Advanced Performance Features
• Dynamic base drive technology provides flexibility in choice of BJT
transistor by dynamically optimizing BJT switching characteristics
• Extends RBSOA of BJT
• Dramatically reduces sensitivity to BJT gain
• Compensates for input line voltage variations
• Compensates for cable voltage drop
• Compensates for external component temperature variations
• Very accurate IC parameter tolerances using proprietary trimming
technology
• Frequency up to 65 kHz to reduce transformer size
• The minimum peak current is fixed to improve transient load response
Enhanced Performance Features
• Easy start for starting into capacitive loads (LNK4114D, LNK4115D)
• Constant power for high current start-up (LNK4214D, LNK4215D)
• 13003 drive improved efficiency with 13003 BJT’s (LNK4302S,
LNK4322S)
Advanced Protection/Safety Features
• Single fault output overvoltage and short-circuit
• Over-temperature protection
• Active clamp
Applications
• Chargers for cell/cordless phones, PDAs, MP3/portable audio
devices, adapters, networking, etc.
Description
The LinkSwitchTM-4 family of ICs dramatically simplifies low power CV/CC
charger design by eliminating an optocoupler and secondary control
circuitry. The LinkSwitch-4 family adaptive BJT drive technology uses
combined base and emitter switching to boost switching performance
and deliver higher efficiency, wider Reverse Bias Safe Operating Area
(RBSOA) margin and the flexibility to accommodate a wide range of low
cost BJT. The device incorporates a multimode PWM/PFM controller
with quasi resonant switch to maximize the efficiency, meets low
no-load power and at same time maintain fast transient response
greater than 4.3 V with a load change from 0% to 100%.