A simple step-up voltage regulator circuit using the IC LM2700 chip is really important when you need to increase a low direct current DC voltage to a higher level.
This is especially useful for battery powered devices where keeping a steady output voltage is crucial even if the input supply changes.
The LM2700 acts as a step up switching converter and has an internal switch that can handle 3.6A and 80 M ohms.
It can work at switching speeds of either 600 kHz or 1.25 MHz.
In this circuit the LM2700 step-up regulator changes a 3V DC input into an 8V DC output making it great for portable electronics and other low power uses.
Just remember the input voltage should not go over 12V.
Circuit Working:
Parts List:
| Component Type | Specification | Quantity |
|---|---|---|
| Resistors (1/4W) | 10k | 1 |
| 160k | 1 | |
| 30k | 1 | |
| Capacitors | Ceramic 3.3nF | 1 |
| Ceramic 100nF | 1 | |
| Electrolytic 47µF 25V | 1 | |
| Electrolytic 22µF 25V | 1 | |
| Semiconductors | IC LM2700 | 1 |
| Schottky Diode MBR1520 | 1 | |
| Inductor | 4.7µH | 1 |
The circuit includes an IC LM2700 step-up regulator, an inductor a Schottky diode, and several passive parts like resistors and capacitors.
The LM2700 acts as a switching regulator efficiently boosting the input voltage from 3V to 8V.
When powered by a 3V DC source the LM2700 starts switching at a high frequency causing current to build up in inductor L1.
While the internal MOSFET switch in the LM2700 is turned ON it captures and stores energy in L1.
When the switch turns OFF the stored energy flows through D1 charging the output capacitor C3 and raising the voltage.
To keep the output voltage steady feedback resistors R2 and R3 provide a reference signal to the feedback pin (FB).
Capacitors C1, C2 and C4 help stabilize the circuit and reduce noise.
Formulas with Calculations:
Below are the formulas with calculations for Simple Step-Up Voltage Regulator Circuit using IC LM2700:
Output Voltage Calculation:
Vout = 1.23V * (1 + R2 / R3)
where,
- Vout is the output voltage of the circuit desired voltage which is 8V
- 1.23V is the internal reference voltage of the IC LM2700 regulator.
- R2 is the feedback resistor 160k in this circuit
- R3 is the feedback resistor 30k in this circuit
Substituting values R2 = 160k and R3 = 30k
Vout = 1.23V * (1 + 160k / 30k)
Vout = 1.23V * (1 + 5.33)
Vout = 1.23V * 6.33
Vout = 7.79V approximately 8V
How to Build:
To build a Simple Step-Up Voltage Regulator Circuit using IC LM2700 follow the below steps for connections:
- Assemble all the components as mentioned in the above circuit diagram
- Connect pin 1 of IC1 LM2700 to GND through resistor R1 and capacitor C2 in series
- Connect pin 2 of IC1 to Vout 8V DC through resistor R2
- Connect pin 5,6 and 7 of IC1 to GND
- Connect pin 10 of IC1 between L1 inductor coil and anode of diode D1
- Connect pin 12 of IC1 to GND through capacitor C1
- Connect capacitor C4 from pin 12 of IC1 and GND
- Connect pin 13 of IC1 to GND
- Connect resistor R3 from the junction of pin 2 of IC1 and resistor R2 and GND
- Connect capacitor C3 between Vout 8V DC and GND
Conclusion:
This Simple Step-Up Voltage Regulator Circuit effectively increases a 3V DC input to 8V by using the LM2700 integrated circuit.
When the right components are chosen, it delivers a steady voltage with very little fluctuation which is perfect for battery operated devices and other uses that need a higher voltage output.
The design is simple, affordable and efficient making it an excellent option for both hobbyists and professionals.