The document describes the features and characteristics of the TOP242-250 TOPSwitch-GX family, including extended power range, no heatsink required, integrated soft-start, programmable current limit, etc.
The document provides an overview of the TOP242‑250 TOPSwitch‑GX family, a flexible off‑line switcher IC that integrates a high‑voltage MOSFET, PWM control, fault protection and a range of programmable functions. It highlights design benefits such as extended power range, no‑heatsink operation up to 34 W, integrated soft‑start, external current‑limit programming, wide duty‑cycle, line‑sense capabilities and energy‑saving EcoSmart features.
Detailed sections describe the functional block diagram, pin assignments, oscillator operation, pulse‑width modulation, light‑load frequency reduction, error‑amplifier behavior, on‑chip current limiting, line‑under‑voltage detection and other protection mechanisms. Application examples and design checklists help engineers implement high‑efficiency flyback power supplies using the TOPSwitch‑GX devices. This manual is written in Chinese.
| Maximum continuous power (non‑ventilated) | 34 W |
|---|---|
| Default switching frequency | 132 kHz |
| Frequency jitter range | ±4 kHz at 250 Hz |
| Standby power consumption (remote off mode) | 80 mW at 110 V AC |
By connecting a resistor between the EXTERNAL CURRENT LIMIT (X) pin (or MULTI‑FUNCTION pin) and the SOURCE pin, the current limit can be set to a lower level between 30 % and 100 % of the default limit.