sergey23 0 January 23 Posted January 23 · Report post There is a PI controller with certain AC behavior. I need to use this PI controller in order to drive a coil (current controlled oscillator) of 1.5 µH inductance. For DC behavior at 10 mV input I need 50 mA current on the coil at most. PI controller has proportional and integrator property. How can I convert this behavior into a driver circuit? Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 24 Posted January 24 · Report post UPDATE: I have tried to drive the inductor threw NPN. How do i connect it to the Integrator? Thanks. Quote Share this post Link to post Share on other sites More sharing options...
mackapp 1 January 24 Posted January 24 · Report post Что именно вы с индуктивностью делать собираетесь? Формировать ток в ней? Напряжение на выводах? Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 24 Posted January 24 (edited) · Report post Hello Mackapp,I can write in russian but i will have lots of errors before I will write as I hear because I am only speaking russian. The inductor threw which the current will flow controlles frequency (Its a current controlled oscilator which called YIG) 20mA threw the inductor will give me 5MHz . I want to convert the AC voltage behavior of the original PI into current.I dont know what is the best configuration to do it? I though of using NPN transistor somehow as shown below. What do you reccomend? Thanks. Edited January 24 by sergey23 Quote Share this post Link to post Share on other sites More sharing options...
1113 14 January 26 Posted January 26 · Report post On 1/24/2025 at 12:44 PM, mackapp said: Что именно вы с индуктивностью делать собираетесь? Формировать ток в ней? Напряжение на выводах? я так понимаю у него есть какая-то нагрузка, которая физически ведет себя как индуктивность. он хочет загонять в нее ток http://www.vhfcomm.co.uk/A Simple Approach tyo YIG Oscil.pdf sergey23, as you can see, for YIG operation you need simple DC power supply Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 27 Posted January 27 (edited) · Report post Hello 1113, yes I understand ,but i need tp build a PI sort of driver. could you help with the circuit I am trying to assemble? Thanks. Edited January 27 by sergey23 Quote Share this post Link to post Share on other sites More sharing options...
rloc 78 January 27 Posted January 27 · Report post https://www.microlambdawireless.com/resources/driverappnote2.pdf sergey23, please write in one topic everything that relates to frequency stabilization. As you can see, it is difficult for forum participants to understand what you are talking about. Preferably in the Rf&Microwave section. Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 28 Posted January 28 (edited) · Report post Hello , I have recreated the circuit in the article as shown bellow and in the attached LTspice file. I use this controller to drive a YIG in PLL , the controller gets two types of errors. DC and AC. The PI=P+I controller handles a DC error using the I integrator and P AC error using the proportional part. Is there a way I could see how my controller handles these two types of error? Thanks. PI_driver (1).asc Edited January 28 by sergey23 Quote Share this post Link to post Share on other sites More sharing options...
rloc 78 January 28 Posted January 28 · Report post The THS3121 amplifier is the final driver for powering the low-impedance FM coil. The LT1028 is not designed for high output currents, its linearity quickly drops with increasing current. The PI circuit is supposed to be installed before the THS3121. Are you sure that the LT1028 bandwidth is enough for the PI circuit? The amplifier bandwidth should be approximately 10 times larger than the calculated one. The RC element values are calculated depending on the loop transfer function. Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 29 Posted January 29 · Report post Hello Rloc,I have built the driver circuit with THS3121 model as shown below in the photos and attached article. I am not sure regarding LT1028. What opamp you reccomend to use? What PI circuit you reccomend to use? How do you reccomend to connect the driver circuit with the controller? Thanks/ YIG driver.zip Quote Share this post Link to post Share on other sites More sharing options...
rloc 78 January 30 Posted January 30 · Report post 14 часов назад, sergey23 сказал: What opamp you reccomend to use? More often I see AD797 and OPA211 for the bandwidth about 1Mhz. 14 часов назад, sergey23 сказал: What PI circuit you reccomend to use? As a first approximation, a 2nd order circuit for the voltage source is suitable, as you drew in the 1st message. But the nominal values of the RC elements must be selected depending on the loop transfer function. The calculation can be similar to the one in the following document after the "PHASE NOISE" section: PLDRO.pdf Quote Share this post Link to post Share on other sites More sharing options...
khach 56 January 30 Posted January 30 · Report post In that application your dont need any YIG driver, because frequency is constant. Try to make PMYIG ( permanent magnet YIG) with mechanically tuned magnetic shunt. Set central frequency of YIG at external resonator frequency and close loop by FM coil. At the other hand PLDRO ( phased locked DRO) may provide more phase noise perfomance than YIG, because Q factor of DRO is better usually. Quote Share this post Link to post Share on other sites More sharing options...
rloc 78 January 30 Posted January 30 · Report post 55 минут назад, khach сказал: At the other hand PLDRO ( phased locked DRO) may provide more phase noise perfomance than YIG, because Q factor of DRO is better usually. Так у автора и задумано, разбросано кусками по разным темам. Quote Share this post Link to post Share on other sites More sharing options...
khach 56 January 30 Posted January 30 · Report post 2 часа назад, rloc сказал: Так у автора и задумано, разбросано кусками по разным темам. Автору мучается уже второй месяц с вадером (гулянием) тока основной обмотки ЖИГ. По опыту- даже крутой токовый источник keythley с 6 знаками точности этот вадер не давит, а соответственно частота гуляет и замкнуть петлю не получается. Была давно показана автору схема от старого аналогового гигатроникса ( без фапч) с одной хитрой цепью, которая к ОС по току добавляла ОС по напряжению от индуктивности обмотки. Проблема вадера сразу исчезала. Quote Share this post Link to post Share on other sites More sharing options...
sergey23 0 January 30 Posted January 30 (edited) · Report post Hello rloc ,Thank you for the answer .So we have a driver and a PI controller ,how do you reccomend to combine these two ? Hello Khach, what is the problem of "Vader" could you please show me the circuit that solves the "Vader" issue? "Была давно показана автору схема от старого аналогового гигатроникса" Thanks. Edited January 30 by sergey23 Quote Share this post Link to post Share on other sites More sharing options...
