Abstract: Methods of verifying a property of a hardware design for an integrated circuit to implement a product of power functions of the form x0t0× . . . ×xntn, wherein t0 . . . tn are fixed, rational numbers, x0 . . . xn are floating point inputs, and n is an integer greater than or equal to one. A first verification phase comprises formally verifying that, for any first non-exception input set X=X0, . . . , Xn and any second non-exception input set Y=Y0, . . . , Yn in an input space wherein corresponding inputs have a same mantissa and (t0X0.exp+ . . . +tnXn.exp)?(t0Y0.exp+ . . . +tnYn.exp) is an integer, an instantiation of the hardware design generates outputs X? and Y? with a same mantissa and X?exp?(t0X0.exp+ . . . +tnXn.exp)=Y?exp?(t0Y0.exp+ . . . +tnYn.exp); and second verification phase comprises verifying the property for the hardware design for a subset of input sets in the input space, the subset of input sets selected based on exponents sets wherein (t0X0.exp+ . . . +tnXn.exp)?(t0Y0.exp+ . . . +tnYn.

Abstract: An image sensor includes a pixel array, and a correlated double sample circuit coupled to one of the pixels in the pixel array. The correlated double sample circuit includes first and second inputs, and first and second sample capacitors respectively coupled to the first and second inputs. The first input is for receiving an analog signal from a pixel, and the second input is for receiving a time varying reference signal. The analog signal varies during a pixel readout period, and has a first level during a first reset period and a second-level during a second read period. A comparator circuit compares the time varying reference signal and the analog signal. The analog signal and the time varying reference signal are constantly read onto one of the first and second sample capacitors during both the first reset period and the second read period.

Abstract: An image sensor includes a pixel array, and a correlated double sample circuit coupled to one of the pixels in the pixel array. The correlated double sample circuit includes first and second inputs, and first and second sample capacitors respectively coupled to the first and second inputs. The first input is for receiving an analog signal from a pixel, and the second input is for receiving a time varying reference signal. The analog signal varies during a pixel readout period, and has a first level during a first reset period and a second-level during a second read period. A comparator circuit compares the time varying reference signal and the analog signal. The analog signal and the time varying reference signal are constantly read onto one of the first and second sample capacitors during both the first reset period and the second read period.