TOP221-227 - TOPSwitch-II Family - Three-terminal Off-line PWM Switch

Oct 12, 2026

Overview of the TOPSwitch-II family three-terminal off-line PWM switch, highlighting cost competitiveness, very low AC/DC losses, and up to 90% efficiency. Describes enhancements versus the first TOPSwitch generation, including extended power range for 100/115/230 VAC and 85-265 VAC inputs, improved tolerance to board layout and line transients, and protective features such as auto-restart with current limiting and latching thermal shutdown. Explains typical flyback application, internal monolithic control functions, and provides an output power table and functional block diagram with key pin behaviors.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages20

Reading Time50 min

AccessFree to download

Product Highlights

Description

Typical Flyback Application

Output Power Table

Functional Block Diagram

Pin Functional Description

TOPSwitch Family Functional Description

Duty Cycle Control

Control, Bias, and Protection Functions

TOP221-227 TOPSwitch ®-II Family Three-terminal Off-line PWM Switch Product Highlights • Lowest cost, lowest component count switcher solution • Cost competitive with linears above 5W • Very low AC/DC losses – up to 90% efficiency • Built-in Auto-restart and Current limiting • Latching Thermal shutdown for system level protection • Implements Flyback, Forward, Boost or Buck topology • Works with primary or opto feedback • Stable in discontinuous or continuous conduction mode • Source connected tab for low EMI • Circuit simplicity and Design Tools reduce time to market Description The second generation TOPSwitch-II family is more cost effective and provides several enhancements over the first generation TOPSwitch family. The TOPSwitch-IIfamily extends the power range from 100W to 150W for 100/115/230 VAC input and from 50W to 90W for 85-265 VAC universal input. This brings TOPSwitch technology advantages to many new applications, i.e. TV, Monitor, Audio amplifiers, etc. Many significant circuit enhancements that reduce the sensitivity to board layout and line transients now make the design even PI-1951-091996 Figure 1. Typical Flyback Application. easier. The standard 8L PDIP package option reduces cost in lower power, high efficiency applications. The internal lead frame of this package uses six of its pins to transfer heat from the chip directly to the board, eliminating the cost of a heat sink. TOPSwitch incorporates all functions necessary for a switched mode control system into a three terminal monolithic IC: power MOSFET, PWM controller, high voltage start up circuit, loop compensation and fault protection circuitry. | OUTPUT POWER TABLE | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | TO-220 (Y) Package1 | | | 8L PDIP (P) or 8L SMD (G) Package2 | | | | | | | PART
ORDER
NUMBER | Single Voltage Input 3 100/115/230 VAC ±15% | Wide Range Input 85 to 265 VAC | PART
ORDER
NUMBER | Single Voltage. Input 3 100/115/230 VAC ±15% | | | Wide Range Input 85 to 265 VAC | | | | PMAX4,6 | PMAX4,6 | | | | PMAX5,6 | | PMAX5,6 | | TOP221Y | 12 W | 7 W | TOP221P or TOP221G | | 9 W | | | 6 W | | TOP222Y | 25 W | 15 W | TOP222P or TOP222G | | 15 W | | | 10 W | | TOP223Y | 50 W | 30 W | TOP223P or TOP223G | | 25 W | | | 15 W | | TOP224Y | 75 W | 45 W | TOP224P or TOP224G | | 30 W | | | 20 W | | TOP225Y | 100 W | 60 W | | | | | | | | TOP226Y | 125 W | 75 W | | | | | | | | TOP227Y | 150 W | 90 W | | | | | | | Notes: 1. Package outline: Y03A 2. Package Outline: P08A or G08A 3. 100/115 VAC with doubler input 4. Assumes appropriate heat sinking to keep the maximum TOPSwitch junction temperature below 100˚ [C.](C. 5. Soldered to 1 sq. in)[ 5](C. 5. Soldered to 1 sq. in)[. Soldered to 1 sq. in](C. 5. Soldered to 1 sq. in).( 6.45 cm2), 2 oz. copper clad (610 gm/m2) 6. PMAX is the maximum practical continuous power output level for conditions shown. The continuous power capability in a given application depends on thermal environment, transformer design, efficiency required, minimum specified input voltage, input storage capacitance, etc. 7. Refer to key application considerations section when using TOPSwitch-IIin an existing TOPSwitch design. TOP221-227 | CONTROL |
Z C
SHUTDOWN/ AUTO-RESTART
0
1
INTERNAL SUPPLY
5.7 V
4.7 V
5.7 V
VILIMIT
IFB
CONTROLLED
TURN-ON
GATE
DRIVER
RE
OSCILLATOR

-
+

D MAX CLOCK
SAW

S
R
Q
Q
VC

MINIMUM ON-TIME DELAY

LEADING EDGE BLANKING

POWER-UP RESET

S
R
Q
Q

÷ 8
THERMAL SHUTDOWN

-
+

+
-

+
- | DRAIN
SOURCE | | --- | --- | --- | | PI-1935-091696 | | | Figure 2. Functional Block Diagram. Pin Functional Description DRAIN Pin: Output MOSFET drain connection. Provides internal bias current during st

FAQs

What are the main product highlights of the TOPSwitch-II three-terminal PWM switch?

It targets lowest cost and component count, offers very low AC/DC losses up to 90% efficiency, and includes auto-restart with current limiting plus latching thermal shutdown. It supports multiple flyback/forward/boost/buck topologies and works with primary or opto feedback.

How does TOPSwitch-II differ from the first TOPSwitch family?

It is the second generation and is more cost effective, with enhancements that extend the power range and reduce sensitivity to board layout and line transients. It also offers standard package options designed to reduce cost in certain applications.

What is the functional role of the DRAIN, CONTROL, and SOURCE pins?

The DRAIN pin connects to the output MOSFET drain, provides internal bias current during start-up, and includes an internal current sense point. The CONTROL pin handles error amplification and feedback current input for duty cycle control and is tied to bias, bypass, and auto-restart/compensation. The SOURCE pin provides the power return and common/reference points for primary circuitry.

Oct 12, 2026

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