US 5,703,472 A · Voltage regulator of vehicle alternator

Abstract

Voltage of a terminal at a high impedance is set to a fixed voltage (2.5 V) by a constant current source and a resistor, and whether the voltage of the terminal is a fixed voltage which is between 3.5 V and 5.5 V or not is detected by comparators and a NOR circuit. A control signal is sent from an ECU to the terminal to turn on a switching transistor to lower a divided voltage so that the alternator generates a high voltage only when the voltage of the terminal is the special voltage, and generates normal voltage otherwise. In case of disconnection of the communication line or grounding of the communication line, or when the battery voltage is applied to the communication line, the voltage of the terminal does not become abnormal voltage but become the normal voltage. Thus, abnormal voltage may not applied to the battery.

Claims13

Dependent claims

A voltage regulator for controlling a field current of a vehicle alternator which generates a battery charging voltage and a specific output voltage different from said battery charging voltage according to signal levels of an external control signal, said voltage regulator comprising:

an input terminal for receiving said external control signal;
means, connected to said input terminal, for setting a terminal voltage corresponding to said battery charging voltage if said external control signal is not received;
means, connected to said input terminal, for discriminating a specific signal level from said signal levels of said external control signal;
and
field current controlling means, connected to said voltage discriminating means, for controlling said field current of said alternator to generate said specific output voltage responsive to said discriminating means discriminating that said signal level of said external control signal at said input terminal has said specific signal level and to generate said battery charging voltage responsive to said discriminating means not discriminating that said signal level of said external control signal at said input terminal has said specific signal level.

2 more elements

A voltage regulator of for controlling a field current of a vehicle alternator which generates a plurality of output voltages for a plurality of electric loads including a battery according to a plurality of signal levels of an external control signal, said voltage regulator comprising:

an input terminal for receiving said external control signal;
means, connected to said input terminal, for setting a voltage of said input terminal to a fixed control voltage if no external control signal is received;
means, connected to said input terminal, for discriminating a fixed control voltage from voltages of said external control signal at said input terminal;
and
field current controlling means, connected to said voltage discriminating means, for controlling said field current of said alternator to generate a fixed output voltage responsive to said voltage of said input terminal being equal to said fixed control voltage, and controlling said field current so that said output voltage of said alternator becomes an output voltage other than said fixed output voltage responsive to said voltage of said input terminal being other than said fixed control voltage, wherein said field current controlling means controls said field current of said alternator to generate a first output voltage corresponding to a first electric load responsive to said voltage of said input terminal being other than said fixed control voltage, and controls said field current to generate an output voltage other than said first output voltage responsive to said voltage of said input terminal being equal to said fixed control voltage.

2 more elements

Dependencies are inferred from the claim text.

Voltage regulator of vehicle alternator

Life of this patent

Voltage regulator of vehicle alternator

Life of this patent

Abstract

Claims13