公开(公告)号：JPH08304478A

公开(公告)日：1996-11-22

申请号：JP33207495

申请日：1995-12-20

Applicant: ADVANCED MICRO DEVICES INC

Inventor： JIEFURII JII BUREEMAA ,  KAARIN DORUU KABURAA

IPC: G01R19/165 ,  G05F3/30 ,  G10H1/18 ,  G10H7/02 ,  H03K19/00 ,  H03K19/0175

Abstract: PROBLEM TO BE SOLVED: To enhance the dynamic range performance of voice by sensing one of a plurality of power supply voltages to be employed and generating a logic level control signal being used for setting the analog reference voltage levels of A/D and D/A conversion circuits in a voice processing integrated circuit. SOLUTION: A VCCDET block 12 decides whether a voice processing integrated circuit or chip is operating in a 5.0V system or a 3.3V system and sets a digital control signal 5 at logic '1' or '0' level. The control signal 5 has effect on the output signal from a hand cap circuit 22 because the hand cap circuit 22 operates with reference to the output signal from an ARFGEN block 14 and the reference voltage depends on the state of control signal 5. The control signal 5 is fed through a TRIMDS block 18 to a sigma delta A/D conversion circuit 38 and D/A conversion circuit 40 as an analog reference voltage thus producing highest dynamic range and voice performance.