Datasheet LYTSwitch-6 (Power Integrations) - 3

LYTSwitch-6 Pin Functional Description ISENSE (IS) Pin (Pin 1)
Connection to the power supply output terminals. An external current sense resistor should be connected between this and the GND pin. If current regulation is not required, this pin should be tied
V 13 12 NC
to the GND pin.
BPP 14 11 NC NC 15 10 NC SECONDARY GROUND (GND) (Pin 2) 9 NC
GND for the secondary IC. Note this is not the power supply output
8 NC S 16-19 7 FWD
GND due to the presence of the sense resistor between this and the
6 VOUT
ISENSE pin.
5 SR 4 BPS FEEDBACK (FB) Pin (Pin 3) 3 FB
Connection to an external resistor divider to set the power supply
2 GND
output voltage.
D 24 1 IS SECONDARY BYPASS (BPS) Pin (Pin 4)
Connection point for an external bypass capacitor for the secondary IC supply. PI-7877-022216
SYNCHRONOUS RECTIFIER DRIVE (SR) Pin (Pin 5)
Figure 5. Pin Configuration. Gate driver for external SR FET.
OUTPUT VOLTAGE (VOUT) Pin (Pin 6) LYTSwitch-6 Functional Description
Connected directly to the output voltage to provide current for the The LYTSwitch-6 combines a high-voltage power MOSFET switch, control er on the secondary-side. along with both primary-side and secondary-side control ers in one
FORWARD (FWD) Pin (Pin 7)
device. The connection point to the switching node of the transformer output The architecture incorporates a novel inductive coupling feedback winding providing information on the primary switch timing. Provides scheme using the package lead frame and bond wires to provide a power for the secondary-side control er when V is below a threshold. safe, reliable, and low-cost means to communicate accurate direct OUT
NC Pin (Pin 8-12)
sensing of the output voltage and output current on the secondary Leave open. Should not be connected to any other pins. control er to the primary control er.
Input Overvoltage (V) Pin (Pin 13)
The primary control er on LYTSwitch-6 is a Quasi-Resonant (QR) A high-voltage pin connected to the AC or DC side of the input bridge flyback control er that has the ability to operate in continuous for detecting overvoltage conditions at the power supply input. This conduction mode (CCM). The control er uses both variable frequency pin should be tied to Source to disable OV protection. and variable current control schemes. The primary control er consists of a frequency jitter oscillator; a receiver circuit magnetical y coupled
PRIMARY BYPASS (BPP) Pin (Pin 14)
to the secondary control er, a current limit control er, 5 V regulator on The connection point for an external bypass capacitor for the the PRIMARY BYPASS pin, audible noise reduction engine for light load primary-side supply. This is also the ILIM selection pin for choosing operation, bypass overvoltage detection circuit, a lossless input line standard ILIM or ILIM+1. sensing circuit, current limit selection circuitry, over-temperature
NC Pin (Pin 15)
protection, leading edge blanking, and a 650 V / 725 V power MOSFET. Leave open. Should not be connected to any other pins. The LYTSwitch-6 secondary control er consists of a transmitter circuit
SOURCE (S) Pin (Pin 16-19)
that is magnetical y coupled to the primary receiver, a constant These pins are the power MOSFET source connection. It is also voltage (CV) and a constant current (CC) control circuit, a 4.4 V regulator on the secondary SECONDARY BYPASS pin, synchronous ground reference for primary BYPASS pin. rectifier MOSFET driver, QR mode circuit, oscillator and timing
DRAIN (D) Pin (Pin 24)
functions, thermal foldback control and a host of integrated Power MOSFET drain connection. protection features. Figure 3 and Figure 4 show the functional block diagrams of the primary and secondary control er with the most important features.
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Rev. E 02/18 www.power.com Document Outline Product Highlights Description Output Power Table Pin Functional Description LYTSwitch-6 Functional Description Primary Controller Secondary Controller Application Example Key Applications Design Considerations Primary-Side Components of LYTSwitch-6 Secondary-Side Components of f LYTSwitch-6 Recommendations for Circuit Board Layout Recommended Position of InSOP-24D Package with Respect to Transformer Quick Design Checklist Other Applications Design Example PCB Layout Example Absolute Maximum Ratings Thermal Resistance Key Electrical Characteristics Typical Performance Curves InSOP-24D Package Drawing MSL Table ESD and Latch-Up Table Part Ordering Information