SEA01 datasheet(7/24 Pages) STMICROELECTRONICS

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DocID024452 Rev 1

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SEA01

Application information

2.1

Constant voltage and current control and with online digital

trimming

Figure 3. Typical application schematic

The online digital trimming allows the user to adjust the VrefV and VrefI internal references in

order to have the highest accuracy of voltage and current of the application (SMPS requiring

an accurate current limitation or regulation and/or very accurate voltage regulation).

This new way of trimming allows the user to have the highest accuracy simply using

software without the use of external discrete components or manual intervention.

The parameters of the IC that the user can trim are VrefV and VrefI.

VrefV is the parameter typically relevant to the voltage regulation and it has to be trimmed as

the first step after measuring the output voltage of the application.

VrefI is typically the parameter relevant to the current regulation and it has to be trimmed to

adjust the value of the measured current to the target current.

The relation between the controlled current and the controlled output voltage can be

described as a square as shown in the following V/I output-power graph (with the power

supply of the device independent from the output voltage).

Vrefv

--------------

–

⎝⎠

⎛⎞

⋅

Rsense

VrefI

Iomax

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SEA01 Datasheet(PDF) 7 Page - STMicroelectronics