Diodes Incorporated AP3766K6TR-G1

Overview

AP3766K6TR-G1 from Diodes Incorporated is a primary-side regulation (PSR) AC/DC controller for offline LED drivers and battery chargers, implementing discontinuous conduction mode (DCM) flyback topology with pulse frequency modulation (PFM). It delivers accurate constant voltage (3.83 V typical feedback threshold) and constant current (510 mV current sense threshold) regulation, achieves ≤30 mW no-load input power, and operates in SOT26 package.

For engineers reviewing the AP3766K6TR-G1 datasheet, AP3766K6TR-G1 pinout, AP3766K6TR-G1 application, or AP3766K6TR-G1 equivalent, key selection criteria include sub-µA start-up current (0.6 µA), integrated open-feedback and short-circuit protection, elimination of opto-coupler and loop compensation circuitry, and thermal performance with 150°C max junction temperature.

Technical Context

The AP3766K6TR-G1 implements primary-side sensing via auxiliary winding feedback (FB pin) and primary current sampling (CS pin), enabling precise CV/CC regulation without secondary-side components. Its PFM control engine dynamically adjusts switching frequency to maintain regulation across line/load variations while suppressing EMI through random frequency modulation.

Internal blocks include UVLO (16–21 V start-up, 7.2–10.2 V operating range), peak-current-controlled driver (50 mA sink capability at OUT), and built-in soft-start with leading-edge blanking (750 ns). The device supports DCM operation only and requires external NPN transistor for power switching.

Key Specifications

Pinout & Package

SOT26 package: 6-pin, surface-mount, lead-free, RoHS- and halogen-free "Green" compliant; dimensions 2.82 × 2.65 × 1.1 mm (max height).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side regulation controller applications.

Compared with BP3122D-SL and CR6842S, the AP3766K6TR-G1 uniquely integrates PFM-based DCM control, sub-µA start-up, and true dual CV/CC regulation without opto-coupler - making it optimal for compact, efficient, and certified LED drivers and USB-charger designs.

Availability

AP3766K6TR-G1 is available at Aetrix Electronics and suitable for LED lighting drivers, mobile phone chargers, and smart home sensor power supplies requiring stable component supply, RoHS/Green compliance, and long-lifecycle support.

Supply support for AP3766K6TR-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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The AP3766 belongs to Diodes' AC/DC PSR controller product line, engineered specifically for cost-sensitive, high-efficiency offline LED drivers and battery chargers that demand regulatory compliance, compact size, and simplified bill-of-materials.

FAQ

What external components are mandatory for AP3766K6TR-G1 to operate?

The AP3766K6TR-G1 requires an external NPN transistor (e.g., MMBT4401) driven by the OUT pin, a current-sense resistor on the CS pin, an auxiliary winding with voltage divider on the FB pin, and a VCC bypass capacitor. No opto-coupler, TL431, or loop compensation network is needed - reducing total component count to under 12 for basic DCM flyback.

How does the AP3766K6TR-G1 achieve constant current regulation without secondary sensing?

It uses primary-side current sensing via the CS pin to set peak primary current, then correlates that to output current using transformer turns ratio and DCM timing. The FB pin monitors auxiliary winding voltage to adjust switching frequency and maintain constant output voltage - enabling simultaneous CV/CC regulation with only primary-side components.

Can AP3766K6TR-G1 be used in continuous conduction mode (CCM)?

No - the AP3766K6TR-G1 is designed exclusively for discontinuous conduction mode (DCM) flyback operation. Its internal timing, peak-current detection, and PFM engine are optimized for DCM. Attempting CCM operation results in loss of regulation, instability, or device shutdown due to incorrect t_ON calculation and lack of valley-switching detection.

What is the purpose of the dual GND pins (pins 2 and 5) in the SOT26 package?

Pins 2 and 5 serve as separate power and signal ground returns: Pin 2 carries high di/dt switching current from the external NPN collector path, while Pin 5 provides quiet reference for FB and CS analog sensing. This separation minimizes ground bounce and improves CV/CC regulation accuracy - especially critical in PSR architectures where feedback relies on small-signal voltage measurements.