| 摘要 |
A comparator circuit for operation at video rate signals includes input switches (22,12) to alternately couple a reference (VRX) and a signal (VIN) potential to a summing capacitor (24). The capacitor (24) is coupled to the input (gate P13) of a first inverting amplifier (A1). The amplifier includes a switch (26) between input and output (gate N33) terminals for selectively autozeroing the amplifier. The amplifier is direct coupled to the input (gate N33) of a second inverting amplifier (A2) having an autozero circuit (28) exclusive of a connection to the input of the second amplifier. Timing circuitry for controlling the autozero function is arranged to minimize the effects of clocking transients upsetting the autozeroed potentials thereby reducing the response time and enhancing the sensitivity of the comparator. |
