5 A Constant Voltage-Constant Current Regulator

A constant voltage constant current  (CVCS) regulator  doesn’t mean a system with a constant load, since there will be no regulation in such case.  What we call CVCS regulator is a regulator with two modes. The first mode is constant voltage, where the regulator trying to regulate the supply to a variable load at a constant voltage. In this mode […]

Read more

Three Cells Produce Regulated 3V – 3.3V with Power Down/Power Saving Mode

This linear voltage regulator circuit provides battery voltage regulation from battery source to power micro controller system. The output can be selected by choosing the right resistor value in the feedback path.  Many today’s micro controllers are featured with power down or power saving mode, and this circuit accommodates this feature by providing low power mode control on its input. […]

Read more

Automotive/Car Power Adapter For 3V, 6V, or 9V DC Operated Devices

In automotive environment, it’s common that only single voltage power outlet is available. Using  the very popular LM317 voltage regulator IC, we can build a general purpose DC adapter to adapt car’s power outlet voltage (12-14 Volts) to supply small DC devices requiring lower voltage level. On the following schematic diagram for the car power adapter,  we can see that […]

Read more

Selectable Voltages 6V, 9V, and 12V Linear Voltage Regulator

  We can build a multiple voltage power supply 6, 9, and 12V  (AC-DC Adapter) with the circuit shown in the following schematic diagram.  Not only provide multiple voltage output with single voltage supply, this circuit add the benefit of regulating the voltage for better stability. The TIP31 transistor should be installed with proper heat-sink to prevent overheating. A transformer […]

Read more

Variable Frequency Switch Mode Regulator

This voltage regulator circuit operates in switch mode. Using the configuration shown in the schematic diagram, this circuit has variable switching frequency, depends on the input voltage and load condition. The core controller of this switching regulator is a TL497 switching regulator controller IC. Here is the schematic diagram of the circuit: When the load is low (draw only small […]

Read more

Logic Power Control for 78xx Regulator

Logic power control of analog regulator can be useful in application where a digital circuit/controller need to control power source, such as in EEPROM programmer or other power controls.  This is a circuit provide ON-OFF control  for 78xx regulator using digital (TTL or CMOS) signal level. This circuit uses transistors in series with the 78XX regulator,  which it’s base is […]

Read more
1 2 3 5