This document describes the application of digital power factor correction technology in tube lamp ballasts and other digital power supplies controlled by an 8-bit microcontroller. It focuses on power control and ballast protection.
This document describes a digital power factor correction (PFC) solution for electronic ballasts and power supplies. It focuses on the first block of a digital ballast scheme, which provides a stable DC bus voltage and controls input current shape to meet IEC standards. The design utilizes an 8-bit microcontroller, specifically the ST7Lite19B, combined with a power management unit, the L6382D5, to replace traditional analog controllers.
The note covers the theoretical basis for using Transition Mode (TM) PWM in boost topologies, the implementation of an Enhanced One Pulse Mode within the microcontroller, and the design of power circuits including input/output capacitors, boost inductors, and MOSFETs. It also details signal measurement, processing, and control strategies for input voltage, output voltage, and zero current detection.
| Microcontroller | ST7FLITE19B |
|---|---|
| Power Management Unit | L6382D5 |
| DC Bus Voltage Stability | 2% |
| Input Voltage Range | European mains |
The design is intended for tube lamp ballasts and other digital power supplies controlled by an 8-bit microcontroller.
The reference design uses the ST7FLITE19B microcontroller.
It acts as a power management unit that provides a stable 5V supply for the microcontroller and supplies a high voltage start-up.