Next-Gen Digital Signal Controller ICs Offer 4X More Memory

May 1, 2010 12:00 PM
Sam Davis, Editor-in-Chief

A new dsPIC33F GS series Plug-in Module (MA330024) is available for the Explorer 16, which enables development with this new DSC family; specifically, the 100-pin dsPIC33FJ64GS610.

APPLICATIONS

Power Factor Correction (PFC) by average current mode control uses a DSC, as shown in Fig. 5. Many power control applications demand a stable, regulated DC power source with reduced input current harmonic content and better power factor, so power factor correction is now a requirement and no longer a matter of choice. The dsPIC devices enable implementation of PFC, in addition to the integration of this algorithm with other functions of the system such as primary side control and communication on a single chip.

Implementing advanced software digital control loops for power conversion applications requires a high-performance DSP engine along with specialized peripherals. The high-performance CPU and rich peripherals of the dsPIC DSC devices enable solutions that require a minimum of external support chips. Besides the space and cost-saving benefits of the dsPIC DSC solutions, special features enable advanced power conversion. Devices that are well suited for PFC applications include devices from the motor control and power conversion family, such as the dsPIC33FJ12MC201/202. For higher performance PFC applications, the dsPIC33FJ06GS101 is a good choice.

DIGITAL 300 WATT AC/DC POWER SUPPLY WITH PFC

SMPS and digital power conversion families include peripherals designed specifically for power conversion applications such as 1-ns resolution PWM, 4 MSPS ADC, and on-chip, high-speed analog comparators with integrated programmable reference voltages.

In this typical application, the ac-dc design unit works with universal input voltage range [85 - 65 VAC], and produces multiple dc outputs (Fig. 6). The design is based on a modular structure, which features three major power stages. The input stage is a PFC Boost Converter, the intermediate stage is a phase-shifted zero voltage transition (ZVT) converter, which includes ZVT full bridge converter and synchronous rectification. The third stage is single-phase and multi-phase buck converters.

Implementing advanced software digital control loops for power applications requires a high-performance DSP engine along with specialized peripherals. The high-performance CPU and rich peripherals of the dsPIC DSC devices enable these solutions. These devices include peripherals specifically designed for power conversion. Peripherals such as a high speed PWM, ADC and analog comparators can be tied together using an internal configurable control fabric that enables them to interact directly with one another, resulting in performance gains in digital power applications.

Isolated dc-dc power supplies are used in a wide variety of applications ranging from telecommunication equipment, industrial equipment, digital televisions, and server racks. As shown in Fig. 7, this application accepts 36V to 75V on the input and supplies a stable 12V output. The design uses a highly efficient phased shift full bridge converter and synchronous current doubler rectification on the secondary side. The single dsPIC device supports the complete power conversion control as well as intelligent power management and system communications. Devices that are well suited for dc-dc converter applications include ones from the SMPS and digital power conversion family, such as the dsPIC33FJ16GS502.

An uninterruptible power supply (UPS) application (Fig. 8) utilizes high-frequency switching techniques to implement three optimized digital power-conversion stages. The dsPIC33F GS series of digital-power DSCs from Microchip is the heart of this offline UPS application. The dsPIC33F GS controls all critical operations of the system, as well as the housekeeping operations. The dsPIC33F GS controller IC ensures that fast and reliable switchover from the power mains to the inverter, and from the inverter back to the mains, is done intelligently to ensure that power to the load is transferred without surges and sags that can interrupt operation.

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