OnSemi's NCP1337 is a chip that combines a current mode regulator and a demagnetization detector to fully ensure boundary/critical conduction mode at any load/transmission line condition along with the lowest drain voltage switch (quasi-resonant operation). Because of the Soxyless concept, transformer core reset detection was done internally without using any external signals. According to the CISPR-22 EMI limiting standard, the internal frequency is limited to 130 kHz to prevent controller operation to 150 kHz. The chip has overload protection and restart function. Once overloaded, the device will automatically restart and recover. This article mainly introduces the NCP1337 chip, chip characteristics, application direction and internal structure diagram. This article also introduced the 60W reference design scheme using the NCP1337 chip as the main chip, giving the introduction of the program, the schematic diagram of the program, the PCB board diagram and the list of parts and components.
The NCP1337 combines a true current mode modulator and a demagneTIzaTIon detector which ensures full Borderline/CriTIcal ConducTIon Mode in any load/line conditions together with minimum drain voltage switching (Quasi−Resonant operation). The transformer core reset detection is done contains, without using The frequency is internally limited to 130 kHz, preventing the controller to operate above the 150 kHz CISPR−22 EMI starting limit.
As monitoring the feedback pin activity, the controller enters skip mode as soon as the power demand falls below a predetermined level. As each restart is softened by an internal Soft−Skip_, and as the frequency cannot go below 25 kHz, no audible noise can Be heard.
The NCP1337 also features an efficient protective circuitry which, in presence of an over current condition, disables the output pulses and enters a safe burst mode, trying to restart. Once the default has gone, the device auto−recovers. Also included is a bulk voltage The monitoring function (known as brown−out protection), an adjustable overpower compensation, and a VCC OVP. The controller immediately restarts after any of these conditions, unless the fault timer has timed out. Finally, an internal 4.0 ms soft−start eliminates the Traditional startup stress.
• Free−Running Borderline/Critical Mode Quasi−Resonant Operation
• Current−Mode
• Soft−Skip Mode with Minimum Switching Frequency for Standby
• Auto-Recovery Short-Circuit Protection Independent of Auxiliary Voltage
• Overvoltage Protection
• Brown-Out Protection
• Two Externally Triggerable Fault Comparators (one for a disable function, and the other for a permanent latch)
• Internal 4.0 ms Soft−Start
• 500 mA Peak Current Drive Sink Capability
• 130 kHz Max Frequency
• Internal Leading Edge Blanking
• Internal Temperature Shutdown
• Direct Optocoupler Connection
• Dynamic Self-Supply with Levels of 12 V (On) and 10 V (Off)
• SPICE Models Available for TRANsient and AC Analysis
• These are Pb-Free Devices*
NCP1337 Application:
• AC-DC Adapters for Notebooks, etc.
• Offline Battery Chargers
• Consumer Electronics (DVD Players, Set-Top Boxes, TVs, etc.)
• Auxiliary Power Supplies (USB, Appliances, TVs, etc.)
Figure 1. Internal block diagram of the NCP1337
NCP1337ADAPGEVB program description:
This design using NCP1337 offers a perfect solution for portable DVD, LCD TV, or monitor and notebook adapter applications. This adapter provides effective protection functions such as over-load protection, over-voltage protection, shortcircuit protection and brown-out protection. Thanks to The quasi-resonant operation and synchronous rectifier, this adapter has high efficiency and improved EMI performance. The standby consumption is lower because of the cycle skipping and soft ripple mode.
Figure 2. Schematic of NCP1337ADAPGEVB scheme
NCP1562-100WGEVB program material list:
PCB component layout:
Mobile Game Accessories,Mobile Finger Sleeve,Mobile Wireless Controller,Gaming Gloves
MICROBITS TECHNOLOGY LIMITED , https://www.hkmicrobits.com