Measure several actual discharge curves on a computerized constant current load analyzer at a low rate 20 to 200 hours to get an actual voltage versus capacity curve. Ive come up with a couple of very easy ways to create constant power loads in ltspice. A constant power load is designed to dynamically adjust the load current inversely with the load voltage so that the load power is constant, p vi. Offline circuit simulation with tina tina design suite is a powerful yet affordable circuit simulator and pcb design software package for analyzing, designing, and real time testing of analog, digital, ibis, hdl, mcu, and mixed electronic circuits and their pcb layouts. Pspice student is sometimes distributed under different names, such as pspice student thinstalled. The current through the device tends to level out once the voltage gets high enough. This tutorial introduces the dependent source elements in pspice. One of the less glamorous but equally important circuits in audio amplifiers is the current source. The norton resistance rn the current source will be equal to the output resistance ro of qb, as determined by the upward slope of that transistors voltagecurrent characteristic. Above are the pspice simulated waveforms for the voltage output and current. Subscripts p and n are used to distinguish the variables and parameters of the two types of transistors. Pdf design of current sources for load common mode. Figure 1 shows the schematic symbol for an ideal current source driving a resistive load.
There are a wide range of software available in the market now a day to serve the purpose of testing the circuit before moving to. The lm4lm234lm334 are 3terminal adjustable current sources featuring 10,000. Simulates fuse connection to be broken at rated current. Adjustable constant current load circuit wiring diagrams. Thyristor converters university of nevada, las vegas. The control loop is implementing constant voltage constant current operation. Pspice is a pc version of spice which is currently available from orcad corp. A new window pop up with the pspice project type, select create a blank project and click ok. This allows the current limit to be adjusted from 0a to 10a with a resistorpotentiometer, or controlled digitally with a voltageout or.
Check final loop gain and run a transient load test vout2 16 cout 220u resr 150m 2 l1 180u 6 rupper 38k rlower 10k 9 5 x2 ampsimp v2 2. The circuit is a current mode buck converter that was derived by christophe basso. Analog behaviour modelling is surely supported in versions 16. One is a resistor whose resistance is a function of the voltage across it, and the other is a voltagedependent current source using a piecewise linear approximation. The simulation model is evaluated with simetrix pspice simulator.
This circuit provides a constant current load through q1 and q2. This is a voltagecontrolled current source, which has a transfer function given in tabular form. Slope compensation can be programmed with an externa. It is this inverse property of a constant power load that is often useful in stability analysis of simulations like those of a switching mode power supply. To obtain current and voltage in a dc circuit, the analysis is performed with the simple load bias point. Show step by steps how to load and create the pspice file at csu. Constant current power supply a regulated power supply that acts to maintain its output current constant in spite of changes in load, line, temperature, etc. Rc and rl transient examples in this tutorial, we will look at simulating rc and rl transients. We want higher voltage to the right so positive wire to pin 3 of the potentiometer place the. For a first best guess on power losses and junction temperatures good results can be achieved. For example, the following order will sweep the dc bias voltage to get the iv characteristics. If you are currently using pspice ad basics or pspice. The pspice user community is your destination to find pspice resources, ask and answer questions, and interact with your industry peers and pspice experts.
Unlike other designs which use a power resistor in series with the output current path, the opa549 senses the load indirectly. Simulate adaptive switching regulators using pspice. Such a gadget is useful if you want to measure the capacity of chinese liion batteries. Voltage sources, in addition to being used for circuit excitation, are the ammeters for spice, that is, zero valued voltage sources may be inserted into the circuit for the purpose of measuring current. Spice does the circuit analysis and puts out an ascii file with the information.
The current being copied can be, and sometimes is, a varying signal current. Click the enabled check box in the bias load point option. From figure 1b, the load current is equal to the driver current, i. Tina analog, digital, mcu and mixed circuit simulator. Differences between pspice and berkeley spice2 101 analog devices analog devices 104 device types 105. Infineon therefore does not assume any liability arising from their use.
