L9918 datasheet(6/109 Pages) STMICROELECTRONICS

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1.4

Internal block diagram

Figure 3. Simplified block diagram

1.4.1

Power supplies

Power Supplies block contains two sub-blocks: the first is always working, even when device is in stand-by state

(Stand-by domain); the latter works just when the device is in active states (OFF in stand-by).

The first sub-block supplies Phase and LIN interfaces (needed for the wake up function) and the Stand-by digital

block.

The second sub-block provides the analog and digital supplies to the whole device when PH or LIN pins are fed

with a valid signal. It even provides voltage references for all the sigma-delta converters and provides currents

reference as well. This sub-block is not supplied in stand-by state.

1.4.2

Phase interface

The task of this block is to detect activity on phase pin and verify if the phase signal voltage levels are correct.

The circuitry in charge of phase activity detection is always supplied in stand-by.

1.4.3

LIN interface

The block controls the LIN bus transmission and reception. The circuitry in charge of LIN bus activity detection is

supplied in stand-by as well.

1.4.4

Stand-by digital block

The Stand-by digital block manages the information coming from interfaces and, taking into account NVM

configuration data, eventually generates a wake-up signal.

1.4.5

Voltage divider & ΣΔ modulator for regulation

The stage has a resistive divider connected to battery and provides the correct signal voltage range to the internal

converter stage. The stage feeds into the digital block a bit-stream converted in a digital code with a proper low

pass filter. The code is managed in the digital block to act the regulation.

L9918

Internal block diagram

DS13000 - Rev 2

page 6/109

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