DC-DC adjustable converter supplies are an essential part of today’s electronics. They fulfill a wide scale of requirements in industrial as well as academic settings such as test bench supplies and load matching applications for variable DC drives. These DC supplies are a must-have for any electronics enthusiast or hobbyist. So, in this project, we are going to design a simple 1.2V To 15V Adjustable Regulated Power Supply Using LM1085 Low dropout positive voltage regulator IC.
The main component of this 1.2V To 15V adjustable supply is an LM1085 IC. LM1084 is a Low Dropout Positive Regulator IC. with a low voltage drop at a high current value. The maximum voltage drop by the LM1085 regulator at 3A of load current is 1.5V. LM1085 also contains features such as overheat protection, limiting of current, etc.
Hardware required
The following components are required to make an Adjustable Power Supply Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Voltage Regulator IC | LM1085 | 1 |
| 2. | DC Supply | 17V – 29V / 3A | 1 |
| 3. | Potentiometer | 5K Ohms | 1 |
| 4. | Heatsink (optional) | – | 1 |
| 5. | Electrolytic Capacitor | 100uF, 10uF | 2 |
| 6. | Resistor | 120 Ohm | 1 |
| 7. | Breadboard | – | 1 |
| 8. | Connecting Wires | – | 1 |
LM1085 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM1085
Adjustable Power Supply Circuit
Working Explanation
The working of this circuit is quite simple. A DC signal (from an external DC source) in the range of 17V – 29V serves as the input for the circuit. The DC signal then passes through a smoothing capacitor (10uF), to eliminate any residual noise from the input DC source. The input DC signal is then sent to the (Vin) pin of an LM1805 Low dropout positive voltage regulator IC.
The LM1085 IC steps down the DC signal (in a range of 1.2V to 15V) while maintaining the output current at 3A. Here, a 5K pot can be connected to the ADJ pin of the IC to tune the output voltage to a desirable level. The regulated DC signal then passes through a smoothing capacitor (100uF) before moving on towards the output.
Applications
- Generally, DC supplies power small electronic devices such as portable DC lamps, test bench supplies for small electronic projects & testing facilities.
