L6728 datasheet(28/31 Pages) STMICROELECTRONICS

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5 A demonstration board

L6728

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If the voltage is between 4.5 V and 12 V it can supply also the device (through the Vcc pin)

and in this case the R16 (0

Ω) resistor must be present.

13.1.2

Output (Vout)

The output voltage is fixed at 1.25 V but it can be changed by replacing the resistors R8

(sense partition lower resistor ) and R13 (feedback partition lower resistor). R18 allows to

adjust OCP threshold.

13.1.3

Signal input (Vcc)

Using the input voltage Vin to supply the controller no power is required at this input.

However the controller can be supplied separately from the power stage through the Vcc

input (4.5-12 V) and, in this case, the R16 (0

Ω) resistor must be unsoldered.

13.1.4

Test points

Several test points are provided to have easy access at all important signal characterizing

the device:

–

COMP: the output of the error amplifier;

–

FB: the inverting input of the error amplifier;

–

PGOOD: signaling the regular functioning (active high);

–

VGDHS: the bootstrap diode anode;

–

PHASE: Phase node;

–

LGATE: Low-side gate pin of the device;

–

HGATE: High-side gate pin of the device.

13.1.5

Board characterization

Figure 18.

5 A demonstration board efficiency

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