Freescale AC-DC 开关电源解决方案

RD56F8300SMPS : Digital AC/DC Switched-Mode Power Supply using a 56F8300 Digital Signal Controllers
A full digital power AC to DC Switched-Mode Power Supply (SMPS) system includes both digital power control and digital power management. In digital power control, the control feedback or feed-forward loop that regulates the output of the power system is directly controlled by a 56800/E Digital Signal Controller (DSC) by driving a power switch duty cycle using a pulse width modulation technique. The DSC also provides the digital power management function, which provides configuration, tracking, monitoring, protection, guiding supply sequence, and communication capabilities. In a more traditional approach, the power control function would be performed using analog circuitry while the power management would be performed with a Microcontroller.

An SMPS fully digitally controlled by software running on a DSC has many advantages over mixed analog- and Microcontroller implementations. The benefits of going to digital power conversion are:

Power applications become more flexible and universal
Improved control algorithms are possible
Intelligent mode management and fault supervision
Operating status is monitored and controlled in real time
Lower system and maintenance cost
Designs can lower the cost of isolation
Improved efficiency and performance
Improved protection of intellectual property

This reference design is a fully digitally controlled high-frequency Switched-Mode Power Supply based on a 56F8323 device. It is composed of two subsystems. The primary side is the AC-DC converter with power factor correction (PFC) and on the secondary side is a full bridge DC-DC converter. The AC-DC part uses an interleaved PFC boost control structure which includes a full bridge rectifier and two assistant switches to realize the zero voltage switch (ZVS) of the main switches. By implementing a ZVS switching scheme, the components stress and switching losses are reduced, and the efficiency is improved. The DC-DC converter portion uses the control structure of a phase-shifted full bridge (PSFB). The integrated features of the on-chip PWM module perform the phase shifting. On the secondary side, a current doubler rectification is implemented. This structure eliminates the expensive analog isolation and reduces the size of both PCB and heatsink and improves the efficiency enabling higher power density.
RD56F8300SMPS Features
General:
500-Watt fully digital switched-mode power supply controlled by
- A 56F8323 with power factor correction
- A 56F8323 for secondary with phase shifting technique
General Benefits:
Power applications become more flexible and universal
High input power factor lowers power pollution to the power grid
Intelligent mode management and fault supervision
Operating status is monitored and controlled in real time
Lower system and maintenance cost
Performance:
Input voltage: 85 ~265VAC
Input frequency: 45 ~65HZ
Rating output voltage:48VDC
Rating output power: 500W
Switch frequency: >100K
Power factor>95%
Efficiency>90%
Communications:
RS232 port for communication with opto-isolation
Visual Interface:
Multi segment LED indicators (input voltage, input current, output voltage, and output current)
电路原理图: