L6566B Ver la hoja de datos (PDF) - STMicroelectronics

Número de pieza

componentes Descripción

Lista de partido

L6566B

Multi-mode controller for SMPS

STMicroelectronics 

L6566B

List of figures

List of figures

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

Figure 11.

Figure 12.

Figure 13.

Figure 14.

Figure 15.

Figure 16.

Figure 17.

Figure 18.

Figure 19.

Figure 20.

Figure 21.

Figure 22.

Figure 23.

Figure 24.

Figure 25.

Figure 26.

Figure 27.

Figure 28.

Figure 29.

Figure 30.

Figure 31.

Figure 32.

Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Typical system block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Pin connection (through top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Multi-mode operation with QR option active . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

High-voltage start-up generator: internal schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Timing diagram: normal power-up and power-down sequences . . . . . . . . . . . . . . . . . . . . 19

Timing diagram showing short-circuit behavior (SS pin clamped at 5V). . . . . . . . . . . . . . . 20

Zero current detection block, triggering block, oscillator block and related logic . . . . . . . . 20

Drain ringing cycle skipping as the load is gradually reduced . . . . . . . . . . . . . . . . . . . . . . 22

Operation of ZCD, triggering and oscillator blocks (QR option active) . . . . . . . . . . . . . . . . 23

Load-dependent operating modes: timing diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Addition of an offset to the current sense lowers the burst-mode operation threshold . . . . 25

Adaptive UVLO block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Possible feedback configurations that can be used with the L6566B . . . . . . . . . . . . . . . . . 26

Externally controlled burst-mode operation by driving pin COMP: timing diagram. . . . . . . 27

Typical power capability change vs. input voltage in QR flyback converters . . . . . . . . . . . 28

Left: Overcurrent setpoint vs. VFF voltage; right: Line Feedforward function block . . . . . . 29

Hiccup-mode OCP: timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Frequency modulation circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Operation after latched disable activation: timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . 33

Soft-start pin operation under different operating conditions and settings . . . . . . . . . . . . . 34

OVP Function: internal block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

OVP function: timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Maximum allowed duty cycle vs. switching frequency for correct OVP detection. . . . . . . . 37

Brownout protection: internal block diagram and timing diagram . . . . . . . . . . . . . . . . . . . . 38

Voltage sensing techniques to implement brownout protection with the L6566B . . . . . . . . 39

Slope compensation waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Typical low-cost application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Typical full-feature application schematic (QR operation) . . . . . . . . . . . . . . . . . . . . . . . . . 44

Typical full-feature application schematic (FF operation) . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Frequency foldback at light load (FF operation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Latched shutdown upon mains overvoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

5/51

Share Link: