L9953LXP datasheet(22/35 Pages) STMICROELECTRONICS

22 / 35 page

Application information

L9953LXP

22/35

Doc ID 16185 Rev 3

3.10

Current monitor

The current monitor output sources a current image at the current monitor output which has

a fixed ratio (1/10000) of the instantaneous current of the selected highside driver. The bits

18 and 19 of the input data register 0 control which of the outputs OUT1, OUT4, OUT5, and

OUT8 will be multiplexed to the current monitor output. The current monitor output allows a

more precise analysis of the actual state of the load rather than the detection of an open- or

overload condition. For example this can be used to detect the motor state (starting, free-

running, stalled). Moreover, it is possible to regulate the power of the defroster more precise

by measuring the load current. The current monitor output is bidirectional (c.f. PWM inputs).

3.11

PWM inputs

Each driver has a corresponding PWM enable bit which can be programmed by the SPI

interface. If the PWM enable bit in input data register 1 is set, the output is controlled by the

logically AND-combination of the PWM signal and the output control bit in input data

output OUT7 is controlled by the bidirectional input CM/PMW2. For example, the two PWM

inputs can be used to dim two lamps independently by external PWM signals.

3.12

Cross-current protection

The six half-bridges of the device are cross-current protected by an internal delay time. If

one driver (LS or HS) is turned-off the activation of the other driver of the same half bridge

will be automatically delayed by the cross-current protection time. After the cross-current

protection time is expired the slew-rate limited switch-off phase of the driver will be changed

to a fast turn-off phase and the opposite driver is turned-on with slew-rate limitation. Due to

this behavior it is always guaranteed that the previously activated driver is totally turned-off

before the opposite driver will start to conduct.

L9953LXP Datasheet(PDF) 22 Page - STMicroelectronics