| 摘要 |
<p>- Frequency synthesizer using a current mirror of which one control branch - transistor (T1), resistor (11) - is powered by a control current source (S) operating in switching mode. - An improvement in the fall time of the mirror is obtained by adding an additional transistor (TA) connected in parallel with the transistor (T1), whose base is biased to a fixed voltage (VA) chosen such that this transistor (TA) is practically turned off when the control current source (S) delivers a nominal current, and is turned on when the control current is cancelled. The additional transistor (TA) is equipped with an anti-saturation device, for example a Schottky diode (18), when a bipolar transistor is used, but it can also be replaced by a field-effect transistor. <IMAGE></p> |
