Adopt two-hose sharing positive excited and topologically and construct the high-performance module power - Technology

Adopt two-hose sharing positive excited and topologically and construct the high-performance module power Two-Switch Forward Topology Power Supply ModuleMaxim power portion to still celebrate the bright foreword High power density, small exterior size with high efficiency have already become key actuator force of power technical development of present module. The double-barrelled forward circuit realizes one of the practical circuit required, while applying to extensively, in the heavy-duty power design. This text has introduced operating principle and advantage of the double-barrelled forward circuit briefly, introduced function and concrete experimental result of PWM control device MAX5051 that applies double-barrelled forward circuit to in detail at the same time.

Positive excited converter of two-hose sharing

Fig. 1 two-hose sharing positive excited converter and schematic diagram and waveform of the double-barrelled positive excitation converter of working waveform is shown as in Fig. 1. The work of the double-barrelled positive excitation converter can be divided into three pieces of course: Stage, voltage transformer magnetism reset stage and inert zone stage in energy transfer. At energy transfer stage, both switches in the primary side are turned on, energy is shifted from input end to the Ausgang. Reset stage in the voltage transformer magnetism, two diodes in the primary sides are both turned on, make the coil of the voltage transformer bear the input voltage of the oppisite phase, thus realize the voltage transformer magnetism is reset. After the voltage transformer is totally reset, the converter works at the stage in the inert zone, there is no flowing, secondary after flow in the primary side. In the course of resetting, two-hose sharing positive excited switch MOSFE T is clamped in the input voltage. The voltage stress on MOSFET is smaller than the single-hose sharing positive excited, at least one -fold lowerly. In this way we can choose the low-voltage MOSFET with low on resistance Rdson, in order to obtain the low loss. It is very steady that the double-barrelled forward circuit runs, receive the designer's extensive concern, and comment on the great. Because two switches in the primary side are not to use the structure of the totem, their shoot-through, this solves and punctures the problem. To semi-bridge and full bridge converter, the primary side switch uses the structure of the totem, once because the electromagnetic noise or electromagnetic radiation causes two pieces of switch shoot-through, the circuit will receive destructive break. This question is essential to power influenced by high-energy radiation, and the double-barrelled forward circuit can avoid this question.

On the basis of reference design MAX5051 of MAX5051 being a clamping type, one pair of switches power control unit IC. This control chip can be applied to the positive excited or anti exciting structure, it is from 11V to 76V to input the voltage range. It offers the overall protection mechanism to various possible troubles, realizes the high reliability power. When cooperating with secondary synchronous rectifier, power efficiency is up to 92% (+3.3V output power supply very easily, the work is on 48V bus line); Integrated high-side and low-side grid driver can offer the grid drive current of the crest value above 2A for two external nchannels MOSFET; The low starting current has reduced the power consumption on the starting resistance; The voltage mode control scheme with feedforword control can offer excellent circuit inhibition, while avoided the defect of the traditional electric current mode control scheme. MAX5051 power control unit can be used for designing the red undant power system if necessary on main side or a side parallel operation. As the parallel operation of main side, can wake up or shut off all and connect the unit in parallel at the same time through the specialized pin, in order to prevent that the unbalance of electric current takes place under starting or trouble situation. The signal is used for driving the secondary synchronous MOSFET MAX5051's advancing through producing No. one, in order to avoid the shoot-through of secondary synchronous rectifier tube and after flow tube. Utilize peculiar main the intersection of side and synchronous the intersection of I/O and pin, can enable two pieces of main side circuit phase difference 180

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