Power Management and Failsafe Circuit Integrated in Single Chip
Reduced Space and Enhanced Energy Efficiency

STMicroelectronics (hereinafter ST) has launched a new monolithic device family that integrates power management and failsafe circuitry—previously implemented using external devices—into a single chip, enhancing the capabilities of automotive door-zone controllers.

The L99DZ100G/GP for front-door applications and the L99DZ120 for rear-door control reduce space requirements, improve reliability and energy efficiency, and offer software compatibility between products to simplify development.

ST's advanced BCD8S automotive technology is the key to developing this unique single-chip solution. Based on this technology, half-bridge and high-side drivers with a maximum current rating of 7.5A have been integrated, meeting the power management and failsafe requirements demanded by door-zone applications.



The solution also includes high-speed CAN (HS-CAN) and LIN 2.2a (SAE J 2602) interfaces, control blocks, and protection circuits. The L99DZ100GP features an ISO 11898-6 HS-CAN selective wake-up function that maximizes energy savings by cutting power to infrequently-used ECUs (Electronic Control Units) while they remain connected to the CAN bus.

Both front-door controllers integrate MOSFET half-bridges capable of driving up to five DC motors and can also drive external H-bridges. Eight LED drivers and two additional drivers for incandescent bulbs, a gate driver for mirror heaters, and a control module for electrochromic glass are included. External circuits such as microcontrollers and sensors, as well as associated timers, watchdogs, reset generators, and voltage regulators for protection circuits are provided. The L99DZ120 includes similar functionality and is specifically tailored to rear-door requirements, including a motor driver for automatic windows.

Since vehicle supply voltage (V_S) varies continuously, an automatic LED duty-cycle correction function is additionally provided to maintain constant brightness. When circuit short conditions occur, the innovative thermal cluster allows outputs to be individually disabled. Unaffected outputs continue to operate normally, further enhancing user satisfaction.