Control apparatus for automotive generator
First Claim
1. A control apparatus for controlling an automotive generator, said control apparatus comprising:
- a field coil to which a DC output voltage of the automotive generator is supplied;
a switching device connected in series with said field coil, whereby switching on/off operation of said switching device controls a field current flowing through said field coil;
a diode connected in parallel with said field coil for recirculating the field current flowing through said field coil when said switching device is in an OFF state;
a field current detector for outputting a voltage generated by a detecting device which is connected in series with said switching device as an analog field current detection value;
an A/D conversion device for converting the analog field current detection value detected by said field current detector into a digital value and outputting said digital value to an external control unit; and
a voltage control circuit for outputting an ON/OFF drive signal to said switching device such that the DC output voltage of the automotive generator follows a specific reference voltage by PWM control operation performed at recurring cycles;
wherein said A/D conversion device includes;
a counter;
a D/A converter for converting a digital output of said counter into an analog value;
a comparator for comparing an output of said D/A converter and the analog field current detection value;
a counter control circuit for controlling said counter according to an output of said comparator such that said counter counts up when the output of said D/A converter is less than the analog field current detection value;
reset means for resetting the output of said counter at a point in time immediately following a rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles; and
transfer means for transferring the output value of said counter to said external control unit at a point in time immediately preceding the rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles.
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Accused Products
Abstract
An A/D conversion device includes a counter for counting a clock signal fed from a clock signal generator, a D/A converter for converting a digital output of the counter into an analog value, a comparator for comparing an analog output of the D/A converter and an analog field current detection value fed from a current detecting resistor and outputting a result of comparison, an AND circuit for calculating a logical product of an output signal of the comparator and the clock signal fed from the clock signal generator and outputting the logical product to the counter, and a memory for storing the output of the counter according to a transfer signal. The output of the counter is reset when a reset signal is input thereinto.
30 Citations
7 Claims
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1. A control apparatus for controlling an automotive generator, said control apparatus comprising:
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a field coil to which a DC output voltage of the automotive generator is supplied; a switching device connected in series with said field coil, whereby switching on/off operation of said switching device controls a field current flowing through said field coil; a diode connected in parallel with said field coil for recirculating the field current flowing through said field coil when said switching device is in an OFF state; a field current detector for outputting a voltage generated by a detecting device which is connected in series with said switching device as an analog field current detection value; an A/D conversion device for converting the analog field current detection value detected by said field current detector into a digital value and outputting said digital value to an external control unit; and a voltage control circuit for outputting an ON/OFF drive signal to said switching device such that the DC output voltage of the automotive generator follows a specific reference voltage by PWM control operation performed at recurring cycles; wherein said A/D conversion device includes; a counter; a D/A converter for converting a digital output of said counter into an analog value; a comparator for comparing an output of said D/A converter and the analog field current detection value; a counter control circuit for controlling said counter according to an output of said comparator such that said counter counts up when the output of said D/A converter is less than the analog field current detection value; reset means for resetting the output of said counter at a point in time immediately following a rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles; and transfer means for transferring the output value of said counter to said external control unit at a point in time immediately preceding the rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles. - View Dependent Claims (4, 5)
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2. A control apparatus for controlling an automotive generator, said control apparatus comprising:
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a field coil to which a DC output voltage of the automotive generator is supplied; a switching device connected in series with said field coil, whereby switching on/off operation of said switching device controls a field current flowing through said field coil; a diode connected in parallel with said field coil for recirculating the field current flowing through said field coil when said switching device is in an OFF state; a field current detector for outputting a voltage generated by a detecting device which is connected in series with said switching device as an analog field current detection value; an A/D conversion device for converting the analog field current detection value detected by said field current detector into a digital value; a current limit value memory for storing a specific current limit value in digital form; a voltage control circuit for outputting an ON/OFF drive signal to said switching device such that the DC output voltage of the automotive generator follows a specific reference voltage by PWM control operation performed at recurring cycles; and a current limiter to which an output of said A/D conversion device and the current limit value are input, whereby said current limiter turns off said switching device when the output value of said A/D conversion device exceeds the current limit value regardless of the ON/OFF drive signal; wherein said A/D conversion device includes; a counter; a D/A converter for converting a digital output of said counter into an analog value; a comparator for comparing an output of said D/A converter and the analog field current detection value; a counter control circuit for controlling said counter according to an output of said comparator such that said counter counts up when the output of said D/A converter is less than the analog field current detection value; reset means for resetting the output of said counter at a point in time immediately following a rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles; and transfer means for transferring the output value of said counter to said current limiter at a point in time immediately preceding the rising edge of said ON/OFF drive signal at intervals of a specific number of PWM control operation cycles. - View Dependent Claims (3, 6, 7)
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Specification