| 摘要 |
The variable lock-in circuits basically include a sensor, triggering transistors, current mirror, current source, an N-bit triggering circuit array, and a feedback line. If the sensing voltage does not reach the expected voltage compared to the midpoint voltage of the sensor, the output voltage of the sensor turns on the triggering transistors, which provide a total current to its output through the current mirror until the voltage at feedback reaches the midpoint voltage. The time to reach the midpoint voltage at a filter is simply equal to the charge stored at the filter divided by the total current, which is controlled by an N-bit digital input and a device aspect ratio of each triggering transistor. Consequently, all variable lock-in circuits provide an initial loop condition closer to the expected loop condition according to schedule.
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