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44 Threads found on edaboard.com: Start And Bandgap
Hello, I need your help. I have to design a bandgap reference. I have studied some design topologies, and I know which topology iam going to use, and I have the specīs But my problem is, that i am a littel bit confused and I dont know how to start the design. :/ i would appreciate if you could give me (...)
To design "anything" , 1st you define all input and output constraints and environmental range and supply range. Then you define stability, tolerance and start/stop behavior. Then you can compare solutions. Using custom L/W ratio bandgap voltage reference you can choose e. g. 1.5 (...)
Hi all: I am design a bandgap circuit, and the operation voltage (AVDD) is 5V ~ 20V. My structure is cascode current mirror. The process is High Voltage BCD process. Each MOS characteristic that in my circuit is : 0
I would suspect that the Schmitt threshold is too close, but on the wrong side of, the bandgap output voltage and yet the startup circuit cannot be removed without the bandgap core collapsing. The startup looks too simple to me. start with breaking that feedback loop and (...)
You could start with just what "didn't work" means. A result you didn't like, or failure to produce a result at all? bandgap / PTAT loops without explicit startup mechanisms, can easily converge in one testbench and fail in another, because when they start up they're doing so on "numerical noise" which (...)
Add some deliberate leakage (a very low current source or large resistor) to prevent it starting. Then add the startup circuit and check it does start. You may be able to do it with "initial conditions" although I usually add deliberate leakage. Keith
i have designed a RC osc circuit, and using a bandgap to generate the reference current and reference voltage of the osc, when simulating the bandgap only, the start up time is 1ms orso; but when i simulate the bandgap and osc together, the bandgap's (...)
look at the figure. there is not only one 'degenerate' bias point in this bandgap and the output would settling down to a strange value in some case (the normal start-up circuit can only eliminate the zero current bias point). I couldn't find a paper discussed the start-up and 'degenerate' bias point of this (...)
Please have a check for your start-up circuit. Is it turned off completely?
I think start-up loop have too big gain. So pls try to reduce some. and pls check start-up loop stability.
you need start-up circuit for bandgap. but i think in terms of simulation, you can get the right operation point even without start-up. anyway, what's the size of Q1 and Q2, respectively?
Hi All, I have a bandgap reference circuit, which works fine in simulation. (Both DC temperature sweep and transient sweep give satisfactory results.) As this is my first fabrication, I am a bit concerned about the start-up and also the stability of the circuits. startup the (...)
How to check the operating point of the start up circuit of the bandgap reference is turn off after the whole circuit is working? (when i ramp my input from 0 to 5V) You can use the writefinal option. See this thread . ... can anyone give me so
break the negative feedback at the output and inject an ac signal, like you do for ac analysis of amplifiers. You may need to set an initial condition for the output voltage to get it to start up, but probably won't
You might try using a wilson current mirror (which has more headroom) rather than a widlar current mirror, or forgo using Q5 and Q6. If you can make Q3, Q4, Q5, Q6 and Q7 pmos, you will not have base current errors, just an idea. I have made startups like this also. Try connecting the emitter of Qs to the base of Q1 or Q2, (...)
Hi there, I am a analog behavioral modeling engineer. I am developing analog power supply behavioral model now. I will develope "bandgap reference model" by using AMS language. During the development i wish to verify the following charasteristic: 1. start-up characteristic: Vout vs Vin 2. load characteristic: Vout vs Iload 3.temperature ch
looks like a simple biasing circuit were Vbn and Vcn can be used to bias the N network of lets say for example an opamp, and Vbp and Vcp are used to bias the P network of the same opamp. All the transistors at the far left seem to be part of the start-up circuit. Hope this helps, diemilio
I designed Bandgap voltage reference and startup circuit for it. I have read topics about BGVR and startup. I verify startup this way: make Vdd constant value (or use vpwl source and ramp on Vdd), set initial conditions for nodes and make transient (...)
Hi All, I would like to work in Analog Design field... I have 2+ years in Std cell & custom memory layout and SOC physical Design knowledge/experience.. Please guide me where to start... What are all the stuffs that I need to concentrate?. Rgds, Kumar
hi i attch the bandgap circuit. Do we need start up circuit for this bandgap and why? thanks