L9945 datasheet(20/151 Pages) STMICROELECTRONICS

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5.2.1

VDD5 supply block

The VDD5 pin is internally split between analog and digital domain to reduce interference between the different

parts of the component. Two regulators are implemented in order to provide separate 3.3 V domains:

•

VDD_int_a is generated out of VDD5. It is the overvoltage protected internal supply of the low voltage

analog part, such as diagnostic comparators, gate drives for integrated low-side, bias currents, bandgap

etc.;

•

VDD_int_d is generated out of VDD5. It is the overvoltage protected internal supply for the digital part.

The component starts operation when VDD5 is higher than the power-on reset threshold (VPOR). Details about

the reset block are given in the Section 5.3 Reset.

The VDD5 is monitored to generate over (OV) and under voltage (UV) disable in case of fault. The disable signal

acts both internally and externally: in case of output disable due to failure on VDD5, the NDIS bidirectional pin is

internally pulled down. The purpose is providing a feedback to the external microcontroller monitoring the device

status. Detailed information about disable sources is given in the Section 6.1 Disable sources paragraph.

Range of characteristic is defined for VDD5 from 4.5 V to 5.5 V. In this range, the component works according to

the specification without any restrictions and all parameters are in the specified range.

The table below lists the electrical characteristics of the VDD5 supply block.

Note:

Tj = Tj_op; VVPS_UV < VVPS < 60 V, all supplies are independent; 4.5 V < VDD5 < 5.5 V; 3.0 V < VIO < 5.5 V,

unless otherwise noted.

Table 8. VDD5 supply block electrical characteristics

Symbol

Parameter

Test condition

Min.

Typ.

Max.

Unit

IVDD5_opm

VDD5 operating mode current

All outputs controlled ON

IVDD5OV

VDD5 current in case of overvoltage

5.5 V < VDD5 ≤ 36 V

VVDD5_UV

VDD5 UV threshold

Undervoltage

4.5

4.7

VVDD5_UV_HYS

VDD5 UV hysteresis

VVDD5_UV

tVDD5_UV1

VDD5 undervoltage filter time

2.6

3.25

tVDD5_UV_react

VDD5_UV Comparator output reaction time

100

700

tVDD5_UV2

VDD5 under voltage filter time for NDIS activation

415

500

625

VVDD5_OV

VDD5 overvoltage disable threshold

Self-checked by HWSC

5.3

5.5

VVDD5_OV_HYS

VDD5 OV disable hysteresis

tVDD5_OV

VDD5 overvoltage filter time

2.0

2.6

3.25

tVDD5_OV_react

VDD5_OV Comparator output reaction time

100

700

VPOR

POR release threshold

Related to VDD5

4.15

4.45

VPOR_HYS

POR hysteresis

0.15

0.25

tPOR_D

POR RESET delay time

POR delay at startup of VDD5

µs

5.2.2

VPS supply block

The VPS pin is a battery supply. It is used for the internal charge pump to drive the N-channel external MOSFETs.

The VPS line is monitored to detect low voltage on VPS. In case the voltage on VPS is lower than VVPS_UV the

pre-drivers are actively turned off. Such event is latched in VPS_LATCH, cleared on SPI readout. The

undervoltage comparator output can be monitored reading VPS_STATE bit via SPI.

The table below lists the electrical characteristics for the VPS supply block:

Note:

Tj = Tj_op; VVPS_UV < VVPS < 60 V, all supplies are independent; 4.5 V < VDD5 < 5.5 V; 3.0 V < VIO < 5.5 V,

unless otherwise noted.

L9945

Supply concept

DS12275 - Rev 8

page 20/151

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