In this DIY project, we will use the TC1044SEOA, a DC-DC inverter chip, to build a negative voltage power supply. This project will help you understand how to invert a positive voltage to a negative one using minimal external components, which can be useful for powering circuits that require negative voltage rails. The TC1044SEOA is a small, efficient IC that provides an ideal solution for creating negative voltage from a positive supply.

The ability to generate a negative supply voltage from a positive voltage is a common requirement in many analog and digital circuits. For instance, operational amplifiers often need both positive and negative supply rails to properly amplify AC signals. With the TC1044SEOA, we can create this negative voltage supply using simple components, which is ideal for compact projects where space and cost are critical factors.

Components Needed:

● TC1044SEOA IC (DC-DC inverter)

● Capacitors (10µF and 0.1µF)

● Resistors (1kΩ, 10kΩ)

● Diodes (1N4007 or similar)

● Voltage regulator (optional) for output stabilization (e.g., LM7812 for 12V output)

● Breadboard or PCB

● Jumper wires

● 5V DC power supply (could be a regulated 5V adapter or a battery pack)

● Multimeter for testing and validation

Project Overview:

The TC1044SEOA is a charge pump inverter that uses a simple capacitor switching technique to generate a negative voltage from a positive input. It can take a positive DC input voltage, such as 5V, and invert it to produce a negative output voltage. This is ideal for projects where you need a -5V, -12V, or similar negative rail, especially when the available power source is a single positive voltage rail.

The TC1044SEOA works by connecting the input voltage to a series of capacitors that are switched between different configurations to create the desired negative voltage. It uses an internal oscillator to drive the capacitor switching, allowing it to step up the current and invert the voltage. The TC1044SEOA is highly efficient and compact, making it an excellent choice for low-power applications.

In this project, we will use the TC1044SEOA to generate a -5V output from a +5V input, but the design can be adapted to generate other negative voltages, such as -12V, by using appropriate capacitors and selecting different resistor values.

Circuit Design:

The key to this project is understanding how the TC1044SEOA operates to create a negative voltage. The chip is a voltage inverter with an integrated charge pump circuit. The basic principle behind a charge pump inverter is the use of capacitors to store and reverse the charge polarity, which ultimately inverts the voltage.

1. Powering the TC1044SEOA:

The TC1044SEOA operates with a positive supply voltage input (Vcc) and outputs a negative voltage (Vout). We will start by applying 5V to the Vcc pin (pin 6). The ground pin (pin 4) of the IC will be connected to the circuit ground.

2. Capacitor Configuration:

The TC1044SEOA requires two external capacitors for the charge pump circuit. These capacitors will be used to store and transfer charge to invert the voltage. The capacitor values we will use are:

● C1 = 10µF (this capacitor will be used to store the charge)

● C2 = 0.1µF (a small capacitor placed near the input to help with high-frequency filtering)

Both capacitors will be connected between the appropriate pins on the TC1044SEOA, following the recommended connections in the datasheet. The capacitor values determine the efficiency and ripple of the output voltage. Higher capacitance typically results in smoother output voltage but can also take up more space.

3. Input and Output Connections:

The input voltage is applied to the Vcc (pin 6) of the TC1044SEOA, and the negative output voltage will be available at the Vout (pin 4). The negative voltage will be generated through the internal charge pump circuit, which switches the polarity of the capacitors to create the negative voltage output.

The GND pin (pin 3) will be connected to the common ground of the circuit. We also need to add a small filter capacitor (C3), typically 0.1µF, between the Vout pin and ground to smooth out any ripple and stabilize the negative voltage.

4. External Diodes (Optional for Stability):

While the TC1044SEOA has internal diodes for rectification, adding external diodes like 1N4007 can improve efficiency, especially if the load requires higher currents. These diodes will protect the IC from any reverse voltage spikes and ensure that the capacitors discharge properly.

5. Voltage Stabilization (Optional):

If your application requires a regulated negative voltage (e.g., -5V or -12V), you can use a voltage regulator circuit after the output of the TC1044SEOA. A voltage regulator like the LM7812 can be used to regulate the output voltage to a stable -12V if needed.

6. Test Points:

Once the circuit is assembled, you can use a multimeter to measure the output voltage at the Vout pin (pin 4). If you're supplying 5V at the Vcc input, the output should be approximately -5V. Make sure to test for any ripple or fluctuations, especially if you're using the negative voltage to power sensitive analog or digital circuits.

Step-by-Step Assembly:

Here’s how you can assemble the inverter circuit:

1. Prepare the Components:

● Get the TC1044SEOA IC, capacitors, diodes, resistors, and voltage regulator (optional) ready.

2. Connect the TC1044SEOA:

● Insert the TC1044SEOA IC into your breadboard or PCB.

● Connect Vcc (pin 6) to the positive input (5V).

● Connect GND (pin 3) to the ground of your power supply.

3. Add the Capacitors:

● Connect C1 (10µF) between Vcc (pin 6) and Vout (pin 4).

● Connect C2 (0.1µF) between Vcc (pin 6) and ground.

● Connect a small 0.1µF capacitor (C3) across the Vout pin (pin 4) and ground for output filtering.

4. Add Optional Diodes:

● If using external diodes, place them between the Vout pin and ground, with the cathode connected to the Vout pin and the anode to ground.

5. Apply Power:

● Apply 5V DC to the Vcc pin of the TC1044SEOA.

● Measure the output voltage across the Vout pin and ground.

6. Testing the Output:

● Check if the output voltage is approximately -5V. If the voltage is fluctuating, adjust the capacitor values or check for poor connections.

7. Voltage Regulation (Optional):

● If you need a regulated voltage, connect a voltage regulator (e.g., LM7812) at the output to stabilize the voltage.

Final Thoughts:

The TC1044SEOA is a powerful, efficient solution for generating negative voltage in projects where a dual-rail power supply is required. In this DIY project, we demonstrated how to convert a simple 5V positive input into a -5V negative output using the TC1044SEOA DC-DC inverter IC. This simple circuit can be expanded for higher negative voltages or more complex power applications by adding appropriate filtering or regulation components.

This project is a great starting point for exploring the world of DC-DC converters and charge pump inverters. Once you become familiar with how the TC1044SEOA works, you can easily adapt the circuit for different input voltages and output requirements. This versatility makes it ideal for use in portable electronics, sensor circuits, and even audio applications, where dual power rails are often necessary.

By using minimal components and following the steps outlined, you can quickly build an efficient negative voltage power supply for your DIY projects.