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-- Copyright (C) 1998-2002 The University of Cincinnati.
-- All rights reserved.
-- This file is part of VESTs (Vhdl tESTs).
-- UC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
-- SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
-- OR NON-INFRINGEMENT. UC SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
-- LICENSEE AS A RESULT OF USING, RESULT OF USING, MODIFYING OR
-- DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
-- By using or copying this Software, Licensee agrees to abide by the
-- intellectual property laws, and all other applicable laws of the U.S.,
-- and the terms of this license.
-- You may modify, distribute, and use the software contained in this
-- package under the terms of the "GNU GENERAL PUBLIC LICENSE" version 2,
-- June 1991. A copy of this license agreement can be found in the file
-- "COPYING", distributed with this archive.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: clipper.ams,v 1.1 2002-03-27 22:11:19 paw Exp $
-- $Revision: 1.1 $
--
-- ---------------------------------------------------------------------
------------------------------------------------------------------------
-- Title : Single diode clipper circuit
-- Project : Mixed signal simulation
------------------------------------------------------------------------
-- File : diode_clipper1.vhd
-- Author(s) : Vasudevan Shanmugasundaram(vasu@ececs.uc.edu)
-- Created : jan 16 1998
------------------------------------------------------------------------
-- Description :
-- Behavioral description of a single diode clipper circuit.
------------------------------------------------------------------------
-- circuit diagram for the diode clipper:
-- the circuit comprises:
-- o______|l______o____|>|______o i) a diode D.
-- | |l | diode D ii) a constant voltage source vd.
-- | const | iii)a sinusoidal voltage source.
-- ( ) Vsource > iv) a resistor R.
-- |Vs >R
-- | >
-- o______________|_____________o
--
------------------------------------------------------------------------
--package definition
PACKAGE electricalSystem IS
NATURE electrical IS real ACROSS real THROUGH ground reference;
FUNCTION SIN (X : real ) RETURN real;
FUNCTION EXP (X : real ) RETURN real;
END PACKAGE electricalSystem;
-------------------------------------------------------------------------------
USE work.electricalSystem.all;
ENTITY diode_clipper IS
END diode_clipper;
ARCHITECTURE behav OF diode_clipper IS
--terminal declarations
terminal t1, t2, t3 : electrical;
--quantity declarations
quantity vDiode across iDiode through t1 TO t2;
quantity v2 across i2 through t2 TO t3;
quantity vd across electrical'reference TO t1;
quantity vs across electrical'reference TO t3;
--constants
CONSTANT saturation_current : real := 0.0000000000001;
CONSTANT Vt : real := 0.025;
CONSTANT BV : real := 100.0;
CONSTANT neg_sat : real := -saturation_current;
BEGIN -- behav
if( vDiode >= (-1.0 * Vt)) USE --diode equations
eqn1_1: iDiode == saturation_current * ( exp(vDiode/Vt) - 1.0 );
ELSIF ((vDiode < (-3.0 * Vt)) AND (vDiode > -BV)) use
eqn1_2: iDiode == neg_sat;
ELSE
eqn1_3: iDiode == neg_sat * (exp(-(BV + vDiode)/Vt) - 1.0 +
saturation_current);
END USE ;
eqn2: v2 == i2 * 100.0; -- resistor eqn.
eqn3: vs == 20.0 * sin(2.0 * 3.1415 * 10000.0 * real(time'pos(now)) *
1.0e-15); -- source
eqn4: vd == 5.0; -- dc source
END behav;
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