NAME_TABLE:

C_Function_Name: cm_divide

Spice_Model_Name: divide

Description: "divider block"

PORT_TABLE:

Port_Name: num den out

Description: "numerator" "denominator" "output"

Direction: in in out

Default_Type: v v v

Allowed_Types: [v,vd,i,id,vnam] [v,vd,i,id,vnam] [v,vd,i,id]

Vector: no no no

Vector_Bounds: - - -

Null_Allowed: no no no

PARAMETER_TABLE:

Parameter_Name: num_offset num_gain

Description: "numerator offset" "numerator gain"

Data_Type: real real

Default_Value: 0.0 1.0

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: den_offset den_gain

Description: "denominator offset" "denominator gain"

Data_Type: real real

Default_Value: 0.0 1.0

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: den_lower_limit

Description: "denominator lower limit"

Data_Type: real

Default_Value: 1.0e-10

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

PARAMETER_TABLE:

Parameter_Name: den_domain

Description: "denominator smoothing domain"

Data_Type: real

Default_Value: 1.0e-10

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

PARAMETER_TABLE:

Parameter_Name: fraction

Description: "smoothing fraction/absolute value switch"

Data_Type: boolean

Default_Value: false

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

PARAMETER_TABLE:

Parameter_Name: out_gain out_offset

Description: "output gain" "output offset"

Data_Type: real real

Default_Value: 1.0 0.0

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

• Description:
  This function is a two-quadrant divider. It takes two inputs; num (numerator) and den (denominator). Divide offsets its inputs, multiplies them by their respective gains, divides the results, multiplies the quotient by the output gain, and offsets the result. The denominator is limited to a value above zero via a user specified lower limit. This limit is approached through a quadratic smoothing function, the domain of which may be specified as a fraction of the lower limit value (default), or as an absolute value. This model will operate in DC, AC and Transient analysis modes. However, in ac analysis it is important to remember that results are invalid unless only one input of the divider is connected to a node that is connected to an ac signal (this is exemplified by the use of the divider to perform a potentiometer function: one input is dc, the other carries the ac signal).

Example SPICE Usage:

a4 1 2 4 divider

.model divider divide(num_offset=0.1 num_gain=2.5 den_offset=-0.1

+ den_gain=5.0 den_lower_limit=1e-5 den_domain=1e-6

+ fraction=FALSE out_gain=1.0 out_offset=0.0)