Rohm currently provides the following spice models. Xiong this tutorial will guide you through the creation and analysis of a simple mosfet circuit in pspice schematic. The easiest way to make a new pspice model library is to download it from the manufacturers website. Evaluation circuits can also be downloaded from reference designs. To model such a load, we can use a voltage dependent current source. The parameters used to define it were the high frequency peak in the output current considering 1 k. In this small project i will show you how to make a simple adjustable constant current load. Pspice tutorial 3 using pspice for circuits with dependent sources the problems in this tutorial and the corresponding homework continue to deal with the dc analysis of circuits, or dc bias analysis in pspice. Using pspice to simulate the discharge behavior of common. A source to be tested should be put in place of vtest. Mosfet pspice simulation 5 4 pspice simulation models pspice is a commonly used simulation tool. Use the component vdc for dc power supplies, and vac for signal sources.
The current source portion of the circuit below is very similar to daves design. Constant resistance, constant current and constant power loads. Pspice tutorial create a new project and select analog or mixed ad. Run an openloop bode plot at full load, lowest input 2. My basic understanding of this kind of circuit is that for variations of input voltage, say between 20v and 30v the current sink should remain constant, fo my application 20ma. The circuit below shows the use of the constant power load macro. In the constant power case the voltage times the current of all of the other pairs is your desired load power. Opa549 data sheet, product information and support. Read all step beforce attemp to build first, cut the perf board to its size 2. The circuit diagram below is what you will build in pspice. Pspice relies on the assumption that, when the supplies are close enough to 0, all devices in the circuit are turned off.
Further, it is not a good model of a real constant power load for low voltages. I have designed various flavours of constant current sink circuits, either by breadboarding or by using orcad and pspice. Spice simulators and spice models basic knowledge rohm. Circuit used for the parametric sweep of the load resistor. In a pspice simulation, a gtable device may be used. The switch node and inductor current are also shown, along with a close up version of the output voltage, which matches the data sheet response very closely. In this case, the current out of the source will be adjusted depending on the voltage across the load so that a constant power is generated. The basic concept has been around for a long time though, and its essentially an opamp based current source design. Current is established with one external resistor and no other parts are required. To find the dc conditions for voltage, current, temperature and parameter global of the. Place a double zero at f 0, a pole at the esr zero and a pole at f sw2 4. Cadence pspice technology offers more than 33,000 models covering various types of devices that are included in the pspice software. Pspice ad reference guide montana state university.
Conceptually, an ideal current mirror is simply an ideal inverting current amplifier that reverses the. So far we have covered circuits with resistors and independent sources. This manual has comprehensive reference material for all of the pspice circuit analysis applications, which include. Basic screen there are three windows that are opened. Cadence pspice technology combines industryleading, native analog, mixedsignal, and analysis engines to deliver a complete circuit simulation and verification solution. Typical with power grid tubes as with eimac, svetlana. To model a cell, start by generating a parameterized pspice lookup table voltage controlled voltage source vcvs using the following steps. This pwm signal gets smoothed out by an rc filter to produce a smooth analog voltage. The ltc3803 is a constant frequency current mode flyback controller optimized for driving nchannel mosfets in high input voltage applications. Same llc average model can be used for both load transient reponse and bode plots. A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it a current source is the dual of a voltage source. Identify the excessdeficiency of gain at the selected cross over 3.
The constantcurrent nature of a jfet is a function of its characteristic curves fig. Pdf simulation of a current source with a colecole load. The latter is associated with the early voltage, as discussed in class and in the text. Creating impedances with behavioral modeling pspice. The constant power load macro is the x2 device at the. In the next tutorial we will learn about the basic components of pspice and how to draw a simple circuit in pspice. There are a variety of methods available to analyze complex electrical circuits, like mesh analysis, nodal analysis, or kirchhoffs circuit laws. The results showed that the constant and high output impedance current sources for multifrequency could be fulfilled both eh and toa current sources prepared with opamp ad844 and a colecole load. Among the tested values of r 3, the ones that lead to similar response are 10 k. Starting from the left, we have a pwm signal that will come from an arduino io pin. Because the current is constant, the load can only increase to the point that the operational amplifier output saturates. Even the free download version is capable to simulate simple circuits with infineon mosfets, which are available on the infineon homepage in the internet.
Constant power load using table in power systems, it is common to encounter loads which draw constant power. The problem is, when youre designing a dc power network youll have a load whose value will change as your design process unfolds. Or you can test how stable your power supply is with a certain lo. This download was checked by our antivirus and was rated as virus free. Power mosfet simulation models infineon technologies. The term current sink is sometimes used for sources fed from a negative voltage supply. Input bias current ib and input offset current ios. Circuit elements and models university of california. Constant frequency operation is maintained down to very light loads, resulting in less low frequency noise generation over a wide range of load currents.
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