ON Semiconductor has introduced new devices that are designed for boosting performance and simplifying the design of offline power supplies, AC lighting infrastructure and motor control systems. Targeted for high efficiency, compact, switch-mode power supplies for power adaptors, the NCP1937is a quasi-resonant (QR) flyback controller device with power factor correction (PFC). This is the first AC-DC device utilizing a hybrid digital core architecture enabling higher efficiency, increased flexibility and easier system design implementation. The device incorporates all the features necessary for building a robust and compact PFC stage in combination with a QR flyback stage while minimizing the number of external components. The quasi-resonant current-mode flyback stage features a proprietary valley-lockout circuitry, ensuring stable valley switching. It has wide voltage range spanning 9 volts (V) to 30 V, plus built-in over-voltage protection, and a skip mode operation which enables higher efficiency in light load conditions.
The NCP1255/NCP1254 is a fixed frequencyPWM controller designed for applications requiring peak power capability. Offered in SOIC-8 and TSOP-6 packages, it operates with a fixed 65 kilohertz (kHz) switching frequency with the ability to scale the frequency up to 130 kHz based on output load requirements. In light load conditions with the power on the secondary side decreasing, the IC automatically folds back its switching frequency to a minimum level (26 kHz). The inclusion of adjustable over-power protection and adjustable brown-out protection functions make this device ideal for products requiring peak-power capabilities such as printers, and ultrabooks. The NCP1255 will be demonstrated in a 15 W nominal 55 W peak power printer adapter.
For LED power supply applications, the high functional integration of theNCL30081 PWM controller IC minimizes the number of external components required for AC powered LED lighting designs. It operates in a quasi-resonant mode to enhance overall efficiency and provides precision regulation of the LED current from the primary side. Dispensing with the need for secondary side feedback control, as well as the associated optocoupler and biasing circuitry, the device is specifically intended for very compact space efficient designs utilizing either flyback or buck-boost topologies. It supports step dimming by monitoring the AC line and detecting when the line has been toggled on-off-on by the user to reduce the light intensity in five steps down to five percent dimming.
The NSIC2020 is a linear constant current regulator based on Self-Biased Transistor (SBT) technology. Because these devices do not require the specification of any external components, they can serve as either high or low side regulators, thus offering a streamlined solution that makes the development process more straight forward and maximizes design flexibility. This compact SMB packaged device is capable of regulating current over a wide voltage range (from 0 V to 120 V). Its negative temperature coefficient enables protection of LED emitters from thermal runaway at extreme voltages and currents.
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