current WEHO pages provide useful shortlist data, but they do not replace the application matrix.
Le WEHO D-120 dual-output power-supply page lists two variants:
- D-120A: 5 V and 12 V outputs;
- D-120B: 5 V and 24 V outputs.
Its published table lists different current ranges, adjustment ranges and load-regulation figures for CH1 and CH2. In particular, the page lists CH1 load regulation as 0.5%, while CH2 is listed as 5% for D-120A and 6% for D-120B. These are model-page values, not an independent laboratory verification and not a prediction for a customer’s wiring or transient loads.
| Published variant | ch1 | ch2 | Published current ranges | Published load-regulation rows |
|---|---|---|---|---|
| D-120A | 5 V | 12 V | 0–12 A / 0–5 A | 0.5% / 5% |
| D-120B | 5 V | 24 V | 0–6 A / 0–4 A | 0.5% / 6% |
The page does not publish the conditions for allocating the headline 120 W between rails. Do not infer that both listed rail maxima may be combined arbitrarily; ask for the applicable combined-load limits for the exact variant.
Le WEHO D-60 page is an additional family reference. Its table lists D-60A (5 V and 12 V) and D-60B (5 V and 24 V), output-current ranges with non-zero lower bounds, rail-specific load-stability values, and voltage adjustment on CH1. The page does not define whether those lower bounds are mandatory minimum-load requirements. Treat them as a question for model-specific confirmation, not as permission to infer that a preload is required.
Official WEHO D-120 product image from the published product catalogue. Confirm the exact variant and current revision before design release.
The pages establish that relevant dual-voltage variants exist and identify several electrical limits to review. They do not publish a complete customer-specific cross-regulation surface, dynamic interaction for the proposed loads, downstream cable drop, or evidence that every load combination in your machine will pass. Request a model-level review and agree a sample-validation plan with WEHO where the documented limits alone do not close the decision.
Quand une unité multi-sorties est la mauvaise architecture
A dual-output supply can reduce component count and wiring, but separate regulation is often the cleaner choice when:
- one rail must stay tightly controlled while the other has large steps;
- one rail operates near zero load and the proposed supply specifies a minimum load;
- the loads require independent enable, shutdown or fault containment;
- different grounding or isolation domains are required;
- one rail’s noise budget cannot tolerate interaction from the other load;
- future options make the combined envelope uncertain.
This is not a universal rule in favor of separate supplies. It is a prompt to compare the cost of validation and mitigation with the cost, space and efficiency of another converter.
Envoyer un RFQ qui peut être techniquement répondu
For a useful model recommendation, attach this evidence to the enquiry:
- required output voltages and their tolerance at the loads;
- minimum, typical and maximum current for every rail;
- the state table and the largest credible load steps;
- input-voltage range, frequency and any source constraints;
- ambient range, enclosure, airflow and mounting orientation;
- startup/shutdown order and fault-recovery requirements;
- isolation, grounding, ripple/noise and compliance requirements;
- available installation envelope and expected quantity.
Use the Page de contact WEHO to paste the key rail-load values into the enquiry, or ask for the approved route for transferring the completed table. The primary next step is a model-level fit review, not an immediate claim that D-60 or D-120 is suitable.
FAQ
La puissance totale de sortie est-elle suffisante pour dimensionner une alimentation à double sortie?
No. Total power is only one boundary. Each rail’s current range, combined limits, voltage tolerance and behavior under uneven loads must also match the application.
Qu 'est-ce que la régulation croisée dans une alimentation multi-sorties?
It is the change in one output voltage caused by a load change on another output. The effect depends on converter design and operating conditions, so it must be assessed from model documentation and relevant tests.
Puis-je laisser une sortie déchargée?
Only if the selected model’s documentation permits it and the remaining rail stays within the project’s limits. The D-60 product page lists non-zero lower bounds in its output-current range, but does not define them as mandatory minimum loads; ask WEHO how the field applies to the exact variant and revision.
Dois-je ajouter une charge factice pour améliorer la réglementation?
Do not add one by default. A dummy load wastes power and adds heat. First confirm the model’s requirements and measured behavior; then evaluate post-regulation, a defined preload or separate supplies as an engineered system decision.
Résumé décision
- GO: documented rail and combined-load limits cover the requirement, and the two-axis test keeps both loads inside their voltage windows.
- HOLD: the real light-load state, combined-load rule, cross-regulation behavior or acceptance evidence remains unknown.
- CHANGE ARCHITECTURE: a credible load pair violates a rail limit or voltage window; evaluate post-regulation or separate supplies.
