Allegro Microsystems, LLC

Thomas J Kovalcik

Paul W Latham, Ii

Glenn A Forrest

Wei Zhang

Christian Feucht

A sensor integrated circuit including a regulator for generating a regulated voltage includes a digital load configured to draw a load current from the regulator in response to a clock signal during in situ operation and a comparator configured to determine the absence or presence of a fault during in situ operation. The load current is less than or equal to a predetermined level in the absence of a fault and is greater than the predetermined level in the presence of a fault. The comparator is responsive to the load current and to a threshold level and is configured to generate a comparator output signal having a level indicative of whether the load current is less than or greater than the threshold level in order to thereby determine the absence or presence of a fault during in situ operation, respectively.

Sensor integrated circuit load current monitoring circuitry and associated methods

Apparatuses, systems, and methods that provide a delayed output signal with reduced sampling error are described. Embodiments include a clock circuit that generates a sample clock signal having a predetermined sample clock period. A sampling circuit may generate samples of a received signal during each sample clock period. An interpolation circuit may estimate a value of the received signal at times between the samples of the received signal based on at least a first sample and a second sample of the received signal. The interpolation circuit may estimate a time that the received signal crosses a threshold, and determine a time delta between the first sample and the estimated time that the received signal crosses the threshold. A delay circuit to generate a time delay substantially equal to the time delta is also included. An output signal changes state after the generated time delay.

Magnetic field sensor with delayed output

An integrated circuit chip includes a MOS driver transistor and a relatively small MOS current-monitor transistor having their sources connected to a circuit ground point and their gates connected together to a control-voltage conductor. Current through the monitor transistor flows to a DC voltage supply conductor through a field effect transistor. A differential amplifier has one input connected to the drain of the driver transistor and the other input connected to the drain of the monitor transistor. The output of the differential amplifier is connected to the gate of the field effect transistor to force the drain voltage of the monitor transistor to be equal to the drain voltage of the driver transistor. The current flowing through the small monitor transistor has a constant proportionality with the load current even as the load current approaches zero. With the addition of a differential voltage amplifier having an output connected to the control-voltage conductor, having one input connected to a circuit ground point, and the other input connected to a control-current input pad, the current from the monitor transistor is fedback via a current mirror circuit to the other input of the voltage amplifier, so that the entire circuit can be made to perform as a current amplifier, e.g. driver-load-current/input-control current. By connecting one end of an external precision resistor to the control-current-input pad of the chip and applying a control voltage to the opposite end of the precision resistor, a control current proportional to the control voltage is caused to flow through the control-circuit-input pad. The combination performs as a current amplifier.

Load current monitor for MOS driver

An amplifier has a first stage employing a pair of differentially connected NMOS amplifier transistors, a second stage composed of a bipolar current mirror circuit and two charge pumps. Each charge pump may be a switching voltage multiplier circuit without the conventional output capacitor. The outputs of the two charge pumps are connected, respectively, to the collector of the current-mirror output transistor and to the commonly connected sources of the NMOS amplifier transistors. Each charge pump serves as both a pulse-voltage energizing source and a load to the amplifier. The amplifier is incorporated with a high-current NMOS transistor in an integrated circuit, wherein one differential input of the amplifier is connected to the source of the driver transistor at which an external load, e.g. a motor, may be connected. The output (collector) of the differential amplifier is connected to the gate of the NMOS driver transistor so that the load current through the driver transistor is held regulated to a value proportional to the input or reference voltage that is applied to the other input of the differential amplifier. The peak pulse voltage of each charge pump is greater than the DC supply voltage from which the driver transistor and the two charge pumps are energized so that the dynamic range of both the input control voltage and the amplifier output to the gate of the NMOS driver transistor is much greater than the DC supply voltage to the integrated circuit.

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Barrington, NH, United States of America

Thomas J Kovalcik