SDH771XRH is a high precision LED constant current drive control chip, which is suitable for 85VAC~265VAC full range AC input voltage non-isolated step-down LED constant current power supply system. The chip integrates rectifier bridge, 500V high voltage power MOS, 600V recovery diode, and does not need start resistor and auxiliary winding to realize the chip's self-supply, saving traditional external VCC power capacitor, and accelerating system startup while reducing system cost. The chip works in the critical conduction mode of the inductive current, and adopts the unique high-precision current sampling technology, which can obtain high constant current accuracy and excellent linearity/load regulation. The internal circuit integrates multiple protection functions, including output open circuit protection, output short circuit protection, cycle by cycle over current protection, over temperature regulation, over temperature protection, sampling resistor open circuit protection, etc., which enhances the safety and reliability of the system.
The SDH771XRH is a high‑precision, non‑isolated buck LED constant‑current driver IC designed for 85 VAC‑265 VAC AC input. It integrates a rectifier bridge, a 500 V high‑voltage MOSFET, and a 600 V fast‑recovery diode, eliminating many external components.
The device includes multiple protection features such as output open‑circuit, short‑circuit, per‑cycle over‑current, over‑temperature, and ROVP pin‑adjustable over‑voltage protection. Pin functions, electrical limits, and typical application circuits are detailed in the document. This manual is written in Chinese.
| Input voltage range | 85 VAC‑265 VAC |
|---|---|
| CS pin voltage range | -0.3 V to 7 V |
| ROVP pin voltage range | -0.3 V to 7 V |
| HV pin voltage range | -0.3 V to 500 V |
| Current on ROVP pin (when set) | 40 µA |
The chip operates with an AC input voltage from 85 VAC to 265 VAC.
OVP is adjusted via the external resistor on the ROVP pin; the pin sources about 40 µA.
It includes output open‑circuit, short‑circuit, per‑cycle over‑current, over‑temperature, over‑temperature protection, and sampling‑resistor open‑circuit protection.