EVL6566A-75WES4 STMicroelectronics, EVL6566A-75WES4 Datasheet

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Multi-mode controller for SMPS with PFC front-end Features ■ Selectable multi-mode operation: fixed frequency or quasi-resonant ■ On-board 700 V high-voltage start-up ■ Advanced light load management ■ Low quiescent current (< 3 mA) ■ Adaptive UVLO ■ Line feedforward ...

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Contents Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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L6566A 6 Application examples and ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 7 Package mechanical ...

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List of tables List of tables Table 1. Pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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L6566A List of figures Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

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Description 1 Description The L6566A is an extremely versatile current-mode primary controller IC specifically designed for high-performance offline flyback converters operated from front-end power factor correction (PFC) stages in applications supposed to comply with EN61000-3-2 or JEITA-MITI regulations. Both fixed-frequency ...

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L6566A Figure 2. Typical system block diagram PFC PRE-REGULATOR Rectified Mains Voltage FLYBACK DC-DC CONVERTER PWM/QR controller is turned off in case of PFC's anomalous operation, for safety L6563/A L6566A PFC PFC is automatically turned off at light load to ...

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Pin settings 2 Pin settings 2.1 Connections Figure 3. Pin connection (through top view) 2.2 Pin description Table 1. Pin functions N° Pin High-voltage start-up. The pin, able to withstand 700 tied directly to the rectified ...

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L6566A Table 1. Pin functions (continued) N° Pin Supply voltage of both the signal part of the IC and the gate driver. The internal high voltage generator charges an electrolytic capacitor connected between this pin and GND (pin 3) as ...

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Pin settings Table 1. Pin functions (continued) N° Pin Transformer demagnetization sensing input for quasi-resonant operation and OVP input. The pin is externally connected to the transformer’s auxiliary winding through a resistor divider. A negative-going edge triggers MOSFET’s turn-on if ...

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L6566A 3 Electrical data 3.1 Maximum rating Table 2. Absolute maximum ratings Symbol Pin V HVS I HVS Vcc_PFC I Vcc_PFC 10, 14 max V 9, 15, 16 max I 11 ZCD V 12 ...

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Electrical characteristics 4 Electrical characteristics (T = -25 to 125 ° GND, unless otherwise specified). Table 4. Electrical characteristics Symbol Parameter Supply voltage Vcc Operating range after turn-on Vcc Turn-on threshold On Vcc Turn-off threshold Off Hys Hysteresis ...

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L6566A Table 4. Electrical characteristics (continued) Symbol Parameter Reference voltage V Output voltage REF V Total variation REF I Short circuit current REF Sink capability in UVLO V Overvoltage threshold OV Internal oscillator f Oscillation frequency sw V Voltage reference ...

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Electrical characteristics Table 4. Electrical characteristics (continued) Symbol Parameter Current sense comparator I Input bias current CS t Leading edge blanking LEB td Delay to output (H-L) V Overcurrent setpoint CSx V Hiccup-mode OCP level CSdis PWM control V Upper ...

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L6566A Table 4. Electrical characteristics (continued) Symbol Parameter Latched shutdown function I Input bias current OTP V Disable threshold OTP Thermal shutdown Vth Shutdown threshold Hys Hysteresis V _PFC function CC I OFF-state leakage current leak V - Vcc ON-state ...

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Electrical characteristics Table 4. Electrical characteristics (continued) Symbol Parameter Gate driver V Output high voltage GDH V Output low voltage GDL I Output source peak current sourcepk I Output sink peak current sinkpk t Fall time f t Rise time ...

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L6566A 5 Application information The L6566A is a versatile peak-current-mode PWM controller specific for offline flyback converters. The device allows either fixed-frequency (FF) or quasi-resonant (QR) operation, selectable with the pin MODE/SC (12): forcing the voltage on the pin over ...

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Application information If FF operation is selected mode from heavy to light load. The system operates exactly like a standard current mode frequency f DCM and CCM transformer operation are possible, depending on whether the power ...

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L6566A With reference to the timing diagram of the voltage on the bulk capacitor (Vin) builds up and, at about 80 V, the HV generator is enabled to operate (HV_EN is pulled high) so that it draws about 1 mA. ...

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Application information Figure 7. Timing diagram showing short-circuit behavior (SS pin clamped Vcc (pin 5) Vcc ON Vcc OFF Vcc restart GD (pin 4) Vcc_OK I charge 0.85 mA Figure 8. Zero current detection block, triggering block, ...

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L6566A 5.2 Zero current detection and triggering block; oscillator block The zero current detection (ZCD) and Triggering blocks switch on the external MOSFET if a negative-going edge falling below applied to the input (pin 11, ZCD). To ...

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Application information Note: When the system operates in valley skipping-mode, uneven switching cycles may be observed under some line/load conditions, due to the fact that the OFF-time of the MOSFET is allowed to change with discrete steps of one ringing ...

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L6566A The operation described so far under different operating conditions for the converter is illustrated in the timing diagrams of If the FF option is selected the operation will be exactly equal to that of a standard current- mode PWM ...

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Application information 5.3 Burst-mode operation at no load or very light load When the voltage at the COMP pin (9) falls 20 mV below a threshold fixed internally at a value depending on the selected operating mode, the ...

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L6566A Figure 12. Addition of an offset to the current sense lowers the burst-mode operation threshold 5.4 Adaptive UVLO A major problem when optimizing a converter for minimum no-load consumption is that the voltage generated by the auxiliary winding under ...

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Application information 5.5 PWM control block The device is specific for secondary feedback. Typically, there is a TL431 on the secondary side and an optocoupler that transfers output voltage information to the PWM control on the primary side, crossing the ...

