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. 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.