L9950 STMicroelectronics, L9950 Datasheet - Page 22

• Manufacturer Part Number: L9950
• Description: IC DRIVER DOOR ACTUATOR PWRSO-36
• Manufacturer: STMicroelectronics
• Type: Door Actuator Driverr

Specifications of L9950

• Applications: Automotive
• Current - Supply: 7mA
• Voltage - Supply: 7 V ~ 28 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: PowerSO-36 Exposed Bottom Pad
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application information
3.9
3.10
3.11
3.12
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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,
OUT6 and OUT11 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).
PWM inputs
Each driver has a corresponding PWM enable bit which can be programmed by the SPI
interface. If the PWM enable bit is set, the output is controlled by the logically AND
combination of the PWM signal and the output control bit in Input Data Register. The outputs
OUT1-OUT8 and OUT11 are controlled by the PWM1 input and the outputs OUT9/10 are
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.
Cross current protection
The six half brides 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.
Programmable soft start function to drive loads with higher
inrush current
Loads with start-up currents higher than the over-current limits (e.g. inrush current of lamps,
start current of motors and cold resistance of heaters) can be driven by using the
programmable soft start function (i.e. overcurrent recovery mode). Each driver has a
corresponding over-current recovery bit. If this bit is set, the device will automatically switch-
on the outputs again after a programmable recovery time. The duty cycle in over-current
condition can be programmed by the SPI interface to be about 12% or 25%. The PWM
modulated current will provide sufficient average current to power up the load (e.g. heat up
the bulb) until the load reaches operating condition.
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. As an example the
microcontroller can switch on light bulbs by setting the over-current Recovery bit for the first
50ms. After clearing the recovery bit the output will be automatically disabled if the overload
condition still exits.
Doc ID 10311 Rev 10
L9950 - L9950XP