Design Of Driver And Protection Circuit For High-Side Switch

The smart power integrated circuit is a monolithic integrated circuit.It integrates power devices,drive modules,control units,and various protection circuits into the same system to achieve target functions.With the rapid development of science and technology,the SPIC technology has become an important technology in the fields of computers,consumer electronics,automotive electronics,and industrial automation.The high-side intelligent power switch is one of the typical applications of the SPIC,and it can control smartly.The purpose of this article is to design a high-side intelligent power switch,including its drive circuit and related protection circuits,so that it can achieve more complete functions.The chip can work within the input voltage of 4.5V?42V.The onresistance of the chip is 30m?,and the chip can reach the maximum working current of6 A.The chip can work at temperature of-40°C?150°C.The chip can also implement functions such as over-voltage protection,short-circuit detection,and over-temperature detection.In the circuit design process,the thesis introduced the overall circuit structure of the high-side power switch chip firstly,including the working principle and the indicators of the chip.Then the thesis analyzed,designed and simulated the protection circuits of the chip,including over-temperature detection,short-circuit detection,gate protection,etc.Then this article analyzed,designed and simulated the high-side switch's drive circuit and control circuit.The working process of the driving circuit is as follows:the oscillator and the charge pump rise the gate voltage to make the power device work normally.The logic control unit can integrate the signals of each protection module to control the driver and oscillator.Finally,this article used the simulation software Cadence Spectre to simulate the driver of the high-side power switch and the protection modules.And the overall circuit of the chip are also simulated and analyzed.At the normal temperature of 25°C,the chip's on-resistance is 30m?,the chip's turn-on time is 124?s,and the turn-off time is40?s.When the working temperature of the chip exceeds 150°C,the over-temperature protection will be activated,and the chip will be started again when the temperature below 140°C.The trigger of the overvoltage protection is 45 V,and the turn-off trigger is42 V,which also has a certain hysteresis.The startup threshold of the under voltage protection is 3.5V.When the supply voltage and the output voltage's difference is greater than 8.3V,the short-circuit protection is activated.After simulation verification,the result meets the design index.