l99dz80ep STMicroelectronics, l99dz80ep Datasheet - Page 35

• Manufacturer Part Number: l99dz80ep
• Description: Door Actuator Driver
• Manufacturer: STMicroelectronics

L99DZ80EP
3.13
3.14
Cross-current protection
The six half-brides of the device are 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 completely turned off before
the opposite driver starts to conduct
Programmable soft-start function to drive loads with higher
inrush current
Loads with start-up currents higher than the overcurrent limits (e.g. inrush current of lamps,
Start current of motors and cold resistance of heaters) can be driven by using the
programmable softstart function (i.e. overcurrent recovery mode). Each driver has a
corresponding overcurrent recovery bit. If this bit is set, the device automatically switches
the outputs on again after a programmable recovery time. The duty cycle in overcurrent
condition can be programmed by the SPI interface to about 12 % or 25 %. The PWM
modulated current provides sufficient average current to power up the load (e.g. heat up the
bulb) until the load reaches operating condition. The PWM frequency settles at 1.7 kHz and
3 kHz. The device itself cannot distinguish between a real overload and a non linear load
like a light bulb. A real overload condition can only be qualified by time. For overload
detection the microcontroller can switch on the light bulbs by setting the overcurrent
recovery bit for the first e.g. 50 ms. After clearing the recovery bit the output is automatically
switched off, if the overload condition remains. This overcurrent detection procedure has to
be followed in order to make it possible to switch on the low side driver of a bridge output, if
the associated high-side driver has been used in recovery mode before.
Doc ID 18260 Rev 4
Application information
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