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US 8,134,402 B1Granted
Apparatus and method for powering up with hysteresis inactive
AssigneeNational Semiconductor Corporation
InventorPerry Scott Lorenz
Life of this patent
Estimating the term…
Abstract
A temperature-sensor circuit is provided. The temperature-sensor circuit may be configured such that an output of the temperature-sensor circuit trips when a specified temperature is reached. The temperature-sensor circuit may also be configured to trigger hysteresis if the specified temperature is reached. Additionally, the temperature-sensor circuit may be configured for powering up with hysteresis disabled. However, after the completion of a settling period, the hysteresis is enabled for triggering based on the temperature.
Claims34
A circuit for temperature sensing, comprising:
- a comparator circuit that is arranged to provide a trigger signal by comparing a reference signal to a temperature sensor signal;
- a power-on-reset generator that is arranged to provide a power-on reset signal;
- a gate circuit that is arranged to provide an output signal by gating a gate input signal subject to control by a gate control signal, wherein the gate input signal is based at least in part on the trigger signal, and wherein the gate control signal is based at least in part on the power-on-reset signal;
- and
- a hysteresis-and-output-sensor circuit that is configured to control the reference signal in response to a sensed signal, wherein the sensed signal is based at least in part on the output signal, and wherein the hysteresis-and-output sensor circuit is arranged to disable a hysteresis at power up, wherein the comparison of the reference signal to the temperature signal made by the comparison circuit is a temperature comparison in which a determination is made as to whether a temperature has reached a predetermined level, wherein the predetermined level is modified by a predetermined amount when hysteresis is enabled.
2 more elements
A method for temperature sensing, comprising:
- employing a circuit to activate hysteresis if a temperature-sensing condition has occurred;
- and
- ensuring that the hysteresis is automatically inactive when the circuit is powering up, wherein the temperature-sensing condition is a temperature comparison in which a determination is made as to whether a temperature has reached a predetermined level, wherein the predetermined level is modified by a predetermined amount when hysteresis is enabled.
A circuit for temperature sensing, comprising:
- means for activating hysteresis if a temperature-sensing condition has occurred;
- and
- means for ensuring that the hysteresis is automatically inactive when the means for activating hysteresis is powering up, wherein the temperature-sensing condition is a temperature comparison in which a determination is made as to whether a temperature has reached a predetermined level, wherein the predetermined level is modified by a predetermined amount when hysteresis is enabled.
A circuit for temperature sensing, comprising:
- a comparator circuit that is arranged to provide a trigger signal by comparing a reference signal to a temperature sensor signal;
- a gate circuit that is arranged to provide an output signal by gating a gate input signal subject to control by a gate control signal, wherein the gate input signal is based at least in part on the trigger signal, and wherein the gate control signal is based at least in part on a power-on-reset signal;
- a hysteresis-and-output-sensor circuit that is configured to control the reference signal in response to a sensed signal, wherein the sensed signal is based at least in part on the output signal;
- and
- a temperature sensor signal generation circuit, wherein the temperature sensor signal generation circuit is arranged to provide the temperature sensor signal such that the temperature sensor signal is indicative of a temperature, wherein the comparison of the reference signal to the temperature signal made by the comparator circuit is a temperature comparison in which a determination is made as to whether a temperature has reached a predetermined level, wherein the predetermined level is modified by a predetermined amount when hysteresis is enabled.
2 more elements
Dependencies are inferred from the claim text.