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LinkSwitch-4 Family
Energy-Efficient, Accurate Primary-Side Regulated CV/CC Switcher for Adapters and Chargers
Product Highlights
Dramatically Simplifies CV/CC Converters • Eliminates optocoupler and all secondary CV/CC control circuitry • Eliminates all control loop compensation circuitry
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
EcoSmart™– Energy Efficient • 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
Green Package • Halogen free and RoHS compliant package
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%.
Figure 3. SOT-23-6 and SO-8 Packages.
LinkSwitch-4 U1
BD
~ LNK4xx2S
ED
VCC CS
FB
GND
Figure 1. Typical Application (SOT-23-6) (S).
+
PI-7462-122315
+
BD
ED
~ LinkSwitch-4
VCC
U1
LNK40x3D
SBD CS
FB
GND
Figure 2. Typical Application (SO-8) (D).
PI-7464-010815
Output Power Table
Product3,4
85 - 265 VAC
Features5
Adapter1 Open Frame2
LNK43x2S LNK40x2S LNK40x3S LNK4323S LNK40x3D LNK4323D LNK40x4D LNK4114D LNK4214D LNK4115D LNK4215D
13003 Drive STD STD STD STD STD STD
Easy Start Easy Start + Constant Power
Easy Start Easy Start + Constant Power
5W 6.5 W 8W 8W 10 W 10 W 15 W 15 W 15 W 18 W 18 W
Table 1. Output Power Table.
Notes: 1. Minimum continuous power in a typical enclosed adapter measured at +50 °C
ambient, 85-265 VAC 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.
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This Product is Covered by Patents and/or Pending Patent Applications.
May 2018
LinkSwitch-4
VDD
VDD(REG) VDD REGULATOR
IFBHT(LO) IFBHT(START)
VHT ESTIMATOR
VIN UVP
FEEDBACK (FB)
VOVP
VOUT OVP
Reset Signal
RESET CIRCUIT
CYCLE TIMING
VVCC(RUN)
CV VOLTAGE CONTROL
CABLE COMPENSATION
VVCC(SLEEP)
THERMAL SHUTDOWN
PFM/PWM
CURRENT SENSE (CS)
CS BLANKING
CC CURRENT CONTROL
VCSTHR
CS
VCMAX
OCP
Figure 4. LNK40x2S, LNK40x3S, LNK4323S and LNK43x2S Functional Block Diagram.
VOLTAGE SUPPLY (VCC)
BASE DRIVE (BD)
EMITTER DRIVE (ED)
GROUND (GND)
PI-7460-033015
2
Rev. F 05/18
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VDD
VDD(REG)
VDD REGULATOR
LinkSwitch-4
VOLTAGE SUPPLY (VCC)
IFBHT(LO) IFBHT(START)
VHT ESTIMATOR
VIN UVP
FEEDBACK (FB)
VOVP
VOUT OVP
Reset Signal
RESET CIRCUIT
CYCLE TIMING
VVCC(RUN)
CV VOLTAGE CONTROL
CABLE COMPENSATION
VVCC(SLEEP)
THERMAL SHUTDOWN
PFM/PWM
CURRENT SENSE (CS)
CS BLANKING
CC CURRENT CONTROL
VCSTHR
CS
VCMAX
OCP
Figure 5. LNK40x3D, LNK4323D, LNK40x4D, LNK4114D, LNK4115D and LNK4215D Functional Block Diagram.
SUPPLEMENTARY BASE DRIVE (SBD)
BASE DRIVE (BD)
SWITCH
EMITTER DRIVE (ED)
GROUND (GND)
PI-7465-033015
Pin Functional Description
VOLTAGE.