L9969X datasheet(30/70 Pages) STMICROELECTRONICS

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3.2.5

Output control

The output stages can be controlled either by two input signals ‘PWM’ and ‘DIR’ (parallel control), or via SPI.

Parallel control is the default state.

In order to operate the power stages via SPI bus, the CONFIG_REG.MUX must be set to 0. In this case, the

bridges follow the bit values of SDIR and SPWM, in the register CONFIG_REG. Both releasing signals DIS and

NABE keep their effectiveness in this (SPI-controlled) mode of operation. However, when SPI-control mode is

selected, signals on PWM and DIR are ignored.

The bit CONFIG_REG.FW is used to switch between the active free wheeling (CONFIG_REG.FW = 1), where the

body diode is short cut by its transistor, or the passive free wheeling (CONFIG_REG.FW = 0), where the free

wheeling is driven only through the body diode. The active free wheeling (CONFIG_REG.FW = 1) is the default

state; the free wheeling strategy (active versus passive) applies not only to the regular operation of the power

stage but also to the current limitation.

3.2.6

Protection and monitoring

Both output stages feature the following diagnostic functions:

•

Short to Battery voltage (SCB). Detection is performed when low side-switches are turned on. The result is

reported in the register DIA_REG1.

•

Short to Ground (SCG). Detection is performed when high side-switches are turned on. The result is

reported in the register DIA_REG1.

•

Short across Load (SCL). Detection is performed by an appropriate procedure (combination SCB, SCG).

The result is reported in the register DIA_REG1.

•

Open Load (OL), available in both active and inactive mode. The result is reported in the register

DIA_REG1. Per default only the OL detection in passive is running. If enabled (CONFIG_REG.OLDA → 1),

the OL detection in active mode (OLDA) is run automatically.

•

Over Temperature (OT), available in active and inactive mode. Once OT is detected, the power stage is

switched off. The result is reported in the register DIA_REG1.

Each short-circuits error has to be confirmed before it is stored in the DIA_REG1. In practice, if any error occurs

the first time, the HBR has to react correctly. For instance, at SCG at OUT1, the HBR is switched off. After the

time tretest the HBR is switched on again. If now the SCG at OUT1 appears again, it is confirmed. If it is not

confirmed, the first entry is to be skipped. Only confirmed errors are stored in the DIA_REG1. Open-load in active

(OLDA) errors has to be retested as well (refer to Section 3.2.6.9: Open Load diagnosis in active mode). After

each confirmed short-circuits error, the HBR is switched off and is not automatically switched on again, even if the

error has disappeared in between.

3.2.6.1

Current feedback

An analog output signal CF proportional to the load current is provided. The signal CF is valid

for 6.5 V < VS < 28 V.

5 V < VBATT < 18 V, 4.5 V < VDD < 5.5 V, TJ= -40 °C to 150 °C, unless otherwise specified.

Table 17. Current feedback parameters

Symbol

Parameter

Condition

Min

Typ

Max

Unit

CF_0%

CF output voltage with current at OUTx = 0% * IL

(CLx)

ICF > -1.2mA

0.008 *

VDD

0.014 *

VDD

0.036 * VDD

CF_5%

CF output voltage with current at OUTx = 5% * IL

(CLx);

percentage vs. VDD

ICF > -1.2mA

5.27

5.73

6.19

CF_40%

CF output voltage with current at OUTx = 40% * IL

(CLx);

percentage vs. VDD

ICF > -1.2mA

33.7

38.3

CF_100%

CF output voltage with current at OUTx = 100% * IL

(CLx);

percentage vs. VDD

ICF > -1.2mA

100

L9969x

Functional description

DS14029 - Rev 6

page 30/70

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