/* -*- tab-width: 4 -*-
*
* Electric(tm) VLSI Design System
*
* File: PowerChannelResistorVoltageReadable.java
* Written by Michael Dayringer and Adam Megacz, Sun Microsystems.
*
* Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved.
*
* Electric(tm) is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* Electric(tm) is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Electric(tm); see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, Mass 02111-1307, USA.
*/
package com.sun.electric.tool.simulation.test;
/**
* Assuming you have a PowerChannel with a resistor attached to the
* output and a VoltageReadable across the resistor, this will act
* like a PowerChannel+CurrentReadable that lets you set the voltage
* across the load as long as it maintains a reasonably stable current
* draw.
*
* +--------------+ resistor +------+
* +--| PowerChannel |---------/\/\/\/\---------| load |---+
* | +--------------+ ^ ^ +------+ |
* | | | |
* | +- VoltageReadable -+ |
* | |
* +-------------------------------------------------------+
*/
public class PowerChannelResistorVoltageReadable extends PowerChannel {
private boolean fastConvergence;
private PowerChannel pc;
private double ohms;
private VoltageReadable vr;
private static float EPSILON_VOLTS = 0.01f;
public void setCurrent(float amps) { pc.setCurrent(amps); }
public float getCurrentSetpoint() { return pc.getCurrentSetpoint(); }
public float readCurrent() {
double pc_current = pc.readCurrent();
double vr_current = vr.readVoltage() / ohms;
if (Math.abs(pc_current - vr_current) > EPSILON_VOLTS * ohms)
throw new RuntimeException("PowerChannel and VoltageReadable disagree on current; perhaps you gave the wrong resistor value?\n" +
" PowerChannel says: " + pc_current + "\n" +
" VoltageReadable says: " + vr_current);
return (float)vr_current;
}
public float readVoltage() {
readCurrent(); // to force the sanity check
return pc.readVoltage() - vr.readVoltage();
}
public void setVoltageNoWait(float volts) { throw new RuntimeException("cannot do this in a "+this.getClass().getName()); }
public void waitForVoltage(float setVolts) { throw new RuntimeException("cannot do this in a "+this.getClass().getName()); }
public float getVoltageSetpoint() { throw new RuntimeException("cannot do this in a "+this.getClass().getName()); }
public void setVoltageWait(float v) {
readCurrent(); // to force the sanity check
while(true) {
double vs = pc.readVoltage();
double vread = vr.readVoltage();
double i = vread/1000;
double vl = (vs-ohms*i);
System.err.print("\r\033[0K\r");
System.err.print(this.getClass().getSimpleName()+
".setVoltageWait():"+
" desired/actual="+v+"/"+vl);
if (vl+EPSILON_VOLTS < v || vl-EPSILON_VOLTS > v) {
if (fastConvergence) {
double delta = v+i*ohms - vs;
delta *= 1.5;
vs = vs + delta;
} else {
vs = v+i*ohms;
}
pc.setVoltageWait((float)vs);
} else {
readCurrent(); // to force the sanity check
System.err.print("\r\033[0K\r");
break;
}
}
}
public PowerChannelResistorVoltageReadable(PowerChannel pc,
float ohmsOfResistor,
VoltageReadable voltMeterAcrossResistor,
boolean fastConvergence) {
this.pc = pc;
this.ohms = ohmsOfResistor;
this.vr = voltMeterAcrossResistor;
this.fastConvergence = fastConvergence;
}
}