Diodes Incorporated AP1661MTR-G1

Overview

AP1661MTR-G1 from BCD Semiconductor Manufacturing Limited is a BiCMOS active power factor correction (PFC) controller IC designed for DCM boundary conduction mode operation in AC-DC adapters, off-line SMPS, and electronic ballasts. It integrates zero-current detection, a one-quadrant multiplier with 0.45–0.75 V⁻¹ gain, 2.5 V ±1% internal reference, and totem-pole gate driver delivering 600 mA source / 800 mA sink current.

For engineers reviewing the AP1661MTR-G1 datasheet, AP1661MTR-G1 pinout, AP1661MTR-G1 application, or AP1661MTR-G1 equivalent, key selection criteria include its 2.5 V error amplifier reference precision, 2.5 V hysteresis UVLO (11 V turn-on / 9.5 V turn-off), adjustable OVP threshold (2.25 V static), low 50 μA typical start-up current, and SOIC-8 green-package compatibility with industrial temperature range (−40°C to +85°C).

Technical Context

The AP1661 operates exclusively in discontinuous conduction mode (DCM) boundary control using zero-current detection on Pin 5 (ZCD) with 2.1 V rising-edge threshold and 0.5 V hysteresis. Its multiplier accepts VMULT (0–3.5 V) and VCOMP (2.0–5.8 V) inputs to generate a dynamic current-sense reference (VCS), enabling sinusoidal input current shaping.

Control logic combines cycle-by-cycle current limiting via CS comparator (clamped at 1.7–1.8 V), fast dynamic OVP triggered at 40 μA error amplifier sink current, and static OVP activation when COMP falls below 2.25 V. The internal 70–400 μs restart timer ensures controlled recovery after fault conditions.

Key Specifications

Pinout & Package

AP1661MTR-G1 is housed in a green RoHS-compliant SOIC-8 package (5.8 mm × 4.9 mm, 1.27 mm pitch), rated for −40°C to +85°C ambient operation and optimized for surface-mount assembly in compact AC-DC converters.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power factor correction controller applications.

Compared with UCC28019DR and FAN7930CMX, AP1661MTR-G1 offers discrete MOSFET control with higher gate drive strength (800 mA sink), explicit ZCD timing interface for precise boundary detection, and lower start-up current-making it optimal for ruggedized, medium-power (65–120 W), thermally managed PFC stages.

Availability

AP1661MTR-G1 is available at Aetrix Electronics and suitable for AC-DC adapters, electronic ballasts, and off-line SMPS requiring stable component supply with green packaging, industrial temperature range, and long-term manufacturing continuity.

Supply support for AP1661MTR-G1 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

BCD Semiconductor Manufacturing Limited is a Shanghai-based analog and power IC designer specializing in high-voltage, high-efficiency power management solutions for consumer, industrial, and lighting markets.

The AP1661 belongs to BCD's active PFC controller product line, engineered specifically for cost-effective, high-reliability DCM boundary-mode operation in universal-input AC-DC conversion systems up to 150 W.

FAQ

What is the recommended minimum ZCD signal amplitude for reliable boundary-mode operation?

The ZCD pin requires ≥2.1 V rising-edge voltage with ≥0.5 V hysteresis to ensure clean zero-current detection. In practice, auxiliary winding design must deliver ≥2.5 V peak at minimum input (85 VAC) and maintain ≥1.6 V at maximum input (265 VAC) to avoid false triggering or missed turn-on events. Layout must minimize noise coupling to Pin 5.

How does the AP1661 implement overvoltage protection without an external sensing resistor?

AP1661 uses dual OVP mechanisms: dynamic OVP monitors current sinking into the COMP pin-excess current (>40 μA) from feedback capacitor discharge triggers immediate shutdown; static OVP activates if COMP voltage drops below 2.25 V, indicating sustained overvoltage. No external resistor is needed because both rely on internal current and voltage thresholds tied to the error amplifier node.

Can the AP1661MTR-G1 operate with a 24 V auxiliary supply instead of high-voltage startup?

Yes-the VCC pin accepts 10.3–20 V, so a regulated 15 V auxiliary supply is fully compatible. However, the internal start-up timer and 50 μA start-up current are optimized for high-voltage startup from rectified line via resistive dropper; using 24 V requires external LDO or zener clamp to stay within 20 V absolute maximum rating.

What is the impact of VCOMP clamping on PFC loop stability and transient response?

VCOMP upper clamp (5.8 V) and lower clamp (2.25 V) limit integrator swing, preventing saturation during overloads or OVP events. This preserves phase margin during recovery and avoids long settling times. Loop compensation must be designed assuming 3.55 V effective output swing (5.8 V – 2.25 V), not full rail-to-rail, to maintain stability across line/load transients.