(EP872014-A1)      A vehicle electrical system has a generator whose exciter circuit is subject to a voltage regulator. Beside a first voltage level of 12 volts, a second voltage level is provided, realised by a parallel circuit with several chopper stages. The voltage regulation takes place at the first voltage level. There is a circuit for voltage transformation using a switch, a choke and a diode in a T-network. The diode is aligned in the direction to generate continuous current flow in the inductance and in the load. The number of parallel converters is inversely proportional to the height of the smallest attainable voltage level. The duty cycle of each stage is constant.    ADVANTAGE -   Apart from 12 V, another stabilised voltage level is given for high power-consuming loads.    (JP11507499-W)      A vehicle electrical system has a generator whose exciter circuit is subject to a voltage regulator. Beside a first voltage level of 12 volts, a second voltage level is provided, realised by a parallel circuit with several chopper stages. The voltage regulation takes place at the first voltage level. There is a circuit for voltage transformation using a switch, a choke and a diode in a T-network. The diode is aligned in the direction to generate continuous current flow in the inductance and in the load. The number of parallel converters is inversely proportional to the height of the smallest attainable voltage level. The duty cycle of each stage is constant.    ADVANTAGE -   Apart from 12 V, another stabilised voltage level is given for high power-consuming loads.    (EP872014-B1)      A vehicle electrical system has a generator whose exciter circuit is subject to a voltage regulator. Beside a first voltage level of 12 volts, a second voltage level is provided, realised by a parallel circuit with several chopper stages. The voltage regulation takes place at the first voltage level. There is a circuit for voltage transformation using a switch, a choke and a diode in a T-network. The diode is aligned in the direction to generate continuous current flow in the inductance and in the load. The number of parallel converters is inversely proportional to the height of the smallest attainable voltage level. The duty cycle of each stage is constant.    ADVANTAGE -   Apart from 12 V, another stabilised voltage level is given for high power-consuming loads.    (US6043567-A)      A vehicle electrical system has a generator whose exciter circuit is subject to a voltage regulator. Beside a first voltage level of 12 volts, a second voltage level is provided, realised by a parallel circuit with several chopper stages. The voltage regulation takes place at the first voltage level. There is a circuit for voltage transformation using a switch, a choke and a diode in a T-network. The diode is aligned in the direction to generate continuous current flow in the inductance and in the load. The number of parallel converters is inversely proportional to the height of the smallest attainable voltage level. The duty cycle of each stage is constant.    ADVANTAGE -   Apart from 12 V, another stabilised voltage level is given for high power-consuming loads.    (JP3135581-B2)      A vehicle electrical system has a generator whose exciter circuit is subject to a voltage regulator. Beside a first voltage level of 12 volts, a second voltage level is provided, realised by a parallel circuit with several chopper stages. The voltage regulation takes place at the first voltage level. There is a circuit for voltage transformation using a switch, a choke and a diode in a T-network. The diode is aligned in the direction to generate continuous current flow in the inductance and in the load. The number of parallel converters is inversely proportional to the height of the smallest attainable voltage level. The duty cycle of each stage is constant.    ADVANTAGE -   Apart from 12 V, another stabilised voltage level is given for high power-consuming loads.