Body control chip combines power window and trunk functionalities
While the development trend in automotive electronics is moving strongly towards the centralisation of functions, there are still some areas where OEMs are working with decentralised ECUs. But even here, a higher degree of integration at the semiconductor level can reduce the number of scattered ECUs and thus reduce the overall complexity. STMicroelectronics is currently leading the way in this direction with the introduction of a chip that brings together the control of power windows, mirrors and certain lighting functions. The rich feature set of the L99DZ200G door-zone system IC brings benefits – such as lower quiescent current consumption of the overall system, greater reliability, less time required for assembly, reduced material costs and shorter development time.
The L99DZ200G contains two H-bridge gate drivers, a gate driver for an external MOSFET to drive the mirror heater, a control section and a high-side driver for electrochromic mirror dimming, and five high-side LED drivers. Three of these high-side drivers can be operated in constant current mode to drive lighting modules with high input capacitance. The two remaining high-side drivers, on the other hand, are suitable for driving conventional LEDs.
With its two H-bridge drivers, the L99DZ200G can drive two spindle motors simultaneously and also control an additional closing motor for closing a boot lid or tailgate. Both drivers also support operation in generator mode, where both low-side MOSFETs are activated simultaneously to protect the device in the event that an overvoltage is detected on the supply line.
The L99DZ200G also provides power management and for this purpose is equipped with two 5 V LDOs (low dropout regulators) for the host microcontroller and the peripheral devices. Connections for control and communication include a LIN 2.2a transceiver (SAEJ2602, SAE J2962-1), a high-speed CAN transceiver (HS-CAN, ISO 11898-2:2003 /-5:2007, SAE J2284, SAE J2962-2) and an SPI 4.0 interface.
Included diagnostic and protection features include temperature monitoring and over-temperature protection, a special fail-safe block to pull the gates of the external high-side MOSFETs to low potential, and open-load and over-current detection for all outputs. A current monitor output is also provided for each high-side channel. Reset after an overcurrent event and cool-down after overheating ensure that operation is automatically resumed after a fault. In addition to battery reverse polarity protection, system safety features are also built in, which include a configurable window watchdog and a programmable reset generator.
The AEC-Q100 qualified L99DZ200G comes in a 10 mm x 10 mm LQFP64 package. Production has already started.
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