MPZ2012S221A datasheet(12/56 Pages) STMICROELECTRONICS

No. de pieza	MPZ2012S221A

Descripción Electrónicos	38 V, 10 W synchronous iso-buck converter for isolated applications

PDF	56 Pages

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Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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Figure 7. Soft-start procedure

EN (t)

VCC (t)

SW (t)

VEN Rising = 1.2 V

VVCC= 3.3 V

EA Reference (t)

VREF= 0.85 V

tSS= 1.3 ms

tSETUP = 540 µs

During normal operation, a new soft-start cycle takes place in case of:

Thermal shutdown event

UVLO event

EN pin rising over VEN threshold. Please refer to Table 6. Electrical characteristics

The device can invert the current even during soft-start, hence enabling the energy transfer to the secondary

winding. Therefore, the secondary isolated output voltage goes up simultaneously with the primary output voltage,

so implementing a tracked soft-start.

Figure 8. Tracked soft-start at secondary side

5.1.3

Undervoltage lockout

The device implements the undervoltage lockout (UVLO) continuously sensing the voltage on the VCC pin, if the

UVLO lasts more than 10 μs, the internal logic resets the device by turning off both LS and HS.

After the reset, if the EN pin is still high, the device repeats the soft-start procedure.

L6983I

Primary side

DS14040 - Rev 1

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MPZ2012S221A Datasheet(PDF) 12 Page - STMicroelectronics