Pins description and connection diagram

L6788A

6/18

Doc ID 15341 Rev 2

6

VR_HOT/

EN

Voltage regulator HOT / enable pin. Internally pulled up by 10 µA (typ) to 3.3 V.

Multifunction pin to enable/disable the system (input-signal) and to provide the

information about the warning temperature (output-signal).

Forced low, the device stops operations with all MOSFETs OFF: all the latched

protections are disabled. Removing the short on VR_HOT/EN pin, the device

starts-up implementing soft-start and the voltage at the pin is clamped by the

device at 1.5 V (typ). When a warning temperature is detected the device

leaves the pin floating.

Thermal monitoring enabled if Vcc > UVLOVCC (See “thermal monitoring”

section for details).

VR_HOT/EN pin is set free when:

• Either TCS pin voltage overcomes the warning threshold voltage (see TCS

pin for details).

• Or Tj_IC Die temperature overcomes the die warning temperature (T_HOT)

Where T_HOT=T_Shutdown-T_Delta

Use a pull-up resistor in the range of 10 k

Ω−30 kΩ when VR_HOT/EN pin is

directly pulled up to 3.3 V. (see VR_HOT/EN pin voltage Electrical

Characteristic table).

Cycle this pin to recover latch from protections.

7

VID1

Voltage identification pins. Internally pulled low by 10 µA.

They allow programming output voltage from the 4-level “power play table” in

PVID mode.

8VID0

9IREF

Current reference pin.

Internally fixed at 1.240 V, connecting a RIREF = 12.4 k

Ω (+/-0.1%) resistor vs.

AGND allows setting 100 µA current that is mirrored into R1, R2, R3 pins in

order to program the three power play table levels voltage. See “power play

table level” section for details.

10

R3

Default “power play table” voltage setting pins.

The device sources from each Rx pin the same constant current sourced from

the IREF pin (

Internally mirrored). As a consequence the Voltage between Rx pin and AGND

is given by the following relationship: VRx= IREF * Rx=100 µA*Rx, where IREF

is the current programmed on IREF pin (100 µA). As soon as the ENABLE is

released the device reads the Rx pin voltage and it stores these value. As a

consequence if the power play table is re-written by serial BUS the analog

values can not be recovered (voltage fixed by Rx resistor). See “power play

table level” section for details.

11

R2

12

R1

13

CS1-

Channel 1 current sense negative input.

Connect through a Rg resistor to the output-side of the channel 1 inductor.

14

CS1+

Channel 1 current sense positive input.

Connect through an R-C filter to the phase-side of the channel 1 inductor.

15

CS2-

Channel 2 current sense negative input.

Connect through a Rg resistor to the output-side of the channel 2 inductor.

Table 2.

Pin description (continued)

Pin n°

Name

Description