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L6566A Figure 15. Externally controlled burst-mode operation by driving pin COMP: timing diagram Vcc (pin 5) Vcc Vcc Vcc COMP (pin 9) GD (pin 4) Vcc_OK I charge 0.85 mA Vcc_PFC (pin 6) Vout 5.6 PWM comparator, PWM latch and ...

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Application information Figure 16. Typical power capability change vs input voltage in QR flyback converters It acts on the overcurrent setpoint V Vin (output of the PFC pre-regulator) sensed through a dedicated pin (15, VFF): the higher the input voltage, ...

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L6566A Experience shows that this value is typically lower than the real one. Once the maximum peak primary current, I the value of Rs can be determined from (2): Equation 7 The converter is then tested on the bench to ...

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Application information Equation 8 where Lp is the inductance of the primary winding. In case a constant maximum power capability vs. the input voltage is not required, the VFF pin can be grounded, directly or through a resistor (see setpoint ...

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L6566A Figure 18. Hiccup-mode OCP: timing diagram Vcc (pin 5) Vcc ON Vcc OFF Vcc restart V CS (pin 7) GD (pin 4) OCP latch Vcc_OK Vcc_PFC (pin 6) 5.8 PFC interface The device is specifically designed to minimize converter’s ...

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Application information Figure 19. Possible interfaces between the L6566A and a PFC controller To prevent intermittent operation of the PFC stage, some hysteresis is provided: if the internal switch is open, it will be closed (which will re-enable the PFC ...

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L6566A Figure 20. Operation after latched disable activation: timing diagram DIS (pin 8) 4.5V Vcc HV generator is turned on (pin 5) Vcc ON Vcc -0.5 ON Vcc OFF Vcc restart GD (pin 4) Vcc_PFC (pin 6) Vin V HVstart ...

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Application information operating, so that the converter will work intermittently, which is very safe. In case of overload the system has a power capability lower than that at nominal load but the output current may be quite high and overstress ...

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L6566A 5.11 OVP block The OVP function of the L6566A monitors the voltage on the ZCD pin (11) in MOSFET’s OFF-time, during which the voltage generated by the auxiliary winding tracks converter’s output voltage. If the voltage on the pin ...

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Application information Figure 23. OVP function: timing diagram GD (pin 4) Vaux 0 ZCD (pin 11) 5V COUT 2 µs STROBE OVP COUNTER RESET COUNTER STATUS 0 0 FAULT Vcc_PFC (pin 6) NORMAL OPERATION The ZCD pin will be connected ...

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L6566A Figure 22 on page 35 Figure 23 on page 36 Note: To use the OVP function effectively, i.e. to ensure that the OVP comparator will be always interrogated during MOSFET’s OFF-time, the duty cycle D under open-loop conditions must ...

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Application information 5.12 Brownout protection Brownout protection is basically a not-latched device shutdown function activated when a condition of mains undervoltage is detected. There are several reasons why it may be desirable to shut down a converter during a brownout ...

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L6566A While the brownout protection is active the start-up generator keeps on working but, being there no PWM activity, the Vcc voltage continuously oscillates between the start-up and the HV generator restart thresholds, as shown in the timing diagram of ...

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Application information the base terminal are several ten kW) but this could distort the signal on the MULT pin of the PFC chip and adversely affect the operation of the pre-regulator. C capacitor (in the μF) to have small residual ...

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L6566A 5.14 Summary of L6566A power management functions It has been seen that the device is provided with a number of power management functions: multiple operating mode upon loading conditions, protection functions, as well as interaction with the PFC pre-regulator. ...

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Application information Table 6. L6566A protections Protection Description Caused by V >V ZCD for 4 h consecutive Output switching OVP overvoltage cycles protection VFF > VFFlatch V COMP =V COMPHi V > SS Output V SSDIS OLP overload V protection ...

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L6566A Table 6. L6566A protections (continued) Protection Description Caused by Shutdown V < 9. going ( cc VCOMP V below V COMPL ccoff ADAPTIVE (lowering of UVLO V < 7. ccoff ( threshold at VCOMP ...

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Application examples and ideas 6 Application examples and ideas Figure 28. Typical low-cost application schematic PFC Pre-regulator Output bus Output capacitor of boost PFC Pre-regulator R3 470k FMOD AC_OK DIS IC1 VFF 15 L6566A 12 10 ...

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L6566A Figure 30. Typical full-feature application schematic (FF operation) PFC Pre-regulator Output bus C1 Output capacitor of boost PFC Pre-regulator to mains to Vcc pin of R15 v oltage sensing PFC controller Vcc_PFC AC_OK 6 VFF 15 IC1 L6566A DIS ...

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Application examples and ideas Figure 31. Frequency foldback at light load (FF operation) Figure 32. Latched shutdown upon mains overvoltage Vcc L6566A 46/51 MODE/SC Vref L6566A 13 OSC R T Vin BC847 5 DIS 8 15 VFF ...

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L6566A 7 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the ...

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Package mechanical data Table 8. SO16N mechanical data Dim ( ( Figure 33. Package dimensions 48/51 mm. Min Typ Max 1.75 0.1 0.25 1.6 ...

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L6566A 8 Order codes Table 9. Order codes Order codes L6566A L6566ATR Package Packaging SO16N SO16N Tape and reel Order codes Tube 49/51 ...

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Revision history 9 Revision history Table 10. Document revision history Date 20-Aug-2007 29-May-2008 02-Dec-2008 50/51 Revision 1 First release 2 Updated V value MODE/SC 3 Updated Figure 1 on page 1 Changes Table 2 on page 11 and Section 5.6 ...

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... L6566A Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...