Field disconnect and indicator circuit for a vehicle charging system

Claim 2

In a charging system for a vehicle battery having a positive terminal and a negative terminal the negative terminal being connected to a point of reference potential, an ignition switch one side of which is connected to said positive terminal and the other side of which is connected to an indicator lamp, a plural phase full wave rectifier connected across said battery, an alternating current generator having a plurality of output windings each of which is connected to a different phase of said rectifier, and a field winding; a semiconductor field disconnect and indicator circuit comprising: a. a first transistor connected to said ignition switch through said indicator lamp and adapted to be rendered conductive upon closure of said switch; b. a second transistor connected with said first transistor and connected in parallel with said lamp between said positive terminal and said field winding, said second transistor being biased conductive by said first transistor upon closure of said ignition switch; c. a third transistor responsive to the voltage at said output windings and connected between said indicator lamp and said point of reference potential, said third transistor being biased conductive when said voltage at said output windings is less than a predetermined value and nonconductive when said generator output voltage is above said predetermined value whereby said indicator lamp is energized when said ignition switch is closed and the voltage at said output windings is less than said predetermined value; and d. impedance means connected in series with said third transistor and establishing a voltage drop for maintaining said first transistor conductive during energization of said indicator lamp.

Claim 3

In a charging system for a vehicle battery having a positive terminal and a negative terminal the negative terminal being connected to a point of reference potential, an ignition switch one side of which is connected to said positive terminal and the other side of which is connected to an indicator lamp, a plural phase full wave rectifier connected across said battery, an alternating current generator having a plurality of output windings each of which is connected to a different phase of said rectifier, and a field winding; a semiconductor field disconnect and indicator circuit comprising: a. a conductor connected to the other side of said indicator lamp; b. a first transistor connected to said ignition switch through said indicator lamp and adapted to be rendered conductive upon closure of said switch; c. a second transistor connected with said first transistor and connected in parallel with said lamp between said positive terminal and said field winding, said second transistor being biased conductive by said first transistor upon closure of said ignition switch; d. a regulator connected to said positive terminal through said second tRansistor to sense the voltage at said positive terminal and control the current through said field winding in accordance with the sensed voltage; e. a third transistor responsive to the voltage at said output windings and connected between said indicator lamp and said point of reference potential, said third transistor being biased conductive when said voltage at said output windings is less than a predetermined value and nonconductive when said generator output voltage is above said predetermined value whereby said indicator lamp is energized when said ignition switch is closed and the voltage at said output windings is less than said predetermined value; and f. a unidirectional current conducting device connected in series with said third transistor and establishing a voltage drop for maintaining said first transistor conductive during energization of said indicator lamp.

Claim 4

In a charging system for a vehicle battery having a positive terminal and a negative terminal the negative terminal being connected to a point of reference potential, an ignition switch one side of which is connected to said positive terminal and the other side of which is connected to an indicator lamp, a plural phase full wave rectifier connected across said battery, an alternating current generator having a plurality of output windings each of which is connected to a different phase of said rectifier, and a field winding; a semiconductor field disconnect and indicator circuit comprising: a. a conductor connected to the other side of said indicator lamp; b. a first transistor connected to said ignition switch through said indicator lamp and adapted to be rendered conductive upon closure of said switch; c. a second transistor connected with said first transistor and connected in parallel with said lamp between said positive terminal and said field winding, said second transistor being biased conductive by said first transistor upon closure of said ignition switch; d. a regulator connected to said positive terminal through said second tRansistor to sense the voltage at said positive terminal and control the current through said field winding in accordance with the sensed voltage; e. a third transistor responsive to the voltage at said output windings and connected between said indicator lamp and said point of reference potential, said third transistor being biased conductive when said voltage at said output windings is less than a predetermined value and nonconductive when said generator output voltage is above said predetermined value whereby said indicator lamp is energized when said ignition switch is closed and the voltage at said output windings is less than said predetermined value; and f. a unidirectional current conducting device connected in series with said third transistor and establishing a voltage drop for maintaining said first transistor conductive during energization of said indicator lamp.

Claim 5

In a charging system for the battery of a vehicle, first and second load conductors connected respectively to the positive and negative terminals of the battery, an ignition switch one side of which is connected to said first load conductor and the other side of which is connected to one side of an indicator lamp, a three phase full-wave rectifier connected to said first and second load conductors, an alternating current generator having a three phase output winding connected to said rectifier, a regulator having an input and an output terminal, a field winding connected to said input and output terminals of said regulator, and an improved indicator and field disconnect circuit comprising: a. a first semiconductor switch the control electrode of which is connected to the other side of said indicator lamp and the input and output electrodes of which are connected respectively to said first and second load conductors, said first switch being biased conductive by the closure of said ignition switch; b. a second semiconductor switch the control electrode of which is connected to the input electrode of said first semiconductor switch and the input and output electrodes of which are connected respectively to said first load conductor and said input terminal of said regulator, said second switch being biased conductive when said first switch is biased conductive; and c. a third semiconductor switch the control electrode of which is connected to said output and the input and output electrodes of which are connected respectively to the other side of said indicator lamp and to said second load conductor, said third switch being biased conductive when said voltage at said output winding is less than a predetermined value and nonconductive when said voltage is above said value, whereby said indicator lamp is energized when said ignition switch is closed and the voltage at said output winding is less than said predetermined value while said first and second semiconductor switches are rendered conductive.

Claim 6

In a charging system for the battery of a vehicle, first and second load conductors connected respectively to the positive and negative terminals of the battery, an ignition switch one side of which is connected to said first load conductor and the other side of which is connected to one side of an indicator lamp, a three phase full-wave rectifier connected to said first and second load conductors, an alternating current generator having a three phase output winding connected to said rectifier, a regulator having an input and an output terminal, a field winding connected to said input and output terminals of said regulator, and an improved indicator and field disconnect circuit comprising: a. a first semiconductor switch the control electrode of which is connected to the other side of said indicator lamp and the input and output electrodes of which are connected respectively to said first and second load conductors, said first switch being biased conductive by the closure of said ignition switch; b. a second semiconductor switch the control electrode of which is connected to the input electrode of said first semiconductor switch and the input and output electrodes of which are connected respectively to said first load conductor and said input terminal of said regulator, said second switch being biased conductive when said first switch is biased conductive; and c. a third semiconductor switch the control electrode of which is connected to said output and the input and output electrodes of which are connected respectively to the other side of said indicator lamp and to said second load conductor, said third switch being biased conductive when said voltage at said output winding is less than a predetermined value and nonconductive when said voltage is above said value, whereby said indicator lamp is energized when said ignition switch is closed and the voltage at said output winding is less than said predetermined value while said first and second semiconductor switches are rendered conductive.