Application of REASUNOS high and low voltage MOS in vehicle inverter

1. Introduction

A car inverter (power converter) is a device that can convert DC 12V direct current into AC 220V alternating current, the same as the mains power, and provide it to general electrical appliances. It is a convenient car power converter.

With the development and progress of automobile product technology, the electronic technology of automobiles is also constantly improving. The development of electric vehicles and plug-in hybrid vehicles with on-board inverters as important components is accelerating rapidly, and the development prospects of the on-board inverter market will be very broad. The increase in the popularization speed of on-board inverters has also promoted the use of MOS tubes in on-board inverters.

2. Product application and working principle

The car inverter can achieve power specifications of 20W, 40W, 80W, 120W and even 500W. Its application range includes: mobile phones, laptops, digital cameras, cameras, lighting, electric shavers, CD players, game consoles, PDAs, power tools, car refrigerators, etc.

The general vehicle inverter is mainly composed of an inverter bridge, a filter circuit, a control circuit, an oscillator, etc. Its working principle is to first convert the 12V DC power provided by the car battery into an AC power of about 30kHz-50kHz and 220V through high-frequency PWM (pulse width modulation) switching power supply technology. Then, the AC power of about 30kHz-50kHz and 220V is converted into an AC power of 50Hz and 220V by using bridge rectification, filtering, pulse width modulation and switching power output technologies.

3. Product application topology diagram

4. Recommended line selection

Two series of MOS solutions are provided for the DC-DC boost circuit + control circuit (push-pull) and DC-AC inverter circuit of the inverter circuit in the figure above:

DC-DC boost circuit (anti-reverse connection) + control circuit (push-pull type)

In the DC-DC boost circuit, MOSFET is selected as the switching device. The maximum voltage that the field effect tube needs to withstand is about 20-30V. When selecting the MOS tube, the maximum withstand voltage should be left with a margin. Generally, MOS above 40V is selected. The MOS tube is recommended to use the Ruisen Semiconductor low-voltage MOS series, and the selection is as follows:

DC-AC inverter circuit (full-bridge PWM control)

The main circuit of the DC-AC inverter circuit adopts a full-bridge structure, and the diode connected in parallel with the switch tube plays a protective role. The MOS tube is recommended to use the Ruisen Semiconductor high-voltage MOS series. Ruisen Semiconductor high-voltage MOS series has ultra-small internal resistance, moderate junction capacitance, good heat dissipation performance, small high-temperature leakage, and small high-temperature voltage drop, which is widely praised by the market.