Here I will explain how a Full-Bridge Pure Sine Wave Inverter designed with Arduino and IR2110 gate driver IC works. It is a sophisticated inverter design to convert 12V DC into 220V AC, because it uses a specialized high-side/low-side gate driver (IR2110) and an LC filter to produce a high-quality output.
Previously, I showed How to Build a Pure Sine Wave Inverter using Arduino SPWM and, in that design, I used totem pole gate driver build using BC547 and BC557 transistors and used half bridge made up of two MOSFETs. In this pure singe wave inverter design, I have used IR2110 dedicated gate driver IC and full H-bridge. So, both inverter design uses Arduino as PWM controller, but this one is more sophisticated and effective inverter design.
The following is the circuit design.
I will begin explaining the inverter circuit by starting with the main DC power supply and then explaining the rest of the circuit by breaking down into four main stages to get AC output voltage.
The DC Power Supply:
The main DC power supply for the inverter comes from the 12V Lead Acid Battery. The IRF2110 gate driver, IRF3205 MOSFETs and the Transformer all receive 12V supply from this Lead acid battery. The PWM controller which is Arduino receive 5V using the LM7805 voltage regulator.
The 7805 Voltage Regulator: The 7805 (U1) ensures the Arduino gets a clean 5V, isolating it from the heavy switching noise on the 12V rail.
Capacitor Bank: The capacitors C1, C3, C2, and C4 are decoupling capacitors. They provide a local reservoir of energy to prevent the battery voltage from dipping during every high-current switch.
Now I will explain the rest of the inverter circuit by breaking down into the four main functional stages:
1. The Arduino Control Stage
The Arduino Nano acts as the "brain." It generates 31.25 KHz Sinusoidal Pulse Width Modulation (SPWM) signals.
It sends high-speed PWM switching pulses to the IR2110 drivers HIN pin 10 and LIN pin 12.
By varying the width of these PWM pulses in a sinusoidal pattern, and after filtering the PWM signal a 50Hz AC signal is generated.
The Arduino pins D11, D10, D9, and D3 are used to drive the HIN (High Input) pin 10 and LIN (Low Input) pin 12 of the upper and lower IR2110 gate drivers respectively.
2. The IR2110 Gate Driver Stage
Here we have used N-Channel IRF3205 MOSFETs on the high side. Since the N-Channel MOSFETs on the high side require a gate voltage higher than the source voltage from 12V battery to turn on, the IR2110 is essential because it has support for bootstrap circuit especially designed to work with N-channel MOSFET on the high side.
The Bootstrap Circuit: In the circuit, the diode D1, capacitor C11 on the top IR2110 gate driver IC and diode D2, capacitor C12 connected to the bottom IR2110 IC form the bootstrap. Here is how it works. When the low-side MOSFET is on, the capacitor charges to 12V. When the high-side MOSFET needs to turn on, this capacitor "lifts" the gate voltage to roughly 22-24V and thus is able to turn the high side MOSFET.
Protection Resistors: The 1kΩ resistors (R1 to R4) protect the Arduino pins from transients, and the 22Ω gate resistors (R5 to R8) prevent oscillations during switching.
Capacitors C5 and C7, C9 are decoupling capacitor for 5V VDD and 12V VC pins repectively for the upper IR2110 IC and capacitors C6 and C8, C10 are decoupling capacitor the +5V and 12V pins of the lower IR2110 IC.
3. Power Stage (H-Bridge)
The H-Bridge consists of four IRF3205 N-channel MOSFETs (Q1to Q4).
The Power MOSFETs: The four IRF3205 MOSFETs switch in pairs. The Q1 and Q4 MOSFETs turn on together to send current through the transformer in one direction; then Q3 and Q2 MOSFETs turn on to reverse the current.
This MOSFETs are switched alternatively ON and OFF thousands of times per second, that is at the PWM frequency which here is 31.25KHz and chops the 12V DC into an alternating ac signal.
The 22 Ohm Gate Resistors (R5 to R8)
Their Role is in Oscillation Dampening and Inrush Control.
First role is Preventing Parasitic Oscillation: The MOSFET gates have internal capacitance. Without the gate resistors, the trace inductance and gate capacitance form a high-frequency LC resonant circuit. This causes "ringing," which can keep the MOSFET in the linear region or even destroy the gate oxide.
The 2nd role is Limiting Peak Current: When the IR2110 switches, it tries to deliver a massive "gulp" of current to the gate. The 22 Ohm resistors limits this peak current to a level the IR2110 can safely handle (typically 2A), protecting the driver’s internal stages.
The Role of these diodes are in Asymmetrical Switching and Dead-Time Security
First, the "Fast-Off" Path: These are placed in parallel with the 22 Ohm gate resistors with their cathode away from the MOSFETs gate. When turning ON, current must go through the resistor (slow). When turning OFF, the diode provides a "short-circuit" path, bypassing the resistor.
Their 2nd role is in Preventing Shoot-Through: By making the MOSFET turn OFF faster than it turns ON, a hardware-level safety margin is created. This ensures the top MOSFET is fully "closed" before the bottom one "opens," preventing a direct short circuit across the 12V battery.
The 10kOhm Pull-Down Resistors
Their role is to create addefined Logic State and Static Protection
First role is Floating Gate Prevention: MOSFET gates are like high-impedance sponges—they can pick up static electricity or stray electromagnetic interference from the air. If the gate "floats" to just 2V or 3V, the MOSFET might partially turn on, overheat, and fail.
2nd role is Failsafe During Startup: When the inverter is first powered on, the Arduino and IR2110 take a few milliseconds to initialize. During this "blind" moment, the 10kOhm pull down resistors ensure the MOSFET gates are tied firmly to Ground (or the Source pin), keeping the H-Bridge safely locked in the OFF state.
4. Transformation & Filtering (Output)
Step-Up Transformer (TR1): This takes the high-current 12V AC and steps it up to the 220V required for the Load, in this case the bulb.
LC Filter (L1 & C13): This is one of most critical part for a "Pure Sine Wave." The 22mH inductor and 2.2uF capacitor act as a low-pass filter. They strip away the high-frequency PWM "noise", leaving the smooth 50Hz sine wave for the 220V bulb.
