The Design Of Low Temperature Cofficient Oscillator Applied To IPM

The monolithic intelligent power module,because of its high integration,low power consumption and high reliability,is widely emplyed in the low-power and high-reliability power electronic application systems(such as motor drive,power management,etc.).Because of its working frequency determined by the oscillator integrated in the chip,and the power switch transistor integrated in its internal work under several hundred voltages,produces in the process of switch power tube amps level of currenit,working in this environment will produce a large quantity of heat to improve the temperature of the chip,the frequency stability of the oscillator will be influenced,so a low temperature coefficient oscillator is particularly important in the chip.This thesis analyses the working principle and performance of the window-type relaxation oscillator,the temperature and electric voltage characteristic of the oscillator is mainly studied.In this thesis,the influence of oscillator frequency stability parameters includes the current source charging the capacitor,the upper and lower voltage of capacitor and the delay of comparator and the trigger in the circuit First,the low temperature coefficient current source can be realaised by the adjustable external input voltage stability of voltage in series parallel temperature compensation of low temperature coefficient of resistance;Second,the threshold voltage of the comparator can be set by using current mode bandgap reference circuit to produce low temperature coefficient voltage;Finally,the delay of the comparator and trigger can be eliminated by using the circuit of charging capacitor in advance.Through the optimization of three key parameters,the stability and temperature characteristic of the oscillator get improved.The layout design and tape-out of the relaxation oscillator circuit proposed in this paper are based based on CSMC 0.5 600V?m SOI process.Test results show that compared with the traditional scheme in this paper,the design of the relaxation oscillator performance has significantly increased.in-40??125? temperature coefficient is 156 ppm/?,the error of the frequency absolute value is less than 2.23%,compared with traditional circuit is reduced by 48%,When the power supply voltage changes from 13 V to 17V,the error of the frequency absolute value is less than 1.97%,compared with traditional circuit is reduced by 34%,maximum power consumption is 1.785mW,the above indexes meet the design requirements.