InnoSwitch3-AQ
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InnoSwitch3-AQ INN3977CQ, INN3996CQ CV/CC QR Flyback Switcher IC with Integrated 750 V and 900 V Switch and FluxLink Feedback for Automotive Applications Product Highlights Highly Integrated, Compact Footprint • Up to 90% efficiency across full load range • Incorporates a multi-mode Quasi-Resonant (QR) / CCM flyback controller, 750 V and 900 V switch and secondary-side sensing • Integrated FluxLink™, HIPOT-isolated, feedback link • Wide input voltage 30 V to 925 V with StackFET™ • AEC-Q100 qualified • Fab, assembly and test site are IATF16949 certified InnoSwitch3-AQ EcoSmart™ – Energy Efficient • Auto-restart fault response for output OVP Optional Current Sense Primary Switch and Controller • Less than 15 mW no-load • Low heat dissipation Advanced Protection / Safety Features Optional Features • Auto-restart output UV protection with option for peak power delivery Figure 1. Typical Application Schematic. Full Safety and Regulatory Compliance • • • • • Reinforced isolation Isolation voltage >4000 VAC 100% production HIPOT testing UL1577 approved and TUV (EN60950) in process Excellent noise immunity enables designs that achieve class “A” performance criteria for EN61000-4 suite; 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), FMC1278 (RI-115) Figure 2. High Creepage, Safety-Compliant InSOP-24D Package. Green Package • Halogen free and RoHS compliant • Auxiliary, standby and bias power supplies for automotive used in traction inverter, DC-DC converter and on-board charger Output Power Table Product 2 Description The InnoSwitch™3-AQ family of ICs dramatically simplifies the design and manufacture of flyback power converters, particularly those requiring high efficiency and/or compact size. The InnoSwitch3-AQ family combines primary and secondary controllers and safety-rated feedback into a single IC allowing accurate output voltage regulation even with wide input voltage range of 30 V to 925 V. InnoSwitch3-AQ family devices incorporate multiple protection features including line over and undervoltage protection, output overvoltage and over-current limiting, and over-temperature shutdown for automotive applications. Devices are available with standard and peak power delivery options, and commonly used auto-restart protection behaviors. Table 1. Output Power Table. Notes: 1. Max output power is dependent on the design. With condition that package temperature must be < 125 °C. Uses PCB copper for heat sinking. 2. Package: InSOP-24D. 3. With StackFET. This Product is Covered

UNDER/OVER INPUT VOLTAGE (V) PRIMARY BYPASS (BPP) PRIMARY BYPASS REGULATOR ENABLE FAULT AUTO-RESTART COUNTER LINE INTERFACE PRIMARY BYPASS PIN CAPACITOR SELECT AND CURRENT LIMIT UV/OV OSCILLATOR/ TIMERS VSHUNT VBP+ From Secondary Controller RECEIVER CONTROLLER Power Switch PRIMARY BYPASS PIN UNDERVOLTAGE THERMAL SHUTDOWN PRIMARY OVP LATCH/ AUTO-RESTART LATCH-OFF/ AUTO-RESTART Figure 3. Primary Controller Block Diagram. SYNC RECTIFIER DRIVE (SR) HANDSHAKE/ AUTO-RESTART CABLE DROP COMPENSATION/ FEEDBACK COMPENSATION tOFF(MIN) OSCILLATOR/ TIMER FEEDBACK DRIVER SECONDARY LATCH/ AUTO-RESTART...

InnoSwitch3-AQ Pin Functional Description Secondary-Side Pins ISENSE (IS) Pin (Pin 1) Connection to the power supply output terminals. An external current sense resistor should be connected between this and the GND pin. If current regulation/accurate over-current protection is not required, this pin should be tied to the GND pin. SECONDARY GROUND (GND) (Pin 2) Ground for the secondary IC. Note this is not the power supply output ground due to the presence of the sense resistor between this and the ISENSE pin. FEEDBACK (FB) Pin (Pin 3) Connection to an external resistor divider to set the...

PRIMARY BYPASS Pin Regulator The PRIMARY BYPASS pin has an internal regulator that charges the PRIMARY BYPASS pin capacitor to VBPP by drawing current from the DRAIN pin whenever the power MOSFET is off. The PRIMARY BYPASS pin is the internal supply voltage node. When the power MOSFET is on, the device operates from the energy stored in the PRIMARY BYPASS pin capacitor. In addition, a shunt regulator clamps the PRIMARY BYPASS pin voltage to VSHUNT when current is provided to the PRIMARY BYPASS pin through an external resistor. This allows the InnoSwitch3-AQ to be powered externally through...

InnoSwitch3-AQ Jitter The normalized current limit is modulated between 100% and 95% at a modulation frequency of fM. This results in a frequency jitter of ~7 kHz with average frequency of ~100 kHz. Auto-Restart In the event a fault condition occurs (such as an output overload, output short-circuit, or external component/pin fault), the InnoSwitch3-AQ enters auto-restart (AR) or latches off. The latching condition is reset by bringing the PRIMARY BYPASS pin below ~3 V. P: Primary Chip S: Secondary Chip Start P: Powered Up, Switching S: Powering Up In auto-restart, switching of the power...

InnoSwitch3-AQ Audible Noise Reduction Engine The InnoSwitch3-AQ features an active audible noise reduction mode whereby the controller (via a “frequency skipping” mode of operation) avoids the resonant band (where the mechanical structure of the power supply is most likely to resonate − increasing noise amplitude) between 7 kHz and 12 kHz - 143 ms and 83 ms. If a secondary controller switch request occurs within this time window from the last conduction cycle, the gate drive to the power MOSFET is inhibited. Maximum Secondary Inhibit Period Secondary requests to initiate primary switching...

InnoSwitch3-AQ the voltage across the primary switch is near its minimum voltage when the converter operates in discontinuous conduction mode (DCM). This mode of operation is automatically engaged in DCM and disabled once the converter moves to continuous-conduction mode (CCM). Rather than detecting the magnetizing ring valley on the primaryside, the peak voltage of the FORWARD pin voltage as it rises above the output voltage level is used to gate secondary requests to initiate the switch “ON” cycle in the primary controller. FORWARD pin. In the event that the voltage on the ISENSE pin...