RDK-158

Title Reference Design Report for a 5 W Charger Using LNK616PG Specification 85-265 VAC Input; 5 V, 1 A Output Application Low-cost Charger or Adapter Author Applications Engineering Department Document Number RDR-158 Date November 25, 2008 Revision 1.1 Summary and Features • Revolutionary control concept provides very low cost, low part-count solution • Primary-side control eliminates secondary-side control and optocoupler • Provides ±5% constant voltage (CV) and ±10% constant current (CC) accuracy including output cable drop compensation for 26 AWG (0.49 Ώ) or 24 AWG (0.3 Ώ) cables
Over-temperature protection – tight tolerance (±5%) with hysteretic recovery for safe PCB temperatures under all conditions
Auto-restart output short circuit and open-loop protection
Extended pin creepage distance for reliable operation in humid environments – >3.2 mm at package • EcoSmart® – Easily meets all current international energy efficiency standards – China (CECP) / CEC / ENERGY STAR 2 / EU CoC
No-load consumption 1.3 for discontinuous mode operation Feedback winding turns Flyback Voltage Forward voltage Bias Winding Voltage. Ensure that VB > VFLY. Bias winding is assumed to be ACSTACKED on top of Feedback winding Bias Winding number of turns Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-158 – 5 V, 1 A, LNK616PG CV/CC Charger DESIGN PARAMETERS DCON 4.5 TON 4.50 4.31 us us RUPPER RLOWER 12.88 9.16 k-ohm k-ohm 25-Nov-08 Output diode conduction time LinkSwitch-II On-time (calculated at minimum inductance) Upper resistor in Feedback resistor divider Lower resistor in resistor divider ENTER TRANSFORMER CORE/CONSTRUCTION VARIABLES Core Type Core EE16 EE16 Enter Transformer Core. Based on the output power the recommended core sizes are EE19 or EE22 Bobbin EE16_BOBBIN Generic EE16_BOBBIN AE 19.20 mm^2 Core Effective Cross Sectional Area LE 35.00 mm^2 Core Effective Path Length AL 1140.00 nH/turn Ungapped Core Effective Inductance ^2 BW 8.60 mm Bobbin Physical Winding Width M 0.00 mm Safety Margin Width (Half the Primary to Secondary Creepage Distance) L 3.00 Number of Primary Layers NS 7.00 Number of Secondary Turns. To adjust Secondary number of turns change DCON DC INPUT VOLTAGE PARAMETERS VMIN VMAX 87.45 374.77 V V Minimum DC bus voltage Maximum DC bus voltage CURRENT WAVEFORM SHAPE PARAMETERS DMAX 0.29 IAVG 0.09 IP 0.39 IR 0.39 IRMS 0.14 A A A A Maximum duty cycle measured at VMIN Input Average current Peak primary current primary ripple current Primary RMS current Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 16 of 40 25-Nov-08 RDR-158 – 5 V, 1 A, LNK616PG CV/CC Charger TRANSFORMER PRIMARY DESIGN PARAMETERS LPMIN 966.73 uH LPTYP 1074.14 uH 10.00 LP_TOLERANCE NP 105.00 ALG 2200.00 2184.51 nH/turn ^2 Gauss Gauss BP 2643.26 Gauss BAC 1092.26 Gauss ur LG BWE OD 165.37 0.25 25.80 0.25 mm mm mm BM_TARGET BM 87.68 2200 INS 0.05 DIA AWG 0.20 33.00 CM 50.80 CMA 362.53 mm TRANSFORMER SECONDARY DESIGN PARAMETERS Lumped parameters ISP 5.84 A ISRMS 2.16 A 1.92 A IRIPPLE CMS 432.77 AWGS 23.00 VOLTAGE STRESS PARAMETERS VDRAIN 568.02 V PIVS 29.98 V Minimum Primary Inductance Typical Primary inductance Tolerance in primary inductance Primary number of turns. To adjust Primary number of turns change BM_TARGET Gapped Core Effective Inductance Target Flux Density Maximum Operating Flux Density (calculated at nominal inductance), BM < 2500 is recommended Peak Operating Flux Density (calculated at maximum inductance and max current limit), BP < 3000 is recommended AC Flux Density for Core Loss Curves (0.5 X Peak to Peak) Relative Permeability of Ungapped Core Gap Length (LG > 0.1 mm) Effective Bobbin Width Maximum Primary Wire Diameter including