Dependent Voltage Sources -- H Elements
H Element syntax statements are described in the following paragraphs. The parameters are defined in the following section.
Current Controlled Voltage Source -- (CCVS)
Syntax
Linear
Hxxx n+ n- <CCVS> vn1 transresistance <MAX=val> <MIN=val> <SCALE=val>
+ <TC1=val><TC2=val> <ABS=1> <IC=val>
Polynomial
Hxxx n+ n- <CCVS> POLY(NDIM) vn1 <... vnndim> <MAX=val>MIN=val>
+ <TC1=val><TC2=val> <SCALE=val> <ABS=1> P0 <P1...> <IC=vals>
Piecewise Linear
Hxxx n+ n- <CCVS> PWL(1) vn1 <DELTA=val> <SCALE=val> <TC1=val> <TC2=val>
+ x1,y1 ... x100,y100 <IC=val>
Multi-Input Gates
Hxxx n+ n- gatetype(k) vn1, ... vnk <DELTA=val> <SCALE=val> <TC1=val
+ <TC2=val> x1,y1 ... x100,y100 <IC=val>
Delay Element
Hxxx n+ n- <CCVS> DELAY vn1 TD=val <SCALE=val> <TC1=val> <TC2=val>
+ <NPDELAY=val>
Parameter Definitions
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ABS
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Output is absolute value if ABS=1.
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CCVS
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Keyword for current controlled voltage source. CCVS is a reserved word and should not be used as a node name.
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DELAY
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Keyword for the delay element. The delay element is the same as a current controlled voltage source except it is associated by a propagation delay TD. This element facilitates the adjustment of propagation delay in the macromodel process. DELAY is a reserved word and should not be used as a node name.
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DELTA
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Used to control the curvature of the piecewise linear corners. The parameter defaults to 1/4 of the smallest breakpoint distances. The maximum is limited to 1/2 of the smallest breakpoint distances.
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gatetype(k)
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Can be one of AND, NAND, OR, NOR. (k) represents the number of inputs of the gate. The x's and y's represent the piecewise linear variation of output as a function of input. In the multi-input gates only one input determines the state of the output.
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Hxxx
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Current controlled voltage source element name. The parameter must begin with an "H" followed by up to 1023 alphanumeric characters.
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IC
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Initial condition. This is the initial estimate of the value(s) of the controlling current(s) in amps. If IC is not specified, the default=0.0.
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MAX
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Maximum voltage value. The default is undefined and sets no maximum value.
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MIN
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Minimum voltage value. The default is undefined and sets no minimum value.
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n+/-
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Positive or negative controlled source connecting nodes
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NDIM
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Polynomial dimensions. If POLY(NDIM) is not specified, a one-dimensional polynomial is assumed. NDIM must be a positive number.
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NPDELAY
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Sets the number of data points to be used in delay simulations. The default value is the larger of 10 or the smaller of TD/tstep and tstop/tstep
That is,
The values of tstep and tstop are specifed in the .TRAN statement.
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P0, P1 . . .
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When one polynomial coefficient is specified, the source is linear, and the polynomial is assumed to be P1 (P0=0.0). When more than one polynomial coefficient is specified, the source is nonlinear, with the polynomials assumed as P0, P1, P2 ...
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POLY
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Polynomial keyword function
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PWL
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Piecewise linear keyword function
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SCALE
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Element value multiplier
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TC1,TC2
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First and second order temperature coefficients. The SCALE is updated by temperature:
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TD
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Time delay keyword
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transresistance
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Current to voltage conversion factor
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vn1 ...
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Names of voltage sources through which the controlling current flows. One name must be specified for each dimension.
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x1,...
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Controlling current through vn1 source. The x values must be in increasing order.
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y1,...
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Corresponding output voltage values of x
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Example
HX 20 10 VCUR MAX=+10 MIN=-10 1000
The example above selects a linear current controlled voltage source. The controlling current flows through the dependent voltage source called VCUR. The defining equation of the CCVS is:
The defining equation specifies that the voltage output of HX is 1000 times the value of current flowing through CUR. If the equation produces a value of HX greater than +10 V or less than -10 V, HX, because of the MAX= and MIN= parameters, would be set to either 10 V or -10 V, respectively. CUR is the name of the independent voltage source that the controlling current flows through. If the controlling current does not flow through an independent voltage source, a dummy independent voltage source must be inserted.
.PARAM CT=1000
HX 20 10 VCUR MAX=+10 MIN=-10 CT
HXY 13 20 POLY(2) VIN1 VIN2 0 0 0 0 1 IC=0.5, 1.3
The example above describes a dependent voltage source with the value:
This two-dimensional polynomial equation specifies FA1=VIN1, FA2=VIN2, P0=0, P1=0, P2=0, P3=0, and P4=1. The controlling current for flowing through VIN1 is initialized at .5 mA. For VIN2, the initial current is 1.3 mA.
The direction of positive controlling current flow is from the positive node, through the source, to the negative node of vnam (linear). The polynomial (nonlinear) specifies the source voltage as a function of the controlling current(s).
Star-Hspice Manual - Release 2001.2 - June 2001
