LNK520 Datasheet, PDF (1/20 Pages) Power Integrations, Inc. – Energy Efficient, CV or CV/CC Switcher for Very Low Cost Adapters and Chargers

LNK520
LinkSwitch^® Family
Energy Efficient, CV or CV/CC Switcher for
Very Low Cost Adapters and Chargers
Product Highlights
Cost Effective Linear/RCC Replacement
• Lowest cost and component count, constant voltage (CV)
or constant voltage/constant current (CV/CC) solutions
• Optimized for bias winding feedback
• Up to 75% lighter power supply reduces shipping cost
• Primary based CV/CC solution eliminates 10 to 20
secondary components for low system cost
• Fully integrated auto-restart for short circuit and open
loop fault protection – saves external component costs
• 42 kHz operation with optimized switching
characteristics for significantly reduced EMI
Much Higher Performance Over Linear/RCC
• Universal input range allows worldwide operation
• Up to 70% reduction in power dissipation – reduces
enclosure size significantly
• CV/CC output characteristic without secondary feedback
• System level thermal and current limit protection
• Meets all single point failure requirements with only one
additional bias capacitor
• Controlled current in CC region provides inherent soft-start
• Optional opto feedback improves output voltage accuracy
EcoSmart^®– Extremely Energy Efficient
• Consumes <300 mW at 265 VAC input with no load
• Meets California Energy Commission (CEC), Energy
Star, and EU requirements
• No current sense resistors – maximizes efficiency
Applications
• Linear transformer replacement in all ≤3 W applications
• Chargers for cell phones, cordless phones, PDAs, digital
cameras, MP3/portable audio devices, shavers, etc.
• Home appliances, white goods and consumer electronics
• Constant output current LED lighting applications
• TV standby and other auxiliary supplies
Description
LinkSwitch is specifically designed to replace low power linear
transformer/RCC chargers and adapters at equal or lower system
cost with much higher performance and energy efficiency.
LNK520 is equivalent to LNK500 but optimized for use with bias
winding feedback and has improved switching characteristics
for significantly reduced EMI. In addition, if bias and output
windings are magnetically well coupled, output voltage load
Wide Range
HV DC Input
D
LinkSwitch
C
S
(a)
Example Characteristic
V_O
Min
(CV only)
Typ
(CV/CC)
V_O
±10%
±5%
+
DC
Output
(V_O)
±24%*
For Circuit
Shown Above
I_O
(b)
±24%*
I_O
With Optional
Secondary Feedback**
*Estimated tolerance achievable in high volume production (external
components with ±7.5% transformer inductance tolerance included).
**See Optional Secondary Feedback section.
PI-3587573-083064034
Figure 1. (a) Typical Application – not a Simplified Circuit and
(b) Output Characteristic Tolerance Envelopes.
OUTPUT POWER TABLE¹
PRODUCT⁴
230 VAC ±15%
85-265 VAC
No-Load
Input
Min² Typ² Min² Typ² _Power
LNK520 ^{3.3 W 4 W 2.4 W 3 W <300 mW}
P or G _{4.2 W 5.5 W 2.9 W 3.5 W <500 mW}³
Table 1. Notes: 1. Output power for designs in an enclosed adapter
measured at 50 °C ambient. 2. See Figure 1 (b) for Min (CV only
designs) and Typ (CV/CC charger designs) power points identified
on output characteristic. 3. Uses higher reflected voltage transformer
designs for increased power capability – see Key Application
Considerations section. 4. For lead-free package options, see Part
Ordering Information.
regulation can be improved. With efficiency of up to 75% and
<300 mW no-load consumption, a LinkSwitch solution can
save the end user enough energy over a linear design to
completely pay for the full power supply cost in less than
one year. LinkSwitch integrates a 700 V power MOSFET,
PWM control, high voltage start-up, current limit, and thermal
shutdown circuitry, onto a monolithic IC.
February 2005