Patent ID: 7126512

Claim:
A machine for time-to-threshold analog-to-digital conversion in a digital imaging system, comprising: a. a first photodetector having a first photodetector output b. a threshold detector having a first analog input and a first digital output, said threshold detector comprising: i. a first transistor having a first gate, said first transistor being an n-type MOS transistor 1. said first transistor having a first transistor drain 2. said first transistor having a first transistor source, said first transistor source being directly connected to a first power supply rail ii. a second transistor having a second gate, said second transistor being a p-type MOS transistor 1. said second transistor having a second transistor drain, said second transistor drain being directly connected to a second power supply rail, said first power supply rail having a more positive potential than said second power supply rail 2. said second transistor having a second transistor source, said second transistor source being directly connected to said first transistor drain iii. means for applying said first analog input to said first gate and to said second gate c. means for applying said first photodetector output as said first analog input.