LNK500 Datasheet, PDF (1/20 Pages) Power Integrations, Inc. – Energy Efficient, CV or CV/CC Switcher for Very Low Cost Adapters and Chargers

LNK500
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) solution
• Extremely simple circuit configuration
• Up to 75% lighter power supply reduces shipping cost
• Primary based CV/CC solution eliminates 10 to 20 secondary
components for low system cost
• Combined primary clamp, feedback, IC supply, and loop
compensation functions – minimizes external components
• Fully integrated auto-restart for short circuit and open loop
fault protection – saves external component costs
• 42 kHz operation simplifies EMI filter design
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 clamp 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.
LNK500 is a lower cost version of the LNK501 with a wider
tolerance output CC characteristic. LinkSwitch introduces a
revolutionary patented topology for the design of low power
switching power supplies that rivals the simplicity and low
LinkSwitch
D
S
C
Wide Range
HV DC Input
DC
Output
(V_O)
(a)
Example Characteristic
V_O
Min
(CV only)
Typ
(CV/CC)
V_O
±10%
±5%
±25%*
For Circuit
Shown Above
I_O
(b)
±25%*
I_O
With Optional
Secondary Feedback**
*Estimated tolerance achievable in high volume production
including transformer and other component tolerances.
**See Optional Secondary Feedback section.
PI-3415-021103
Figure 1. Typical Application – Not a Simplified Circuit (a) and
Output Characteristic Tolerance Envelopes (b).
OUTPUT POWER TABLE¹
PRODUCT⁴
230 VAC ±15%
85-265 VAC
No-Load
Input
Min² Typ² Min² Typ² _Power
LNK500 ^{3.2 W 4 W 2.4 W 3 W <300 mW}
P or G _{4.3 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.
cost of linear adapters, and enables a much smaller, lighter, and
attractive package when compared with the traditional “brick.”
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