InnoSwitch3-TN
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InnoSwitch3-TN Family High Efficiency Off-line CV/CC QR Flyback Switcher IC with Integrated 725 V Primary MOSFET, Synchronous Rectification and Integrated Secondary-Side Control Product Highlights Ideal for Isolated and Non-Isolated Applications The InnoSwitch™3-TN family dramatically increases the efficiency of auxiliary power supplies used in appliances, consumer products and industrial applications. Ideal for both isolated and non-isolated designs, this advanced flyback controller can achieve up to 90% full load efficiency, flat efficiency across the load range and very low no-load consumption. The InnoSwitch3-TN may be used as an accurate 5 V single-output power supply, with two positive rails or with both positive and negative rails. • Flybacks with positive and negative output rails • Incorporates a multi-mode Quasi Resonant (QR) / CCM flyback controller, 725 V primary MOSFET, secondary voltage and current sensing, SR driver • Integrated FluxLink™ feedback • Compact package reduces PCB area • High efficiency across load range • Accurate CV/CC independent of transformer design or external components • Easily meets 20% regulation limit on 5 V output during zero load to full-load transients The 725 V primary MOSFET, primary and secondary flyback controllers are coupled using the proprietary FluxLink communications channel. Safety-rated FluxLink communication ensures reliable synchronous rectification and accurate output CV and CC. Comprehensive safety features include output over-current protection and over-temperature protection. The small MinSOP package and a low number of external components make the InnoSwitch3-TN ICs ideal for compact designs. EcoSmart™ – Energy Efficient • Less than 5 mW no-load at 230 VAC • Enables designs that easily meet global energy efficiency regulations • Achieves up to 90% full load efficiency Advanced Protection / Safety Features Integrated output OVP Open-gate detection for SR FET Hysteretic thermal shutdown Overload power limited <15 W (5 V and <3 A) • Using accurate internal CC (constant-current) limit Figure 2. Compact MinSOP-16A M Package. Full Safety and Regulatory Compliance Maximum Output Power Table • Reinforced insulation with isolation voltage >4000 VAC • 100% production Hipot testing • UL1577, TUV (EN62368-1), CQC (GB4943.1) safety approved. VDE 0884-17 (EN60747-17) pending approval • Enables designs that have “class A” performance criteria for EN61000-4 suite of test standards, including EN61000-4-2, 4-3 (30 V/m), 4-4, 4-5, 4-6, 4-8 (100 A/m) and 4-9 (1000 A/m) Table 1. Output Power Table. Notes: 1. Minimum peak power capability. 2. Max output power is dependent on the design. Limit package temperature to <125 ºC. 3. Assumes internal output current sensing is disabled (IS-GND pins shorted) 4. Package: MinSOP-16A. • Halogen free and RoHS compliant • Auxiliary supplies in appliances and industrial systems Positive and Negative Output Dual Positive Output Green Package Figure 1. Power Supply Configuration Examples using InnoSwitch3-TN. www.power.com This Product is Covered by Patent

PRIMARY BYPASS (BPP) PRIMARY BYPASS REGULATOR RECEIVER CONTROLLER CONTROL LOGIC From Secondary Controller FluxLink THERMAL SHUTDOWN Power Switch Figure 3. Primary Controller Block Diagram. SYNC RECTIFIER DRIVE (SR) VOUT REGULATOR 4.4 V VOUT FEEDBACK DRIVER OSCILLATOR/ TIMER Figure 4. Secondary Controller Block Diagram.

InnoSwitch3-TN Pin Functional Description ISENSE (IS) Pin (Pin 1) Connection to the power supply output terminals. Internal current sense is connected between this pin and the SECONDARY GROUND pin. SECONDARY GROUND (GND) Pin (Pin 2) Ground connection for the secondary IC. COMPENSATION (COMP) Pin (Pin 3) This pin is connected to internal feedback network. This pin should be left open. SECONDARY BYPASS (BPS) Pin (Pin 4) It is the connection point for an external bypass capacitor for the secondary IC supply. SYNCHRONOUS RECTIFIER DRIVE (SR) Pin (Pin 5) Connection to gate terminal of external...

Figure 6. Schematic RDK-710, 5 V, 1.4 A and 12 V, 0.5 A for HVAC (Heating, Ventilation and Air-Conditioning) Application. The circuit shown in Figure 6 is a low component count 5 V, 1.4 A and 12 V, 0.4 A dual output power supply using the INN3074M IC. This dual output design features a highly efficient design satisfying cross regulation requirements without a post-regulator. Bridge rectifier BR1 rectifies the AC input supply. Capacitors C1 and C2 provide filtering of the rectified AC input and together with inductor L1 form a pi-filter to attenuate differential mode EMI. Y capacitor C6...

InnoSwitch3-TN the power switch is turned off when the voltage drop across the switch falls below 0 V. Secondary-side control of the primary-side power switch avoids any possibility of cross conduction of the two switches and provides extremely reliable synchronous rectification. The secondary-side of the IC is self-powered from either the secondary winding forward voltage or the output voltage. Capacitor C7 connected to the SECONDARY BYPASS pin of InnoSwitch3-TN IC U1, provides decoupling for the internal circuitry. Total output current is monitored by an internal sense resistor between...

InnoSwitch3-TN aluminum capacitor of at least 22 mF with a voltage rating 1.2 times greater than the highest voltage developed across the capacitor is recommended. Highest voltage is typically developed across this capacitor when the supply is operated at the highest rated output voltage and load with the lowest input AC supply voltage. Primary Sensed OVP (Overvoltage Protection) The voltage developed across the output of the bias winding tracks the power supply output voltage. Though not precise, a reasonably accurate detection of the amplitude of the output voltage can be achieved by the...

InnoSwitch3-TN rated with a 12 V, 0.4 A output. The SR FET driver uses the SECONDARY BYPASS pin for its supply rail, and this voltage is typically 4.4 V. A FET with a high threshold voltage is therefore not suitable; FETs with a threshold voltage of 1.5 V to 2.5 V are ideal. There is a slight delay between the commencement of the flyback cycle and the turn-on of the SR FET. During this time, the body diode of the SR FET conducts. If an external parallel Schottky diode is used, this current mostly flows through the Schottky diode. Once the InnoSwitch3-TN IC detects end of the flyback cycle,...