In variable bench power supply, how current adjust and voltage adjust works.
Is it somekind of current divider and voltage divider circuit implementation.
Is it somekind of current divider and voltage divider circuit implementation.
In a DC power supply design, the voltage and current controls are not implemented with divider circuits in the traditional sense of voltage dividers.In variable bench power supply, how current adjust and voltage adjust works.
Is it somekind of current divider and voltage divider circuit implementation.
Then How this works??In a DC power supply design, the voltage and current controls are not implemented with divider circuits in the traditional sense of voltage dividers.
Think of the VOLTAGE setting the CURRENT setting as hard limits.
If the output voltage exceeds the set voltage, the voltage is limited using a voltage "fold-back" circuit that actively controls the output voltage.
Similarly, if the output current exceeds the set current, the current is limited using a similar active feed-back control circuit. In order to drop the current to the desired setting the output voltage must be reduced accordingly.
You cannot have both constant current and constant voltage at the same time. The power supply will hit one of the two limits, which ever comes first.
Plz give a schematics.To control the output voltage, a sample of the voltage from the output via the voltage setting knob is compared to a fixed known reference voltage, and the comparing circuit generates an control voltage that is fed to the main voltage regulator to turn it on more or less to make the output voltage what is selected by the voltage setting knob.
To limit the current, a similar action takes place. When the current reaches the preset limit set by the current knob, this generates a signal that is used to modify the voltage setting and reduce the output voltage, over riding the voltage setting knob. The current limit setting will have no effect at all on the power supply UNTIL the preset current limit is reached. For a real explanation of actually how a power supply works you will have to read something like that PDFs above. There are a number of different ways to make a power supply so a specific answer is a bit hard.