| The urge of high quality power supply for portable devices, have accelerated the researchand design of DC-DC switch-mode power supply (SMPS). The switching DC-DC convertersare widespread used in consumer electronics for its high efficiency, high precision and highpower density. A DC-DC inverting converter chip based on Buck-Boost topology andsynchronous rectification control, combined with high efficiency, good stability is achieved.In this thesis, a modeling method using Ridley’s theory of this inverting converter isdiscussed in Chapter Ⅱ.In order to make the simulated results close to actual working status,the poles and zeros of the controlling loop and its stability are analyzed.The loop stability based on Ridley’s theory is proposed in Chapter Ⅲ,a suitable erroramplifier is required in this loop for the system operating in a stable loop. The simulatedresults for this model show that: the system can meet the requirements of stability in theestablished range of input voltage and load current.According to the design specification of the chip, combined with the loop stability theoryderived in Chapter Ⅲ, the design methods was proposed in Chapter Ⅳ, the power tubes ofthis are integrated in this chip, The converter contains these modules: oscillator, erroramplifier, synchronous rectification control block, slope compensation, voltage regulator,band gap reference, and other blocks with the reliability function such as soft start, undervoltage lockout, over temperature protection, over load protection.This converter, designed in ST BCD6S0.35μm process, is able to work properlybetween the temperature range of-40~85°С with a input range2.3~4.5V. The output of theinverting converter is set to be-4.9V with a maximum load current0.5A. Simulated resultsshow that the efficiency of the entire chip maintains above80%in most states. This designscheme proposed in this thesis can provide some theoretical reference for engineering practicein DC-DC inverting converter chip. |
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