Matsushita Electric Industrial Co., Ltd.

Isao Ihara

Takeshi Fujita

Yoshiaki Sone

Shinichi Tashiro

A counter circuit includes counting stages of n bits where n is a natural number. The counter circuit also includes a logic decoding circuit for determining the inputs of the counting stages, a logic circuit for adjusting the number of simultaneous changes so that the number of simultaneous changes of the logic decoding circuit can be made uniform, and a logic circuit for adjusting the load capacitance of the counting stages so that the load capacitance can be made uniform. The counter circuit may also include a test logic circuit for creating a test wave form on the basis of the outputs from the logic circuits for adjusting the number of simultaneous changes and the logic circuits for adjusting the load capacitance. Accordingly, it is possible to detect a failure of the logic circuits for adjusting the number of simultaneous changes and the logic circuits for adjusting the load capacitance which does not effect the counting output.

Driving circuit for solid-state image sensor and counter circuit used

A counter circuit which incurs a uniform number of logic changes whether the clock signal is rising or falling is used in both a first counter circuit for measuring the reference signal for horizontal scanning period and a second counter circuit for measuring signals in the vertical blanking period. Since the number of logic changes of the flip-flops with respect to the clock signal is uniform, a driving circuit for a solid-state image sensor is realized in which noise in the vertical blanking period does not appear in the video period even if by using 1H delay line.

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Takatsuki, Japan

Isao Ihara