LC5546AD/LD

LC5546AD/LD-DSE Rev.3.0

SANKEN ELECTRIC CO., LTD.

2

Dec. 12, 2022

https://www.sanken-ele.co.jp/en/

© SANKEN ELECTRIC CO., LTD. 2011

Contents

Description ------------------------------------------------------------------------------------------------------ 1

Contents --------------------------------------------------------------------------------------------------------- 2

1. Absolute Maximum Ratings----------------------------------------------------------------------------- 3

2. Electrical Characteristics -------------------------------------------------------------------------------- 4

2.1.

Electrical Characteristics of Control Parts----------------------------------------------------- 4

2.2.

Electrical Characteristics of Power MOSFET------------------------------------------------- 5

3. Mechanical Characteristics ----------------------------------------------------------------------------- 5

4. Block Diagram --------------------------------------------------------------------------------------------- 6

5. Pin Configuration Definitions--------------------------------------------------------------------------- 6

6. Typical Application --------------------------------------------------------------------------------------- 7

7. Physical Dimensions -------------------------------------------------------------------------------------- 8

8. Marking Diagram ----------------------------------------------------------------------------------------- 9

9. Operational Description ------------------------------------------------------------------------------- 10

9.1.

Startup Operation--------------------------------------------------------------------------------- 10

9.1.1.

Startup Time --------------------------------------------------------------------------------- 10

9.1.2.

Undervoltage Lockout (UVLO) ---------------------------------------------------------- 10

9.1.3.

Bias Assist Function------------------------------------------------------------------------- 10

9.1.4.

Auxiliary Winding -------------------------------------------------------------------------- 11

9.1.5.

Soft Start Function -------------------------------------------------------------------------- 12

9.1.6.

Operation Mode at Startup---------------------------------------------------------------- 12

9.2.

On-time Control Operation --------------------------------------------------------------------- 13

9.3.

Quasi-resonant Operation and Bottom-on Timing ----------------------------------------- 14

9.3.1.

Quasi-resonant Operation ----------------------------------------------------------------- 14

9.3.2.

Bottom-on Timing Setup------------------------------------------------------------------- 14

9.3.3.

BD Blanking Time--------------------------------------------------------------------------- 17

9.4.

Overvoltage Protection (OVP) ------------------------------------------------------------------ 17

9.4.1.

VCC Pin Overvoltage Protection (VCC_OVP)---------------------------------------- 17

9.4.2.

OCP Pin Overvoltage Protection (OCP_OVP) ---------------------------------------- 18

9.4.3.

OVP Pin Overvoltage Protection (OVP_OVP) ---------------------------------------- 18

9.5.

Overload Protection (OLP)---------------------------------------------------------------------- 19

9.6.

Overcurrent Protection (OCP) ----------------------------------------------------------------- 20

9.6.1.

OCP Detection Method and Leading Edge Blanking Function -------------------- 20

9.6.2.

Input Compensation Function ------------------------------------------------------------ 21

9.6.3.

OCP Threshold Voltage with or without Compensation Circuit ------------------ 22

9.6.4.

Determining OCP Input Compensation Circuit Component Values ------------- 23

9.6.5.

Reference Design for OCP Input Compensation Circuit with Universal Input - 23

9.7.

Thermal Shutdown (TSD) ----------------------------------------------------------------------- 24

9.8.

Maximum On-time Limitation Function ----------------------------------------------------- 25

10. Design Notes ---------------------------------------------------------------------------------------------- 26

10.1. External Components ---------------------------------------------------------------------------- 26

10.2. Transformer Design ------------------------------------------------------------------------------ 26

10.3. Trace and Component Layout Design--------------------------------------------------------- 28

Important Notes---------------------------------------------------------------------------------------------- 30