Datasheet

L6460 Power bridges

Doc ID 17713 Rev 1 75/139

voltage thresholds) using serial interface. The feedback reference voltage is selected by

writing the SelFBRef[1:0] bits in the Aux1SwCfg or Aux2SwCfg registers.

The switching regulators have four possible PWM duty cycles that can be changed using

SPI according to Tabl e 28 .

14.1.7 Regulation loop

As seen before L6460 contains 2 regulation loops for switching regulators that are used

when bridge 3 is used as a regulator. These loops are assembled using internal

comparators and filters similar to that used in main switching regulator.

When bridge 3 is not used for this purpose or when only one regulation loop is needed, the

control loop is available on a GPIO output thus enabling the customer to assembly a basic

buck switching regulator using an external Power FET. The comparators used in the above

mentioned regulation loops are general purpose low voltage (3.3 V) comparators; when the

relative regulation loop is not used they can be accessed as shown in the Figure 20.

Figure 20. Internal comparator functional block diagram

Table 28. PWM specification

AuxXPWMTable[1:0] Typical duty cycle value Comments

00 10%

01 13% Default state for AUX1

10 24% Default state for AUX2

11 61%

GPIOz

GPIOx

DECODE

LOGIC

GPIOy

DECODE

LOGIC

GPIOz Logic

Driver

3v3

GPIOz

DECODE

LOGIC

GPIOz Value From SPI

GPIOxMode

GPIOzMod

GPIOyMode