Energy-Efficient, Accurate Primary-Side Regulated CV/CC Switcher for Adapters and Chargers

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Data Sheets

Product Details

The LinkSwitch™-4 Family of offline power conversion ICs targets chargers and adapters required to meet stringent new efficiency rules from the US Department of Energy (DoE) and European Code of Conduct (CoC). The new DoE rules, known as DoE-6, require efficiency compliance measurements to be taken at the end of the charger USB cable; LinkSwitch-4 exceeds this requirement while using a low-complexity Schottky diode secondary, even for high-current 1.5 A and 2 A smartphone chargers.

The LinkSwitch-4 Family features an advanced adaptive base-emitter switched drive scheme for bipolar junction transistor (BJT) switches to substantially improve power conversion efficiency and eliminate reliability concerns due to secondary breakdown. The device incorporates a multimode PWM/PFM controller with quasi-resonant switch to maximize the efficiency and meet <30 mW no-load while still maintaining fast transient response.

Product Highlights

Advanced Performance Features

  • Adaptive base-emitter switched drive technology provides flexibility in choice of BJT transistor by optimizing BJT switching characteristics
  • Extends reverse bias safe operating area (RBSOA) of BJT
  • Dramatically reduces sensitivity to BJT gain
  • Meets DoE 6 and CoC V5 2016 via an optimized quasi-resonant switching PWM/PFM control
  • No-load consumption of <30 mW at 230 VAC input
  • Compensates for transformer inductance tolerances, input line voltage variations, cable voltage drop, and external component temperature variations
  • Accurate IC parameter tolerances using proprietary trimming technology
  • Fixed minimum peak current to improve transient load response

Enhanced Performance Features

  • Easy start for starting into capacitive loads
  • Constant power for high current start-up
  • 13003 drive improved efficiency with 13003 BJT's

Simplifies CV/CC Converters

  • Eliminates optocoupler and secondary CV/CC control circuitry
  • Eliminates control loop compensation circuitry

Advanced Protection/Safety Features

  • Single fault output overvoltage and short-circuit

Green Package

  • Halogen Free and RoHS Compliant package


Power Table

Output Power (Watts)

85-265 VAC

Features5 Adapter1
Open Frame2
LNK43x2S 13003 Drive 5
LNK40x2S STD 6.5
LNK40x3S STD 8
LNK40x3D STD 10
LNK40x4D STD 15
LNK4114D Easy Start 15
LNK4214D Easy Start + Constant Power 15
LNK4115D Easy Start 18
LNK4215D Easy Start + Constant Power 18


  1. Minimum continuous power in a typical non-ventilated enclosed adapter measured at +50 °C ambient, device TJ ≤ 100 °C.
  2. Maximum practical continuous power in an open frame design with adequate heat sinking, measured at +50 °C.
  3. Package: D: SO-8 , S: SOT-23-6.
  4. Cable compensation factor. x = 0 (no cable compensation), x = 1 (3% cable compensation) x = 2 (6% cable compensation).
  5. Easy Start feature uses the BJT current to directly charge CVCC, allowing start-up into large output capacitors. 13003 drive feature has the gate drive optimized for maximum efficiency when using 13003 BJTs. Constant power feature provides 175% of rated current at start-up, allowing start-up into large output capacitors (see Figure 15). STD are standard products with all the advanced performance and protection/safety features.

Product Documents

Design Examples

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