Design Of A Current-Type PWM Controller With Fast Response

With the rapid development of electronic products,as a necessary chip of electronic products,power management chip are facing opportunities and challenges.The demand for power management chip of high performance electronic products is continuously improved,and it will also improve the design technology of power management chip.In the power module,the controller chip has the advantages of high integration,high cost-effective and wide application range.Then,a high performance power system can be achieved by using the controller with simple peripheral circuit.In this thesis,PWM controller chip is designed with peak current mode.It has the advantages of simple compensation network,fast response and better uniform flow characteristics and can achieve high efficiency and low output voltage ripple.In addition,the drive circuit uses the design architecture of the active clamp to generate the driver signal with current capability of ampere level.The power supply generation module with using self-power technology and integrated overcurrent protection can produce a good 5 V output voltage to supply the internal sub-module of chip.At the same time,the internal oscillator adopts the current mode comparator and the constant current source discharge circuit to produce the frequency of the high-precision high duty-cycle.PWM controller chip has been designed in the 0.35μm BCD process.The electrical parameters of the controller chips has been tested at high and low temperature.The output current of the controller chips are more than 1 A.In the case of controller with 1nF capacitor,the upper and lower edge of the gate drive signal is no more than 20ns.The VREF can be kept within 1%under various load,temperature and input voltage.The frequency determined by the oscillator can reach 2MHz.The electrical paramaters of the controller are in accordance with the design values.The test results show that the controller chip meets the design requirements and has good electrical performance.At the same time,the controller chip is applied to the forward converter system.Under different temperature conditions,the forward converter can be started and closed orderly.The linear adjustment rate is lower than 0.369%,and the load adjustment rate is lower than 0.042%.The results show that the controller chip can be applied to forward converter and the forward has good performance.Therefore,the controller chip can be applied to the actual power supply system.At present,the controller chip designed in this paper has realized the batch production.