Patent ID: 7362128
Filing Date: 2008-04-22
Classification: H03K

Abstract:
1. A programmable impedance control circuit for use in a semiconductor device, the circuit comprising: an impedance detector, which includes a first array driver responding to control code data for an impedance control, a second array driver responding to range shifting data for an impedance range shifting, an impedance matching transistor array and a range shifting transistor array controlled by the first and second array drivers; a comparator for comparing first and second output voltage levels of the impedance detector with an array reference voltage, and outputting an up/down signal as the comparison result; a counter for performing an up/down counting in response to the up/down signal, and outputting control code data for turning on or off transistors of the impedance matching transistor array; and a range shifting circuit for monitoring a counting output of the counter, generating the range shifting data when an impedance locking is failed, and applying the range shifting data to the second array driver of the impedance detector.