This post explains for the semiconductor STR-X6750.

The Part Number is STR-X6750F.

The function of this this is Power IC for Quasi-Resonant Type Switching Power Supply.

Package: TO-3PF-7L Type

Manufacturer: Sanken

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Description

The STR-X6750F is power IC for quasi-resonant type switching power supply, incorporating a power MOSFET and a controller IC. The product achieves high efficiency and low noise power supply systems by the quasi-resonant operation.

An IC (Integrated Circuit) for a quasi-resonant type switching power supply is a specialized semiconductor device designed to control and regulate the operation of a quasi-resonant (QR) switching power supply. Quasi-resonant power supplies are a type of switch-mode power supply (SMPS) that offer advantages in terms of reduced electromagnetic interference (EMI), improved efficiency, and lower switching losses compared to traditional fixed-frequency SMPS designs.

Features

1. Quasi-resonant operation mode

(1) Achieves the optimal high efficiency and low noise power supply systems.

2. Current mode control

3.  Built-in PWM oscillator

(1) The PWM operates with the minimum frequency of around 22kHz, until the quasi-resonant signal becomes valid, reduces the stress on components at startup and load-shorted.

4. Built-in soft start function

5. Step-drive function, reducing switching noise

1. Specification :

(1) MOSFET 650V(MIN), 0.62Ω(MAX)

 

Applications:

1. Home appliances

2. OA equipments

3. Industry machines

4. Communication devices

STR-X6750F PDF Datasheet

This post explains for the PWM Controller. A current mode PWM (Pulse-Width Modulation) controller is a type of electronic control circuit used in various applications, especially in power electronics and switch-mode power supplies (SMPS). This controller regulates the output voltage or current by adjusting the duty cycle of a PWM signal based on the feedback from the load current.

The Part Number is SD4841.

The function of this semiconductor is Current Mode PWM Controller.

The package is DIP 8 Pin Type

Manufacturer: Silan Microelectronics

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Description

SD4840, SD4841, SD4842, SD4843, SD4844 is a current mode PWM controller with low standby power and low start current for power switch. In standby mode, the circuit enters burst mode to reduce the standby power dissipation.

The switch frequency is 67KHz with ±2.5 KHz jitter frequency for low EMI. stress on transformer during power on is reduced by the builtin 15ms soft start circuit to avoid the saturation of transformer.

Block Diagram

1. PWM Generation: The error signal is fed into a comparator that compares it with a sawtooth waveform (typically generated by an oscillator). The output of this comparator generates the PWM signal.

2. Duty Cycle Adjustment: The duty cycle of the PWM signal is adjusted to control the power delivered to the load. If the sensed current is below the setpoint, the duty cycle is increased, and if it’s above the setpoint, the duty cycle is decreased.

Features

1. Lower start-up current (Typ.6μA)

2. Frequency jitter for low EMI

3. Overcurrent protection

4. Overvoltage protection

5. Undervoltage lockout

6. Built-in temperature protection

7. Built-in high voltage MOSFET

8. Auto restart mode

9. Built-in soft start

10. Burst mode operation

 

Applications:

1. Switch power

 

Other data sheets are available within the file:

SD4840P67K65, SD4841P67K65, SD4842P67K65, SD4843P67K65, SD4844P67K65

SD4841 PDF Datasheet