NCP1207ADR2G

AC DC Converters, Offline Switchers Overview

The NCP1207ADR2G is a PWM current-mode controller designed for free-running quasi-resonant operation in flyback topologies. It integrates a true current mode modulator and demagnetization detector to ensure borderline or critical conduction mode under all load and line conditions, minimizing drain voltage switching losses. The device features an internal timer that prevents the free-run frequency from exceeding 125 kHz, keeping it below the CISPR-22 EMI starting limit. It supports adjustable skip-cycle capability for burst mode operation at low loads to eliminate audible noise. The Dynamic Self-Supply (DSS) feature simplifies transformer design by eliminating the need for an auxiliary winding for IC supply.

AC DC Converters, Offline Switchers Feature Summary

• Integrates current mode modulation with demagnetization detection for optimized quasi-resonant switching
• Features Dynamic Self-Supply (DSS) to simplify transformer design by removing auxiliary winding requirements
• Includes internal timing control to restrict maximum frequency below EMI limits while allowing user-adjustable skip-cycle foldback

AC DC Converters, Offline Switchers Applications

• High-volume consumer application power supplies
• Set-top box AC-to-DC power converters
• Battery chargers with varying output voltages

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific ordering suffix ADR2G against the manufacturer's latest datasheet to confirm package type and tape/reel specifications. Confirm RoHS compliance status and lead times directly with authorized distributors, as availability may vary. Ensure the component matches the required pinout and electrical characteristics for your specific flyback design before finalizing procurement.

AC DC Converters, Offline Switchers Selection Notes

Select this controller for cost-sensitive, high-volume designs requiring simplified transformer layouts due to the DSS feature. It is suitable for applications where maintaining critical conduction mode across wide load ranges is necessary. Consider the fixed 125 kHz upper limit if higher frequencies are required, in which case the NCP1207B variant should be evaluated instead.

AC DC Converters, Offline Switchers Part Context

This component belongs to the NCP1207 family of PWM controllers from onsemi. It is specifically engineered for primary-side regulation or simple secondary-side feedback schemes in isolated flyback converters. The device leverages high-voltage technology to connect directly to the HV DC rail, enhancing short-circuit protection reliability independent of auxiliary supply levels.

AC DC Converters, Offline Switchers Replacement Considerations

The NCP1207B is a functional alternative within the same family but operates at higher frequencies up to 200 kHz. Verify compatibility regarding EMI filtering requirements and transformer design when substituting.