insulation Estimated Total Insulation Thickness (= 2 * film thickness) Bare conductor diameter Primary Wire Gauge (Rounded to next smaller standard AWG value) Bare conductor effective area in circular mils Primary Winding Current Capacity (200 < CMA < 500) Peak Secondary Current Secondary RMS Current Output Capacitor RMS Ripple Current Secondary Bare Conductor minimum circular mils Secondary Wire Gauge (Rounded up to next larger standard AWG value) Maximum Drain Voltage Estimate (Assumes 20% Zener clamp tolerance and an additional 10% temperature tolerance) Output Rectifier Maximum Peak Inverse Voltage Note: Different spreadsheet revisions may give slightly different spreadsheet values. Page 17 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-158 – 5 V, 1 A, LNK616PG CV/CC Charger 25-Nov-08 9 Performance Data All measurements were taken at room temperature unless otherwise specified, with 60 Hz input frequency. Measurements were taken at the end of a 6 ft, 0.3 Ω, 24 AWG output cable. 9.1 Efficiency 85% Vin=85 VAC Vin=115 VAC Vin=230 VAC Vin=265 VAC Energy Star v1.1 / CEC (2008) Energy Star v2 (April 2008) Efficiency 80% 75% 70% Energy Star v2 Average Active Mode Efficiency (67%) 65% Energy Star v1.1 / CEC (2008) Average Active Mode Efficiency (64%) 60% 0 1 2 3 4 5 6 Output Power (Watts) Figure 6 – Efficiency vs. Output Power. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 18 of 40 25-Nov-08 RDR-158 – 5 V, 1 A, LNK616PG CV/CC Charger 9.2 Active Mode CEC Measurement Data The power supply passes both Energy Star v1.1 and v2 (April 2008) limits. % of Full Load Efficiency (%) 115 VAC 230 VAC 25 74.8 74.0 50 75.0 74.7 75 73.5 74.4 100 72.2 73.5 Average 73.9% 74.2% Energy Star v1.1 Energy Star v2 64% 67% 64% 67% Figure 7 – Average Active Mode Efficiency. 9.2.1 Energy Star v1.1 / CEC (2008) As part of the U. S. Energy Independence and Security Act of 2007 all single-output adapters, including those provided with products for sale in the USA after July 1, 2008, must meet the Energy Star v1.1 specification for minimum active-mode efficiency and noload input power. Note that battery chargers are exempt from these requirements except in the state of California, where they must also be compliant. Minimum active-mode efficiency is defined as the average efficiency at 25%, 50%, 75%, and 100% of rated output power with the limit based on the nameplate output power: Nameplate Output (PNP) Minimum Efficiency in Active Mode of Operation 49 W 0.5 × PNP 0.09 × ln (PNP) + 0.5 [ln = natural log] 0.84 Nameplate Output (PNP) Maximum No-load Input Power All ≤ 0.5 W For single-input voltage adapters the measurement is made at the rated (single) nominal input voltage only (either 115 VAC or 230 VAC). For universal input adapters, the measurement is made at both nominal input voltages (115 VAC and 230 VAC). To meet the standard, the measured average efficiency (or efficiencies for universal input supplies) must be greater than or equal to the efficiency specified by the CEC/Energy Star v1.1 standard. Page 19 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-158 – 5 V, 1 A, LNK616PG CV/CC Charger 25-Nov-08 9.2.2 Energy Star v2 (April 2008) The Energy Star v2 specification (planned to take effect Nov 1, 2008) increases the previously stated requirements. Standard Models Nameplate Output (PNP) Minimum Efficiency in Active Mode of Operation (Rounded to Hundreds) ≤1W > 1 W to ≤ 49 W ≥ 0.48 × PNP + 0.14 ≥ 0.0626 × ln (PNP) + 0.622 > 49 W 0.87 [ln = natural log] Nameplate Output (PNP) Maximum No-load Input Power 0 to 1 W to ≤49 W >49 W ≥ 0.497 × PNP + 0.067 ≥ 0.075 × ln (PNP) + 0.561 [ln = natural log] ≥ 0.86 Nameplate Output (PNP) Maximum No-load Input Power 0 to