Patent ID: 7256724
Filing Date: 2007-08-14
Classification: H04N

Abstract:
1. An image sensor comprising: an image sensing element which converts incident light into an analogue signal; a voltage generator which includes a variable resistor circuit and which generates a ramping voltage, wherein a slope of the ramping voltage is variable and corresponds a resistance value of the variable resistor circuit; a converter which converts a voltage of the analogue signal into a digital signal using the ramping voltage generated by the voltage generator; and a controller which controls the resistance value of the variable resistance circuit; wherein a slope of the ramping voltage is linear, and wherein the voltage generator further includes an operational amplifier including an input connected to the variable resistance circuit, and a capacitor connected across the input and an output of the operational amplifier, and wherein the variable resistance circuit comprises: a nonvolatile storage unit which stores a first address in response to a first control signal; an address selector which selectively outputs the first address from the nonvolatile storage unit or a second address from the controller in response to a second control signal; a variable resistor chain coupled between an input terminal of the voltage generator and the input of the operational amplifier; and a resistance adjustor which sets a resistance value of the variable resistor chain in accordance with the output from the address selector.