This adjustable power supply circuit uses a surprising trick.
The TDA2030 chip, normally used to crank up the volume for speakers can also be configured to act like a voltage regulator.
With some clever circuit design, it can provide a stable DC voltage with adjustable output making it useful for powering electronics projects at different voltage levels.
It is not the most common way to use the TDA2030 and there might be better suited circuits specifically designed for adjustable power supplies.
Circuit Working:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistors | Potentiometer 25k | 1 |
| Preset 25k | 1 | |
| Capacitors | Ceramic 100nF | 3 |
| Electrolytic 100µF 63V | 1 | |
| Semiconductors | IC TDA2030 | 1 |
| IC 78L05 | 1 |
This circuit combines a standard 78L05 with an integrated audio amplifier, the TDA2030 to create a straightforward adjustable voltage regulator.
The output voltage can be set up to 20V, with a maximum current of 3A.
The TDA2030 includes reliable thermal and short circuit protection ensuring the regulators durability.
The circuit design, as shown in the schematic is remarkably simple.
Aside from the two ICs it only requires two potentiometers and a few capacitors.
To adjust the output voltage, first, set potentiometer P1 to its maximum position wiper towards the 78L05 and then adjust trimpot P2 until the desired maximum output voltage is achieved.
P1 can then be used to fine tune the voltage between the maximum and nearly zero volts.
For low output currents, no special cooling is needed.
However, if the output current exceeds 1 A or if there is a significant difference between the input and output voltages, the amplifier IC will generate too much heat requiring a small heatsink for proper dissipation.
Electrical Characteristic for IC 78L05:
| Parameter | Test Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| VO (Output voltage) | TJ = 25°C, VIN = 7 V to 20 V, IO = 1 mA to 40 mA (3) | 4.75 | 5 | 5.25 | V |
| IO = 1 mA to 70 mA (3) | 4.75 | 5 | 5.25 | V | |
| VIN = 7 V to 20 V, TJ = 25°C | 18 | 75 | mV | ||
| ΔVO (Line regulation) | VIN = 8 V to 20 V, TJ = 25°C | 10 | 54 | mV | |
| IO = 1 mA to 100 mA, TJ = 25°C | 20 | 60 | mV | ||
| Load regulation | IO = 1 mA to 40 mA, TJ = 25°C | 5 | 30 | mV | |
| IQ (Quiescent current) | TJ = 25°C | 3 | 5 | mA | |
| ΔIQ (Quiescent current change) | VIN = 8 V to 20 V | 1 | mA | ||
| IO = 1 mA to 40 mA | 0.1 | mA | |||
| Vn (Output noise voltage) | f = 10 Hz to 100 kHz (4) | 40 | μV | ||
| ΔVIN/ΔVO (Ripple rejection) | f = 120 Hz, VIN = 8 V to 16 V, TJ = 25°C | 47 | 62 | dB | |
| IPK (Peak output current) | 140 | mA | |||
| ΔVO/ΔT (Average output voltage temperature coefficient) | IO = 5 mA | -0.65 | mV/°C | ||
| VIN(MIN) (Minimum value of input voltage required to maintain line regulation) | TJ = 25°C | 6.7 | 7 | V |
How to Build:
To build a Simple Adjustable Power Supply Circuit using IC TDA2030 below are the steps mentioned:-
Mount Components:
- Place the 78L05, TDA2030, potentiometers and capacitors on the breadboard or PCB according to the schematic diagram.
Connect Components:
- Connect the input of the 78L05 to the power supply.
- Connect the output of the 78L05 to the input of the TDA2030 through potentiometer.
- Connect the output of the TDA2030 to the output load.
- Connect the common ground for all components.
Adjustment Potentiometers:
- Set potentiometer P1 to its maximum position.
- Adjust trimpot P2 to achieve the desired maximum output voltage.
- Power on the circuit and measure the output voltage using a multimeter.
- Adjust potentiometer P1 to vary the output voltage between the maximum and nearly zero volts.
Finalize and Secure:
- Once the circuit is functioning as desired finalize the connections and secure all components in place.
Testing and Optimization:
- Test the circuit under different load conditions to ensure stability and adjust as necessary.
Note:
- Please note that working with electronic circuits involves handling potentially hazardous voltages and components.
- Take necessary precautions such as working in a static safe environment and disconnecting power before making any modifications.
- If you are not familiar with electronics, consider seeking assistance from someone experienced in electronics projects.
Conclusion:
To conclude, an adjustable power supply circuit using the TDA2030 IC provides a versatile and efficient solution for various electronic projects.
By utilizing the TDA2030s capabilities as a voltage regulator and amplifier combined with components such as a bridge rectifier, capacitors and a potentiometer for voltage adjustment a stable and adjustable output voltage can be achieved.
Care should be taken to ensure proper heat dissipation for the TDA2030 especially at higher output currents to maintain its reliability and performance.