Primary-side switcher increases power supply efficiency

Primary‑side power switchers that enable power supply designers to achieve high conversion efficiency to meet Energy Star Level 6 and EU CoC Tier 2 requirements, are announced by Diodes.

The AP3983 operates at up to 80kHz and employs piecewise Pulse Frequency Modulation (p‑PFM) in discontinuous conduction mode to regulate the primary-side voltage and current to better than ±5 per cent. It provides audible noise-free switching for chargers, ADSL adapters and home appliance power supplies, says the company.

With an integrated 650V or 700V BVDSS MOSFET, the switcher eliminates opto-couplers and secondary-side CV/CC control circuitry to minimise external component count. There is also built-in fixed cable voltage-drop compensation, adjustable line-voltage compensation and safety functions, such as, over-voltage and over-temperature protection, and a hiccup function to improve response to short circuits.

A low start-up current (0.6microA, max) is combined with a no-load power consumption (75mW, max) and load transient stability for cost-effective switching for consumer power supplies.

Devices in the family support six to 20W adapter ratings and package types are SO-7 or PDIP-7.


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