Fairchild SG6742ML, SG6742MR, SG6742ML, SG6742MR Schematic [ru]

SG6742ML/MR Highly Integrated Green-Mode PWM Controller

SG6742ML/MR — Highly Integrated Green-Mode PWM Controller

June 2009

Features

 High-Voltage Startup  Low Operating Current: 2.7mA  Linearly Decreasing PWM Frequency to 22KHz  Frequency Hopping to Reduce EMI Emission  Fixed PWM Frequency: 65KHz  Peak-Current-Mode Control  Cycle-by-Cycle Current Limiting  Leading-Edge Blanking  Synchronized Slope Compensation  Internal Open-Loop Protection  GATE Output Maximum Voltage Clamp: 18V  V  V

Under-Voltage Lockout (UVLO)

Over-Voltage Protection (OVP)

 Programmable Over-Temperature Protection (OTP)  Internal Latch Circuit (OVP, OTP)  Internal Sense Short-Circuit Protection  Build-in 5ms Soft-Start Function  Constant Power Limit (Full AC Input Range)  Internal OTP Sensor with Hysteresis

Applications

General-purpose switch-mode power supplies and flyback power converters, including:

 Power Adapters  Open-Frame SMPS

Description

The highly integrated SG6742ML/MR PWM controller provides several features to enhance the performance of flyback converters.

To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency at light-load conditions. To avoid acoustic-noise problems, the minimum PWM frequency is set above 22KHz. The green-mode function enables the power supply to meet international power conservation requirements. With the internal high-voltage startup circuitry, the power loss due to bleeding resistors is also eliminated. To further reduce power consumption, SG6742ML/MR is manufactured using the BiCMOS process, which allows an operating current of only 2.7mA.

SG6742ML/MR integrates a frequency-hopping function that helps reduce EMI emission of a power supply with minimum line filters. Its built-in synchronized slope compensation achieves stable peak-current-mode control. The proprietary, internal line compensation ensures constant output power limit over a wide AC input voltage range, from 90V

SG6742ML/MR provides many protection functions. In addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety should an open-loop or output short-circuit failure occur. PWM output is disabled until V limit, when the controller starts up again. As long as V exceeds ~26V, the internal OVP circuit is triggered.

SG6742ML/MR is available in an 8-pin SOP package.

to 264VAC.

drops below the UVLO lower

Ordering Information

Part

Number

SG6742MLSY -40 to +105°C Latch 8-Lead Small Outline Package (SOP) Green Tape & Reel

SG6742MRSY -40 to +105°C Restart 8-Lead Small Outline Package (SOP) Green Tape & Reel

For Fairchild’s definition of Eco Status, please vis it: http://www.fairchildsemi.com/company/green/rohs_green.html.

Operating

Temperature

Range

OLP

Function

Package

Eco

Status

Packing

Method

Application Diagram

SG6742ML/MR — Highly Integrated Green-Mode PWM Controller

Internal Block Diagram

Figure 1. Typical Application

SG6742ML

SG6742MR

Figure 2. Functional Block Diagram

Marking Information

ZXYTT 6742MR TPM

Pin Configuration

ZXYTT 6742ML TPM

Figure 3. Top Mark

SG6742ML/MR — Highly Integrated Green-Mode PWM Controller

F- Fairchild Logo

Z- Plant Code X- 1 Digit Year Code Y- 1 Digit week Code TT: 2 Digits Die Run Code T: Package Type (D=DIP, S=SOP) P: Y: Green Package M: Manufacture Flow Code

SOP-8

GND

GATE

VDD

SENSE

Figure 4. Pin Configuration (Top View)

Pin Definitions

Pin # Name Description

1 GND Ground.

2 FB

3 NC No connection.

4 HV For startup, this pin is pulled high to the line input or bulk capacitor via resistors.

5 RT

6 SENSE

7 VDD

8 GATE The totem-pole output driver. Soft driving waveform is implemented for improved EMI.

The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is determined in response to the signal on this pin and the current-sense signal on the SENSE pin.

For over-temperature protection, an external NTC thermistor is connected from this pin to the GND pin. The impedance of the NTC decreases at high temperatures. Once the voltage of the RT pin drops below a fixed limit, PWM output is latched.

Current sense. The sensed voltage is used for peak-current-mode control and cycle-by-cycle current limiting.

Power supply. The internal protection circuit disables PWM output as long as V OVP trigger point.

exceeds the

SG6742ML/MR — Highly Integrated Green-Mode PWM Controller

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.

Symbol Parameter Min. Max. Unit

DC Supply Voltage

VDD

VFB FB Pin Input Voltage -0.3 7.0 V

SENSE Pin Input Voltage -0.3 7.0 V

SENSE

VRT RT Pin Input Voltage -0.3 7.0 V

VHV HV Pin Input Voltage 500 V

ΘJA

Power Dissipation (T

Thermal Resistance (Junction-to-Air) 141

TJ Operating Junction Temperature -40 +125

Storage Temperature Range -55 +150

STG

TL Lead Temperature (Wave Soldering or IR, 10 Seconds) +260

Electrostatic Discharge Capability,

ESD

Human Body Model, JESD22-A114

Electrostatic Discharge Capability, Machine Model, JESD22-A115

Notes:

1. All voltage values, except differential voltages, are given with respect to the network ground terminal.

2. Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.

(1, 2)

30 V

＜50°C)

400 mW

°C/W

°C

All Pins Except HV Pin 4 kV

All Pins Except HV Pin 200 V

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