Design Of Isolation And Feedback Circuit For Power Management Utilities

In order to make sure the signal output of the power supply is more stable and secure, electric isolation should be considered in the output sample circuit and controlled circuit to prevent the noise disturbance between the primary and secondary. Usually, the coupling circuit is used to isolates the noise and transfers the signal. There will be many defaults if we use classical separated elements in the circuit, for example, the volume will be very large; the system will not stable etc. In other words, the circuit using classical separated elements is not fit for the high quality power supply. The aim of this thesis is to design a power management integrated circuit(IC) to meet the development of the modern power supply. The IC we designed can instead the classical coupling circuit in the future.The details of this IC are described following: the modules in the circuit are reference source module, voltage comparator module, high frequency oscillator module, modulator module and so on. The low frequency error signal which is obtained by comparing the amplified output voltage with the reference source voltage is modulated to the high frequency carrier wave that is outputted from the oscillator, and then the modulated signal transfer to the outer pulse width modulation (PWM) unit. Then the isolation is realized. The main virtue of this circuit is stable and feedback controllable. In this work, we also use the Workview EDA and HSPICE software to simulate and verify the whole circuit. The test results are in agreement with the initial design. In many aspects, the results such as the precision of the reference voltage and the comparing amplifier factor are even better than the anticipation. The physical layout is designed in the end based on the Standard Buried Collector(SBC) bipolar IC process and the size is 2×3mm~2. In conclusion, not only the coupling transformer mode but also the more advanced optical coupler mode could be applied in the signal transfer, which makes the IC is more convenient. Moreover, for the bipolar process, the circuit radiation capability is excellent and can be used in the aeronautic field.