Diodes Incorporated AL1677-20BS-13

Overview

AL1677-20BS-13 from Diodes Incorporated is a universal AC-input (85–277 VAC) buck LED driver IC with integrated 2 A/500 V MOSFET, delivering ±3% current accuracy and 90% efficiency at full load in boundary conduction mode (BCM). It serves as a constant-current source for retrofit GU10/bulb LED lamps up to 15 W, featuring built-in UVLO, OTP, LED short/open protection, and thermal fold-back.

For engineers reviewing the AL1677-20BS-13 datasheet, AL1677-20BS-13 pinout, AL1677-20BS-13 application, or AL1677-20BS-13 equivalent, key selection criteria include integrated high-voltage MOSFET rating (2 A/500 V), BCM operation for EMI reduction, thermal fold-back threshold, line/load regulation performance, and SO-8 package compatibility with high-temperature PCB layouts.

Technical Context

The AL1677-20BS-13 implements a primary-side sensing buck converter topology operating in boundary conduction mode (BCM), eliminating the need for an auxiliary winding or external high-voltage MOSFET. Its internal 2 A/500 V MOSFET enables direct high-voltage switching with minimal external components.

Control logic integrates cycle-by-cycle current limiting, UVLO (12.5 V turn-on / 8.5 V turn-off), overtemperature protection (OTP), and automatic thermal fold-back triggered above 145 °C. Line and load regulation remain within ±3% across 85–277 VAC input and full output current range.

Key Specifications

Pinout & Package

AL1677-20BS-13 is housed in a standard SO-8 surface-mount package with exposed thermal pad (pin 8 connected to GND), optimized for thermal dissipation in compact LED lamp modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED driver applications.

Compared with AL1677-10BS-13, the -20BS-13 delivers 33% higher output current in identical SO-8 packaging; versus AP1685, it reduces component count by integrating the HV switch but sacrifices external MOSFET customization and package size reduction.

Availability

AL1677-20BS-13 is available at Aetrix Electronics and suitable for retrofit LED bulbs, high-voltage DC-DC LED drivers, and general-purpose constant-current sources requiring stable component supply and long-lifecycle support.

Supply support for AL1677-20BS-13 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

Diodes Incorporated is a global semiconductor manufacturer specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and connectivity.

The AL1677 product line targets cost-sensitive, high-volume LED lighting applications requiring integrated high-voltage switching and robust protection in compact form factors.

FAQ

What is the maximum continuous LED current supported by AL1677-20BS-13?

The AL1677-20BS-13 supports up to 240 mA of continuous LED current with ±3% accuracy across line, load, and temperature. This rating assumes proper PCB thermal design with the SO-8 exposed pad soldered to ≥1 cm² copper area and ambient temperature ≤60 °C. Derating applies above 60 °C ambient per the thermal fold-back curve.

Does AL1677-20BS-13 require an external high-voltage MOSFET?

No. The AL1677-20BS-13 integrates a fully rated 2 A/500 V MOSFET, eliminating the need for any external high-voltage switching device. External components are limited to the inductor, sense resistor, input/output capacitors, and freewheeling diode - enabling a total BOM count of under 10 active/passive parts for a complete 15 W LED driver.

How does thermal fold-back operate in AL1677-20BS-13?

Thermal fold-back activates when the internal junction temperature exceeds 145 °C, progressively reducing LED current to maintain safe operating temperature. The fold-back slope is approximately −1.2 mA/°C above threshold, reaching zero current near 165 °C. Recovery occurs automatically once junction temperature falls below 135 °C, with hysteresis preventing oscillation.

Can AL1677-20BS-13 be used in triac-dimmable LED lamps?

No. The AL1677-20BS-13 lacks triac dimming compatibility circuitry and is not specified for leading-edge or trailing-edge phase-cut dimmer interfaces. It is designed for non-dimmable, constant-output applications. For dimmable solutions, Diodes recommends the AP169x series or AL166x family with dedicated dimming control inputs.