| 摘要 |
PURPOSE:To shorten the D/A converting time by setting the setting value and then performing the converting action with the value approximate to the analog amount to be converted and on the basis of the setting value. CONSTITUTION:With application of the start pulse to terminal 32, the contents of setting circuit 33, i.e., target value Vo is preset to counter 31 and then converted 34 into the analog signal. The analog signal is then supplied to comparator 18 to be compared with input signal Vi sent from terminal 16. And in case signal Vi is larger than Vo, gate 27 is opened. Then the signals are added to value Vo at counter 31 after passing through gate 27. And when the output of terminal 17 becomes larger than signal Vi, comparator 18 is inverted to close gate 27. Then the signal of counter 31 is used for the A/D conversion output. In the same way, the conversion output is obtained via AND gate 28 when signal Vi is small to the analog output of target value Vo which is preset to counter 31. In this way, the converting action is secured with the value approximate to the analog amount to be converted, thus shortening the converting time. |
