SEE (single event effects) generator



NAME_TABLE:

C_Function_Name:       cm_seegen
Spice_Model_Name:      seegen
Description:           "single event effect generator"


PORT_TABLE:

Port_Name:             ctrl                 out
Description:          "control input"       "output"
Direction:             in                   out
Default_Type:          v                    i
Allowed_Types:         [v,vd,i,id]          [i,id]
Vector:                no                   yes
Vector_Bounds:         -                    [1 -]
Null_Allowed:          yes                  no


PARAMETER_TABLE:

Parameter_Name:     talpha                   tbeta
Description:        "alpha"                 "beta"
Data_Type:          real                     real
Default_Value:      500e-12                  20e-12
Limits:             -                        -
Vector:              no                      no
Vector_Bounds:       -                       -
Null_Allowed:       yes                      yes


PARAMETER_TABLE:

Parameter_Name:     tdelay                inull
Description:        "pulse delay"         "max current"
Data_Type:          real                   real
Default_Value:      0                      200e-6
Limits:             -                      -
Vector:              no                    no
Vector_Bounds:       -                      -
Null_Allowed:       yes                    yes

PARAMETER_TABLE:

Parameter_Name:     tperiod                ctrlthres
Description:        "pulse repetition"     "control voltage threshold"
Data_Type:          real                   real
Default_Value:      0                      0.5
Limits:             -                      -
Vector:              no                    no
Vector_Bounds:      -                      -
Null_Allowed:       yes                    yes

STATIC_VAR_TABLE:

Static_Var_Name:    last_t_value
Data_Type:          pointer
Vector:              no
Description:        "next pulse start time"

STATIC_VAR_TABLE:

Static_Var_Name:    pulse_number
Data_Type:          pointer
Vector:              no
Description:        "number of pulse"

STATIC_VAR_TABLE:

Static_Var_Name:    last_ctrl
Data_Type:          pointer
Vector:              no
Description:        "last control value"

Description
This code model generates "double exponentially" formed current pulses according to
i(t) = inull * (exp(-(t-tdelay)/talpha) - (exp(-(t-tdelay)/tbeta) for t > tdelay
i(t) = 0       for t < tdelay
Minimum is one pulse output (a node pair, or a single node with the other grounded).
Several output node pairs may be defined per code model instance. Parameter tperiod
may then be used to create pulses in sequence. The first pulse is issued in the first
node pair of the node list in the vector [], the second (after time tperiod has elapsed), is injected by the
second node (pair) of the list and so on. The control input ctrl (voltage or current) may be used
to start or repeat the whole sequence, depending on the circuit status. A rising voltage
at ctrl, when crossing the threshold given by ctrlthres, will initiate the sequence (including
tdelay and tperiod).

This model will work in transient analysis.

Example ngspice usage (with control)

aseegen1 ctrl [%id(n1 m1) %id(n2 m2) %id(n1 m1) %id(n2 m2)] seemod1
.model seemod1 seegen (tdelay = 8n tperiod=25n)

Example ngspice usage (without control, parameters as offered by default)

aseegen2 NULL [%id(n1 m1) %id(n5 n6) %id(n6 n7) %i(isingle) ] seemod2
.model seemod2 seegen (tdelay = 0 tperiod=0 ctrlthres=0.5 inull=200u talpha=500p tbeta=20p)