Patent ID: 8436677
Filing Date: 2013-05-07
Classification: G11C,H03M

Abstract:
1. A circuit for a reference voltage generator, the circuit comprising: a first capacitor; an analog to digital converter having its voltage reference coupled to the first capacitor, wherein the first capacitor supplies the voltage reference to the analog to digital converter; a control loop, configured to resupply charges to the first capacitor that are lost when the first capacitor supplies the voltage reference to the analog to digital converter, the control loop comprises: a second capacitor connected to a comparator in which the comparator causes the second capacitor to charge the first capacitor in response to the comparator determining that the voltage reference is less than a main voltage; output of the comparator coupled to gates of a first transistor and a second transistor; a source of the first transistor coupled to a voltage source; a drain of the first transistor coupled to the second capacitor and coupled to a drain of the second transistor; and a source of the second transistor coupled to the first capacitor at the junction of the voltage reference; the second capacitor electrically connected to the first capacitor through the second transistor to charge the first capacitor when the second transistor is turned on by the comparator.