# US 9,520,871 B2 · Methods and apparatus for supply voltage transient protection for maintaining a state of a sensor output signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,871 B2 - Document ID: US9520871B2 - Status: Granted - Kind: B2 - Application number: 13/344,052 - Filed: 2012-01-05 - Published: 2013-07-11 - Granted: 2016-12-13 - Earliest claimed: 2012-01-05 - Assignees: Allegro MicroSystems, LLC - Applicants: Jeff Eagen; Devon Fernandez; P. Karl Scheller - Inventors: Jeff Eagen; Devon Fernandez; P. Karl Scheller - Web page: https://patentgrep.com/patent/US9520871B2 ## CPC - H03K 17/24: Storing the actual state when the supply voltage fails - H02M 1/32: Means for protecting converters other than automatic disconnection - H03K 17/94: characterised by the way in which the control signals are generated - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract Methods and apparatus for an integrated circuit that includes a supply voltage transient detection module to activate a hold signal that causes the output to remain in its present state. In one embodiment, the output remains in that state until the supply voltage returns to a normal operating range and the hold signal transitions to an inactive state. ## Claims ### Claim 1 A magnetic sensor in an IC package, comprising: a sensing element to sense magnetic field changes in response to movement of a target and generate a data signal corresponding to the movement of the target; a regulator voltage monitor module to receive a regulated output voltage and transition a first hold signal to an active state when the regulated output voltage drops below a first threshold and transition a second hold signal to an active state when the regulated output voltage drops below a second threshold; a signal processing module to receive the first hold signal from the regulator voltage monitor module and hold processing in a state corresponding to a time the first hold signal transitions to the active state; and an output module for outputting a sensor data output signal output from an output pin of the IC package, wherein the sensor data output signal corresponds to the data signal from the sensing element, the output module to receive the second hold signal from the regulator voltage monitor module and to maintain a state of the sensor data output signal at the time the second hold signal transitions to an active state, wherein the regulator voltage monitor is configured to generate a third hold signal for the output module to cause the output module to transition the output pin to a high impedance state, the third hold signal to transition to an active state when the regulator voltage drops below a third threshold lower than the first threshold. ### Claim 2 (depends on 1) The sensor according to claim 1, further including a regulator to provide the regulated output voltage. ### Claim 3 (depends on 1) The sensor according to claim 1, wherein the first hold signal remains in the active state until the regulated voltage signal rises above the first threshold. ### Claim 4 (depends on 1) The sensor according to claim 1, wherein the sensor resets when the regulated output voltage drops below a reset threshold voltage level. ### Claim 5 (depends on 1) The sensor according to claim 1, wherein the signal processing module includes at least one counter that does not change in value during a time in which the first hold signal is in the active state. ### Claim 6 A sensor in an IC package, comprising: a sensing element to sense magnetic field changes in response to movement of a target and generate a data signal corresponding to the movement of the target; a regulator voltage monitor means to receive a regulated output voltage and transition a first hold signal to an active state when the regulated output voltage drops below a first threshold and transition a second hold signal to an active state when the regulated output voltage drops below a second threshold; a signal processing means to receive the first hold signal from the regulator voltage monitor means and hold processing in a state corresponding to a time the first hold signal transitions to the active state; and an output means for outputting a sensor output signal output from the IC package, wherein the sensor output signal corresponds to the data signal from the sensing element, the output means to receive the second hold signal from the regulator voltage monitor means and to maintain a state of the sensor output signal at the time the second hold signal transitions to an active state, wherein the regulator voltage monitor means is configured to generate a third hold signal for the output means to cause the output means to transition the output pin to a high impedance state, the third hold signal to transition to an active state when the regulator voltage drops below a third threshold lower than the first threshold. ### Claim 7 (depends on 6) The sensor according to claim 6, wherein the output means comprises a switch. ### Claim 8 A method, comprising: receiving a regulated output voltage for a sensor in an IC package having a sensing element to sense magnetic field changes in response to movement of a target and generate a data signal corresponding to the movement of the target; transitioning a first hold signal to an active state when the regulated output voltage drops below a first threshold; transitioning a second hold signal to an active state when the regulated output voltage drops below a second threshold; receiving the first hold signal and holding signal processing in a state corresponding to a time at which the first hold signal transitioned to the active state; receiving the second hold signal; and outputting a sensor output signal from the IC package and maintaining a state of the sensor output signal present at the time at which the second hold signal transitioned to the active state, wherein the output signal corresponds to the data signal from the sensing element; generating a third hold signal to transition the sensor output signal to a high impedance state, the third hold signal to transition to an active state when the regulator voltage drops below a third threshold lower than the first threshold. ### Claim 9 (depends on 8) The method according to claim 8, wherein the first hold signal remains in the active state until the regulated voltage signal rises above the first threshold. ### Claim 10 (depends on 8) The method according to claim 8, wherein the sensor resets when the regulated output voltage drops below a reset threshold voltage level. ### Claim 11 (depends on 8) The method according to claim 8, wherein the signal processing includes at least one counter that does not change in value during a time in which the first hold signal is in the active state.