Caterpillar Inc.

Steven O Hart

Brian G McGee

Paul C Gottshall

Brian L Boggs

A driver for producing a desired pulse width modulated current through a load has a driver control for storing diagnostics codes in a diagnostic register responsive to detection of at least one electrical fault condition in a circuit including the load. A short circuit detection signal is generated in response a sensed current exceeding a programmed load current range for the driver, whereupon the driver control disables the load current and generates an interrupt signal to a microprocessor. Open circuits and shorts across the load are distinguished by way of a minimum current signal representative of a sensed current flowing through the load exceeding a predetermined minimum.

Fault detection for a pulse width modulation driver

A pulse width modulation driver provides programmable current control for a variety of load current ranges using a modulation feedback block. The block scales a signal representative of a sensed current flowing through the load by a selectable gain multiplier. The scaled signal is compared to a target current value to indicate to a driver control when to generate trigger signals for switching current through the load. In this way, load currents can be amplified to match the operational range of the comparator.

Pulse width modulation driver having programmable current control

A driver for producing a desired pulse width modulated current through a load is provided with a sequencer for generating a plurality of wave forms phase-shifted so as to have non-overlapping duty cycles. A target generator supplies a target current value to a comparator, which compares the target current value to a signal representative of a sensed current flowing through the load. A driver control is responsive to a duty-cycle of only one of the plurality of wave forms to selectively generate trigger signals for switching current through the load in response to the result of the comparison.

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Morton, IL, United States of America

Steven O Hart