PLL不能后仿问题,急啊
初始化VCO的控制电压为0V,前仿真可以正确运行,但是后仿一直卡在数据出来之前那个状态,不能继续往下进行;但是我取消控制线上的电压初始化后,却可以正确的往下进行!
请问这是怎么一回事啊,等了好久都没有仿真数据出来!只能不初始化了么?
刚刚看了下,就是卡在这里:
Trying homotopy = gmin for nodests;
Trying homotopy = source fornodests;
Trying homotopy = dptram for nodests;
再往下就不能动了!
你把初始电压改变下呢?
你后仿真网表是不是太大了?
是啊,网表很大,大概十几M的样子,寄生参数很多啊。昨晚上跑了一晚上,最后出现了ERROR:
Trying `homotopy = gmin' for nodesets.
Trying `homotopy = source' for nodesets.
Trying `homotopy = dptran' for nodesets.
Trying `homotopy = ptran' for nodesets.
Trying `homotopy = arclength' for nodesets.
Error found by spectre during DC solution estimation, during IC analysis,
during transient analysis `tran'.
There were 7 attempts to find the DC solution. In 1 of those attempts, a
signal exceeded the blowup limit of it's quantity. The last signal that
failed is V(I0.I4|I3|NM3:int_s) = 1.60081 GV, for which the quantity is
`V' and the blowup limit is (1 GV). It is possible that the circuit has
no DC solution. If you really want signals this large, set the `blowup'
parameter of this quantity to a larger value.
Trying `homotopy = gmin' for initial conditions.
Trying `homotopy = source' for initial conditions.
Trying `homotopy = dptran' for initial conditions.
Trying `homotopy = ptran' for initial conditions.
Trying `homotopy = arclength' for initial conditions.
Error found by spectre during IC analysis, during transient analysis `tran'.
There were 7 attempts to find the DC solution. In 1 of those attempts, a
signal exceeded the blowup limit of it's quantity. The last signal that
failed is V(I0.I4|I3|NM3:int_s) = 1.60081 GV, for which the quantity is
`V' and the blowup limit is (1 GV). It is possible that the circuit has
no DC solution. If you really want signals this large, set the `blowup'
parameter of this quantity to a larger value.
No DC solution found (no convergence).
你抽取网表的时候是怎么选的?RC都抽吗?还是只抽C?
如果RC都抽的话,最小的R和C给了多少
RC都抽的。我没有改设置,都是默认值!您觉得是抽取参数的时候,设置的不对是吧?
你可以只抽C或者RC都抽.
默认值可能都太小了,比如Rmin=0.001ohm, Cmin=0.01fF.
改成Rmin=0.1ohm, Cmin=1fF,
这样抽取的后仿网表文件会小些。
仿真时,你可以先看能不能快速的跑起来(比如power supply设定固定值,vco control voltage设置成最终稳定值附近),如果能跑起来,就是那进度条开始出现....的时候,再加你需要的激励。
不然等过了N长时间,就像你开始列出来那几条信息一样,还是跑不下去,时间就浪费了。
好的啊,谢谢了!我再试试!