LNK564PN pinout | circuit diagram | datasheet

{276} LNK564PN, Datasheet, Application Circuit Diagram, Equivalent, for LNK562, LNK563 & LNK564 Urdu

LNK564PN Circuit Diagram

LNK564PN is an integrated IC commonly used in low-power flyback switching power supply designs, with low cost, low power consumption, high efficiency, and few external components. In this article, we will introduce the principle and structure of low-power integrated switching power supply ICs LNK564PN

1、LNK564PN Principle

LNK564PN is a controller switch IC that provides up to 3 W of output power due to its cost-effective alternative to power supplies based on unregulated isolated linear transformers (50/60 Hz). It is a design based on a single common input instead of multiple linear transformers. The self-made bias circuit outputs very low no-load power consumption of 150 mW. Internal oscillator frequency jitter to the symbol Fi does not reduce the quasi-peak sum
Average EMI, optimize filter cost

2. LNK564PN Internal structure circuitry

The internal structure of the chip consists of a 700 V power MOSFET switch and a power controller. Unlike traditional PWM (Pulse Width Modulation) controllers, it uses simple ON/OFF control to regulate the output voltage. The controller consists of an oscillator, feedback (sensing and logic) circuitry, a 5.8 V regulator, BP pin undervoltage circuitry, overtemperature protection, frequency jitter, current limiting circuitry, and leading-edge blanking. The compact structure facilitates PCB layout and routing, as shown in the figure LNK564PN Functional Block Diagram

LNK564PN Internal Circuit Diagram

3. Classical circuit analysis

Input stage: BR1 rectifier bridge + C/L filtering
Transformer: E-type core, the ratio of turns of secondary to bias winding determines the output voltage of 25V.
Output stage: secondary rectifier diode (e.g., 1N4007) + filter capacitor (e.g., 470μF) 24V.
Feedback network: Resistor divider (R1/R2) or Zener diode (VR) connected to FB pin
LNK564PN the advantages of high efficiency, low cost, small number of components, high parameter accuracy, and use proprietary IC fine-tuning technology and transformer structure technology; Precise parameter tolerances enable clamping design, reduce costs and improve efficiency; Meets the industry standard requirements for thermal overload protection, hysteresis thermal shutdown protection and auto-recovery to prevent overheating damage improves field reliability, low-cost input filtering configuration, and the IC enters auto-restart mode when the output is short-circuited or open-loop, limiting the output power to ≥85% of normal.

LNK564DN Classic circuitry