ON Semiconductor

The NCP1126 products integrates a fixed−frequency peak current mode controller with a low on− resistance high voltage, 650 V MOSFET. Available in a PDIP−7 package, the NCP1126 offers a high level of integration, including soft−start, frequency−jittering, short−circuit protection, thermal shutdown protection, frequency foldback mode and skip−cycle to reduce power consumption in light load condition, peak current mode control with adjustable internal ramp compensation and adjustable peak current set point. During nominal load operation, the part switches at one of the available frequencies (65 or 100 kHz). When the output power demand diminishes, the IC automatically enters frequency foldback mode and provides excellent efficiency at light loads. When the power demand reduces further, it enters into a skip mode to reduce the standby consumption down to no load condition. Protection feature include: a timer to detect an overload or a short−circuit event with auto−recovery or latch protection, and a built−in VCC overvoltage protection.The switcher also provides a jittered 65 kHz or 100 kHz switching frequency to improve the EMI.

The NCP1129 switcher offers everything needed to build reliable and compact AC-DC switching power supplies with minimal surrounding elements. Incorporating an avalanche rated 650 V MOSFET, converters built with the NCP1129 can be safely designed for international conditions without jeopardizing the overall reliability.The NCP1129 implements peak current mode control with adjustable ramp compensation that ensures stability in Continuous Conduction Mode (CCM) operation. With an external resistor, the maximum peak current is adjustable, allowing the designer the ability to inject ramp compensation to stabilize CCM power supplies.A short circuit fault condition is independently detected from the auxiliary winding voltage resulting in improved short circuit protection with true overload detection. The Source pin provides access to the MOSFET source, allowing for overpower compensation.With a supply range up to 26 V, the switcher also provides a jittered 65 kHz or 100 kHz switching frequency operated in peak current mode control. When the power on the secondary side starts to decrease, the switcher automatically folds back its switching frequency down to a minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while limiting the peak current.

The NCP114 is 300 mA LDO that provides the engineer with a very stable, accurate voltage with low noise suitable for space constrained, noise sensitive applications. In order to optimize performance for battery operated portable applications, the NCP114 employs the dynamic quiescent current adjustment for very low IQ consumption at no−load.

The NCP115 is 300 mA LDO that provides a very stable, accurate voltage with low noise suitable for space constrained, noise sensitive applications. In order to optimize performance for battery operated portable applications, the NCP115 employs the dynamic quiescent current adjustment for very low IQ consumption at no−load. The NCP115 is offered in both a small XDFN-4 1 mmx1 mm, 0.4mm Thin package as well as in a standard TSOP5 package.

NCP120 is a 150 mA VLDO equipped with NMOS passtransistor and a separate bias supply voltage (VBIAS). The deviceprovides very stable, accurate output voltage with low noise suitablefor space constrained, noise sensitive applications. In order tooptimize performance for battery operated portable applications, theNCP120 features low IQ consumption. The XDFN6 1.2 mm x 1.2 mmpackage is optimized for use in space constrained applications

Housed in SO-8 or DIP8 package, the NCP1203 represents a major leap toward ultra-compact Switch-Mode Power Supplies and represents an excellent candidate to replace the UC384X devices.Thanks to its proprietary SmartMOS Very High Voltage Technology, the circuit allows the implementation of complete off-line AC/DC adapters, battery charger and a high-power SMPS with few external components.With an internal structure operating at a fixed 40 kHz, 60 kHz or 100 kHz switching frequency, the controller features a high-voltage start-up FET which ensures a clean and loss-less start up sequence. Its current-mode control naturally provides good audio susceptibility and inherent pulse-by-pulse control.When the current set point falls below a given value, e.g. the output power demand diminishes, the IC automatically enters the so-called skip cycle mode and provides improved efficiency at light loads while offering excellent performance in standby conditions. Because this occurs at a user adjustable low peak current, no acoustic noise takes place.The NCP1203 also includes an efficient protective circuitry which, in presence of an output over load condition, disables the output pulses while the device enters a safe burst mode, trying to restart. Once the default has gone, the device auto-recovers. Finally, atemperature shutdown with hysteresis helps building safe and robust power supplies.

The NCP1207A/B combines a true current mode modulator and a demagnetization detector to ensure full borderline/critical Conduction Mode in any load/line conditions and minimum drain voltage switching (Quasi-Resonant operation). Due to its inherent skip cycle capability, the controller enters burst mode as soon as the power demand falls below a predetermined level. As this happens at low peak current, no audible noise can be heard. For the NCP1207A, an internal 8.0 micro s timer prevents the free-run frequency to exceed 125 kHz (therefore below the 150 kHz CISPR-22 EMI starting limit), while the skip adjustment capability lets the user select the frequency at which the burst foldback takes place. For the NCP1207B, the internal timer duration is reduced to 4.5 micro s to allow operation at higher frequencies (up to 200 kHz).The Dynamic Self-Supply (DSS) drastically simplifies the transformer design in avoiding the use of an auxiliary winding to supply the NCP1207A/B. This feature is particularly useful in applications where the output voltage varies during operation (e.g. battery chargers). Due to its high-voltage technology, the IC is directly connected to the high-voltage DC rail. As a result, the short-circuit trip point is not dependent upon any VCC auxiliary level.The transformer core reset detection is done through an auxiliary winding which, brought via a dedicated pin, also enables fast overvoltage Protection (OVP). Once an OVP has been detected, the IC permanently latches off.Finally, the continuous feedback signal monitoring implemented with an overcurrent fault protection circuitry (OCP) makes the final design rugged and reliable.