InnoSwitch4-CZ
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InnoSwitch4-CZ Family Off-Line CV/CC ZVS Flyback Integrated Switcher IC with 750 V PowiGaN, Active Clamp Drive and Synchronous Rectification Product Highlights • Zero voltage switching (ZVS) flyback controller with driver for ClampZeroTM (active clamp IC) • Unique control algorithm to enable ZVS in both DCM and CCM • Robust 750 V PowiGaNTM primary switch • Steady-state switching frequency up to 140 kHz minimizes transformer size • Synchronous rectification driver and secondary-side sensing • Integrated FluxLinkTM, HIPOT-isolated, feedback link • Exceptional CV/CC accuracy, independent of external components • Adjustable accurate output current sense using external sense resistor Highly Integrated, Compact Footprint Primary Switch and Controller S HSD Figure 1. Typical Application schematic EcoSmart™ – Energy Efficient • Up to 95% efficient • Less than 30 mW no-load consumption including line sense Advanced Protection / Safety Features • Open SR FET-gate detection • Fast input line UV/OV protection Optional Features • • • • Variable output voltage, constant current profiles Auto-restart or latching fault response for output OVP/UVP Multiple output UV fault thresholds Latching or hysteretic primary over-temperature protection Figure 2. High Creepage, Safety-Compliant InSOP-24D Package. Full Safety and Regulatory Compliance • • • • Reinforced isolation >4000 VAC 100% production HIPOT testing UL1577 and TUV (EN60950) safety approved 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) Output Power Table 85-264 VAC Product 3 Green Package • Halogen free and RoHS compliant • High density flyback designs up to 110 W • High efficiency CV/CC power supplies • High efficiency USB PD adapters Description The InnoSwitch™4-CZ family of ICs partners with the ClampZero family of active clamp ICs to dramatically improve the efficiency of flyback power converters, particularly those requiring a compact form-factor. The InnoSwitch4-CZ family incorporates primary and secondary controllers and safety-rated feedback into a single IC. Table 1. Output Power Table. Notes: 1. Minimum continuous power in a typical non-ventilated enclosed typical size adapter measured at 40 °C ambient. Max output power is dependent on the design. With condition that package temperature must be < 125 °C. 2. Minimum peak power capability. 3. Package: InSOP-24D. The combination of InnoSwitch4-CZ with ClampZero greatly reduces system and primary switch losses, allowing for extremely high power densities. InnoSwitch4-CZ also incorporates multiple protection features including output overvoltage and over-current limiting, and over-temperature shutdown. Devices are available that support the common combinations of latching and auto-restart protection mode required by applications such as chargers, adapters, consumer electronics and industrial systems. This Product

LINE INTERFACE CONTROL LOGIC RECEIVER CONTROLLER From Secondary Contoller THERMAL SHUTDOWN Power Switch Figure 3. Primary Controller Block Diagram. FW FW_VALLEY HANDSHAKE /LATCH-OFF SECONDARY LATCH FEEDBACK DRIVER TSMAX OSCILLATOR /TIMER Figure 4. Secondary Controller Block Diagram.

InnoSwitch4-CZ Pin Functional Description ISENSE (IS) Pin (Pin 1) Connection to the power supply return output terminals. An external current sense resistor should be connected between this and the GND pin. If current regulation is not required, this pin should be tied to the GND pin. SECONDARY GROUND (GND) (Pin 2) GND for the secondary IC. Note this is not the power supply output GND 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 power supply output voltage. SECONDARY BYPASS (BPS)...

InnoSwitch4-CZ is a variable frequency controller allowing CCM/DCM operation for enhanced efficiency and extended output power capability. 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 switch is off. The PRIMARY BYPASS pin is the internal supply voltage node. When the power switch 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...

InnoSwitch4-CZ The auto-restart is reset as soon as an AC reset occurs. SOA Protection In the event that there are two consecutive cycles where the ILIM is reached within ~500 ns (the blanking time + current limit delay time), the controller will skip 2.5 cycles or ~25 ms. This provides sufficient time for the transformer to reset with large capacitive loads without extending the start-up time. Input Line Voltage Monitoring The UNDER/OVER INPUT VOLTAGE pin is used for input undervoltage and overvoltage sensing and protection. A sense resistor is tied between the high-voltage DC bulk...

InnoSwitch4-CZ Audible Noise Reduction Engine The InnoSwitch4-CZ 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 switch is inhibited. Secondary Controller As shown in the block diagram in Figure 4, the IC is powered...

SR Disable Protection In each cycle SR is only engaged if a set cycle was requested by the secondary controller and the negative edge is detected on the FORWARD pin. In the event that the voltage on the ISENSE pin exceeds approximately 3 times the CC threshold, the SR FET drive is disabled until the surge current has diminished to nominal levels. SR Static Pull-Down To ensure that the SR gate is held low when the secondary is not in control, the SYNCHRONOUS RECTIFIER DRIVE pin has internal pull down circuit “ON” device to pull the pin low and reduce any voltage on the SR gate due to...