International Rectifier Corp. (IR, El Segundo, CA) introduced the IR2161, an intelligent control IC specifically designed for electronic transformers that drive low-voltage halogen lamps. All necessary features are integrated into a single eight-pin DIP or SOIC. The IR2161 can adapt to changing supply voltage, frequency conditions and lamp conditions, enabling the introduction of highly reliable halogen transformers while streamlining the design and manufacture.
The device incorporates a 600 V half-bridge driver, advanced overload and short-circuit protection circuitry with high-temperature shutdown, and adaptive control techniques. The IR2161 includes an output drive capability of 250 mA/400 mA, a 15.6 V zener diode clamp on Vcc, a micropower startup of less than 300 µA, and a built-in 30 kHz to 125 kHz oscillator.
Adaptive Deadtime Control is a key feature of the IR2161, which increases transformer reliability by continually maintaining soft switching. The IC has an active deadtime circuit that detects the point at which the dc bus voltage in the half bridge slews to 0 V and sets the low-side driver (LO output) high. An internal sample and hold system allows approximately the same delay to be used to set the high-side driver high after LO has gone low. Adaptive deadtime control reacts on a cycle-by-cycle basis of the oscillator and adjusts dead time as necessary to maintain soft switching regardless of external conditions.
The IR2161 converter IC is available immediately in eight-pin DIP, eight-pin SOIC, and eight-pin SOIC tape and reel. Pricing for the IR2161 begins at $0.73 each (IR2163S) in 100,000-piece quantities.