L6460 datasheet(44/139 Pages) STMICROELECTRONICS

44 / 139 page

Power sequencing

L6460

44/139

Doc ID 17713 Rev 1

Power sequencing

As soon as VSupply and VSupplyInt are above their power on reset level, L6460 will start the

charge pump circuit; once VPump voltage reaches its under voltage rising threshold, L6460

begins a sequence that starts the regulators considered system regulators.

A regulator is considered a System regulator if:

–

It has to start in on state without any user action.

–

It is included in the power-up sequence.

–

Its under-voltage event is considered by L6460 as an error condition to be

signaled through nRESET pin.

Once VSupply and VSupplyInt, VPump and all the system regulators are over their under

voltage rising threshold, L6460 enters in the normal operating state, that will release

nRESET pin and will wait for SPI commands.

L6460 will reduce the noise introduced in the system by switching out of phase all its power

circuits (switching regulators, bridges and charge pump).

The L6460's startup sequence of operation is the following:

–

start V3v3 internal linear regulator

–

sample startup configuration

–

wait enable if slave device

–

start charge pump

–

start system regulators (see order in Section 8.6)

–

if master send enable to slave device

–

wait until VGPIO_SPI becomes ok

L6460 Fiches technique(PDF) 44 Page - STMicroelectronics