Dual power supply using L165

This dual power supply utilizes the L165 power operational amplifier from SGS-Thomson Microelectronics. The L165 IC can deliver up to 3.5A of current, with internal current limiting. It is available in a Pentawatt package, making it well-suited for power supply applications. In this configuration, the L165 is set up as a voltage amplifier, amplifying the voltage at the junction between resistors R1 and R2. The output voltage is always half of the input voltage (Vin). For instance, if the input voltage (Vin) is 24V, the output will be +12V and -12V. Capacitor C2 serves as the input filter capacitor, while C1 acts as the input decoupling capacitor. Capacitors C4 and C5 are used to enhance the symmetry of the output voltage.

The dual power supply circuit based on the L165 operational amplifier is designed to provide a stable dual output voltage, which is essential for various electronic applications. The operational amplifier is configured to function as a voltage amplifier, where the output voltage is derived from the input voltage through a specific resistor network. The resistors R1 and R2 form a voltage divider, determining the gain of the amplifier circuit.

The input voltage (Vin) is supplied to the circuit, and the output is generated as a symmetrical dual voltage, typically +12V and -12V for a 24V input. This configuration is particularly beneficial for powering op-amps and other analog devices that require dual polarity supplies.

Capacitor C1 plays a crucial role in decoupling, ensuring that high-frequency noise does not affect the operational amplifier's performance. It provides a low-impedance path to ground for high-frequency signals, effectively stabilizing the power supply. Capacitor C2, as the input filter capacitor, smooths out any ripples or fluctuations in the input voltage, providing a more stable voltage to the L165.

To improve the output voltage symmetry, capacitors C4 and C5 are strategically placed in the circuit. These capacitors help to balance the output characteristics, ensuring that both the positive and negative outputs remain equal and stable under varying load conditions. This is critical for applications requiring precise voltage levels, such as audio equipment, instrumentation, and analog signal processing.

Overall, this dual power supply circuit exemplifies a robust design using the L165 operational amplifier, providing reliable performance for a variety of electronic applications.This dual power supply is based on the L165 power operational amplifier from SGS-Thomson Micro electronics. The IC L165 can easily deliver up to 3. 5A of current (internally limited). The IC is available in Pentawatt package and is very suitable for power supply applications like this.

Here the L165 is wired as a voltage amplifier which amplifies t he voltage available at the junction between R1 and R2. The output voltage will be always half of the input voltage (Vin). For example if you give 24V at the input (Vin), you will get a +12V/-12 V at the output. C2 is the input filter capacitor and C1 is the input decoupling capacitor. C4 and C5 and meant for improving the symmetry of the output voltage. 🔗 External reference