How It Works

The spycey module works by creating a parent/child tree and builds a SPICE netlist for DC operating point analysis.

Consider the following power tree:

P12V = PNode.IN_DC("P12V0", 12)
P5V0 = PNode.SMPS("P5V0-BUCK", 5, 0.9, P12V)
LOAD = PNode.CC_LOAD("Load", 1, P5V0)

print(P12V.Netlist())

Below is the generated netlist. Every node instantiates a subcircuit model for a specific power supply type. Refer to Models section to see details for the SPICE models.

.title INPUT_12V_5jA3
.subckt INPUT_12V_5jA3 n1 n3 n4
V1 n1 0 12
BVO n3 0 v=V(n1)
BIO n4 0 v=-I(V1)
.ends INPUT_12V_5jA3

.subckt SMPS_5V_4Fdk n1 n2 n3 n4 n5 n6 n7
V2 n1 n11 0
B1 n11 0 i=-I(V1) * V(n2)/V(n1)
B2 n11 0 i=( V(n2) * -I(V1) * (1-0.9) ) / 0.9 / V(n11)
V1 n2 0 5
BVO n3 0 v=V(n2)
BIO n4 0 v=-I(V1)
BVI n5 0 v=V(n1)
BII n6 0 v=I(V2)
BEF n7 0 v=0.9
.ends SMPS_5V_4Fdk

.subckt LOAD_CC_1A_77Dn n1 n5 n6
B1 n1 0 i=1
BVI n5 0 v=V(n1)
BII n6 0 v=I(B1)
.ends LOAD_CC_1A_77Dn
XINPUT_12V_5jA3 INPUT_12V_5jA3 VO-INPUT_12V_5jA3 IO-INPUT_12V_5jA3 INPUT_12V_5jA3
XSMPS_5V_4Fdk INPUT_12V_5jA3 SMPS_5V_4Fdk VO-SMPS_5V_4Fdk IO-SMPS_5V_4Fdk VI-SMPS_5V_4Fdk II-SMPS_5V_4Fdk EF-SMPS_5V_4Fdk SMPS_5V_4Fdk
XLOAD_CC_1A_77Dn SMPS_5V_4Fdk VI-LOAD_CC_1A_77Dn II-LOAD_CC_1A_77Dn LOAD_CC_1A_77Dn

This netlist could be copied into LTspice with the .op command and would yield the following output.

INSERT LTSPICE Screenshot

The edge and node parameters can also be solved using spycey which is using pyspice and ngspice under the hood.

P12