Unity gain positive feedback integrator with programmable charging currents and polarities
 An integrator includes a capacitor and a bootstrap circuit for detecting any leaking charge from the capacitor and replacing it. The integrator also includes a charge injection circuit for adjusting the charge applied to the capacitor in response to a digital control input to the charge injection circuit. The bootstrap circuit has two transistors to sense leaking charge, and two further transistors forming a differential pair. The bootstrap circuit uses positive feedback and unity gain to replenish the lost charge. 
Hewlett-Packard Company
G
G06G
inventional
Benny W. H. Richard C.
Lai Walker