AN1320 L6574 Microcontroller Interface Application Note

About this manual

The document addresses the need for flexible ballasts that can operate with different tubes without changing soldered components. It proposes using a microcontroller to supervise and control the L6574 integrated circuit, allowing key application parameters to be modified by changing the micro-code.

The text details how to interface a microcontroller with the L6574 to control preheat timing, frequency shifting, fault signals, and lamp dimming. It explains that while traditional settings use external resistors and capacitors, this approach uses PWM outputs from the microcontroller to set voltage references on specific pins of the IC.

What's inside

• Introduction
• L6574 Overview
• Setting Frequencies in Analog Application
• Fault Signals EN1 and EN2
• Closed Loop Control with Sense Op-Amp
• Microcontroller Interface for Frequency and Timing
• PWM Output Usage
• Demo Application Board

Specifications

Frequently asked questions

What is the main aim of using a microcontroller with the L6574?

To allow key parameters of the application to be modified according to tube characteristics just by changing the micro-code, saving money on parts and models.

How can lamp dimming be achieved with the L6574?

By changing the reference voltage on the non-inverting input of the sense op-amp, which changes the oscillator frequency and thus the current in the load.