L99MC6 datasheet(14/55 Pages) STMICROELECTRONICS

14 / 55 page

Description

L99MC6

14/55

Doc ID 16523 Rev 1

2.4.1

Direct input IN/PWM

The IN/PWM input allows channel 2 to be enabled without the use of SPI. The IN/PWM pin

is OR-ed with the SPI command bit. This pin can be left open if the channel 2 is controlled

only via the SPI. This input has an internal pull-down.

The IN/PWM signal can also be applied to any other switches by the activation of the PWM

mode.

This input is suited for non-inductive loads that are pulse width modulated. This allows PWM

control without further use of the SPI.

2.4.2

Temperature warning and thermal shutdown

If the junction temperature rises above Tj TW a temperature warning flag is set and is

detectable via the SPI. If the junction temperature increases above the second threshold

TjSD, the thermal shutdown bit is set and power DMOS transistors of all output stages are

switched-off to protect the device. Temperature warning flag and thermal shutdown bits are

latched. In order to reactivate the output stages, the junction temperature must decrease

below TjSD- TjSDHYS and the thermal shutdown bit has to be cleared by the

microcontroller.

2.4.3

Open-load detection in off-state

The open-load detection monitors the load at each output stage in off mode. A current

source of 150 µA (IOLD1-6, IOLS 1-3) is connected between drain and source or GND. An

open-load failure is detected if the drain or source voltage reaches an internal VOLD/S (2.0 V)

for at least 3 ms (tdOL typ.). The corresponding open-load bit is set in the status register. In

LED mode the open-load detection is disabled and the current source is switched-off, which

avoids a turn-on of the LEDs in off-state.

2.4.4

Overload detection

In case of an overcurrent condition, a flag is set in the corresponding status register. If the

overcurrent signal is valid for at least tISC = 32 µs, the overcurrent flag is set and the

corresponding driver is switched-off to reduce the power dissipation and to protect the

integrated circuit. If the overcurrent recovery bit of the output is zero the microcontroller has

to clear the status bit to reactivate the corresponding driver.

2.5

Bridge mode

The L99MC6 can be configured as bridge driver. Up to three half bridges can be used. In

Bridge mode the device is crosscurrent 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 is automatically

delayed by the crosscurrent protection time. After the crosscurrent protection time is expired

the slew rate limited switch-off phase of the driver is 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

starts to conduct.

Due to the built-in reverse diodes of the output transistors, inductive loads can be driven at

the outputs without external free-wheeling diodes.

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