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What is the topology of a bidirectional current source?
We’ve looked at a straightforward bidirectional-current-source topology that is built around a high-precision operational amplifier and a high-precision instrumentation amplifier. In the next article, we’ll use some LTspice simulations to further explore the operation and performance of this circuit.
How does a current source in a circuit work?
The key to the operation of this current source is the use of the instrumentation amplifier. By sensing the voltage across a fixed resistance that is in series with the load, we can generate an output current that is not influenced by the value of the load resistance. Below is my attempt at a step-by-step explanation of how this circuit works.
Is it good to have a current source?
This doesn’t change the fact, though, that current sources are sometimes very useful, and it’s a good thing that clever engineers have created a variety of practical current-source circuits. In this article, I want to share with you an interesting current source that I found in an old application note published by Linear Technology.
Who is the inventor of the current source?
This is by no means the official name for the circuit, and I certainly don’t want to imply that it’s the only current source that Jim Williams ever designed—I wouldn’t be surprised to learn that he came up with half a dozen innovative, high-performance current-source topologies.
What makes a circuit a good current source?
The circuit has good stability and is compatible with rapid changes in input voltage. The key to the operation of this current source is the use of the instrumentation amplifier.
How is the output voltage of a bipolar power supply controlled?
The output voltage is controlled by the voltage source CONTROL signal at the CTRL pin of controller U1. Figure 1. Electrical schematic of bipolar, bidirectional, 2-terminal power supply: V IN = 5 V to 24 V, V OUT = ±10 V at 3 A. The low-pass filter C F, R F alleviates sharp changes in control voltage.
Is the output current proportional to the resistor R?
Since the load is in series with the resistor R, the output current is always proportional to the input voltage, regardless of the load resistance (within limits, of course—e.g., you won’t be able to drive 10 mA through a 1 MΩ load unless you can find amplifiers that accept supply voltages up to 10,000 V or so).
Which is easier to draw a voltage source or a current source?
When all you’re doing is drawing a schematic, voltage sources and current sources are equally easy to implement. However, after we enter the real world of circuit design, we gradually realize that generating a more or less constant current is, for some reason, much more difficult than generating a more or less constant voltage.
What makes a current sink a current source?
Efficiency vs. load current. This 2-stage regulator can operate as a current source or a current sink. In current sink mode, current and power flow in reverse from the output, V OUT, to the input, V IN. This is important for automotive electronics and some audio systems.