How does a constant current sink circuit work?

How does a constant current sink circuit work?

This circuit is a floating current source with two different ranges. Because 7 mA/1.5 µA = 4667, it exceeds the 12-bit range of your DAC of 2 12 = 4096, so I split it into two approximately equal ranges (at least as much as the E24 series of resistor values would allow). V1 is your battery and V2 is your DAC to set the desired current.

How do I control a constant current load circuit?

Current range and power to be dissipated by this CC load. For example, discharging a 10AH 12V battery vs a 500AH 12V battery in say an hour could produce power dissipation levels in the 100W to 6kW range. How do you control starting and stopping (turning off and on) this CC load.

Which is the DAC to set the desired current?

V1 is your battery and V2 is your DAC to set the desired current. V3 and V4 are digital signals from your microcontroller, which select the desired current range: when V3 (the signal to M1’s gate) is high and V4 (the signal to M2’s gate) is low, the low-current range is selected; when V3 is low and V4 is high, the high-current range is selected.

A constant current sink circuit actually sinks current irrespective of the load resistance as long as the input voltage is not changed. For a circuit with 1-ohm resistance, powered using 1V input, the constant current is 1A according to Ohms Law.

What’s the difference between a source and sink circuit?

The main difference is that the source circuit has to the source (supply) enough current to the load, while the sink circuit has to just limit the current through the circuit. Voltage-controlled constant current sink circuit works exactly in the same way as voltage-controlled current source circuit that we built earlier.

How is an op-amp used in a sink circuit?

For a current sink circuit, the op-amp connection is changed, that is the negative input is connected to a shunt resistor. This will provide the necessary negative feedback to the op-amp. Then we have a PNP transistor, that is connected across the Op-amp output so that the op-amp output pin can drive the PNP transistor.

How does current pass through a power supply circuit?

A current passes via Q2 and D5 and so creates a voltage of 5V1 around D5. The base of Q2 is attached to the output with a set of resistors, R2, 3, 4 and RV1. If the output voltage increases, then more current will pass via Q2. This leads to the voltage at the base of Q1 to drop, which often decreases the voltage at the output.

What does the tlc591x constant current led sink driver do?

The TLC591x Constant-Current LED Sink Drivers are 1• Eight Constant-Current Output Channels designed to work alone or cascaded. Since each • Output Current Adjusted Through Single External output is independently controlled, they can be Resistor programmed to be on or off by the user.

How does an op-amp sink the base voltage?

The PNP transistor will sink this 1A of current and the op-amp will use this voltage drop and get the desired 1V feedback. This way, changing the input voltage will control the Base as well as the current through the shunt resistor.