| 摘要 |
<p>A linear ramp generating and control circuit (10) finding particular applicability in a time interval measurement system. The linear ramp circuit includes a hold capacitor (58) which may be linearly discharged during one operating mode of the circuit by coupling a constant current source (26) to the capacitor (58). The voltage on the hold capacitor (58) is linearly discharged away from a baseline voltage level to a data voltage level which is subsequently passed to an analog-to-digital converter. The hold capacitor voltage is returned to the baseline voltage level during a recovery mode of circuit operation by a recovery or a recharge network (28). The recharge network (28) may include an active-feedback circuit which implements an approximately second order voltage response to the hold capacitor (58) during the recovery mode of operation. The circuit may also include a composite amplifier (124) for buffering the hold capacitor voltage level to a circuit output during a hold mode of circuit operation. The effect of this invention is that the errors such as drift, signal noise, and baseline voltage instability can be minimized.</p> |
