Patent ID: 7573451
Filing Date: 2009-08-11
Classification: G09G

Abstract:
1. A sample hold circuit for sampling an input potential, holding the sampled potential and outputting the same, comprising: a first switching element receiving said input potential on one of its electrodes, and being turned on for a first period; a second switching element connected at one of its electrodes to the other electrode of said first switching element, and being turned on for a second period; a capacitor connected at one of its electrodes to the other electrode of said second switching element, and receiving on the other electrode a predetermined potential; and a drive circuit having an input node connected to the other electrode of said second switching element and an output node connected to the other electrode of said first switching element, and providing a potential corresponding to a potential of said input node to the output node, wherein said drive circuit includes: a first current limiting element receiving a first power supply potential on one of its electrodes, a first transistor of a first conductivity type having a first electrode and an input node connected to the other electrode of said first current limiting element, a second transistor of a second conductivity type having a first electrode connected to the second electrode of said first transistor, a second electrode receiving a second power supply potential and an input electrode receiving an potential of said input node, a third transistor of the first conductivity type having a first electrode receiving a third power supply potential, and an input electrode connected to the other electrode of said first current limiting element, and a fourth transistor of the second conductivity type having a first electrode connected to the second electrode of said third transistor, and having a second electrode and an input electrode connected to said output node.