应用笔记 3928

Automotive Linear Regulators Minimize Quiescent Current


摘要 : Many automotive mechanical functions have been replaced or amended by electronic circuits in recent years. One consequence has been a rapid increase in the number of microcontrollers per car, producing a similar increase in the total current drawn from the car battery. As long the car motor is running and the alternator is operating properly, this power consumption is not a concern.

When you turn off the motor, however, the car battery must immediately deliver all currents demanded by the various subsystems: windshield wiper-blade motors, window lifters, radio/CD player/stereos, and any of the \"comfort electronics systems\" now found in most cars. Even when all passengers have left the car, many systems draw a keep-alive current to be ready for wake-up when their service is next required. Keeping these quiescent currents as low as possible requires linear regulators with low quiescent current as well as combinations of linear and switch-mode regulators. This article discusses the problem of minimizing quiescent current and introduces some solutions.