Question

Orcad9.2,pspice电路仿真出错，请高人指点 能解决问题的我会加分

这是仿真的错误：
**** SIMULATION ERRORS

******************************************************************************

DIGITAL Message ID#1 (SERIOUS):
DIGITAL INPUT VOLTAGE Hazard at time 93.4ns
Device: X$N05688_AtoD1.O0
Voltage V(N05688,0)= 7.0050 is beyond the ranges defined in model DO74ALS00

ERROR -- Convergence problem in transient analysis at Time = 100.3E-06
Time step = 7.788E-15, minimum allowable step size = 10.00E-15

These supply currents failed to converge:

I(V_VA) = 33.15mA \ 33.11mA
I(V_VB) = -69.01mA \ -69.27mA

Last node voltages tried were:

NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE

(N02690) 263.1400 (N02732) -274.1700 (N02774) 9.7987 (N02800) -331.8900

(N02801) -274.1000 (N02828) 264.3000 (N04776) .1200 (N05688) 7.0049

(N07838) 263.1300 (N18289) .1200 (N21970) -268.6700 (N22009) -331.9500

($G_DGND) 0.0000 ($G_DPWR) 5.0000

(SIGNAL1) .1197 (SIGNAL2) 3.5025

(X$N04776_AtoD1.1) .3300 (X$N04776_AtoD1.2) .1650

(X$N04776_AtoD1.3) .7788 (X$N05688_AtoD1.1) -2.0434

(X$N05688_AtoD1.2) -1.0217 (X$N05688_AtoD1.3) -1.7971

(X$N04776_AtoD2.NORM) .0240 (X$N18289_AtoD1.NORM) .0240

(X$N18289_AtoD2.NORM) .0240

DGTL NODE : STATE DGTL NODE : STATE DGTL NODE : STATE DGTL NODE : STATE

(N04776$AtoD2) : 0 (N05688$AtoD) : 1 ( N04926) : 1

( N06513) : 0 ( N05101) : 1 (N18289$AtoD2) : 0

(SIGNAL2$DtoA) : 1 ( N05235) : 0 (N04776$DtoA) : 0

(SIGNAL1$DtoA) : 0 (N04776$AtoD) : 0 ( N05277) : 1

(N18289$AtoD) : 0

有人说把steptime改小些，可是我不知道在哪里改，请高人指点
能解决问题的我会加分感谢

Answer 1

因为没仔细看你的电路图，steptime主要就是一个收敛的问题。你仿真参数设置的时候把那个步长设置小一点，看行不行。但是那个步长越小，计算时间越长，以前计算一个数模混合电路，一次仿真要花2个小时左右，经常最后快到100%了就出错，很无语。

试试吧