Convergence problem in transient bias point calculation (please help me)

Hi there

I need help on this ckt to to transient analaysis. I am getting the error . I have copied and paste the some of the similar error but there are more there i also have attached the pic of whole unit and a Individual unit. please help me why i cant get the transient analysis. My ckt has no error for sure.
thank you


ERROR -- Convergence problem in transient bias point calculation


Last node voltages tried were:

NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE


( P0) 24.75E-06 ( P1) 34.58E-06 ( P2) 34.58E-06 ( P3) 34.58E-06

( P4) 34.66E-06 ( P5) -.2063 ( P6) .2518 ( P9) 34.58E-06
.........


Adder_N50023) 37.89E-06 (Adder_N50037) 16.93E-06

(Adder_N50111) 11.49E-06 (Adder_N50203) 35.68E-06

(Adder_N50219) 18.58E-06 (Adder_N50249) 26.23E-06

(Adder1_N50023) 38.18E-06 (Adder1_N50037) 16.99E-06

(Adder1_N50111) 16.17E-06 (Adder1_N50203) 35.75E-06

(Adder1_N50219) 18.62E-06 (Adder1_N50249) 26.47E-06
......
hese voltages failed to converge:

V(Adder18_N50203) = 601.23mV \ 627.10mV
V(N85109) = -690.41mV \ -874.50mV
V(Adder18_N50111) = -899.23mV \ -1.111V
V(Q46) = -328.02mV \ -306.49mV
V(Adder18_N50249) = -630.38mV \ -656.34mV
V(N84819) = 296.24mV \ 322.15mV
V(N84863) = -190.00mV \ 412.54mV
V(N85113) = 66.87mV \ 61.76mV
V(SUM8) = -905.65mV \ -67.78V
V(Adder18_N50219) = -690.42mV \ -874.50mV
V(Adder18_N50037) = -342.38mV \ -295.94mV
V(Adder18_N50023) = -......
These supply currents failed to converge:

I(V_V1) = 340.32nA \ -2.290uA
I(V_V2) = -37.31pA \ -67.84pA
I(V_V3) = -16.48pA \ -28.01pA
I(V_V4) = -14.39pA \ -25.70pA
I(V_V5) = -32.07pA \ -57.02pA
I(V_V8) = -3.928nA \ -6.559nA
I(V_V14) = 34.32pA \ 58.58pA
I(V_V17) = 5.268pA \ 9.223pA
I(V_V13) = 969.57pA \ 1.628nA
I(V_V10) = 31.52pA \ 55.24pA
I(V_V12) = 57.61pA \ 99.34pA
I(V_V15) = 5.856nA \ 9.63nA

These devices failed to converge:
M_Adder18_M4 M_Adder18_M8 M_Adder18_M17 M_Adder18_M3 M_Adder18_M7
M_Adder18_M13 M_Adder18_M1 M_Adder18_M20 M_Adder18_M9 M_Adder18_M6
M_Adder18_M12 M_Adder18_M15 M_Adder18_M5 M_Adder18_M11 M_Adder5_M8
M_Adder5_M17 M_Adder5_M13 M_Adder5_M1 M_Adder5_M20 M_Adder5_M12
M_Adder5_M19 M_Adder5_M5 M_Adder5_M11 M_Adder7_M8 M_Adder7_M17 M_Adder7_M3
M_Adder7_M7 M_Adder7_M1 M_Adder7_M20 M_Adder7_M6 M_Adder7_M12 M_Adder7_M19
M_Adder7_M11 M_Adder22_M4 M_Adder22_M8 M_Adder22_M14 M_Adder22_M3 .......

patdrige said:

i cant get the transient analysis. My ckt has no error for sure.

Click to expand...

Where's the transient stimulus?

Did the DC analysis work correctly? I can't see any VDD supply source, nor a GND symbol or any globals.
There are negative voltages shown!?

Does the single full adder work correctly?

I have mention the image again here. all the adder and And gate as a single unit works properly. there is global Vdd and Gnd in the ckt.

The first thing I would ask is, is there one and only one
valid initial state for every node? For example, are there
flip-flops or latches whose initial condition is "unknown"?
At t=0 there can be no prior clock edge and you need an
asynchronous reset unless you want to try to solve for
the third stable point (meta-).

Then I would ask whether a DC operating point can be
produced for exactly equal dc=(t=0) stimuli. If yes, then
go use that for initial conditions and save the simulator
some work. If no, double down on the lack-of-authority
angle.

Now there do seem to be a lot of crazy looking voltages,
negative Vf looking, as if maybe the positive supply was
not there, or something has pumped body nodes below
ground. Unless this is ECL/SCL or something unusual.

In any case it's not good form to assert your circuit is
error free when you can't even get it to run. Strike a
pose after you get the medal.

Hi, i have a problem with the simulation of that circuit:

and the error is this one :

Anybody can help me please?

Thanks!

I've the same problem of convergence problem but this time when I give -ve supply to PNP Q2N2907 then it occurs. However when I interchange terminals then there is no error & bias point calculated which should not happen.

I am designing this circuit for simple amplifier where 250K resistor should be a sensor to sense small input signal. Will this circuit work?