Development of a Custom Integrated Circuit for Continuously Variable Valve Lift Mechanism System Control

To improve fuel efficiency in a conventional gasoline engine, Toyota Motor Corporation has developed and mass-produced a continuously-variable valve lift (CVVL) system that reduces the pumping loss at low engine load by continuously changing the stroke of the intake valve of the engine. The electronic driver unit (EDU) controls the actuator in an integrated structure. In the EDU, the application specific integrated circuit (ASIC) has an important function to control the motor and to secure failsafe by executing mutual watch with the CPU. We developed this ASIC by using silicon on insulator (SOI) processes suitable for the high temperature system requirements.