Abnormal clock rate detection in imaging sensor arrays
First Claim
1. A device comprising:
- a counter configured to receive a clock signal and adjust a count value in response to the clock signal;
a ramp generator configured to generate a ramp signal;
a first comparator configured to receive a reference signal via a first input and the ramp signal via a second input, and select a first count value of the counter at a first time in response to the reference signal and the ramp signal;
a temperature sensor configured to detect a temperature associated with the device and provide a temperature-dependent analog signal;
a second comparator configured to receive the temperature-dependent analog signal and the ramp signal, and select a second count value of the counter at a second time in response to the temperature-dependent analog signal and the ramp signal; and
a processor configured to determine a predetermined range for the detected temperature based on the second count value such that a maximum of the predetermined range used by the processor decreases as a frequency of the clock signal increases, and determine if the frequency of the clock signal is within a specified range based on whether the first count value is within the predetermined range for the detected temperature.
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Accused Products
Abstract
Various techniques are provided to detect abnormal clock rates in devices such as imaging sensor devices (e.g., infrared and/or visible light imaging devices). In one example, a device may include a clock rate detection circuit that may be readily integrated as part of the device to provide effective detection of an abnormal clock rate. The device may include a ramp generator, a counter, and/or other components which may already be implemented as part of the device. The ramp generator may generate a ramp signal independent of a clock signal provided to the device, while the counter may increment or decrement a count value in response to the clock signal. The device may include a comparator adapted to select a current count value of the counter when the ramp signal reaches a reference signal. A processor of the device may be adapted to determine whether the clock signal is operating in an acceptable frequency range, based on the selected count value.
26 Citations
16 Claims
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1. A device comprising:
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a counter configured to receive a clock signal and adjust a count value in response to the clock signal; a ramp generator configured to generate a ramp signal; a first comparator configured to receive a reference signal via a first input and the ramp signal via a second input, and select a first count value of the counter at a first time in response to the reference signal and the ramp signal; a temperature sensor configured to detect a temperature associated with the device and provide a temperature-dependent analog signal; a second comparator configured to receive the temperature-dependent analog signal and the ramp signal, and select a second count value of the counter at a second time in response to the temperature-dependent analog signal and the ramp signal; and a processor configured to determine a predetermined range for the detected temperature based on the second count value such that a maximum of the predetermined range used by the processor decreases as a frequency of the clock signal increases, and determine if the frequency of the clock signal is within a specified range based on whether the first count value is within the predetermined range for the detected temperature. - View Dependent Claims (2, 3, 4, 5, 11, 12, 13)
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6. A method comprising:
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adjusting a count value in response to a clock signal, wherein the clock signal is provided to a device; generating a ramp signal; comparing the ramp signal with a reference signal; selecting a first count value of the count value at a first time in response to the comparing of the ramp signal with the reference signal; and detecting a temperature associated with the device; providing a temperature-dependent analog signal indicative of the temperature associated with the device; comparing the ramp signal with the temperature-dependent analog signal; selecting a second count value of the count value at a second time in response to the comparing of the ramp signal with the temperature-dependent analog signal; determining a predetermined range for the detected temperature based on the second count value such that a maximum of the predetermined range for the detected temperature decreases as a frequency of the clock signal increases; and determining if the frequency of the clock signal is within a specified range based on whether the first count value is within the predetermined range for the detected temperature. - View Dependent Claims (7, 8, 9, 10, 14, 15, 16)
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Specification