Patent ID: 6219384
Filing Date: 2001-04-17
Classification: G06F,H03K,H04J,H04L

Abstract:
A circuit apparatus for determining a charge transfer time during which current flows in a line, comprising:a current mirror having a current sensing element for sensing current flow in said line and Producing an activation signal in response to said current flow, a first current source responsive to said activation signal for producing a charging current output, and a second current source responsive to said activation signal for producing a discharging current output;a storage capacitor, said first current source being coupled to said storage capacitor for charging said storage capacitor, said second current source being coupled to said storage capacitor via a voltage-controlled switch for discharging said storage capacitor;a voltage controlled delay element responsive to said storage capacitor and effective for applying a discharge disabling signal to said voltage-controlled switch a delay time period after the initiation of current flow in said line, said delay time period being proportional to the potential across said storage capacitor, said discharge disabling signal applied to said voltage-controlled switch being effective for disconnecting said second current source from said storage capacitor thereby preventing said discharging current output of said second current source from discharging said storage capacitor.