UM0971 datasheet(9/45 Pages) STMICROELECTRONICS

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UM0971

Board description

Doc ID 17701 Rev 1

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2.2

Power supply circuit

The STEVAL-IHM031V1 board is designed to work with an input voltage bus ranging from

12 V up to 24 V (nominal values). The bus voltage supplies the three-phase inverter stage.

To allow proper working below the nominal 12 V lower voltage limit, an opportune power

supply stage has been designed, taking into account several aspects, such as:

●

ensuring supply voltage for the gate driver L6387E (+8 V)

●

+5 VDC generation with current capability of 800 mA

●

+3.3 VDC generation with current capability of 800 mA

●

providing externally auxiliary 8 VDC power supply

Figure 3 is a block diagram representation of the power supply stage used for the

STEVAL-IHM031V1 board:

Figure 3.

Power supply block diagram

In a case where the bus voltage input is below nominal voltage (12 VDC), the L4976

regulator is no longer able to provide 8 V voltage level at its output. Nevertheless, it is still

possible to continue using the board by providing an external +8 V voltage through

connector J21.

2.2.1

LD1117xx33 and LD1117xx50 characteristics

The LD1117xx33/50 is a low drop voltage regulator able to provide up to 800 mA of output

current at 3.3 V/5 V output voltage. The main features follow.

UM0971 数据表(PDF) 9 Page - STMicroelectronics