| 摘要 |
PROBLEM TO BE SOLVED: To provide a charge amplification circuit that produces a stable output even if a capacitance value varies owing to a process variation.SOLUTION: The charge amplification circuit formed on a semiconductor substrate 1 includes: an operational amplifier 2; a capacitive element 3 connected in parallel with the operational amplifier 2; a reset switch 4 connected in parallel with the operational amplifier 2 and the capacitive element 3; and a CR oscillation circuit 5 for generating a clock signal to control the reset switch 4. The oscillation circuit using a capacitance formed by the same process and on the same semiconductor substrate as a storage capacitance is a clock source for generating a signal to control charging/discharging of the storage capacitance to whereby cancel an output variation due to a change in the storage capacitance with a charging time change and suppress an output variation due to a process variation. |
