Technology Update: Power Integrations

April 1, 2010
Power Integrations, Inc. designs and manufactures ICs used in switch-mode power supplies. Most of the company's ICs are used in ac-dc switchers, although it also targets certain high-voltage dc-dc applications, such as power over Ethernet (PoE). Following


LinkSwitch Family products incorporate a high-voltage power MOSFET, oscillator, simple ON/OFF control scheme, a high-voltage switched current source, frequency jittering, cycle-by-cycle current limit and thermal shutdown circuitry onto a monolithic IC. The startup and operating power are derived directly from the DRAIN pin, eliminating the need for a bias winding and associated circuitry. Typical applications include: chargers/adapters for cell/cordless phones, PDAs, digital cameras, MP3/portable audio players, and shavers and supplies for appliances, industrial systems, and metering. Following are members of the LinkSwitch family:

LINKSWITCH-CV - The LinkSwitch-CV (Figure 1) dramatically simplifies CV power supply design with tight CV requirements and by eliminating an optocoupler and secondary control circuitry. The device introduces a revolutionary control technique to provide very tight output voltage regulation, along with input voltage variations and temperature.

LINKSWITCH-II - For low power adapters and chargers (cell/cordless phones, PDAs, digital cameras, portable audio etc), LinkSwitch-II dramatically simplifies low power CV/CC charger designs by eliminating an optocoupler and secondary control circuitry. The device introduces a revolutionary control technique to provide very tight output voltage and current regulation, compensating for transformer and internal parameter tolerances along with input voltage variations.

LINKSWITCH-XT - For low power adapters and chargers (cell/cordless phones, PDAs, digital cameras, portable audio etc), as well as auxiliary supplies employed in applications such as white goods

LINKSWITCH-LP - Replace inefficient line frequency linear transformer based power supplies with output powers 2.5 W in applications such as cell/cordless phones, PDAs, digital cameras, and portable audio players, as well as auxiliary supplies employed in applications such as white goods.

LINKSWITCH-TN - Replace all linear and capacitor-fed (cap dropper) non-isolated power supplies in the under 360 mA output current range at equal system cost while offering much higher performance and energy efficiency.


The TinySwitch families of products combine a high voltage power MOSFET switch with a power supply controller in one device, offering a flexible design solution with low system cost and extended power capability. Unlike conventional PWM (Pulse Width Modulator) controllers, TinySwitch uses a simple ON/OFF control to regulate the output voltage.

TINYSWITCH-III - TinySwitch-III incorporates a 700 V power MOSFET, oscillator, high voltage switched current source, current limit (user selectable) and thermal shutdown circuitry. The controller consists of an oscillator, enable circuit (sense and logic), current limit state machine, 5.85 V regulator, bypass/ multi-function pin undervoltage, overvoltage circuit, and current limit selection circuitry, over- temperature protection, current limit circuit, leading edge blanking, and a 700 V power MOSFET. TinySwitch-III incorporates additional circuitry for line undervoltage sense, auto-restart, adaptive switching cycle on-time extension, and frequency jitter.

TINYSWITCH-PK - For applications with higher peak current requirements. Its peak mode feature boosts current limit and frequency for peak load conditions. The boosted current limit provides the peak output power while the increased peak mode frequency ensures the transformer can be sized for continuous load conditions rather than peak power demands.


The proven topology of TOPSwitch cost effectively integrates the high voltage power MOSFET, PWM control, fault protection and other control circuitry onto a single CMOS chip. Both incorporate a 700 V power MOSFET, high voltage switched current source, PWM control, oscillator, thermal shutdown circuit, fault protection and other control circuitry onto a monolithic device.

TOPSWITCH-JX is the latest generation product in the TOPSwitch line, TOPSwitch-JX (Figure 2) features an integrated PSU controller and 725 V power MOSFET and delivers 20 mW output power for 100 mW input power in standby mode. Multi-mode control maximizes power efficiency across the entire load range. The IC also incorporates a fast AC-reset circuit, which significantly reduces the number of primary-side components required.


The DPA-Switch IC family is a highly integrated solution for dc-dc conversion applications with 16-75 VDC input. DPA-Switch uses the same proven topology as TOPSwitch, effectively integrating a power MOSFET, PWM control, fault protection and other control circuitry onto a single CMOS chip. High performance features are enabled with three user-configurable pins. Hysteretic thermal shutdown is also provided. Also, all critical parameters (i.e. current limit, frequency, PWM gain) have tight temperature and absolute tolerance, to simplify design and reduce system cost.

Table 1 lists the maximum power output for members of this family. The maximum power is limited by device internal current limit. Available packages include, but are not available for all family members:

P: DIP-8

G: SMD-8

R: TO-263-7C


The Hiper family of highly integrated, high efficiency, high power ICs is Power Integrations' newest line of product. HiperPLC (Figure 3) is the first member of the family, and combines a Continuous Conduction Mode (CCM) PFC controller, an LLC resonant converter and high voltage (600V) half-bridge drivers in a single IC package. It is targeted at applications for high-efficiency offline power converters in the power range of 200 to 600 watts, such as flat-panel TVs, high- efficiency PC main power and workstation power supplies, and the latest generations of high-brightness LED streetlights.


Audio amplifiers that typically use bulky linear power supplies can instead use PeakSwitch ICs to provide higher effiiciency, smaller, low-cost power supplies that allow better audio quality, dynamic response, and peak power capability. PeakSwitch supplies can support audio power systems rated to more than 500 watt rms. Their ability to supply very high peak requirements means that the 75W (continuous) rated PKS607YN can effortlessly support a home theater system rated at 500 W. Characteristics of PeakSwitch power supplies include:

  • Excellent transient response that improves audio quality

  • Low component count, compact and lightweight

  • High energy efficiency, >75% efficiency at full load and 300 mW no-load power consumption at 265 VAC

  • Reduced heat sink requirements

  • Eliminates need for separate standby supply

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Power Integrations offers a broad range of highly integrated high power constant current LED driver ICs for use in LED applications where offline power supplies are required at universal input line cord voltages from 85 to 265 VAC. Topologies include: boost, buck, buck-boost, and flyback. These LED driver ICs offer:

  • High efficiency

  • Long life

  • Low maintenance

  • Resistance to shocks and vibrations

  • Generation of pure colored light

  • Small size

  • PSU Design Software Optimizes Power Supply Design

PI Expert power supply design software includes:

  • Improved support for PI's HiperPLC controller IC for offline resonant converters. Choose from a variety of magnetic core materials and sizes for both for the LLC and PFC stages.

  • Accurate calculation of the external resistor required to reduce no-load consumption in designs using PI's LinkSwitch®-II and LinkSwitch-CV product families in flyback topologies.

  • Expanded Help feature to include traditional Chinese language support.

PI Expert is an interactive program that takes your power supply specifications, automatically generates the electrical design, and selects the critical components required. It also provides a detailed electrical and mechanical transformer design using PI's EShield EMI reduction techniques.


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