A motor vehicle built-in device comprising:
- a plurality of electrical components energized by an external power supply;
- and
- an electrical circuit for providing an electrical operable connection of said external power supply and said motor vehicle built-in device,
- wherein said electrical circuit comprises:
- a main input for coupling to said external power supply;
- a main output for coupling to said motor vehicle built-in device;
- a first electrical operable switch interconnected between said main input and said main output, said first electrical operable switch having an open position and a closed position, said first electrical operable switch being conductive in said closed position and being non-conductive in said open position;
- at least one wake-up input to receive a wake-up signal;
- at least one sleep input to receive a sleep signal;
- and
- a bi-stable sub-circuit coupled to said main input and coupled to said first electrical operable switch, said sub-circuit being connected to said at least one wake-up input and to said least one sleep input such that
- a received wake-up signal energizes said bi-stable sub-circuit and a received sleep signal de-energizes said bi-stable sub-circuit;
- wherein said energized bi-stable sub-circuit causes said first electrical operable switch to close and said de-energized bi-stable sub-circuit causes said first electrical operable switch to open;
- wherein said bi-stable sub-circuit comprises:
- a first transistor having an emitter terminal, a collector terminal and a base terminal, wherein said first transistor is configured with a bridge resistor interconnected between its emitter terminal and its base terminal and a base resistor connected to its base terminal;
- a second transistor having an emitter terminal, a collector terminal and a base terminal, wherein said second transistor is configured with a bridge resistor interconnected between its emitter terminal and its base terminal and a base resistor connected to its base terminal;
- and
- an interposed resistor;
- wherein said first transistor is coupled via its emitter terminal to said main input, via its collector terminal to a first terminal of said interposed resistor and via its base resistor to said collector terminal of said second transistor;
- wherein said second transistor is coupled via its emitter to ground, via its base resistor to a second terminal of said interposed resistor and via its collector to said base resistor of said first transistor;
- wherein said at least one wake-up input is coupled to a first connection line between said base resistor of said first transistor and said collector terminal of said second transistor, both being coupled;
- wherein said at least one sleep input is coupled to a second connection line between said base resistor of said second transistor and said second terminal of said interposed resistor, both being coupled;
- and
- wherein said first electrical operable switch is operable with said bi-stable sub-circuit being coupled to said second connection line.