LNK33x2-7D LinkSwitch-TNZ Family Energy Efficient Off-line Switcher IC with Best-in-Class Light Load Efficiency and Lossless AC Zero-Cross Detection Product Highlights Highest Performance and Design Flexibility Lossless zero cross signal generation LinkSwitch-TNZ Supports buck, buck-boost and flyback topologies FB BP/M Enables 3% regulation across line and load D S Selectable device current limit Z1 Z2 66 kHz operation with accurate current limit Zero Cross DC Allows the use of low-cost off-the-shelf inductors Signal Output Reduces size and cost of magnetics and output capacitor Frequency jittering reduces EMI filter complexity X capacitor discharge function (LNK331x only) Enhanced Safety and Reliability Features PI-9175-060820 Figure 1. Typical Buck Converter Application (See Application Examples Section for Flyback and other Circuit Configurations). Soft-start limits system component stress at start-up Auto-restart for short-circuit and open loop faults Output overvoltage protection (OVP) Line input overvoltage protection (OVL) Hysteretic over-temperature protection (OTP) Extended creepage between DRAIN pin and all other pins improves field reliability Figure 2. Package D: SO-8C. 725 V MOSFET rating for excellent surge withstand Nemko (EN62368-1) and CB (IEC62368-1) certifications 1 Output Current in Buck Table EcoSmart Extremely Energy Efficient IC standby supply current <100 mA 230 VAC 15% 85-265 VAC On/Off control provides constant efficiency over a wide load range Product Easily meets all global energy efficiency regulations 2 3 2 3 MDCM CCM MDCM CCM No-load consumption <30 mW with external bias LNK33x2D 63 mA 80 mA 63 mA 80 mA Applications LNK33x4D 120 mA 170 mA 120 mA 170 mA Home and building automation Dimmers, switches and sensors with and w/o Neutral wire LNK33x6D 225 mA 360 mA 225 mA 360 mA Appliances LNK33x7D 360 mA 575 mA 360 mA 575 mA IoT and industrial controls Table 1. Output Power Table. Description Notes: 1. Typical output current in a non-isolated buck converter with devices operating The LinkSwitch-TNZ family of ICs combine power conversion with at default current limit and adequate heat sinking. Output power capability lossless generation of AC zero crossing signal used typically for system depends on respective output voltage and thermal requirements. See Key clock and timing functions. Designs using the highly integrated Applications Considerations section for complete description of assumptions, LinkSwitch-TNZ ICs are more efl xible than discrete implementations including fully discontinuous conduction mode (DCM) operation. reducing component count by 40% or higher. Besides enabling 80+ 2. Mostly discontinuous conduction mode. 3. Continuous conduction mode. efficiencies in low power flyback designs, very low consumption at light loads enabled by On/Off control allow for more functions (display, wireless 6 connectivity, sensors etc.) to be active during system standby. The Output Power in Flyback Table device family supports buck, buck-boost and yfl back converter topologies. 4 Open Frame Each device incorporates a 725 V power MOSFET, oscillator, a Product high-voltage switched current source for self-biasing, frequency jittering, 230 VAC 15% 85-265 VAC fast (cycle-by-cycle) current limit, hysteretic thermal shutdown, and output and input overvoltage protection circuitry onto a monolithic IC. LNK33x2D 5 W 3 W LNK33x4D 10 W 6 W LinkSwitch-TNZ ICs consume <100 mA current in standby resulting in 5 power supply designs that can meet no-load and standby regulations LNK33x6/7D 18 W 12 W worldwide. MOSFET current limit modes can be selected through the BYPASS pin capacitor value. The high current limit level provides Table 2. Output Power Table. maximum continuous output current while the low level permits using Notes: 4. Maximum practical continuous power in an open frame design with adequate very low-cost and small surface mount inductors. A full suite of heat sinking, measured at 25 C ambient. protection features enables safe and reliable power supplies protecting 5. LNK33x6 is recommended in Flyback for highest efficiency. the device and the system against input and output overvoltage faults, 6. See Key Application Considerations section for complete description of device over-temperature faults, lost regulation, and power supply assumptions. output overload or short-circuit faults. www.power.com June 2021 This Product is Covered by Patents and/or Pending Patent Applications. +LinkSwitch-TNZ BYPASS DRAIN (BP/M) (D) REGULATOR 5.0 V FAULT I I FBSD FB PRESENT BYPASS PIN ZERO-DETECT 1 CAPACITOR (Z1) 5.2 V DETECT AUTO-RESTART BYPASS PIN I SUPPLY COUNTER UNDERVOLTAGE + OVL CURRENT LIMIT CLOCK COMPARATOR 5.0 V - RESET 4.5 V Z1, Z2 Control V & I LIMIT Timer JITTER CLOCK THERMAL SHUTDOWN I DC SUPPLY MAX ZERO-DETECT 2 OSCILLATOR (Z2) S Q FEEDBACK (FB) R Q 2.0 V -V T LEADING EDGE BLANKING OVP DETECT SOURCE (S) PI-9174-060820 Figure 3. Functional Block Diagram. FEEDBACK (FB) Pin Pin Functional Description During normal operation, switching of the power MOSFET is con- Z1 and Z2 Pins trolled by the FEEDBACK pin. MOSFET switching is terminated when Z1 and Z2 are used in combination for zero cross detect (ZCD) a current greater than I (49 mA) is delivered into this pin. Line FB signal generation, X capacitor discharge or both. overvoltage protection is detected when a current greater than I FBSD For zero crossing, Z1 is connected to one of the input AC lines (670 mA) is delivered into this pin for 2 consecutive switching cycles. through an external resistor while Z2 forms the ZCD signal output. SOURCE (S) Pin For X capacitor discharge (LNK331x only), Z1 is connected to one This pin is the power MOSFET source connection. It is also the AC line input through an external resistor and Z2 is connected to ground reference for the BYPASS and FEEDBACK pins. the other AC input line input through a separate external resistor. Z1 and Z2 can also be used to combine X capacitor discharge and ZCD signal generation functions (LNK331x only) see Application Section for details. Z1 and Z2 can be connected to SOURCE (S) pins if not used. Z1 and Z2 are interchangeable. DRAIN (D) Pin D Package (SO-8C) Power MOSFET drain connection. Provides internal operating current for both start-up and steady-state operation. 1 8 BYPASS (BP/M) Pin Z1 FB This pin has multiple functions: 2 7 Z2 BP/M It is the connection point for an external bypass capacitor for the 6 internally generated 5.0 V supply. S It is a mode selector for the current limit value, depending on the 4 5 value of the capacitance added. Use of a 0.1 mF capacitor results D S in the standard current limit value. Use of a 1 mF capacitor results in the current limit being reduced, allowing design with lowest cost surface mount buck chokes. It provides a shutdown function. When the current into the BYPASS pin exceeds I for a time equal to 2 to 3 cycles of the PI-7842b-060820 BPSD internal oscillator (f ), the device enters auto-restart. This can be OSC Figure 4. Pin Configuration. used to provide an output overvoltage protection function with external circuitry. 2 Rev. D 06/21 www.power.com - +