SLUAAJ7 June   2022 UCC256402 , UCC256403 , UCC256404

 

  1.   Abstract
  2.   Trademarks
  3. 1UCC25640x Selection Guide
  4. 2UCC25640x Features Brief Overview
    1. 2.1 High Voltage(HV) Startup
      1. 2.1.1 HV Startup Procedure
      2. 2.1.2 HV Startup with External Bias
      3. 2.1.3 HV Start-up, VCC, X-cap Discharge Internal Block Diagram
      4. 2.1.4 HV Startup External Resistor
    2. 2.2 XCAP Discharge
      1. 2.2.1 IEC Standards
      2. 2.2.2 Detecting AC presence
      3. 2.2.3 Test Current Injection for Zero Crossing Detection
      4. 2.2.4 Typical Waveforms of HV Startup and XCAP Discharge
    3. 2.3 Feedback Chain
      1. 2.3.1 FBreplica Generation
      2. 2.3.2 Vcomp Signal and Threshold Voltages
      3. 2.3.3 FB Pin Voltage Typical Waveform at no Load
    4. 2.4 Hybrid Hysteretic Control and VCR Pin Voltage and Gate Pulse Generation
      1. 2.4.1 Hybrid Hysteretic Control
      2. 2.4.2 VCR Pin Voltage
      3. 2.4.3 VCR Typical Waveform
    5. 2.5 Soft Start
      1. 2.5.1 Soft Start Timing
      2. 2.5.2 Soft Start Initial Voltage Programming
    6. 2.6 Burst Mode
      1. 2.6.1 Burst Patterns
      2. 2.6.2 BMTL/BMTH Ratio Programming
      3. 2.6.3 BMTH Generation
      4. 2.6.4 Interpreting BMTL and BMTH
      5. 2.6.5 Soft On or Off
      6. 2.6.6 Operation when Burst Mode Disabled
      7. 2.6.7 Typical Waveforms
    7. 2.7 Adaptive Dead Time Control
    8. 2.8 Fault Management
      1. 2.8.1 OCP Protection
      2. 2.8.2 OCP Fault Typical Waveforms
      3. 2.8.3 Over Voltage Protection using Bias Winding (BW OVP)
      4. 2.8.4 Restart or Latch
    9. 2.9 ZCS Region Prevention Scheme
      1. 2.9.1 ZCS Effects
      2. 2.9.2 ZCS Detection and Prevention and Disabling
  5. 3UCC25640x Power Up Guidelines and Debugging Notes
    1. 3.1  Power Up Procedure
    2. 3.2  HV Pin
    3. 3.3  VCC Pin
    4. 3.4  BLK Pin
    5. 3.5  FB Pin
    6. 3.6  ISNS Pin
    7. 3.7  VCR Pin
    8. 3.8  BW Pin
    9. 3.9  LL/SS Pin
    10. 3.10 LO Pin
    11. 3.11 RVCC Pin
    12. 3.12 HS, HO, HB Pins
  6. 4References

1 UCC25640x Selection Guide

Table 1-1 Device Comparison Table
UCC256402 UCC256402A UCC256403 UCC256403A UCC256404 UCC256404A UCC256404B
Key Application Lighting/Industrial Lighting/Industrial TV OLED Screen/Telecom/Industrial TV OLED Screen/Telecom/Industrial TV - WLLC TV - WLLC TV - WLLC
Burst Packet Size 16 16 40 16 40 16 40
Burst Soft On/Off No No Yes No Yes No Yes
HV Startup Yes Yes No No Yes Yes Yes
Auxiliary Supply Required No No Yes Yes No No No
X-Cap Discharge (XCD) No No No No Yes Yes Yes
BLK/DC Start (1) 3 V/340 V 3 V/340 V 3 V/340 V 3 V/340 V 1 V/113 V 1 V/113 V 1 V/113 V
BLK/DC Stop (1) 2.2 V/249 V 2.2 V/249 V 2.2 V/249 V 2.2 V/249 V 0.9 V/102 V 0.9 V/102 V 0.9 V/102 V
BLK/DC OVP (1) NA 4 V/453 V NA NA NA NA NA
BW OVP Mode Restart Restart Restart Latch Restart Latch Restart
Other Fault Mode Restart Restart Restart Restart Restart Restart Restart
PFC Off in Standby Mode No No No No Yes Yes Yes
VCC startup voltage that will initiate startup process 26 V 26 V 10.9 V 10.9 V 26 V 26 V 26 V
(1) Typical startup, shutdown and overvoltage values assume Bulk Divider ratio 113.33:1

The UCC256404B maximum XCD test current is lower (1.3mA) compared to the maximum XCD test currents of the 404 and 404A (1.7mA). This difference helps to reduce stand-by power loss when using the UCC256404B during very-light-load to no-load conditions.