STMicroelectronics EVAL6574B

Overview

EVAL6574B from STMicroelectronics is an evaluation board for the L6574 high-voltage CFL/TL ballast controller IC, designed to drive half-bridge MOSFETs in fluorescent lamp electronic ballasts. It supports preheat, ignition, and closed-loop current regulation with 600V rail capability, ±50 V/ns dV/dt immunity, 250mA source / 450mA sink gate drive, 80/40ns rise/fall times (1nF load), and integrated bootstrap diode functionality.

For engineers reviewing the EVAL6574B datasheet, EVAL6574B pinout, EVAL6574B application, or EVAL6574B equivalent, this board enables rapid validation of L6574-based ballast designs-including preheat timing calibration, frequency shifting behavior, op-amp feedback loop implementation, and HV gate driver performance under real lamp load conditions.

Technical Context

The EVAL6574B implements the full L6574 functional block diagram: preheat timing via CPRE capacitor charging, frequency shift control using RPRE and RIGN resistors, oscillator frequency setting with CF, and closed-loop lamp current regulation via the integrated op-amp (OPIN+, OPIN−, OPOUT). The board routes all critical signals-including VS, VBOOT, OUT, HVG, LVG, and EN1/EN2-to accessible test points and connectors.

It supports both SO16N and DIP16 L6574 variants, incorporates clamping on VS, integrates the patented bootstrap DMOS switch replacing external diodes, and provides direct access to the sense op-amp inputs/outputs for custom feedback network prototyping-enabling accurate verification of lamp current control stability and transient response.

Key Specifications

Availability

EVAL6574B is available at Aetrix Electronics and suitable for fluorescent lamp ballast development, lighting system qualification, power electronics education, and industrial lighting retrofit programs requiring stable component supply and documented reference design validation.

Supply support for EVAL6574B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, microcontrollers, and automotive-grade ICs with broad industrial and consumer applications.

EVAL6574B belongs to ST's Lighting & Power Conversion Evaluation Kit portfolio, developed specifically to accelerate design-in of high-voltage AC-DC ballast controllers for compact fluorescent and T5/T8 lamp systems.

FAQ

What lamp types and wattages does EVAL6574B support?

EVAL6574B is configured for standard 22–40W T8/T5 fluorescent lamps operating at 50–60Hz line frequency. It supports preheat times from 0.5–2s and ignition frequencies from 58–126kHz, adjustable via CPRE, RPRE, RIGN, and CF components per L6574 datasheet guidelines.

Does EVAL6574B include protection features like lamp removal detection?

Yes - EVAL6574B exposes EN1 and EN2 pins to implement lamp removal or open-circuit protection using external comparators or logic. EN1 triggers latched shutdown on fault; EN2 restarts preheat sequence. UVLO (9.5–10.9V turn-on threshold) and internal VS clamping (15.6V typical) are fully operational on the board.

Can EVAL6574B be used with MOSFETs other than those specified in the reference design?

Yes - the board provides solder pads and test points for gate resistors on both HVG and LVG outputs, enabling direct substitution of discrete MOSFETs. Layout maintains low-inductance paths for VS, VBOOT, and OUT, supporting devices rated ≥600V with gate charge compatible with L6574's 250mA/450mA drive capability.

Is closed-loop lamp current control demonstrated on EVAL6574B?

Yes - the board includes jumper-selectable op-amp feedback paths and provision for shunt resistor placement at the lamp cathode. With OPOUT connected to RIGN via RC network (per AN993), it validates real-time frequency modulation based on sensed lamp current, achieving stable burning-phase regulation.