Specifying a Converter's Forced-PWM and Pulse-Skip Modes

1. Distinguish the Documented Mode Names

Identify the exact converter and the released mode requirement before collecting candidate descriptions. Retain the document reference used by the power-stage owner. A short label such as pulse-skip can leave the actual behavior unspecified, particularly when it was copied from a distributor summary. Ask which manufacturer's definition the requirement uses and which operating conditions the owner expects it to cover.

TI's TPS62135 documentation distinguishes forced PWM from its Power Save operation, described in PWM/PFM terms. The MODE discussion connects the permitted behavior to configuration and load context. Use those terms for this family example. Preserve another converter's own terminology when examining it, rather than assigning the same mechanism to every device advertised with a broad light-load mode label.

Keep a candidate's mode description intact when it differs from the incumbent's wording. Record the difference as a question for the power-stage reviewer, without declaring the implementations equivalent. A shared abbreviation can help locate documents but does not provide the decision itself. The inquiry should name the required behavior and its source, allowing the reviewer to assess the relevant evidence for the exact device.

2. Record Load Range and Mode Control

Request the load range associated with the accepted requirement, keeping relevant operating states separately identified. A catalogue output-current rating does not describe the whole load profile of the customer assembly. Retain the power-stage owner's records for light load and other applicable conditions, noting where the basis remains incomplete. This guide provides no invented load waveform or application current example.

The TPS62135 MODE description associates a high state with forced PWM and a low state with permitted load-dependent PWM/PFM operation. Preserve the actual required selection with the design reference that supports it. This is a logical configuration question, not a physical pin assignment or wiring instruction. The presence of a feature in a datasheet does not document how an unidentified board selects it.

Distinguish the component's available function from the released system requirement. If another converter provides a different selection mechanism or mode description, keep that difference visible. Ask the owner whether it changes the necessary control or application review. Purchasing can request the accepted mode requirement while a proposed configuration change remains unresolved; it should not silently convert that proposal into the confirmed component description.

3. Retain Mode-Specific Electrical Conditions

Retain the conditions attached to any mode-specific specification used in the comparison. The TPS62135 description relates its operating behavior to the selected mode and load context; a nominal switching-frequency entry does not describe every operating point. Keep the relevant manufacturer's conditions available rather than replacing them with a general claim that a named mode guarantees a constant application result.

Ask engineering which output-quality or other electrical requirements it needs to assess at the stated operating conditions. Link its accepted criteria to the exact device and supporting document entries. This article supplies no ripple, efficiency or noise value. It also supplies no board measurement that could resolve a difference between the customer's operating point and the context attached to a published specification.

Keep typical characteristics, specification limits and existing application evidence distinguishable. A curve or feature heading should retain its stated meaning and scope in the review record. Where further evidence is required, identify the question and its owner. Avoid completing an unknown application result from a mode name, or presenting a supplier's mode description as a report that the customer's power stage has met its criteria.

4. Preserve the Approved Mode in the Inquiry

Create a converter-mode summary covering the exact part, manufacturer terminology, required behavior, selection context and relevant load states. Keep mode-specific evidence references beside the corresponding requirement. This makes the light-load decision more precise than a generic converter-family request, without substituting the preparation record for the engineering work needed to assess the actual power stage and any proposed change.

Keep a proposed converter or configuration separate from the released selection until the design owner has recorded its decision. An accepted change may need the requirement record and controlled BOM to be updated together. Preserve the technical difference that prompted review, rather than presenting the candidate under the incumbent's mode label. A sourcing offer does not independently settle how the application should configure or evaluate it.

For an ICULTRA converter inquiry, provide the approved full code and the permitted mode/configuration requirement, identifying light-load evidence or terminology differences still awaiting review. Keep the engineering disposition with the request so the recipient can distinguish the confirmed item from a candidate. This article establishes neither a universally best mode nor an available substitute, tested waveform or guaranteed improvement in output quality.

Sources and further reading

• Texas Instruments TPS62135/TPS621351 datasheet

TI TPS62135 documentation supports the MODE and Power Save/PFM examples. Load and comparison records are preparation suggestions; no universal pulse-skip definition, computed efficiency, board waveform or ripple/noise guarantee is supplied.