L6728D

20 A demonstration board

Doc ID 16498 Rev 1

25/33

12.1

Board description

12.1.1

Power input (Vin)

This is the input voltage for the power conversion. The high-side drain is connected to this

input. This voltage can range from 1.5 V to 12 V bus.

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

and in this case the R16 (0

Ω) resistor must be present.

12.1.2

Output (Vout)

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

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

adjustment of the OCP threshold.

12.1.3

Signal input (Vcc)

When 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.

12.1.4

Test points

Several test points are provided for easy access to all the important signals that characterize

the device:

–

COMP: The output of the error amplifier

–

FB: The inverting input of the error amplifier

–

PGOOD: Signaling 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

12.1.5

Board characterization

Figure 14.

20 A demonstration board efficiency