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149 Threads found on Feedback Compensation
Hello, The MAX16833 datasheet, on pages 18 & 19 gives a really easy, clear and simple explanation of how to compensate the feedback loop of LED drivers done with the MAX16833 chip. The LT3756 LED driver IC, and other similar ones by have the same type of internal components, so why have never layed out such a clear and
then how error amp works in linear region ? amplifiers working with negative feedback
Hi This question is a nice one. I remember having entire courses at university on feedback loop compensation. I'll try to make it short though feedback loop compensation for an op-amp is a must have, in order to get a stable transient response. Not having a feedback loop compensated leads to unstabilities, (...)
hello frnds....i am using SG3525 for closed loop control in my project... I gave feedback to SG3525 without any compensation ..RESULT: initially i got stable pulses from SG3525 ,but when i am giving power to main converter ckt,there is fluctuation in the pulses and suddenly they got vanished.... I think the feedback needs some (...)
Do you agree with the following ?rules? (A to D) on the checking of type 2 compensator pole and zero positions? This is with regard to a CCM, Current mode flyback with a type 2 feedback compensation network..That is, making sure it is not going to be unstable.. ?The Type 2 compensator zero MUST BE at (or very near) the same freq
Hello, On pages 212 to 217 of ?Power supply cookbook? by Brown, it goes through a type 2 error amplifier feedback compensation scheme for a CCM flyback in current mode. It discusses the placement of the error amplifier's poles and zero, but does not do this with respect to the power stage RHPZ. Why is no mention made of the RHPZ? Surely an error
Hi, I went through your pdf. i suppose this is like a some what an open loop design as i see no feedback path to regulate the output voltage to guard against variations that may arise due to load fluctuations. That means as the load varies you may have to manually vary the duty cycle to cope up with regulation. The design requirement is some w
Yeah your feedback compensation needs some tuning. You have a lot of ringing, but the low frequency gain is also too low. Try increasing your zero frequencies while decreasing your pole frequencies (basically reduce your k factor ).
One nice thing about the transconductance type is that the FB pin is actually a high impedance, which can simplify the design of compensation and feedback networks. Also since the COMP output is high impedance, you can override it with external circuitry easily. Major con is that the transconductance may have a large tolerance to it.
Hi, LM339 is a comparator and no OPAMP. But the feedback is on inverting input, this is very unusual for a comparator. Please check if pin4 and pin5 is connected like in your schematic. (the other way round makes more sense) Klaus
is your controller shutting off on overload protection function? Or your feedback compensation may be bad maybe your output capacitor is too small?
I'm not sure what kind of stability is addressed here. If you look at feedback loop stability, the MOSFET input capacitance can cause problems with high speed OPs and require additional compensation. Apart from this point, it's a well known and usually good working current source topology. MOSFET power dissipation occurs according to requested c
I see your point, connected the opposite way to hysteresis feedback
Most of the application notes on compensation of error amp only talk about restive divider network used for scaling feedback voltage. When differential amplifiers (or single ended amplifiers) are used we need to add a resistor in between Output of the first stage amplifier and inverting pin of the error amplifier (please correct me if I am wrong).
An amplifier has transistors that have some capacitance and wiring also has some capacitance. The capacitance causes a phase shift at high frequencies. An amplifier usually has negative feedback to reduce its very high gain to a useable amount and to reduce its distortion. The phase shift at a high frequency causes the negative feedback to become p
The voltage gain and bandwidth in opamps ARE NOT INFINITY! The open-loop (no negative feedback) voltage gain for most opamps is about 200,000 at DC and very low frequencies up to about 10Hz. The frequency compensation capacitor in an opamp reduces its gain 6db per octave (20dB per decade) so that at a frequency where phase shifts in the opamp woul
I was reading an article regarding insure stability of op amp in optical application. And I do not understand the reason of below statement: "Figure 4 depicts three different scenarios for the intersection of the closed-loop response curve with the open-loop gain curve. Stability degradation will occur when fP falls outside the open-loop gain cu
You should insert probe before inp input of opamp not at it output. Yes - thatīs correct. In case of two loops of equal "degree" you must open the positive feedback loop only. Otherwise you loose the dc operating point (stabilized by negative feedback). However, one can argue if this gives the "correct"
Hello. I designed a half bridge converter by using tl494 chip. and so it's 2pole - 2zero compensation network. but this configuration is suitable for inverting error amp configuration not non inverting like tl494. Now I confused how to solve this problem for make circuit to be stable! Actually using a RC feedback in non inverting configuration s
I think of MC1496+PLL feedback form could produce FM signal, due to PLL Chip lack some compensation .